Smack: unify all ptrace accesses in the smack

[platform/adaptation/renesas_rcar/renesas_kernel.git] / security / smack / smack_lsm.c

/*
 *  Simplified MAC Kernel (smack) security module
 *
 *  This file contains the smack hook function implementations.
 *
 *  Authors:
 *      Casey Schaufler <casey@schaufler-ca.com>
 *      Jarkko Sakkinen <jarkko.sakkinen@intel.com>
 *
 *  Copyright (C) 2007 Casey Schaufler <casey@schaufler-ca.com>
 *  Copyright (C) 2009 Hewlett-Packard Development Company, L.P.
 *                Paul Moore <paul@paul-moore.com>
 *  Copyright (C) 2010 Nokia Corporation
 *  Copyright (C) 2011 Intel Corporation.
 *
 *      This program is free software; you can redistribute it and/or modify
 *      it under the terms of the GNU General Public License version 2,
 *      as published by the Free Software Foundation.
 */

#include <linux/xattr.h>
#include <linux/pagemap.h>
#include <linux/mount.h>
#include <linux/stat.h>
#include <linux/kd.h>
#include <asm/ioctls.h>
#include <linux/ip.h>
#include <linux/tcp.h>
#include <linux/udp.h>
#include <linux/dccp.h>
#include <linux/slab.h>
#include <linux/mutex.h>
#include <linux/pipe_fs_i.h>
#include <net/cipso_ipv4.h>
#include <net/ip.h>
#include <net/ipv6.h>
#include <linux/audit.h>
#include <linux/magic.h>
#include <linux/dcache.h>
#include <linux/personality.h>
#include <linux/msg.h>
#include <linux/shm.h>
#include <linux/binfmts.h>
#include "smack.h"

#define task_security(task)     (task_cred_xxx((task), security))

#define TRANS_TRUE      "TRUE"
#define TRANS_TRUE_SIZE 4

#define SMK_CONNECTING  0
#define SMK_RECEIVING   1
#define SMK_SENDING     2

LIST_HEAD(smk_ipv6_port_list);

/**
 * smk_fetch - Fetch the smack label from a file.
 * @ip: a pointer to the inode
 * @dp: a pointer to the dentry
 *
 * Returns a pointer to the master list entry for the Smack label
 * or NULL if there was no label to fetch.
 */
static struct smack_known *smk_fetch(const char *name, struct inode *ip,
                                        struct dentry *dp)
{
        int rc;
        char *buffer;
        struct smack_known *skp = NULL;

        if (ip->i_op->getxattr == NULL)
                return NULL;

        buffer = kzalloc(SMK_LONGLABEL, GFP_KERNEL);
        if (buffer == NULL)
                return NULL;

        rc = ip->i_op->getxattr(dp, name, buffer, SMK_LONGLABEL);
        if (rc > 0)
                skp = smk_import_entry(buffer, rc);

        kfree(buffer);

        return skp;
}

/**
 * new_inode_smack - allocate an inode security blob
 * @smack: a pointer to the Smack label to use in the blob
 *
 * Returns the new blob or NULL if there's no memory available
 */
struct inode_smack *new_inode_smack(char *smack)
{
        struct inode_smack *isp;

        isp = kzalloc(sizeof(struct inode_smack), GFP_NOFS);
        if (isp == NULL)
                return NULL;

        isp->smk_inode = smack;
        isp->smk_flags = 0;
        mutex_init(&isp->smk_lock);

        return isp;
}

/**
 * new_task_smack - allocate a task security blob
 * @smack: a pointer to the Smack label to use in the blob
 *
 * Returns the new blob or NULL if there's no memory available
 */
static struct task_smack *new_task_smack(struct smack_known *task,
                                        struct smack_known *forked, gfp_t gfp)
{
        struct task_smack *tsp;

        tsp = kzalloc(sizeof(struct task_smack), gfp);
        if (tsp == NULL)
                return NULL;

        tsp->smk_task = task;
        tsp->smk_forked = forked;
        INIT_LIST_HEAD(&tsp->smk_rules);
        mutex_init(&tsp->smk_rules_lock);

        return tsp;
}

/**
 * smk_copy_rules - copy a rule set
 * @nhead - new rules header pointer
 * @ohead - old rules header pointer
 *
 * Returns 0 on success, -ENOMEM on error
 */
static int smk_copy_rules(struct list_head *nhead, struct list_head *ohead,
                                gfp_t gfp)
{
        struct smack_rule *nrp;
        struct smack_rule *orp;
        int rc = 0;

        INIT_LIST_HEAD(nhead);

        list_for_each_entry_rcu(orp, ohead, list) {
                nrp = kzalloc(sizeof(struct smack_rule), gfp);
                if (nrp == NULL) {
                        rc = -ENOMEM;
                        break;
                }
                *nrp = *orp;
                list_add_rcu(&nrp->list, nhead);
        }
        return rc;
}

/**
 * smk_ptrace_mode - helper function for converting PTRACE_MODE_* into MAY_*
 * @mode - input mode in form of PTRACE_MODE_*
 *
 * Returns a converted MAY_* mode usable by smack rules
 */
static inline unsigned int smk_ptrace_mode(unsigned int mode)
{
        switch (mode) {
        case PTRACE_MODE_READ:
                return MAY_READ;
        case PTRACE_MODE_ATTACH:
                return MAY_READWRITE;
        }

        return 0;
}

/**
 * smk_ptrace_rule_check - helper for ptrace access
 * @tracer: tracer process
 * @tracee_label: label of the process that's about to be traced
 * @mode: ptrace attachment mode (PTRACE_MODE_*)
 * @func: name of the function that called us, used for audit
 *
 * Returns 0 on access granted, -error on error
 */
static int smk_ptrace_rule_check(struct task_struct *tracer, char *tracee_label,
                                 unsigned int mode, const char *func)
{
        int rc;
        struct smk_audit_info ad, *saip = NULL;
        struct task_smack *tsp;
        struct smack_known *skp;

        if ((mode & PTRACE_MODE_NOAUDIT) == 0) {
                smk_ad_init(&ad, func, LSM_AUDIT_DATA_TASK);
                smk_ad_setfield_u_tsk(&ad, tracer);
                saip = &ad;
        }

        tsp = task_security(tracer);
        skp = smk_of_task(tsp);

        rc = smk_tskacc(tsp, tracee_label, smk_ptrace_mode(mode), saip);
        return rc;
}

/*
 * LSM hooks.
 * We he, that is fun!
 */

/**
 * smack_ptrace_access_check - Smack approval on PTRACE_ATTACH
 * @ctp: child task pointer
 * @mode: ptrace attachment mode (PTRACE_MODE_*)
 *
 * Returns 0 if access is OK, an error code otherwise
 *
 * Do the capability checks.
 */
static int smack_ptrace_access_check(struct task_struct *ctp, unsigned int mode)
{
        int rc;
        struct smack_known *skp;

        rc = cap_ptrace_access_check(ctp, mode);
        if (rc != 0)
                return rc;

        skp = smk_of_task(task_security(ctp));

        rc = smk_ptrace_rule_check(current, skp->smk_known, mode, __func__);
        return rc;
}

/**
 * smack_ptrace_traceme - Smack approval on PTRACE_TRACEME
 * @ptp: parent task pointer
 *
 * Returns 0 if access is OK, an error code otherwise
 *
 * Do the capability checks, and require PTRACE_MODE_ATTACH.
 */
static int smack_ptrace_traceme(struct task_struct *ptp)
{
        int rc;
        struct smack_known *skp;

        rc = cap_ptrace_traceme(ptp);
        if (rc != 0)
                return rc;

        skp = smk_of_task(current_security());

        rc = smk_ptrace_rule_check(ptp, skp->smk_known,
                                   PTRACE_MODE_ATTACH, __func__);
        return rc;
}

/**
 * smack_syslog - Smack approval on syslog
 * @type: message type
 *
 * Returns 0 on success, error code otherwise.
 */
static int smack_syslog(int typefrom_file)
{
        int rc = 0;
        struct smack_known *skp = smk_of_current();

        if (smack_privileged(CAP_MAC_OVERRIDE))
                return 0;

        if (smack_syslog_label != NULL && smack_syslog_label != skp)
                rc = -EACCES;

        return rc;
}


/*
 * Superblock Hooks.
 */

/**
 * smack_sb_alloc_security - allocate a superblock blob
 * @sb: the superblock getting the blob
 *
 * Returns 0 on success or -ENOMEM on error.
 */
static int smack_sb_alloc_security(struct super_block *sb)
{
        struct superblock_smack *sbsp;

        sbsp = kzalloc(sizeof(struct superblock_smack), GFP_KERNEL);

        if (sbsp == NULL)
                return -ENOMEM;

        sbsp->smk_root = smack_known_floor.smk_known;
        sbsp->smk_default = smack_known_floor.smk_known;
        sbsp->smk_floor = smack_known_floor.smk_known;
        sbsp->smk_hat = smack_known_hat.smk_known;
        /*
         * smk_initialized will be zero from kzalloc.
         */
        sb->s_security = sbsp;

        return 0;
}

/**
 * smack_sb_free_security - free a superblock blob
 * @sb: the superblock getting the blob
 *
 */
static void smack_sb_free_security(struct super_block *sb)
{
        kfree(sb->s_security);
        sb->s_security = NULL;
}

/**
 * smack_sb_copy_data - copy mount options data for processing
 * @orig: where to start
 * @smackopts: mount options string
 *
 * Returns 0 on success or -ENOMEM on error.
 *
 * Copy the Smack specific mount options out of the mount
 * options list.
 */
static int smack_sb_copy_data(char *orig, char *smackopts)
{
        char *cp, *commap, *otheropts, *dp;

        otheropts = (char *)get_zeroed_page(GFP_KERNEL);
        if (otheropts == NULL)
                return -ENOMEM;

        for (cp = orig, commap = orig; commap != NULL; cp = commap + 1) {
                if (strstr(cp, SMK_FSDEFAULT) == cp)
                        dp = smackopts;
                else if (strstr(cp, SMK_FSFLOOR) == cp)
                        dp = smackopts;
                else if (strstr(cp, SMK_FSHAT) == cp)
                        dp = smackopts;
                else if (strstr(cp, SMK_FSROOT) == cp)
                        dp = smackopts;
                else if (strstr(cp, SMK_FSTRANS) == cp)
                        dp = smackopts;
                else
                        dp = otheropts;

                commap = strchr(cp, ',');
                if (commap != NULL)
                        *commap = '\0';

                if (*dp != '\0')
                        strcat(dp, ",");
                strcat(dp, cp);
        }

        strcpy(orig, otheropts);
        free_page((unsigned long)otheropts);

        return 0;
}

/**
 * smack_sb_kern_mount - Smack specific mount processing
 * @sb: the file system superblock
 * @flags: the mount flags
 * @data: the smack mount options
 *
 * Returns 0 on success, an error code on failure
 */
static int smack_sb_kern_mount(struct super_block *sb, int flags, void *data)
{
        struct dentry *root = sb->s_root;
        struct inode *inode = root->d_inode;
        struct superblock_smack *sp = sb->s_security;
        struct inode_smack *isp;
        struct smack_known *skp;
        char *op;
        char *commap;
        char *nsp;
        int transmute = 0;
        int specified = 0;

        if (sp->smk_initialized)
                return 0;

        sp->smk_initialized = 1;

        for (op = data; op != NULL; op = commap) {
                commap = strchr(op, ',');
                if (commap != NULL)
                        *commap++ = '\0';

                if (strncmp(op, SMK_FSHAT, strlen(SMK_FSHAT)) == 0) {
                        op += strlen(SMK_FSHAT);
                        nsp = smk_import(op, 0);
                        if (nsp != NULL) {
                                sp->smk_hat = nsp;
                                specified = 1;
                        }
                } else if (strncmp(op, SMK_FSFLOOR, strlen(SMK_FSFLOOR)) == 0) {
                        op += strlen(SMK_FSFLOOR);
                        nsp = smk_import(op, 0);
                        if (nsp != NULL) {
                                sp->smk_floor = nsp;
                                specified = 1;
                        }
                } else if (strncmp(op, SMK_FSDEFAULT,
                                   strlen(SMK_FSDEFAULT)) == 0) {
                        op += strlen(SMK_FSDEFAULT);
                        nsp = smk_import(op, 0);
                        if (nsp != NULL) {
                                sp->smk_default = nsp;
                                specified = 1;
                        }
                } else if (strncmp(op, SMK_FSROOT, strlen(SMK_FSROOT)) == 0) {
                        op += strlen(SMK_FSROOT);
                        nsp = smk_import(op, 0);
                        if (nsp != NULL) {
                                sp->smk_root = nsp;
                                specified = 1;
                        }
                } else if (strncmp(op, SMK_FSTRANS, strlen(SMK_FSTRANS)) == 0) {
                        op += strlen(SMK_FSTRANS);
                        nsp = smk_import(op, 0);
                        if (nsp != NULL) {
                                sp->smk_root = nsp;
                                transmute = 1;
                                specified = 1;
                        }
                }
        }

        if (!smack_privileged(CAP_MAC_ADMIN)) {
                /*
                 * Unprivileged mounts don't get to specify Smack values.
                 */
                if (specified)
                        return -EPERM;
                /*
                 * Unprivileged mounts get root and default from the caller.
                 */
                skp = smk_of_current();
                sp->smk_root = skp->smk_known;
                sp->smk_default = skp->smk_known;
        }
        /*
         * Initialize the root inode.
         */
        isp = inode->i_security;
        if (isp == NULL) {
                isp = new_inode_smack(sp->smk_root);
                if (isp == NULL)
                        return -ENOMEM;
                inode->i_security = isp;
        } else
                isp->smk_inode = sp->smk_root;

        if (transmute)
                isp->smk_flags |= SMK_INODE_TRANSMUTE;

        return 0;
}

/**
 * smack_sb_statfs - Smack check on statfs
 * @dentry: identifies the file system in question
 *
 * Returns 0 if current can read the floor of the filesystem,
 * and error code otherwise
 */
static int smack_sb_statfs(struct dentry *dentry)
{
        struct superblock_smack *sbp = dentry->d_sb->s_security;
        int rc;
        struct smk_audit_info ad;

        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
        smk_ad_setfield_u_fs_path_dentry(&ad, dentry);

        rc = smk_curacc(sbp->smk_floor, MAY_READ, &ad);
        return rc;
}

/*
 * BPRM hooks
 */

/**
 * smack_bprm_set_creds - set creds for exec
 * @bprm: the exec information
 *
 * Returns 0 if it gets a blob, -EPERM if exec forbidden and -ENOMEM otherwise
 */
static int smack_bprm_set_creds(struct linux_binprm *bprm)
{
        struct inode *inode = file_inode(bprm->file);
        struct task_smack *bsp = bprm->cred->security;
        struct inode_smack *isp;
        int rc;

        rc = cap_bprm_set_creds(bprm);
        if (rc != 0)
                return rc;

        if (bprm->cred_prepared)
                return 0;

        isp = inode->i_security;
        if (isp->smk_task == NULL || isp->smk_task == bsp->smk_task)
                return 0;

        if (bprm->unsafe & (LSM_UNSAFE_PTRACE | LSM_UNSAFE_PTRACE_CAP)) {
                struct task_struct *tracer;
                rc = 0;

                rcu_read_lock();
                tracer = ptrace_parent(current);
                if (likely(tracer != NULL))
                        rc = smk_ptrace_rule_check(tracer,
                                                   isp->smk_task->smk_known,
                                                   PTRACE_MODE_ATTACH,
                                                   __func__);
                rcu_read_unlock();

                if (rc != 0)
                        return rc;
        } else if (bprm->unsafe)
                return -EPERM;

        bsp->smk_task = isp->smk_task;
        bprm->per_clear |= PER_CLEAR_ON_SETID;

        return 0;
}

/**
 * smack_bprm_committing_creds - Prepare to install the new credentials
 * from bprm.
 *
 * @bprm: binprm for exec
 */
static void smack_bprm_committing_creds(struct linux_binprm *bprm)
{
        struct task_smack *bsp = bprm->cred->security;

        if (bsp->smk_task != bsp->smk_forked)
                current->pdeath_signal = 0;
}

/**
 * smack_bprm_secureexec - Return the decision to use secureexec.
 * @bprm: binprm for exec
 *
 * Returns 0 on success.
 */
static int smack_bprm_secureexec(struct linux_binprm *bprm)
{
        struct task_smack *tsp = current_security();
        int ret = cap_bprm_secureexec(bprm);

        if (!ret && (tsp->smk_task != tsp->smk_forked))
                ret = 1;

        return ret;
}

/*
 * Inode hooks
 */

/**
 * smack_inode_alloc_security - allocate an inode blob
 * @inode: the inode in need of a blob
 *
 * Returns 0 if it gets a blob, -ENOMEM otherwise
 */
static int smack_inode_alloc_security(struct inode *inode)
{
        struct smack_known *skp = smk_of_current();

        inode->i_security = new_inode_smack(skp->smk_known);
        if (inode->i_security == NULL)
                return -ENOMEM;
        return 0;
}

/**
 * smack_inode_free_security - free an inode blob
 * @inode: the inode with a blob
 *
 * Clears the blob pointer in inode
 */
static void smack_inode_free_security(struct inode *inode)
{
        kfree(inode->i_security);
        inode->i_security = NULL;
}

/**
 * smack_inode_init_security - copy out the smack from an inode
 * @inode: the inode
 * @dir: unused
 * @qstr: unused
 * @name: where to put the attribute name
 * @value: where to put the attribute value
 * @len: where to put the length of the attribute
 *
 * Returns 0 if it all works out, -ENOMEM if there's no memory
 */
static int smack_inode_init_security(struct inode *inode, struct inode *dir,
                                     const struct qstr *qstr, const char **name,
                                     void **value, size_t *len)
{
        struct inode_smack *issp = inode->i_security;
        struct smack_known *skp = smk_of_current();
        char *isp = smk_of_inode(inode);
        char *dsp = smk_of_inode(dir);
        int may;

        if (name)
                *name = XATTR_SMACK_SUFFIX;

        if (value) {
                rcu_read_lock();
                may = smk_access_entry(skp->smk_known, dsp, &skp->smk_rules);
                rcu_read_unlock();

                /*
                 * If the access rule allows transmutation and
                 * the directory requests transmutation then
                 * by all means transmute.
                 * Mark the inode as changed.
                 */
                if (may > 0 && ((may & MAY_TRANSMUTE) != 0) &&
                    smk_inode_transmutable(dir)) {
                        isp = dsp;
                        issp->smk_flags |= SMK_INODE_CHANGED;
                }

                *value = kstrdup(isp, GFP_NOFS);
                if (*value == NULL)
                        return -ENOMEM;
        }

        if (len)
                *len = strlen(isp) + 1;

        return 0;
}

/**
 * smack_inode_link - Smack check on link
 * @old_dentry: the existing object
 * @dir: unused
 * @new_dentry: the new object
 *
 * Returns 0 if access is permitted, an error code otherwise
 */
static int smack_inode_link(struct dentry *old_dentry, struct inode *dir,
                            struct dentry *new_dentry)
{
        char *isp;
        struct smk_audit_info ad;
        int rc;

        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
        smk_ad_setfield_u_fs_path_dentry(&ad, old_dentry);

        isp = smk_of_inode(old_dentry->d_inode);
        rc = smk_curacc(isp, MAY_WRITE, &ad);

        if (rc == 0 && new_dentry->d_inode != NULL) {
                isp = smk_of_inode(new_dentry->d_inode);
                smk_ad_setfield_u_fs_path_dentry(&ad, new_dentry);
                rc = smk_curacc(isp, MAY_WRITE, &ad);
        }

        return rc;
}

/**
 * smack_inode_unlink - Smack check on inode deletion
 * @dir: containing directory object
 * @dentry: file to unlink
 *
 * Returns 0 if current can write the containing directory
 * and the object, error code otherwise
 */
static int smack_inode_unlink(struct inode *dir, struct dentry *dentry)
{
        struct inode *ip = dentry->d_inode;
        struct smk_audit_info ad;
        int rc;

        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
        smk_ad_setfield_u_fs_path_dentry(&ad, dentry);

        /*
         * You need write access to the thing you're unlinking
         */
        rc = smk_curacc(smk_of_inode(ip), MAY_WRITE, &ad);
        if (rc == 0) {
                /*
                 * You also need write access to the containing directory
                 */
                smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_INODE);
                smk_ad_setfield_u_fs_inode(&ad, dir);
                rc = smk_curacc(smk_of_inode(dir), MAY_WRITE, &ad);
        }
        return rc;
}

/**
 * smack_inode_rmdir - Smack check on directory deletion
 * @dir: containing directory object
 * @dentry: directory to unlink
 *
 * Returns 0 if current can write the containing directory
 * and the directory, error code otherwise
 */
static int smack_inode_rmdir(struct inode *dir, struct dentry *dentry)
{
        struct smk_audit_info ad;
        int rc;

        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
        smk_ad_setfield_u_fs_path_dentry(&ad, dentry);

        /*
         * You need write access to the thing you're removing
         */
        rc = smk_curacc(smk_of_inode(dentry->d_inode), MAY_WRITE, &ad);
        if (rc == 0) {
                /*
                 * You also need write access to the containing directory
                 */
                smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_INODE);
                smk_ad_setfield_u_fs_inode(&ad, dir);
                rc = smk_curacc(smk_of_inode(dir), MAY_WRITE, &ad);
        }

        return rc;
}

/**
 * smack_inode_rename - Smack check on rename
 * @old_inode: the old directory
 * @old_dentry: unused
 * @new_inode: the new directory
 * @new_dentry: unused
 *
 * Read and write access is required on both the old and
 * new directories.
 *
 * Returns 0 if access is permitted, an error code otherwise
 */
static int smack_inode_rename(struct inode *old_inode,
                              struct dentry *old_dentry,
                              struct inode *new_inode,
                              struct dentry *new_dentry)
{
        int rc;
        char *isp;
        struct smk_audit_info ad;

        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
        smk_ad_setfield_u_fs_path_dentry(&ad, old_dentry);

        isp = smk_of_inode(old_dentry->d_inode);
        rc = smk_curacc(isp, MAY_READWRITE, &ad);

        if (rc == 0 && new_dentry->d_inode != NULL) {
                isp = smk_of_inode(new_dentry->d_inode);
                smk_ad_setfield_u_fs_path_dentry(&ad, new_dentry);
                rc = smk_curacc(isp, MAY_READWRITE, &ad);
        }
        return rc;
}

/**
 * smack_inode_permission - Smack version of permission()
 * @inode: the inode in question
 * @mask: the access requested
 *
 * This is the important Smack hook.
 *
 * Returns 0 if access is permitted, -EACCES otherwise
 */
static int smack_inode_permission(struct inode *inode, int mask)
{
        struct smk_audit_info ad;
        int no_block = mask & MAY_NOT_BLOCK;

        mask &= (MAY_READ|MAY_WRITE|MAY_EXEC|MAY_APPEND);
        /*
         * No permission to check. Existence test. Yup, it's there.
         */
        if (mask == 0)
                return 0;

        /* May be droppable after audit */
        if (no_block)
                return -ECHILD;
        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_INODE);
        smk_ad_setfield_u_fs_inode(&ad, inode);
        return smk_curacc(smk_of_inode(inode), mask, &ad);
}

/**
 * smack_inode_setattr - Smack check for setting attributes
 * @dentry: the object
 * @iattr: for the force flag
 *
 * Returns 0 if access is permitted, an error code otherwise
 */
static int smack_inode_setattr(struct dentry *dentry, struct iattr *iattr)
{
        struct smk_audit_info ad;
        /*
         * Need to allow for clearing the setuid bit.
         */
        if (iattr->ia_valid & ATTR_FORCE)
                return 0;
        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
        smk_ad_setfield_u_fs_path_dentry(&ad, dentry);

        return smk_curacc(smk_of_inode(dentry->d_inode), MAY_WRITE, &ad);
}

/**
 * smack_inode_getattr - Smack check for getting attributes
 * @mnt: unused
 * @dentry: the object
 *
 * Returns 0 if access is permitted, an error code otherwise
 */
static int smack_inode_getattr(struct vfsmount *mnt, struct dentry *dentry)
{
        struct smk_audit_info ad;
        struct path path;

        path.dentry = dentry;
        path.mnt = mnt;

        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
        smk_ad_setfield_u_fs_path(&ad, path);
        return smk_curacc(smk_of_inode(dentry->d_inode), MAY_READ, &ad);
}

/**
 * smack_inode_setxattr - Smack check for setting xattrs
 * @dentry: the object
 * @name: name of the attribute
 * @value: unused
 * @size: unused
 * @flags: unused
 *
 * This protects the Smack attribute explicitly.
 *
 * Returns 0 if access is permitted, an error code otherwise
 */
static int smack_inode_setxattr(struct dentry *dentry, const char *name,
                                const void *value, size_t size, int flags)
{
        struct smk_audit_info ad;
        struct smack_known *skp;
        int check_priv = 0;
        int check_import = 0;
        int check_star = 0;
        int rc = 0;

        /*
         * Check label validity here so import won't fail in post_setxattr
         */
        if (strcmp(name, XATTR_NAME_SMACK) == 0 ||
            strcmp(name, XATTR_NAME_SMACKIPIN) == 0 ||
            strcmp(name, XATTR_NAME_SMACKIPOUT) == 0) {
                check_priv = 1;
                check_import = 1;
        } else if (strcmp(name, XATTR_NAME_SMACKEXEC) == 0 ||
                   strcmp(name, XATTR_NAME_SMACKMMAP) == 0) {
                check_priv = 1;
                check_import = 1;
                check_star = 1;
        } else if (strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0) {
                check_priv = 1;
                if (size != TRANS_TRUE_SIZE ||
                    strncmp(value, TRANS_TRUE, TRANS_TRUE_SIZE) != 0)
                        rc = -EINVAL;
        } else
                rc = cap_inode_setxattr(dentry, name, value, size, flags);

        if (check_priv && !smack_privileged(CAP_MAC_ADMIN))
                rc = -EPERM;

        if (rc == 0 && check_import) {
                skp = smk_import_entry(value, size);
                if (skp == NULL || (check_star &&
                    (skp == &smack_known_star || skp == &smack_known_web)))
                        rc = -EINVAL;
        }

        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
        smk_ad_setfield_u_fs_path_dentry(&ad, dentry);

        if (rc == 0)
                rc = smk_curacc(smk_of_inode(dentry->d_inode), MAY_WRITE, &ad);

        return rc;
}

/**
 * smack_inode_post_setxattr - Apply the Smack update approved above
 * @dentry: object
 * @name: attribute name
 * @value: attribute value
 * @size: attribute size
 * @flags: unused
 *
 * Set the pointer in the inode blob to the entry found
 * in the master label list.
 */
static void smack_inode_post_setxattr(struct dentry *dentry, const char *name,
                                      const void *value, size_t size, int flags)
{
        struct smack_known *skp;
        struct inode_smack *isp = dentry->d_inode->i_security;

        if (strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0) {
                isp->smk_flags |= SMK_INODE_TRANSMUTE;
                return;
        }

        if (strcmp(name, XATTR_NAME_SMACK) == 0) {
                skp = smk_import_entry(value, size);
                if (skp != NULL)
                        isp->smk_inode = skp->smk_known;
                else
                        isp->smk_inode = smack_known_invalid.smk_known;
        } else if (strcmp(name, XATTR_NAME_SMACKEXEC) == 0) {
                skp = smk_import_entry(value, size);
                if (skp != NULL)
                        isp->smk_task = skp;
                else
                        isp->smk_task = &smack_known_invalid;
        } else if (strcmp(name, XATTR_NAME_SMACKMMAP) == 0) {
                skp = smk_import_entry(value, size);
                if (skp != NULL)
                        isp->smk_mmap = skp;
                else
                        isp->smk_mmap = &smack_known_invalid;
        }

        return;
}

/**
 * smack_inode_getxattr - Smack check on getxattr
 * @dentry: the object
 * @name: unused
 *
 * Returns 0 if access is permitted, an error code otherwise
 */
static int smack_inode_getxattr(struct dentry *dentry, const char *name)
{
        struct smk_audit_info ad;

        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
        smk_ad_setfield_u_fs_path_dentry(&ad, dentry);

        return smk_curacc(smk_of_inode(dentry->d_inode), MAY_READ, &ad);
}

/**
 * smack_inode_removexattr - Smack check on removexattr
 * @dentry: the object
 * @name: name of the attribute
 *
 * Removing the Smack attribute requires CAP_MAC_ADMIN
 *
 * Returns 0 if access is permitted, an error code otherwise
 */
static int smack_inode_removexattr(struct dentry *dentry, const char *name)
{
        struct inode_smack *isp;
        struct smk_audit_info ad;
        int rc = 0;

        if (strcmp(name, XATTR_NAME_SMACK) == 0 ||
            strcmp(name, XATTR_NAME_SMACKIPIN) == 0 ||
            strcmp(name, XATTR_NAME_SMACKIPOUT) == 0 ||
            strcmp(name, XATTR_NAME_SMACKEXEC) == 0 ||
            strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0 ||
            strcmp(name, XATTR_NAME_SMACKMMAP)) {
                if (!smack_privileged(CAP_MAC_ADMIN))
                        rc = -EPERM;
        } else
                rc = cap_inode_removexattr(dentry, name);

        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
        smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
        if (rc == 0)
                rc = smk_curacc(smk_of_inode(dentry->d_inode), MAY_WRITE, &ad);

        if (rc == 0) {
                isp = dentry->d_inode->i_security;
                isp->smk_task = NULL;
                isp->smk_mmap = NULL;
        }

        return rc;
}

/**
 * smack_inode_getsecurity - get smack xattrs
 * @inode: the object
 * @name: attribute name
 * @buffer: where to put the result
 * @alloc: unused
 *
 * Returns the size of the attribute or an error code
 */
static int smack_inode_getsecurity(const struct inode *inode,
                                   const char *name, void **buffer,
                                   bool alloc)
{
        struct socket_smack *ssp;
        struct socket *sock;
        struct super_block *sbp;
        struct inode *ip = (struct inode *)inode;
        char *isp;
        int ilen;
        int rc = 0;

        if (strcmp(name, XATTR_SMACK_SUFFIX) == 0) {
                isp = smk_of_inode(inode);
                ilen = strlen(isp) + 1;
                *buffer = isp;
                return ilen;
        }

        /*
         * The rest of the Smack xattrs are only on sockets.
         */
        sbp = ip->i_sb;
        if (sbp->s_magic != SOCKFS_MAGIC)
                return -EOPNOTSUPP;

        sock = SOCKET_I(ip);
        if (sock == NULL || sock->sk == NULL)
                return -EOPNOTSUPP;

        ssp = sock->sk->sk_security;

        if (strcmp(name, XATTR_SMACK_IPIN) == 0)
                isp = ssp->smk_in;
        else if (strcmp(name, XATTR_SMACK_IPOUT) == 0)
                isp = ssp->smk_out->smk_known;
        else
                return -EOPNOTSUPP;

        ilen = strlen(isp) + 1;
        if (rc == 0) {
                *buffer = isp;
                rc = ilen;
        }

        return rc;
}


/**
 * smack_inode_listsecurity - list the Smack attributes
 * @inode: the object
 * @buffer: where they go
 * @buffer_size: size of buffer
 *
 * Returns 0 on success, -EINVAL otherwise
 */
static int smack_inode_listsecurity(struct inode *inode, char *buffer,
                                    size_t buffer_size)
{
        int len = strlen(XATTR_NAME_SMACK);

        if (buffer != NULL && len <= buffer_size) {
                memcpy(buffer, XATTR_NAME_SMACK, len);
                return len;
        }
        return -EINVAL;
}

/**
 * smack_inode_getsecid - Extract inode's security id
 * @inode: inode to extract the info from
 * @secid: where result will be saved
 */
static void smack_inode_getsecid(const struct inode *inode, u32 *secid)
{
        struct inode_smack *isp = inode->i_security;

        *secid = smack_to_secid(isp->smk_inode);
}

/*
 * File Hooks
 */

/**
 * smack_file_permission - Smack check on file operations
 * @file: unused
 * @mask: unused
 *
 * Returns 0
 *
 * Should access checks be done on each read or write?
 * UNICOS and SELinux say yes.
 * Trusted Solaris, Trusted Irix, and just about everyone else says no.
 *
 * I'll say no for now. Smack does not do the frequent
 * label changing that SELinux does.
 */
static int smack_file_permission(struct file *file, int mask)
{
        return 0;
}

/**
 * smack_file_alloc_security - assign a file security blob
 * @file: the object
 *
 * The security blob for a file is a pointer to the master
 * label list, so no allocation is done.
 *
 * Returns 0
 */
static int smack_file_alloc_security(struct file *file)
{
        struct smack_known *skp = smk_of_current();

        file->f_security = skp->smk_known;
        return 0;
}

/**
 * smack_file_free_security - clear a file security blob
 * @file: the object
 *
 * The security blob for a file is a pointer to the master
 * label list, so no memory is freed.
 */
static void smack_file_free_security(struct file *file)
{
        file->f_security = NULL;
}

/**
 * smack_file_ioctl - Smack check on ioctls
 * @file: the object
 * @cmd: what to do
 * @arg: unused
 *
 * Relies heavily on the correct use of the ioctl command conventions.
 *
 * Returns 0 if allowed, error code otherwise
 */
static int smack_file_ioctl(struct file *file, unsigned int cmd,
                            unsigned long arg)
{
        int rc = 0;
        struct smk_audit_info ad;

        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
        smk_ad_setfield_u_fs_path(&ad, file->f_path);

        if (_IOC_DIR(cmd) & _IOC_WRITE)
                rc = smk_curacc(file->f_security, MAY_WRITE, &ad);

        if (rc == 0 && (_IOC_DIR(cmd) & _IOC_READ))
                rc = smk_curacc(file->f_security, MAY_READ, &ad);

        return rc;
}

/**
 * smack_file_lock - Smack check on file locking
 * @file: the object
 * @cmd: unused
 *
 * Returns 0 if current has lock access, error code otherwise
 */
static int smack_file_lock(struct file *file, unsigned int cmd)
{
        struct smk_audit_info ad;

        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
        smk_ad_setfield_u_fs_path(&ad, file->f_path);
        return smk_curacc(file->f_security, MAY_LOCK, &ad);
}

/**
 * smack_file_fcntl - Smack check on fcntl
 * @file: the object
 * @cmd: what action to check
 * @arg: unused
 *
 * Generally these operations are harmless.
 * File locking operations present an obvious mechanism
 * for passing information, so they require write access.
 *
 * Returns 0 if current has access, error code otherwise
 */
static int smack_file_fcntl(struct file *file, unsigned int cmd,
                            unsigned long arg)
{
        struct smk_audit_info ad;
        int rc = 0;


        switch (cmd) {
        case F_GETLK:
                break;
        case F_SETLK:
        case F_SETLKW:
                smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
                smk_ad_setfield_u_fs_path(&ad, file->f_path);
                rc = smk_curacc(file->f_security, MAY_LOCK, &ad);
                break;
        case F_SETOWN:
        case F_SETSIG:
                smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
                smk_ad_setfield_u_fs_path(&ad, file->f_path);
                rc = smk_curacc(file->f_security, MAY_WRITE, &ad);
                break;
        default:
                break;
        }

        return rc;
}

/**
 * smack_mmap_file :
 * Check permissions for a mmap operation.  The @file may be NULL, e.g.
 * if mapping anonymous memory.
 * @file contains the file structure for file to map (may be NULL).
 * @reqprot contains the protection requested by the application.
 * @prot contains the protection that will be applied by the kernel.
 * @flags contains the operational flags.
 * Return 0 if permission is granted.
 */
static int smack_mmap_file(struct file *file,
                           unsigned long reqprot, unsigned long prot,
                           unsigned long flags)
{
        struct smack_known *skp;
        struct smack_known *mkp;
        struct smack_rule *srp;
        struct task_smack *tsp;
        char *osmack;
        struct inode_smack *isp;
        int may;
        int mmay;
        int tmay;
        int rc;

        if (file == NULL)
                return 0;

        isp = file_inode(file)->i_security;
        if (isp->smk_mmap == NULL)
                return 0;
        mkp = isp->smk_mmap;

        tsp = current_security();
        skp = smk_of_current();
        rc = 0;

        rcu_read_lock();
        /*
         * For each Smack rule associated with the subject
         * label verify that the SMACK64MMAP also has access
         * to that rule's object label.
         */
        list_for_each_entry_rcu(srp, &skp->smk_rules, list) {
                osmack = srp->smk_object;
                /*
                 * Matching labels always allows access.
                 */
                if (mkp->smk_known == osmack)
                        continue;
                /*
                 * If there is a matching local rule take
                 * that into account as well.
                 */
                may = smk_access_entry(srp->smk_subject->smk_known, osmack,
                                        &tsp->smk_rules);
                if (may == -ENOENT)
                        may = srp->smk_access;
                else
                        may &= srp->smk_access;
                /*
                 * If may is zero the SMACK64MMAP subject can't
                 * possibly have less access.
                 */
                if (may == 0)
                        continue;

                /*
                 * Fetch the global list entry.
                 * If there isn't one a SMACK64MMAP subject
                 * can't have as much access as current.
                 */
                mmay = smk_access_entry(mkp->smk_known, osmack,
                                                &mkp->smk_rules);
                if (mmay == -ENOENT) {
                        rc = -EACCES;
                        break;
                }
                /*
                 * If there is a local entry it modifies the
                 * potential access, too.
                 */
                tmay = smk_access_entry(mkp->smk_known, osmack,
                                                &tsp->smk_rules);
                if (tmay != -ENOENT)
                        mmay &= tmay;

                /*
                 * If there is any access available to current that is
                 * not available to a SMACK64MMAP subject
                 * deny access.
                 */
                if ((may | mmay) != mmay) {
                        rc = -EACCES;
                        break;
                }
        }

        rcu_read_unlock();

        return rc;
}

/**
 * smack_file_set_fowner - set the file security blob value
 * @file: object in question
 *
 * Returns 0
 * Further research may be required on this one.
 */
static int smack_file_set_fowner(struct file *file)
{
        struct smack_known *skp = smk_of_current();

        file->f_security = skp->smk_known;
        return 0;
}

/**
 * smack_file_send_sigiotask - Smack on sigio
 * @tsk: The target task
 * @fown: the object the signal come from
 * @signum: unused
 *
 * Allow a privileged task to get signals even if it shouldn't
 *
 * Returns 0 if a subject with the object's smack could
 * write to the task, an error code otherwise.
 */
static int smack_file_send_sigiotask(struct task_struct *tsk,
                                     struct fown_struct *fown, int signum)
{
        struct smack_known *skp;
        struct smack_known *tkp = smk_of_task(tsk->cred->security);
        struct file *file;
        int rc;
        struct smk_audit_info ad;

        /*
         * struct fown_struct is never outside the context of a struct file
         */
        file = container_of(fown, struct file, f_owner);

        /* we don't log here as rc can be overriden */
        skp = smk_find_entry(file->f_security);
        rc = smk_access(skp, tkp->smk_known, MAY_WRITE, NULL);
        if (rc != 0 && has_capability(tsk, CAP_MAC_OVERRIDE))
                rc = 0;

        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK);
        smk_ad_setfield_u_tsk(&ad, tsk);
        smack_log(file->f_security, tkp->smk_known, MAY_WRITE, rc, &ad);
        return rc;
}

/**
 * smack_file_receive - Smack file receive check
 * @file: the object
 *
 * Returns 0 if current has access, error code otherwise
 */
static int smack_file_receive(struct file *file)
{
        int may = 0;
        struct smk_audit_info ad;

        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
        smk_ad_setfield_u_fs_path(&ad, file->f_path);
        /*
         * This code relies on bitmasks.
         */
        if (file->f_mode & FMODE_READ)
                may = MAY_READ;
        if (file->f_mode & FMODE_WRITE)
                may |= MAY_WRITE;

        return smk_curacc(file->f_security, may, &ad);
}

/**
 * smack_file_open - Smack dentry open processing
 * @file: the object
 * @cred: unused
 *
 * Set the security blob in the file structure.
 *
 * Returns 0
 */
static int smack_file_open(struct file *file, const struct cred *cred)
{
        struct inode_smack *isp = file_inode(file)->i_security;

        file->f_security = isp->smk_inode;

        return 0;
}

/*
 * Task hooks
 */

/**
 * smack_cred_alloc_blank - "allocate" blank task-level security credentials
 * @new: the new credentials
 * @gfp: the atomicity of any memory allocations
 *
 * Prepare a blank set of credentials for modification.  This must allocate all
 * the memory the LSM module might require such that cred_transfer() can
 * complete without error.
 */
static int smack_cred_alloc_blank(struct cred *cred, gfp_t gfp)
{
        struct task_smack *tsp;

        tsp = new_task_smack(NULL, NULL, gfp);
        if (tsp == NULL)
                return -ENOMEM;

        cred->security = tsp;

        return 0;
}


/**
 * smack_cred_free - "free" task-level security credentials
 * @cred: the credentials in question
 *
 */
static void smack_cred_free(struct cred *cred)
{
        struct task_smack *tsp = cred->security;
        struct smack_rule *rp;
        struct list_head *l;
        struct list_head *n;

        if (tsp == NULL)
                return;
        cred->security = NULL;

        list_for_each_safe(l, n, &tsp->smk_rules) {
                rp = list_entry(l, struct smack_rule, list);
                list_del(&rp->list);
                kfree(rp);
        }
        kfree(tsp);
}

/**
 * smack_cred_prepare - prepare new set of credentials for modification
 * @new: the new credentials
 * @old: the original credentials
 * @gfp: the atomicity of any memory allocations
 *
 * Prepare a new set of credentials for modification.
 */
static int smack_cred_prepare(struct cred *new, const struct cred *old,
                              gfp_t gfp)
{
        struct task_smack *old_tsp = old->security;
        struct task_smack *new_tsp;
        int rc;

        new_tsp = new_task_smack(old_tsp->smk_task, old_tsp->smk_task, gfp);
        if (new_tsp == NULL)
                return -ENOMEM;

        rc = smk_copy_rules(&new_tsp->smk_rules, &old_tsp->smk_rules, gfp);
        if (rc != 0)
                return rc;

        new->security = new_tsp;
        return 0;
}

/**
 * smack_cred_transfer - Transfer the old credentials to the new credentials
 * @new: the new credentials
 * @old: the original credentials
 *
 * Fill in a set of blank credentials from another set of credentials.
 */
static void smack_cred_transfer(struct cred *new, const struct cred *old)
{
        struct task_smack *old_tsp = old->security;
        struct task_smack *new_tsp = new->security;

        new_tsp->smk_task = old_tsp->smk_task;
        new_tsp->smk_forked = old_tsp->smk_task;
        mutex_init(&new_tsp->smk_rules_lock);
        INIT_LIST_HEAD(&new_tsp->smk_rules);


        /* cbs copy rule list */
}

/**
 * smack_kernel_act_as - Set the subjective context in a set of credentials
 * @new: points to the set of credentials to be modified.
 * @secid: specifies the security ID to be set
 *
 * Set the security data for a kernel service.
 */
static int smack_kernel_act_as(struct cred *new, u32 secid)
{
        struct task_smack *new_tsp = new->security;
        struct smack_known *skp = smack_from_secid(secid);

        if (skp == NULL)
                return -EINVAL;

        new_tsp->smk_task = skp;
        return 0;
}

/**
 * smack_kernel_create_files_as - Set the file creation label in a set of creds
 * @new: points to the set of credentials to be modified
 * @inode: points to the inode to use as a reference
 *
 * Set the file creation context in a set of credentials to the same
 * as the objective context of the specified inode
 */
static int smack_kernel_create_files_as(struct cred *new,
                                        struct inode *inode)
{
        struct inode_smack *isp = inode->i_security;
        struct task_smack *tsp = new->security;

        tsp->smk_forked = smk_find_entry(isp->smk_inode);
        tsp->smk_task = tsp->smk_forked;
        return 0;
}

/**
 * smk_curacc_on_task - helper to log task related access
 * @p: the task object
 * @access: the access requested
 * @caller: name of the calling function for audit
 *
 * Return 0 if access is permitted
 */
static int smk_curacc_on_task(struct task_struct *p, int access,
                                const char *caller)
{
        struct smk_audit_info ad;
        struct smack_known *skp = smk_of_task(task_security(p));

        smk_ad_init(&ad, caller, LSM_AUDIT_DATA_TASK);
        smk_ad_setfield_u_tsk(&ad, p);
        return smk_curacc(skp->smk_known, access, &ad);
}

/**
 * smack_task_setpgid - Smack check on setting pgid
 * @p: the task object
 * @pgid: unused
 *
 * Return 0 if write access is permitted
 */
static int smack_task_setpgid(struct task_struct *p, pid_t pgid)
{
        return smk_curacc_on_task(p, MAY_WRITE, __func__);
}

/**
 * smack_task_getpgid - Smack access check for getpgid
 * @p: the object task
 *
 * Returns 0 if current can read the object task, error code otherwise
 */
static int smack_task_getpgid(struct task_struct *p)
{
        return smk_curacc_on_task(p, MAY_READ, __func__);
}

/**
 * smack_task_getsid - Smack access check for getsid
 * @p: the object task
 *
 * Returns 0 if current can read the object task, error code otherwise
 */
static int smack_task_getsid(struct task_struct *p)
{
        return smk_curacc_on_task(p, MAY_READ, __func__);
}

/**
 * smack_task_getsecid - get the secid of the task
 * @p: the object task
 * @secid: where to put the result
 *
 * Sets the secid to contain a u32 version of the smack label.
 */
static void smack_task_getsecid(struct task_struct *p, u32 *secid)
{
        struct smack_known *skp = smk_of_task(task_security(p));

        *secid = skp->smk_secid;
}

/**
 * smack_task_setnice - Smack check on setting nice
 * @p: the task object
 * @nice: unused
 *
 * Return 0 if write access is permitted
 */
static int smack_task_setnice(struct task_struct *p, int nice)
{
        int rc;

        rc = cap_task_setnice(p, nice);
        if (rc == 0)
                rc = smk_curacc_on_task(p, MAY_WRITE, __func__);
        return rc;
}

/**
 * smack_task_setioprio - Smack check on setting ioprio
 * @p: the task object
 * @ioprio: unused
 *
 * Return 0 if write access is permitted
 */
static int smack_task_setioprio(struct task_struct *p, int ioprio)
{
        int rc;

        rc = cap_task_setioprio(p, ioprio);
        if (rc == 0)
                rc = smk_curacc_on_task(p, MAY_WRITE, __func__);
        return rc;
}

/**
 * smack_task_getioprio - Smack check on reading ioprio
 * @p: the task object
 *
 * Return 0 if read access is permitted
 */
static int smack_task_getioprio(struct task_struct *p)
{
        return smk_curacc_on_task(p, MAY_READ, __func__);
}

/**
 * smack_task_setscheduler - Smack check on setting scheduler
 * @p: the task object
 * @policy: unused
 * @lp: unused
 *
 * Return 0 if read access is permitted
 */
static int smack_task_setscheduler(struct task_struct *p)
{
        int rc;

        rc = cap_task_setscheduler(p);
        if (rc == 0)
                rc = smk_curacc_on_task(p, MAY_WRITE, __func__);
        return rc;
}

/**
 * smack_task_getscheduler - Smack check on reading scheduler
 * @p: the task object
 *
 * Return 0 if read access is permitted
 */
static int smack_task_getscheduler(struct task_struct *p)
{
        return smk_curacc_on_task(p, MAY_READ, __func__);
}

/**
 * smack_task_movememory - Smack check on moving memory
 * @p: the task object
 *
 * Return 0 if write access is permitted
 */
static int smack_task_movememory(struct task_struct *p)
{
        return smk_curacc_on_task(p, MAY_WRITE, __func__);
}

/**
 * smack_task_kill - Smack check on signal delivery
 * @p: the task object
 * @info: unused
 * @sig: unused
 * @secid: identifies the smack to use in lieu of current's
 *
 * Return 0 if write access is permitted
 *
 * The secid behavior is an artifact of an SELinux hack
 * in the USB code. Someday it may go away.
 */
static int smack_task_kill(struct task_struct *p, struct siginfo *info,
                           int sig, u32 secid)
{
        struct smk_audit_info ad;
        struct smack_known *skp;
        struct smack_known *tkp = smk_of_task(task_security(p));

        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK);
        smk_ad_setfield_u_tsk(&ad, p);
        /*
         * Sending a signal requires that the sender
         * can write the receiver.
         */
        if (secid == 0)
                return smk_curacc(tkp->smk_known, MAY_WRITE, &ad);
        /*
         * If the secid isn't 0 we're dealing with some USB IO
         * specific behavior. This is not clean. For one thing
         * we can't take privilege into account.
         */
        skp = smack_from_secid(secid);
        return smk_access(skp, tkp->smk_known, MAY_WRITE, &ad);
}

/**
 * smack_task_wait - Smack access check for waiting
 * @p: task to wait for
 *
 * Returns 0
 */
static int smack_task_wait(struct task_struct *p)
{
        /*
         * Allow the operation to succeed.
         * Zombies are bad.
         * In userless environments (e.g. phones) programs
         * get marked with SMACK64EXEC and even if the parent
         * and child shouldn't be talking the parent still
         * may expect to know when the child exits.
         */
        return 0;
}

/**
 * smack_task_to_inode - copy task smack into the inode blob
 * @p: task to copy from
 * @inode: inode to copy to
 *
 * Sets the smack pointer in the inode security blob
 */
static void smack_task_to_inode(struct task_struct *p, struct inode *inode)
{
        struct inode_smack *isp = inode->i_security;
        struct smack_known *skp = smk_of_task(task_security(p));

        isp->smk_inode = skp->smk_known;
}

/*
 * Socket hooks.
 */

/**
 * smack_sk_alloc_security - Allocate a socket blob
 * @sk: the socket
 * @family: unused
 * @gfp_flags: memory allocation flags
 *
 * Assign Smack pointers to current
 *
 * Returns 0 on success, -ENOMEM is there's no memory
 */
static int smack_sk_alloc_security(struct sock *sk, int family, gfp_t gfp_flags)
{
        struct smack_known *skp = smk_of_current();
        struct socket_smack *ssp;

        ssp = kzalloc(sizeof(struct socket_smack), gfp_flags);
        if (ssp == NULL)
                return -ENOMEM;

        ssp->smk_in = skp->smk_known;
        ssp->smk_out = skp;
        ssp->smk_packet = NULL;

        sk->sk_security = ssp;

        return 0;
}

/**
 * smack_sk_free_security - Free a socket blob
 * @sk: the socket
 *
 * Clears the blob pointer
 */
static void smack_sk_free_security(struct sock *sk)
{
        kfree(sk->sk_security);
}

/**
* smack_host_label - check host based restrictions
* @sip: the object end
*
* looks for host based access restrictions
*
* This version will only be appropriate for really small sets of single label
* hosts.  The caller is responsible for ensuring that the RCU read lock is
* taken before calling this function.
*
* Returns the label of the far end or NULL if it's not special.
*/
static char *smack_host_label(struct sockaddr_in *sip)
{
        struct smk_netlbladdr *snp;
        struct in_addr *siap = &sip->sin_addr;

        if (siap->s_addr == 0)
                return NULL;

        list_for_each_entry_rcu(snp, &smk_netlbladdr_list, list)
                /*
                * we break after finding the first match because
                * the list is sorted from longest to shortest mask
                * so we have found the most specific match
                */
                if ((&snp->smk_host.sin_addr)->s_addr ==
                    (siap->s_addr & (&snp->smk_mask)->s_addr)) {
                        /* we have found the special CIPSO option */
                        if (snp->smk_label == smack_cipso_option)
                                return NULL;
                        return snp->smk_label;
                }

        return NULL;
}

/**
 * smack_netlabel - Set the secattr on a socket
 * @sk: the socket
 * @labeled: socket label scheme
 *
 * Convert the outbound smack value (smk_out) to a
 * secattr and attach it to the socket.
 *
 * Returns 0 on success or an error code
 */
static int smack_netlabel(struct sock *sk, int labeled)
{
        struct smack_known *skp;
        struct socket_smack *ssp = sk->sk_security;
        int rc = 0;

        /*
         * Usually the netlabel code will handle changing the
         * packet labeling based on the label.
         * The case of a single label host is different, because
         * a single label host should never get a labeled packet
         * even though the label is usually associated with a packet
         * label.
         */
        local_bh_disable();
        bh_lock_sock_nested(sk);

        if (ssp->smk_out == smack_net_ambient ||
            labeled == SMACK_UNLABELED_SOCKET)
                netlbl_sock_delattr(sk);
        else {
                skp = ssp->smk_out;
                rc = netlbl_sock_setattr(sk, sk->sk_family, &skp->smk_netlabel);
        }

        bh_unlock_sock(sk);
        local_bh_enable();

        return rc;
}

/**
 * smack_netlbel_send - Set the secattr on a socket and perform access checks
 * @sk: the socket
 * @sap: the destination address
 *
 * Set the correct secattr for the given socket based on the destination
 * address and perform any outbound access checks needed.
 *
 * Returns 0 on success or an error code.
 *
 */
static int smack_netlabel_send(struct sock *sk, struct sockaddr_in *sap)
{
        struct smack_known *skp;
        int rc;
        int sk_lbl;
        char *hostsp;
        struct socket_smack *ssp = sk->sk_security;
        struct smk_audit_info ad;

        rcu_read_lock();
        hostsp = smack_host_label(sap);
        if (hostsp != NULL) {
#ifdef CONFIG_AUDIT
                struct lsm_network_audit net;

                smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net);
                ad.a.u.net->family = sap->sin_family;
                ad.a.u.net->dport = sap->sin_port;
                ad.a.u.net->v4info.daddr = sap->sin_addr.s_addr;
#endif
                sk_lbl = SMACK_UNLABELED_SOCKET;
                skp = ssp->smk_out;
                rc = smk_access(skp, hostsp, MAY_WRITE, &ad);
        } else {
                sk_lbl = SMACK_CIPSO_SOCKET;
                rc = 0;
        }
        rcu_read_unlock();
        if (rc != 0)
                return rc;

        return smack_netlabel(sk, sk_lbl);
}

/**
 * smk_ipv6_port_label - Smack port access table management
 * @sock: socket
 * @address: address
 *
 * Create or update the port list entry
 */
static void smk_ipv6_port_label(struct socket *sock, struct sockaddr *address)
{
        struct sock *sk = sock->sk;
        struct sockaddr_in6 *addr6;
        struct socket_smack *ssp = sock->sk->sk_security;
        struct smk_port_label *spp;
        unsigned short port = 0;

        if (address == NULL) {
                /*
                 * This operation is changing the Smack information
                 * on the bound socket. Take the changes to the port
                 * as well.
                 */
                list_for_each_entry(spp, &smk_ipv6_port_list, list) {
                        if (sk != spp->smk_sock)
                                continue;
                        spp->smk_in = ssp->smk_in;
                        spp->smk_out = ssp->smk_out;
                        return;
                }
                /*
                 * A NULL address is only used for updating existing
                 * bound entries. If there isn't one, it's OK.
                 */
                return;
        }

        addr6 = (struct sockaddr_in6 *)address;
        port = ntohs(addr6->sin6_port);
        /*
         * This is a special case that is safely ignored.
         */
        if (port == 0)
                return;

        /*
         * Look for an existing port list entry.
         * This is an indication that a port is getting reused.
         */
        list_for_each_entry(spp, &smk_ipv6_port_list, list) {
                if (spp->smk_port != port)
                        continue;
                spp->smk_port = port;
                spp->smk_sock = sk;
                spp->smk_in = ssp->smk_in;
                spp->smk_out = ssp->smk_out;
                return;
        }

        /*
         * A new port entry is required.
         */
        spp = kzalloc(sizeof(*spp), GFP_KERNEL);
        if (spp == NULL)
                return;

        spp->smk_port = port;
        spp->smk_sock = sk;
        spp->smk_in = ssp->smk_in;
        spp->smk_out = ssp->smk_out;

        list_add(&spp->list, &smk_ipv6_port_list);
        return;
}

/**
 * smk_ipv6_port_check - check Smack port access
 * @sock: socket
 * @address: address
 *
 * Create or update the port list entry
 */
static int smk_ipv6_port_check(struct sock *sk, struct sockaddr_in6 *address,
                                int act)
{
        __be16 *bep;
        __be32 *be32p;
        struct smk_port_label *spp;
        struct socket_smack *ssp = sk->sk_security;
        struct smack_known *skp;
        unsigned short port = 0;
        char *object;
        struct smk_audit_info ad;
#ifdef CONFIG_AUDIT
        struct lsm_network_audit net;
#endif

        if (act == SMK_RECEIVING) {
                skp = smack_net_ambient;
                object = ssp->smk_in;
        } else {
                skp = ssp->smk_out;
                object = smack_net_ambient->smk_known;
        }

        /*
         * Get the IP address and port from the address.
         */
        port = ntohs(address->sin6_port);
        bep = (__be16 *)(&address->sin6_addr);
        be32p = (__be32 *)(&address->sin6_addr);

        /*
         * It's remote, so port lookup does no good.
         */
        if (be32p[0] || be32p[1] || be32p[2] || bep[6] || ntohs(bep[7]) != 1)
                goto auditout;

        /*
         * It's local so the send check has to have passed.
         */
        if (act == SMK_RECEIVING) {
                skp = &smack_known_web;
                goto auditout;
        }

        list_for_each_entry(spp, &smk_ipv6_port_list, list) {
                if (spp->smk_port != port)
                        continue;
                object = spp->smk_in;
                if (act == SMK_CONNECTING)
                        ssp->smk_packet = spp->smk_out->smk_known;
                break;
        }

auditout:

#ifdef CONFIG_AUDIT
        smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net);
        ad.a.u.net->family = sk->sk_family;
        ad.a.u.net->dport = port;
        if (act == SMK_RECEIVING)
                ad.a.u.net->v6info.saddr = address->sin6_addr;
        else
                ad.a.u.net->v6info.daddr = address->sin6_addr;
#endif
        return smk_access(skp, object, MAY_WRITE, &ad);
}

/**
 * smack_inode_setsecurity - set smack xattrs
 * @inode: the object
 * @name: attribute name
 * @value: attribute value
 * @size: size of the attribute
 * @flags: unused
 *
 * Sets the named attribute in the appropriate blob
 *
 * Returns 0 on success, or an error code
 */
static int smack_inode_setsecurity(struct inode *inode, const char *name,
                                   const void *value, size_t size, int flags)
{
        struct smack_known *skp;
        struct inode_smack *nsp = inode->i_security;
        struct socket_smack *ssp;
        struct socket *sock;
        int rc = 0;

        if (value == NULL || size > SMK_LONGLABEL || size == 0)
                return -EACCES;

        skp = smk_import_entry(value, size);
        if (skp == NULL)
                return -EINVAL;

        if (strcmp(name, XATTR_SMACK_SUFFIX) == 0) {
                nsp->smk_inode = skp->smk_known;
                nsp->smk_flags |= SMK_INODE_INSTANT;
                return 0;
        }
        /*
         * The rest of the Smack xattrs are only on sockets.
         */
        if (inode->i_sb->s_magic != SOCKFS_MAGIC)
                return -EOPNOTSUPP;

        sock = SOCKET_I(inode);
        if (sock == NULL || sock->sk == NULL)
                return -EOPNOTSUPP;

        ssp = sock->sk->sk_security;

        if (strcmp(name, XATTR_SMACK_IPIN) == 0)
                ssp->smk_in = skp->smk_known;
        else if (strcmp(name, XATTR_SMACK_IPOUT) == 0) {
                ssp->smk_out = skp;
                if (sock->sk->sk_family == PF_INET) {
                        rc = smack_netlabel(sock->sk, SMACK_CIPSO_SOCKET);
                        if (rc != 0)
                                printk(KERN_WARNING
                                        "Smack: \"%s\" netlbl error %d.\n",
                                        __func__, -rc);
                }
        } else
                return -EOPNOTSUPP;

        if (sock->sk->sk_family == PF_INET6)
                smk_ipv6_port_label(sock, NULL);

        return 0;
}

/**
 * smack_socket_post_create - finish socket setup
 * @sock: the socket
 * @family: protocol family
 * @type: unused
 * @protocol: unused
 * @kern: unused
 *
 * Sets the netlabel information on the socket
 *
 * Returns 0 on success, and error code otherwise
 */
static int smack_socket_post_create(struct socket *sock, int family,
                                    int type, int protocol, int kern)
{
        if (family != PF_INET || sock->sk == NULL)
                return 0;
        /*
         * Set the outbound netlbl.
         */
        return smack_netlabel(sock->sk, SMACK_CIPSO_SOCKET);
}

/**
 * smack_socket_bind - record port binding information.
 * @sock: the socket
 * @address: the port address
 * @addrlen: size of the address
 *
 * Records the label bound to a port.
 *
 * Returns 0
 */
static int smack_socket_bind(struct socket *sock, struct sockaddr *address,
                                int addrlen)
{
        if (sock->sk != NULL && sock->sk->sk_family == PF_INET6)
                smk_ipv6_port_label(sock, address);

        return 0;
}

/**
 * smack_socket_connect - connect access check
 * @sock: the socket
 * @sap: the other end
 * @addrlen: size of sap
 *
 * Verifies that a connection may be possible
 *
 * Returns 0 on success, and error code otherwise
 */
static int smack_socket_connect(struct socket *sock, struct sockaddr *sap,
                                int addrlen)
{
        int rc = 0;

        if (sock->sk == NULL)
                return 0;

        switch (sock->sk->sk_family) {
        case PF_INET:
                if (addrlen < sizeof(struct sockaddr_in))
                        return -EINVAL;
                rc = smack_netlabel_send(sock->sk, (struct sockaddr_in *)sap);
                break;
        case PF_INET6:
                if (addrlen < sizeof(struct sockaddr_in6))
                        return -EINVAL;
                rc = smk_ipv6_port_check(sock->sk, (struct sockaddr_in6 *)sap,
                                                SMK_CONNECTING);
                break;
        }
        return rc;
}

/**
 * smack_flags_to_may - convert S_ to MAY_ values
 * @flags: the S_ value
 *
 * Returns the equivalent MAY_ value
 */
static int smack_flags_to_may(int flags)
{
        int may = 0;

        if (flags & S_IRUGO)
                may |= MAY_READ;
        if (flags & S_IWUGO)
                may |= MAY_WRITE;
        if (flags & S_IXUGO)
                may |= MAY_EXEC;

        return may;
}

/**
 * smack_msg_msg_alloc_security - Set the security blob for msg_msg
 * @msg: the object
 *
 * Returns 0
 */
static int smack_msg_msg_alloc_security(struct msg_msg *msg)
{
        struct smack_known *skp = smk_of_current();

        msg->security = skp->smk_known;
        return 0;
}

/**
 * smack_msg_msg_free_security - Clear the security blob for msg_msg
 * @msg: the object
 *
 * Clears the blob pointer
 */
static void smack_msg_msg_free_security(struct msg_msg *msg)
{
        msg->security = NULL;
}

/**
 * smack_of_shm - the smack pointer for the shm
 * @shp: the object
 *
 * Returns a pointer to the smack value
 */
static char *smack_of_shm(struct shmid_kernel *shp)
{
        return (char *)shp->shm_perm.security;
}

/**
 * smack_shm_alloc_security - Set the security blob for shm
 * @shp: the object
 *
 * Returns 0
 */
static int smack_shm_alloc_security(struct shmid_kernel *shp)
{
        struct kern_ipc_perm *isp = &shp->shm_perm;
        struct smack_known *skp = smk_of_current();

        isp->security = skp->smk_known;
        return 0;
}

/**
 * smack_shm_free_security - Clear the security blob for shm
 * @shp: the object
 *
 * Clears the blob pointer
 */
static void smack_shm_free_security(struct shmid_kernel *shp)
{
        struct kern_ipc_perm *isp = &shp->shm_perm;

        isp->security = NULL;
}

/**
 * smk_curacc_shm : check if current has access on shm
 * @shp : the object
 * @access : access requested
 *
 * Returns 0 if current has the requested access, error code otherwise
 */
static int smk_curacc_shm(struct shmid_kernel *shp, int access)
{
        char *ssp = smack_of_shm(shp);
        struct smk_audit_info ad;

#ifdef CONFIG_AUDIT
        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_IPC);
        ad.a.u.ipc_id = shp->shm_perm.id;
#endif
        return smk_curacc(ssp, access, &ad);
}

/**
 * smack_shm_associate - Smack access check for shm
 * @shp: the object
 * @shmflg: access requested
 *
 * Returns 0 if current has the requested access, error code otherwise
 */
static int smack_shm_associate(struct shmid_kernel *shp, int shmflg)
{
        int may;

        may = smack_flags_to_may(shmflg);
        return smk_curacc_shm(shp, may);
}

/**
 * smack_shm_shmctl - Smack access check for shm
 * @shp: the object
 * @cmd: what it wants to do
 *
 * Returns 0 if current has the requested access, error code otherwise
 */
static int smack_shm_shmctl(struct shmid_kernel *shp, int cmd)
{
        int may;

        switch (cmd) {
        case IPC_STAT:
        case SHM_STAT:
                may = MAY_READ;
                break;
        case IPC_SET:
        case SHM_LOCK:
        case SHM_UNLOCK:
        case IPC_RMID:
                may = MAY_READWRITE;
                break;
        case IPC_INFO:
        case SHM_INFO:
                /*
                 * System level information.
                 */
                return 0;
        default:
                return -EINVAL;
        }
        return smk_curacc_shm(shp, may);
}

/**
 * smack_shm_shmat - Smack access for shmat
 * @shp: the object
 * @shmaddr: unused
 * @shmflg: access requested
 *
 * Returns 0 if current has the requested access, error code otherwise
 */
static int smack_shm_shmat(struct shmid_kernel *shp, char __user *shmaddr,
                           int shmflg)
{
        int may;

        may = smack_flags_to_may(shmflg);
        return smk_curacc_shm(shp, may);
}

/**
 * smack_of_sem - the smack pointer for the sem
 * @sma: the object
 *
 * Returns a pointer to the smack value
 */
static char *smack_of_sem(struct sem_array *sma)
{
        return (char *)sma->sem_perm.security;
}

/**
 * smack_sem_alloc_security - Set the security blob for sem
 * @sma: the object
 *
 * Returns 0
 */
static int smack_sem_alloc_security(struct sem_array *sma)
{
        struct kern_ipc_perm *isp = &sma->sem_perm;
        struct smack_known *skp = smk_of_current();

        isp->security = skp->smk_known;
        return 0;
}

/**
 * smack_sem_free_security - Clear the security blob for sem
 * @sma: the object
 *
 * Clears the blob pointer
 */
static void smack_sem_free_security(struct sem_array *sma)
{
        struct kern_ipc_perm *isp = &sma->sem_perm;

        isp->security = NULL;
}

/**
 * smk_curacc_sem : check if current has access on sem
 * @sma : the object
 * @access : access requested
 *
 * Returns 0 if current has the requested access, error code otherwise
 */
static int smk_curacc_sem(struct sem_array *sma, int access)
{
        char *ssp = smack_of_sem(sma);
        struct smk_audit_info ad;

#ifdef CONFIG_AUDIT
        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_IPC);
        ad.a.u.ipc_id = sma->sem_perm.id;
#endif
        return smk_curacc(ssp, access, &ad);
}

/**
 * smack_sem_associate - Smack access check for sem
 * @sma: the object
 * @semflg: access requested
 *
 * Returns 0 if current has the requested access, error code otherwise
 */
static int smack_sem_associate(struct sem_array *sma, int semflg)
{
        int may;

        may = smack_flags_to_may(semflg);
        return smk_curacc_sem(sma, may);
}

/**
 * smack_sem_shmctl - Smack access check for sem
 * @sma: the object
 * @cmd: what it wants to do
 *
 * Returns 0 if current has the requested access, error code otherwise
 */
static int smack_sem_semctl(struct sem_array *sma, int cmd)
{
        int may;

        switch (cmd) {
        case GETPID:
        case GETNCNT:
        case GETZCNT:
        case GETVAL:
        case GETALL:
        case IPC_STAT:
        case SEM_STAT:
                may = MAY_READ;
                break;
        case SETVAL:
        case SETALL:
        case IPC_RMID:
        case IPC_SET:
                may = MAY_READWRITE;
                break;
        case IPC_INFO:
        case SEM_INFO:
                /*
                 * System level information
                 */
                return 0;
        default:
                return -EINVAL;
        }

        return smk_curacc_sem(sma, may);
}

/**
 * smack_sem_semop - Smack checks of semaphore operations
 * @sma: the object
 * @sops: unused
 * @nsops: unused
 * @alter: unused
 *
 * Treated as read and write in all cases.
 *
 * Returns 0 if access is allowed, error code otherwise
 */
static int smack_sem_semop(struct sem_array *sma, struct sembuf *sops,
                           unsigned nsops, int alter)
{
        return smk_curacc_sem(sma, MAY_READWRITE);
}

/**
 * smack_msg_alloc_security - Set the security blob for msg
 * @msq: the object
 *
 * Returns 0
 */
static int smack_msg_queue_alloc_security(struct msg_queue *msq)
{
        struct kern_ipc_perm *kisp = &msq->q_perm;
        struct smack_known *skp = smk_of_current();

        kisp->security = skp->smk_known;
        return 0;
}

/**
 * smack_msg_free_security - Clear the security blob for msg
 * @msq: the object
 *
 * Clears the blob pointer
 */
static void smack_msg_queue_free_security(struct msg_queue *msq)
{
        struct kern_ipc_perm *kisp = &msq->q_perm;

        kisp->security = NULL;
}

/**
 * smack_of_msq - the smack pointer for the msq
 * @msq: the object
 *
 * Returns a pointer to the smack value
 */
static char *smack_of_msq(struct msg_queue *msq)
{
        return (char *)msq->q_perm.security;
}

/**
 * smk_curacc_msq : helper to check if current has access on msq
 * @msq : the msq
 * @access : access requested
 *
 * return 0 if current has access, error otherwise
 */
static int smk_curacc_msq(struct msg_queue *msq, int access)
{
        char *msp = smack_of_msq(msq);
        struct smk_audit_info ad;

#ifdef CONFIG_AUDIT
        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_IPC);
        ad.a.u.ipc_id = msq->q_perm.id;
#endif
        return smk_curacc(msp, access, &ad);
}

/**
 * smack_msg_queue_associate - Smack access check for msg_queue
 * @msq: the object
 * @msqflg: access requested
 *
 * Returns 0 if current has the requested access, error code otherwise
 */
static int smack_msg_queue_associate(struct msg_queue *msq, int msqflg)
{
        int may;

        may = smack_flags_to_may(msqflg);
        return smk_curacc_msq(msq, may);
}

/**
 * smack_msg_queue_msgctl - Smack access check for msg_queue
 * @msq: the object
 * @cmd: what it wants to do
 *
 * Returns 0 if current has the requested access, error code otherwise
 */
static int smack_msg_queue_msgctl(struct msg_queue *msq, int cmd)
{
        int may;

        switch (cmd) {
        case IPC_STAT:
        case MSG_STAT:
                may = MAY_READ;
                break;
        case IPC_SET:
        case IPC_RMID:
                may = MAY_READWRITE;
                break;
        case IPC_INFO:
        case MSG_INFO:
                /*
                 * System level information
                 */
                return 0;
        default:
                return -EINVAL;
        }

        return smk_curacc_msq(msq, may);
}

/**
 * smack_msg_queue_msgsnd - Smack access check for msg_queue
 * @msq: the object
 * @msg: unused
 * @msqflg: access requested
 *
 * Returns 0 if current has the requested access, error code otherwise
 */
static int smack_msg_queue_msgsnd(struct msg_queue *msq, struct msg_msg *msg,
                                  int msqflg)
{
        int may;

        may = smack_flags_to_may(msqflg);
        return smk_curacc_msq(msq, may);
}

/**
 * smack_msg_queue_msgsnd - Smack access check for msg_queue
 * @msq: the object
 * @msg: unused
 * @target: unused
 * @type: unused
 * @mode: unused
 *
 * Returns 0 if current has read and write access, error code otherwise
 */
static int smack_msg_queue_msgrcv(struct msg_queue *msq, struct msg_msg *msg,
                        struct task_struct *target, long type, int mode)
{
        return smk_curacc_msq(msq, MAY_READWRITE);
}

/**
 * smack_ipc_permission - Smack access for ipc_permission()
 * @ipp: the object permissions
 * @flag: access requested
 *
 * Returns 0 if current has read and write access, error code otherwise
 */
static int smack_ipc_permission(struct kern_ipc_perm *ipp, short flag)
{
        char *isp = ipp->security;
        int may = smack_flags_to_may(flag);
        struct smk_audit_info ad;

#ifdef CONFIG_AUDIT
        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_IPC);
        ad.a.u.ipc_id = ipp->id;
#endif
        return smk_curacc(isp, may, &ad);
}

/**
 * smack_ipc_getsecid - Extract smack security id
 * @ipp: the object permissions
 * @secid: where result will be saved
 */
static void smack_ipc_getsecid(struct kern_ipc_perm *ipp, u32 *secid)
{
        char *smack = ipp->security;

        *secid = smack_to_secid(smack);
}

/**
 * smack_d_instantiate - Make sure the blob is correct on an inode
 * @opt_dentry: dentry where inode will be attached
 * @inode: the object
 *
 * Set the inode's security blob if it hasn't been done already.
 */
static void smack_d_instantiate(struct dentry *opt_dentry, struct inode *inode)
{
        struct super_block *sbp;
        struct superblock_smack *sbsp;
        struct inode_smack *isp;
        struct smack_known *skp;
        struct smack_known *ckp = smk_of_current();
        char *final;
        char trattr[TRANS_TRUE_SIZE];
        int transflag = 0;
        int rc;
        struct dentry *dp;

        if (inode == NULL)
                return;

        isp = inode->i_security;

        mutex_lock(&isp->smk_lock);
        /*
         * If the inode is already instantiated
         * take the quick way out
         */
        if (isp->smk_flags & SMK_INODE_INSTANT)
                goto unlockandout;

        sbp = inode->i_sb;
        sbsp = sbp->s_security;
        /*
         * We're going to use the superblock default label
         * if there's no label on the file.
         */
        final = sbsp->smk_default;

        /*
         * If this is the root inode the superblock
         * may be in the process of initialization.
         * If that is the case use the root value out
         * of the superblock.
         */
        if (opt_dentry->d_parent == opt_dentry) {
                if (sbp->s_magic == CGROUP_SUPER_MAGIC) {
                        /*
                         * The cgroup filesystem is never mounted,
                         * so there's no opportunity to set the mount
                         * options.
                         */
                        sbsp->smk_root = smack_known_star.smk_known;
                        sbsp->smk_default = smack_known_star.smk_known;
                }
                isp->smk_inode = sbsp->smk_root;
                isp->smk_flags |= SMK_INODE_INSTANT;
                goto unlockandout;
        }

        /*
         * This is pretty hackish.
         * Casey says that we shouldn't have to do
         * file system specific code, but it does help
         * with keeping it simple.
         */
        switch (sbp->s_magic) {
        case SMACK_MAGIC:
        case PIPEFS_MAGIC:
        case SOCKFS_MAGIC:
        case CGROUP_SUPER_MAGIC:
                /*
                 * Casey says that it's a little embarrassing
                 * that the smack file system doesn't do
                 * extended attributes.
                 *
                 * Casey says pipes are easy (?)
                 *
                 * Socket access is controlled by the socket
                 * structures associated with the task involved.
                 *
                 * Cgroupfs is special
                 */
                final = smack_known_star.smk_known;
                break;
        case DEVPTS_SUPER_MAGIC:
                /*
                 * devpts seems content with the label of the task.
                 * Programs that change smack have to treat the
                 * pty with respect.
                 */
                final = ckp->smk_known;
                break;
        case PROC_SUPER_MAGIC:
                /*
                 * Casey says procfs appears not to care.
                 * The superblock default suffices.
                 */
                break;
        case TMPFS_MAGIC:
                /*
                 * Device labels should come from the filesystem,
                 * but watch out, because they're volitile,
                 * getting recreated on every reboot.
                 */
                final = smack_known_star.smk_known;
                /*
                 * No break.
                 *
                 * If a smack value has been set we want to use it,
                 * but since tmpfs isn't giving us the opportunity
                 * to set mount options simulate setting the
                 * superblock default.
                 */
        default:
                /*
                 * This isn't an understood special case.
                 * Get the value from the xattr.
                 */

                /*
                 * UNIX domain sockets use lower level socket data.
                 */
                if (S_ISSOCK(inode->i_mode)) {
                        final = smack_known_star.smk_known;
                        break;
                }
                /*
                 * No xattr support means, alas, no SMACK label.
                 * Use the aforeapplied default.
                 * It would be curious if the label of the task
                 * does not match that assigned.
                 */
                if (inode->i_op->getxattr == NULL)
                        break;
                /*
                 * Get the dentry for xattr.
                 */
                dp = dget(opt_dentry);
                skp = smk_fetch(XATTR_NAME_SMACK, inode, dp);
                if (skp != NULL)
                        final = skp->smk_known;

                /*
                 * Transmuting directory
                 */
                if (S_ISDIR(inode->i_mode)) {
                        /*
                         * If this is a new directory and the label was
                         * transmuted when the inode was initialized
                         * set the transmute attribute on the directory
                         * and mark the inode.
                         *
                         * If there is a transmute attribute on the
                         * directory mark the inode.
                         */
                        if (isp->smk_flags & SMK_INODE_CHANGED) {
                                isp->smk_flags &= ~SMK_INODE_CHANGED;
                                rc = inode->i_op->setxattr(dp,
                                        XATTR_NAME_SMACKTRANSMUTE,
                                        TRANS_TRUE, TRANS_TRUE_SIZE,
                                        0);
                        } else {
                                rc = inode->i_op->getxattr(dp,
                                        XATTR_NAME_SMACKTRANSMUTE, trattr,
                                        TRANS_TRUE_SIZE);
                                if (rc >= 0 && strncmp(trattr, TRANS_TRUE,
                                                       TRANS_TRUE_SIZE) != 0)
                                        rc = -EINVAL;
                        }
                        if (rc >= 0)
                                transflag = SMK_INODE_TRANSMUTE;
                }
                /*
                 * Don't let the exec or mmap label be "*" or "@".
                 */
                skp = smk_fetch(XATTR_NAME_SMACKEXEC, inode, dp);
                if (skp == &smack_known_star || skp == &smack_known_web)
                        skp = NULL;
                isp->smk_task = skp;
                skp = smk_fetch(XATTR_NAME_SMACKMMAP, inode, dp);
                if (skp == &smack_known_star || skp == &smack_known_web)
                        skp = NULL;
                isp->smk_mmap = skp;

                dput(dp);
                break;
        }

        if (final == NULL)
                isp->smk_inode = ckp->smk_known;
        else
                isp->smk_inode = final;

        isp->smk_flags |= (SMK_INODE_INSTANT | transflag);

unlockandout:
        mutex_unlock(&isp->smk_lock);
        return;
}

/**
 * smack_getprocattr - Smack process attribute access
 * @p: the object task
 * @name: the name of the attribute in /proc/.../attr
 * @value: where to put the result
 *
 * Places a copy of the task Smack into value
 *
 * Returns the length of the smack label or an error code
 */
static int smack_getprocattr(struct task_struct *p, char *name, char **value)
{
        struct smack_known *skp = smk_of_task(task_security(p));
        char *cp;
        int slen;

        if (strcmp(name, "current") != 0)
                return -EINVAL;

        cp = kstrdup(skp->smk_known, GFP_KERNEL);
        if (cp == NULL)
                return -ENOMEM;

        slen = strlen(cp);
        *value = cp;
        return slen;
}

/**
 * smack_setprocattr - Smack process attribute setting
 * @p: the object task
 * @name: the name of the attribute in /proc/.../attr
 * @value: the value to set
 * @size: the size of the value
 *
 * Sets the Smack value of the task. Only setting self
 * is permitted and only with privilege
 *
 * Returns the length of the smack label or an error code
 */
static int smack_setprocattr(struct task_struct *p, char *name,
                             void *value, size_t size)
{
        struct task_smack *tsp;
        struct cred *new;
        struct smack_known *skp;

        /*
         * Changing another process' Smack value is too dangerous
         * and supports no sane use case.
         */
        if (p != current)
                return -EPERM;

        if (!smack_privileged(CAP_MAC_ADMIN))
                return -EPERM;

        if (value == NULL || size == 0 || size >= SMK_LONGLABEL)
                return -EINVAL;

        if (strcmp(name, "current") != 0)
                return -EINVAL;

        skp = smk_import_entry(value, size);
        if (skp == NULL)
                return -EINVAL;

        /*
         * No process is ever allowed the web ("@") label.
         */
        if (skp == &smack_known_web)
                return -EPERM;

        new = prepare_creds();
        if (new == NULL)
                return -ENOMEM;

        tsp = new->security;
        tsp->smk_task = skp;

        commit_creds(new);
        return size;
}

/**
 * smack_unix_stream_connect - Smack access on UDS
 * @sock: one sock
 * @other: the other sock
 * @newsk: unused
 *
 * Return 0 if a subject with the smack of sock could access
 * an object with the smack of other, otherwise an error code
 */
static int smack_unix_stream_connect(struct sock *sock,
                                     struct sock *other, struct sock *newsk)
{
        struct smack_known *skp;
        struct socket_smack *ssp = sock->sk_security;
        struct socket_smack *osp = other->sk_security;
        struct socket_smack *nsp = newsk->sk_security;
        struct smk_audit_info ad;
        int rc = 0;

#ifdef CONFIG_AUDIT
        struct lsm_network_audit net;

        smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net);
        smk_ad_setfield_u_net_sk(&ad, other);
#endif

        if (!smack_privileged(CAP_MAC_OVERRIDE)) {
                skp = ssp->smk_out;
                rc = smk_access(skp, osp->smk_in, MAY_WRITE, &ad);
        }

        /*
         * Cross reference the peer labels for SO_PEERSEC.
         */
        if (rc == 0) {
                nsp->smk_packet = ssp->smk_out->smk_known;
                ssp->smk_packet = osp->smk_out->smk_known;
        }

        return rc;
}

/**
 * smack_unix_may_send - Smack access on UDS
 * @sock: one socket
 * @other: the other socket
 *
 * Return 0 if a subject with the smack of sock could access
 * an object with the smack of other, otherwise an error code
 */
static int smack_unix_may_send(struct socket *sock, struct socket *other)
{
        struct socket_smack *ssp = sock->sk->sk_security;
        struct socket_smack *osp = other->sk->sk_security;
        struct smack_known *skp;
        struct smk_audit_info ad;

#ifdef CONFIG_AUDIT
        struct lsm_network_audit net;

        smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net);
        smk_ad_setfield_u_net_sk(&ad, other->sk);
#endif

        if (smack_privileged(CAP_MAC_OVERRIDE))
                return 0;

        skp = ssp->smk_out;
        return smk_access(skp, osp->smk_in, MAY_WRITE, &ad);
}

/**
 * smack_socket_sendmsg - Smack check based on destination host
 * @sock: the socket
 * @msg: the message
 * @size: the size of the message
 *
 * Return 0 if the current subject can write to the destination host.
 * For IPv4 this is only a question if the destination is a single label host.
 * For IPv6 this is a check against the label of the port.
 */
static int smack_socket_sendmsg(struct socket *sock, struct msghdr *msg,
                                int size)
{
        struct sockaddr_in *sip = (struct sockaddr_in *) msg->msg_name;
        struct sockaddr_in6 *sap = (struct sockaddr_in6 *) msg->msg_name;
        int rc = 0;

        /*
         * Perfectly reasonable for this to be NULL
         */
        if (sip == NULL)
                return 0;

        switch (sip->sin_family) {
        case AF_INET:
                rc = smack_netlabel_send(sock->sk, sip);
                break;
        case AF_INET6:
                rc = smk_ipv6_port_check(sock->sk, sap, SMK_SENDING);
                break;
        }
        return rc;
}

/**
 * smack_from_secattr - Convert a netlabel attr.mls.lvl/attr.mls.cat pair to smack
 * @sap: netlabel secattr
 * @ssp: socket security information
 *
 * Returns a pointer to a Smack label entry found on the label list.
 */
static struct smack_known *smack_from_secattr(struct netlbl_lsm_secattr *sap,
                                                struct socket_smack *ssp)
{
        struct smack_known *skp;
        int found = 0;
        int acat;
        int kcat;

        if ((sap->flags & NETLBL_SECATTR_MLS_LVL) != 0) {
                /*
                 * Looks like a CIPSO packet.
                 * If there are flags but no level netlabel isn't
                 * behaving the way we expect it to.
                 *
                 * Look it up in the label table
                 * Without guidance regarding the smack value
                 * for the packet fall back on the network
                 * ambient value.
                 */
                rcu_read_lock();
                list_for_each_entry(skp, &smack_known_list, list) {
                        if (sap->attr.mls.lvl != skp->smk_netlabel.attr.mls.lvl)
                                continue;
                        /*
                         * Compare the catsets. Use the netlbl APIs.
                         */
                        if ((sap->flags & NETLBL_SECATTR_MLS_CAT) == 0) {
                                if ((skp->smk_netlabel.flags &
                                     NETLBL_SECATTR_MLS_CAT) == 0)
                                        found = 1;
                                break;
                        }
                        for (acat = -1, kcat = -1; acat == kcat; ) {
                                acat = netlbl_secattr_catmap_walk(
                                        sap->attr.mls.cat, acat + 1);
                                kcat = netlbl_secattr_catmap_walk(
                                        skp->smk_netlabel.attr.mls.cat,
                                        kcat + 1);
                                if (acat < 0 || kcat < 0)
                                        break;
                        }
                        if (acat == kcat) {
                                found = 1;
                                break;
                        }
                }
                rcu_read_unlock();

                if (found)
                        return skp;

                if (ssp != NULL && ssp->smk_in == smack_known_star.smk_known)
                        return &smack_known_web;
                return &smack_known_star;
        }
        if ((sap->flags & NETLBL_SECATTR_SECID) != 0) {
                /*
                 * Looks like a fallback, which gives us a secid.
                 */
                skp = smack_from_secid(sap->attr.secid);
                /*
                 * This has got to be a bug because it is
                 * impossible to specify a fallback without
                 * specifying the label, which will ensure
                 * it has a secid, and the only way to get a
                 * secid is from a fallback.
                 */
                BUG_ON(skp == NULL);
                return skp;
        }
        /*
         * Without guidance regarding the smack value
         * for the packet fall back on the network
         * ambient value.
         */
        return smack_net_ambient;
}

static int smk_skb_to_addr_ipv6(struct sk_buff *skb, struct sockaddr_in6 *sip)
{
        u8 nexthdr;
        int offset;
        int proto = -EINVAL;
        struct ipv6hdr _ipv6h;
        struct ipv6hdr *ip6;
        __be16 frag_off;
        struct tcphdr _tcph, *th;
        struct udphdr _udph, *uh;
        struct dccp_hdr _dccph, *dh;

        sip->sin6_port = 0;

        offset = skb_network_offset(skb);
        ip6 = skb_header_pointer(skb, offset, sizeof(_ipv6h), &_ipv6h);
        if (ip6 == NULL)
                return -EINVAL;
        sip->sin6_addr = ip6->saddr;

        nexthdr = ip6->nexthdr;
        offset += sizeof(_ipv6h);
        offset = ipv6_skip_exthdr(skb, offset, &nexthdr, &frag_off);
        if (offset < 0)
                return -EINVAL;

        proto = nexthdr;
        switch (proto) {
        case IPPROTO_TCP:
                th = skb_header_pointer(skb, offset, sizeof(_tcph), &_tcph);
                if (th != NULL)
                        sip->sin6_port = th->source;
                break;
        case IPPROTO_UDP:
                uh = skb_header_pointer(skb, offset, sizeof(_udph), &_udph);
                if (uh != NULL)
                        sip->sin6_port = uh->source;
                break;
        case IPPROTO_DCCP:
                dh = skb_header_pointer(skb, offset, sizeof(_dccph), &_dccph);
                if (dh != NULL)
                        sip->sin6_port = dh->dccph_sport;
                break;
        }
        return proto;
}

/**
 * smack_socket_sock_rcv_skb - Smack packet delivery access check
 * @sk: socket
 * @skb: packet
 *
 * Returns 0 if the packet should be delivered, an error code otherwise
 */
static int smack_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb)
{
        struct netlbl_lsm_secattr secattr;
        struct socket_smack *ssp = sk->sk_security;
        struct smack_known *skp;
        struct sockaddr_in6 sadd;
        int rc = 0;
        struct smk_audit_info ad;
#ifdef CONFIG_AUDIT
        struct lsm_network_audit net;
#endif
        switch (sk->sk_family) {
        case PF_INET:
                /*
                 * Translate what netlabel gave us.
                 */
                netlbl_secattr_init(&secattr);

                rc = netlbl_skbuff_getattr(skb, sk->sk_family, &secattr);
                if (rc == 0)
                        skp = smack_from_secattr(&secattr, ssp);
                else
                        skp = smack_net_ambient;

                netlbl_secattr_destroy(&secattr);

#ifdef CONFIG_AUDIT
                smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net);
                ad.a.u.net->family = sk->sk_family;
                ad.a.u.net->netif = skb->skb_iif;
                ipv4_skb_to_auditdata(skb, &ad.a, NULL);
#endif
                /*
                 * Receiving a packet requires that the other end
                 * be able to write here. Read access is not required.
                 * This is the simplist possible security model
                 * for networking.
                 */
                rc = smk_access(skp, ssp->smk_in, MAY_WRITE, &ad);
                if (rc != 0)
                        netlbl_skbuff_err(skb, rc, 0);
                break;
        case PF_INET6:
                rc = smk_skb_to_addr_ipv6(skb, &sadd);
                if (rc == IPPROTO_UDP || rc == IPPROTO_TCP)
                        rc = smk_ipv6_port_check(sk, &sadd, SMK_RECEIVING);
                else
                        rc = 0;
                break;
        }
        return rc;
}

/**
 * smack_socket_getpeersec_stream - pull in packet label
 * @sock: the socket
 * @optval: user's destination
 * @optlen: size thereof
 * @len: max thereof
 *
 * returns zero on success, an error code otherwise
 */
static int smack_socket_getpeersec_stream(struct socket *sock,
                                          char __user *optval,
                                          int __user *optlen, unsigned len)
{
        struct socket_smack *ssp;
        char *rcp = "";
        int slen = 1;
        int rc = 0;

        ssp = sock->sk->sk_security;
        if (ssp->smk_packet != NULL) {
                rcp = ssp->smk_packet;
                slen = strlen(rcp) + 1;
        }

        if (slen > len)
                rc = -ERANGE;
        else if (copy_to_user(optval, rcp, slen) != 0)
                rc = -EFAULT;

        if (put_user(slen, optlen) != 0)
                rc = -EFAULT;

        return rc;
}


/**
 * smack_socket_getpeersec_dgram - pull in packet label
 * @sock: the peer socket
 * @skb: packet data
 * @secid: pointer to where to put the secid of the packet
 *
 * Sets the netlabel socket state on sk from parent
 */
static int smack_socket_getpeersec_dgram(struct socket *sock,
                                         struct sk_buff *skb, u32 *secid)

{
        struct netlbl_lsm_secattr secattr;
        struct socket_smack *ssp = NULL;
        struct smack_known *skp;
        int family = PF_UNSPEC;
        u32 s = 0;      /* 0 is the invalid secid */
        int rc;

        if (skb != NULL) {
                if (skb->protocol == htons(ETH_P_IP))
                        family = PF_INET;
                else if (skb->protocol == htons(ETH_P_IPV6))
                        family = PF_INET6;
        }
        if (family == PF_UNSPEC && sock != NULL)
                family = sock->sk->sk_family;

        if (family == PF_UNIX) {
                ssp = sock->sk->sk_security;
                s = ssp->smk_out->smk_secid;
        } else if (family == PF_INET || family == PF_INET6) {
                /*
                 * Translate what netlabel gave us.
                 */
                if (sock != NULL && sock->sk != NULL)
                        ssp = sock->sk->sk_security;
                netlbl_secattr_init(&secattr);
                rc = netlbl_skbuff_getattr(skb, family, &secattr);
                if (rc == 0) {
                        skp = smack_from_secattr(&secattr, ssp);
                        s = skp->smk_secid;
                }
                netlbl_secattr_destroy(&secattr);
        }
        *secid = s;
        if (s == 0)
                return -EINVAL;
        return 0;
}

/**
 * smack_sock_graft - Initialize a newly created socket with an existing sock
 * @sk: child sock
 * @parent: parent socket
 *
 * Set the smk_{in,out} state of an existing sock based on the process that
 * is creating the new socket.
 */
static void smack_sock_graft(struct sock *sk, struct socket *parent)
{
        struct socket_smack *ssp;
        struct smack_known *skp = smk_of_current();

        if (sk == NULL ||
            (sk->sk_family != PF_INET && sk->sk_family != PF_INET6))
                return;

        ssp = sk->sk_security;
        ssp->smk_in = skp->smk_known;
        ssp->smk_out = skp;
        /* cssp->smk_packet is already set in smack_inet_csk_clone() */
}

/**
 * smack_inet_conn_request - Smack access check on connect
 * @sk: socket involved
 * @skb: packet
 * @req: unused
 *
 * Returns 0 if a task with the packet label could write to
 * the socket, otherwise an error code
 */
static int smack_inet_conn_request(struct sock *sk, struct sk_buff *skb,
                                   struct request_sock *req)
{
        u16 family = sk->sk_family;
        struct smack_known *skp;
        struct socket_smack *ssp = sk->sk_security;
        struct netlbl_lsm_secattr secattr;
        struct sockaddr_in addr;
        struct iphdr *hdr;
        char *hsp;
        int rc;
        struct smk_audit_info ad;
#ifdef CONFIG_AUDIT
        struct lsm_network_audit net;
#endif

        if (family == PF_INET6) {
                /*
                 * Handle mapped IPv4 packets arriving
                 * via IPv6 sockets. Don't set up netlabel
                 * processing on IPv6.
                 */
                if (skb->protocol == htons(ETH_P_IP))
                        family = PF_INET;
                else
                        return 0;
        }

        netlbl_secattr_init(&secattr);
        rc = netlbl_skbuff_getattr(skb, family, &secattr);
        if (rc == 0)
                skp = smack_from_secattr(&secattr, ssp);
        else
                skp = &smack_known_huh;
        netlbl_secattr_destroy(&secattr);

#ifdef CONFIG_AUDIT
        smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net);
        ad.a.u.net->family = family;
        ad.a.u.net->netif = skb->skb_iif;
        ipv4_skb_to_auditdata(skb, &ad.a, NULL);
#endif
        /*
         * Receiving a packet requires that the other end be able to write
         * here. Read access is not required.
         */
        rc = smk_access(skp, ssp->smk_in, MAY_WRITE, &ad);
        if (rc != 0)
                return rc;

        /*
         * Save the peer's label in the request_sock so we can later setup
         * smk_packet in the child socket so that SO_PEERCRED can report it.
         */
        req->peer_secid = skp->smk_secid;

        /*
         * We need to decide if we want to label the incoming connection here
         * if we do we only need to label the request_sock and the stack will
         * propagate the wire-label to the sock when it is created.
         */
        hdr = ip_hdr(skb);
        addr.sin_addr.s_addr = hdr->saddr;
        rcu_read_lock();
        hsp = smack_host_label(&addr);
        rcu_read_unlock();

        if (hsp == NULL)
                rc = netlbl_req_setattr(req, &skp->smk_netlabel);
        else
                netlbl_req_delattr(req);

        return rc;
}

/**
 * smack_inet_csk_clone - Copy the connection information to the new socket
 * @sk: the new socket
 * @req: the connection's request_sock
 *
 * Transfer the connection's peer label to the newly created socket.
 */
static void smack_inet_csk_clone(struct sock *sk,
                                 const struct request_sock *req)
{
        struct socket_smack *ssp = sk->sk_security;
        struct smack_known *skp;

        if (req->peer_secid != 0) {
                skp = smack_from_secid(req->peer_secid);
                ssp->smk_packet = skp->smk_known;
        } else
                ssp->smk_packet = NULL;
}

/*
 * Key management security hooks
 *
 * Casey has not tested key support very heavily.
 * The permission check is most likely too restrictive.
 * If you care about keys please have a look.
 */
#ifdef CONFIG_KEYS

/**
 * smack_key_alloc - Set the key security blob
 * @key: object
 * @cred: the credentials to use
 * @flags: unused
 *
 * No allocation required
 *
 * Returns 0
 */
static int smack_key_alloc(struct key *key, const struct cred *cred,
                           unsigned long flags)
{
        struct smack_known *skp = smk_of_task(cred->security);

        key->security = skp->smk_known;
        return 0;
}

/**
 * smack_key_free - Clear the key security blob
 * @key: the object
 *
 * Clear the blob pointer
 */
static void smack_key_free(struct key *key)
{
        key->security = NULL;
}

/*
 * smack_key_permission - Smack access on a key
 * @key_ref: gets to the object
 * @cred: the credentials to use
 * @perm: unused
 *
 * Return 0 if the task has read and write to the object,
 * an error code otherwise
 */
static int smack_key_permission(key_ref_t key_ref,
                                const struct cred *cred, unsigned perm)
{
        struct key *keyp;
        struct smk_audit_info ad;
        struct smack_known *tkp = smk_of_task(cred->security);
        int request = 0;

        keyp = key_ref_to_ptr(key_ref);
        if (keyp == NULL)
                return -EINVAL;
        /*
         * If the key hasn't been initialized give it access so that
         * it may do so.
         */
        if (keyp->security == NULL)
                return 0;
        /*
         * This should not occur
         */
        if (tkp == NULL)
                return -EACCES;
#ifdef CONFIG_AUDIT
        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_KEY);
        ad.a.u.key_struct.key = keyp->serial;
        ad.a.u.key_struct.key_desc = keyp->description;
#endif
        if (perm & KEY_NEED_READ)
                request = MAY_READ;
        if (perm & (KEY_NEED_WRITE | KEY_NEED_LINK | KEY_NEED_SETATTR))
                request = MAY_WRITE;
        return smk_access(tkp, keyp->security, request, &ad);
}
#endif /* CONFIG_KEYS */

/*
 * Smack Audit hooks
 *
 * Audit requires a unique representation of each Smack specific
 * rule. This unique representation is used to distinguish the
 * object to be audited from remaining kernel objects and also
 * works as a glue between the audit hooks.
 *
 * Since repository entries are added but never deleted, we'll use
 * the smack_known label address related to the given audit rule as
 * the needed unique representation. This also better fits the smack
 * model where nearly everything is a label.
 */
#ifdef CONFIG_AUDIT

/**
 * smack_audit_rule_init - Initialize a smack audit rule
 * @field: audit rule fields given from user-space (audit.h)
 * @op: required testing operator (=, !=, >, <, ...)
 * @rulestr: smack label to be audited
 * @vrule: pointer to save our own audit rule representation
 *
 * Prepare to audit cases where (@field @op @rulestr) is true.
 * The label to be audited is created if necessay.
 */
static int smack_audit_rule_init(u32 field, u32 op, char *rulestr, void **vrule)
{
        char **rule = (char **)vrule;
        *rule = NULL;

        if (field != AUDIT_SUBJ_USER && field != AUDIT_OBJ_USER)
                return -EINVAL;

        if (op != Audit_equal && op != Audit_not_equal)
                return -EINVAL;

        *rule = smk_import(rulestr, 0);

        return 0;
}

/**
 * smack_audit_rule_known - Distinguish Smack audit rules
 * @krule: rule of interest, in Audit kernel representation format
 *
 * This is used to filter Smack rules from remaining Audit ones.
 * If it's proved that this rule belongs to us, the
 * audit_rule_match hook will be called to do the final judgement.
 */
static int smack_audit_rule_known(struct audit_krule *krule)
{
        struct audit_field *f;
        int i;

        for (i = 0; i < krule->field_count; i++) {
                f = &krule->fields[i];

                if (f->type == AUDIT_SUBJ_USER || f->type == AUDIT_OBJ_USER)
                        return 1;
        }

        return 0;
}

/**
 * smack_audit_rule_match - Audit given object ?
 * @secid: security id for identifying the object to test
 * @field: audit rule flags given from user-space
 * @op: required testing operator
 * @vrule: smack internal rule presentation
 * @actx: audit context associated with the check
 *
 * The core Audit hook. It's used to take the decision of
 * whether to audit or not to audit a given object.
 */
static int smack_audit_rule_match(u32 secid, u32 field, u32 op, void *vrule,
                                  struct audit_context *actx)
{
        struct smack_known *skp;
        char *rule = vrule;

        if (unlikely(!rule)) {
                WARN_ONCE(1, "Smack: missing rule\n");
                return -ENOENT;
        }

        if (field != AUDIT_SUBJ_USER && field != AUDIT_OBJ_USER)
                return 0;

        skp = smack_from_secid(secid);

        /*
         * No need to do string comparisons. If a match occurs,
         * both pointers will point to the same smack_known
         * label.
         */
        if (op == Audit_equal)
                return (rule == skp->smk_known);
        if (op == Audit_not_equal)
                return (rule != skp->smk_known);

        return 0;
}

/**
 * smack_audit_rule_free - free smack rule representation
 * @vrule: rule to be freed.
 *
 * No memory was allocated.
 */
static void smack_audit_rule_free(void *vrule)
{
        /* No-op */
}

#endif /* CONFIG_AUDIT */

/**
 * smack_ismaclabel - check if xattr @name references a smack MAC label
 * @name: Full xattr name to check.
 */
static int smack_ismaclabel(const char *name)
{
        return (strcmp(name, XATTR_SMACK_SUFFIX) == 0);
}


/**
 * smack_secid_to_secctx - return the smack label for a secid
 * @secid: incoming integer
 * @secdata: destination
 * @seclen: how long it is
 *
 * Exists for networking code.
 */
static int smack_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
{
        struct smack_known *skp = smack_from_secid(secid);

        if (secdata)
                *secdata = skp->smk_known;
        *seclen = strlen(skp->smk_known);
        return 0;
}

/**
 * smack_secctx_to_secid - return the secid for a smack label
 * @secdata: smack label
 * @seclen: how long result is
 * @secid: outgoing integer
 *
 * Exists for audit and networking code.
 */
static int smack_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid)
{
        *secid = smack_to_secid(secdata);
        return 0;
}

/**
 * smack_release_secctx - don't do anything.
 * @secdata: unused
 * @seclen: unused
 *
 * Exists to make sure nothing gets done, and properly
 */
static void smack_release_secctx(char *secdata, u32 seclen)
{
}

static int smack_inode_notifysecctx(struct inode *inode, void *ctx, u32 ctxlen)
{
        return smack_inode_setsecurity(inode, XATTR_SMACK_SUFFIX, ctx, ctxlen, 0);
}

static int smack_inode_setsecctx(struct dentry *dentry, void *ctx, u32 ctxlen)
{
        return __vfs_setxattr_noperm(dentry, XATTR_NAME_SMACK, ctx, ctxlen, 0);
}

static int smack_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen)
{
        int len = 0;
        len = smack_inode_getsecurity(inode, XATTR_SMACK_SUFFIX, ctx, true);

        if (len < 0)
                return len;
        *ctxlen = len;
        return 0;
}

struct security_operations smack_ops = {
        .name =                         "smack",

        .ptrace_access_check =          smack_ptrace_access_check,
        .ptrace_traceme =               smack_ptrace_traceme,
        .syslog =                       smack_syslog,

        .sb_alloc_security =            smack_sb_alloc_security,
        .sb_free_security =             smack_sb_free_security,
        .sb_copy_data =                 smack_sb_copy_data,
        .sb_kern_mount =                smack_sb_kern_mount,
        .sb_statfs =                    smack_sb_statfs,

        .bprm_set_creds =               smack_bprm_set_creds,
        .bprm_committing_creds =        smack_bprm_committing_creds,
        .bprm_secureexec =              smack_bprm_secureexec,

        .inode_alloc_security =         smack_inode_alloc_security,
        .inode_free_security =          smack_inode_free_security,
        .inode_init_security =          smack_inode_init_security,
        .inode_link =                   smack_inode_link,
        .inode_unlink =                 smack_inode_unlink,
        .inode_rmdir =                  smack_inode_rmdir,
        .inode_rename =                 smack_inode_rename,
        .inode_permission =             smack_inode_permission,
        .inode_setattr =                smack_inode_setattr,
        .inode_getattr =                smack_inode_getattr,
        .inode_setxattr =               smack_inode_setxattr,
        .inode_post_setxattr =          smack_inode_post_setxattr,
        .inode_getxattr =               smack_inode_getxattr,
        .inode_removexattr =            smack_inode_removexattr,
        .inode_getsecurity =            smack_inode_getsecurity,
        .inode_setsecurity =            smack_inode_setsecurity,
        .inode_listsecurity =           smack_inode_listsecurity,
        .inode_getsecid =               smack_inode_getsecid,

        .file_permission =              smack_file_permission,
        .file_alloc_security =          smack_file_alloc_security,
        .file_free_security =           smack_file_free_security,
        .file_ioctl =                   smack_file_ioctl,
        .file_lock =                    smack_file_lock,
        .file_fcntl =                   smack_file_fcntl,
        .mmap_file =                    smack_mmap_file,
        .mmap_addr =                    cap_mmap_addr,
        .file_set_fowner =              smack_file_set_fowner,
        .file_send_sigiotask =          smack_file_send_sigiotask,
        .file_receive =                 smack_file_receive,

        .file_open =                    smack_file_open,

        .cred_alloc_blank =             smack_cred_alloc_blank,
        .cred_free =                    smack_cred_free,
        .cred_prepare =                 smack_cred_prepare,
        .cred_transfer =                smack_cred_transfer,
        .kernel_act_as =                smack_kernel_act_as,
        .kernel_create_files_as =       smack_kernel_create_files_as,
        .task_setpgid =                 smack_task_setpgid,
        .task_getpgid =                 smack_task_getpgid,
        .task_getsid =                  smack_task_getsid,
        .task_getsecid =                smack_task_getsecid,
        .task_setnice =                 smack_task_setnice,
        .task_setioprio =               smack_task_setioprio,
        .task_getioprio =               smack_task_getioprio,
        .task_setscheduler =            smack_task_setscheduler,
        .task_getscheduler =            smack_task_getscheduler,
        .task_movememory =              smack_task_movememory,
        .task_kill =                    smack_task_kill,
        .task_wait =                    smack_task_wait,
        .task_to_inode =                smack_task_to_inode,

        .ipc_permission =               smack_ipc_permission,
        .ipc_getsecid =                 smack_ipc_getsecid,

        .msg_msg_alloc_security =       smack_msg_msg_alloc_security,
        .msg_msg_free_security =        smack_msg_msg_free_security,

        .msg_queue_alloc_security =     smack_msg_queue_alloc_security,
        .msg_queue_free_security =      smack_msg_queue_free_security,
        .msg_queue_associate =          smack_msg_queue_associate,
        .msg_queue_msgctl =             smack_msg_queue_msgctl,
        .msg_queue_msgsnd =             smack_msg_queue_msgsnd,
        .msg_queue_msgrcv =             smack_msg_queue_msgrcv,

        .shm_alloc_security =           smack_shm_alloc_security,
        .shm_free_security =            smack_shm_free_security,
        .shm_associate =                smack_shm_associate,
        .shm_shmctl =                   smack_shm_shmctl,
        .shm_shmat =                    smack_shm_shmat,

        .sem_alloc_security =           smack_sem_alloc_security,
        .sem_free_security =            smack_sem_free_security,
        .sem_associate =                smack_sem_associate,
        .sem_semctl =                   smack_sem_semctl,
        .sem_semop =                    smack_sem_semop,

        .d_instantiate =                smack_d_instantiate,

        .getprocattr =                  smack_getprocattr,
        .setprocattr =                  smack_setprocattr,

        .unix_stream_connect =          smack_unix_stream_connect,
        .unix_may_send =                smack_unix_may_send,

        .socket_post_create =           smack_socket_post_create,
        .socket_bind =                  smack_socket_bind,
        .socket_connect =               smack_socket_connect,
        .socket_sendmsg =               smack_socket_sendmsg,
        .socket_sock_rcv_skb =          smack_socket_sock_rcv_skb,
        .socket_getpeersec_stream =     smack_socket_getpeersec_stream,
        .socket_getpeersec_dgram =      smack_socket_getpeersec_dgram,
        .sk_alloc_security =            smack_sk_alloc_security,
        .sk_free_security =             smack_sk_free_security,
        .sock_graft =                   smack_sock_graft,
        .inet_conn_request =            smack_inet_conn_request,
        .inet_csk_clone =               smack_inet_csk_clone,

 /* key management security hooks */
#ifdef CONFIG_KEYS
        .key_alloc =                    smack_key_alloc,
        .key_free =                     smack_key_free,
        .key_permission =               smack_key_permission,
#endif /* CONFIG_KEYS */

 /* Audit hooks */
#ifdef CONFIG_AUDIT
        .audit_rule_init =              smack_audit_rule_init,
        .audit_rule_known =             smack_audit_rule_known,
        .audit_rule_match =             smack_audit_rule_match,
        .audit_rule_free =              smack_audit_rule_free,
#endif /* CONFIG_AUDIT */

        .ismaclabel =                   smack_ismaclabel,
        .secid_to_secctx =              smack_secid_to_secctx,
        .secctx_to_secid =              smack_secctx_to_secid,
        .release_secctx =               smack_release_secctx,
        .inode_notifysecctx =           smack_inode_notifysecctx,
        .inode_setsecctx =              smack_inode_setsecctx,
        .inode_getsecctx =              smack_inode_getsecctx,
};


static __init void init_smack_known_list(void)
{
        /*
         * Initialize rule list locks
         */
        mutex_init(&smack_known_huh.smk_rules_lock);
        mutex_init(&smack_known_hat.smk_rules_lock);
        mutex_init(&smack_known_floor.smk_rules_lock);
        mutex_init(&smack_known_star.smk_rules_lock);
        mutex_init(&smack_known_invalid.smk_rules_lock);
        mutex_init(&smack_known_web.smk_rules_lock);
        /*
         * Initialize rule lists
         */
        INIT_LIST_HEAD(&smack_known_huh.smk_rules);
        INIT_LIST_HEAD(&smack_known_hat.smk_rules);
        INIT_LIST_HEAD(&smack_known_star.smk_rules);
        INIT_LIST_HEAD(&smack_known_floor.smk_rules);
        INIT_LIST_HEAD(&smack_known_invalid.smk_rules);
        INIT_LIST_HEAD(&smack_known_web.smk_rules);
        /*
         * Create the known labels list
         */
        smk_insert_entry(&smack_known_huh);
        smk_insert_entry(&smack_known_hat);
        smk_insert_entry(&smack_known_star);
        smk_insert_entry(&smack_known_floor);
        smk_insert_entry(&smack_known_invalid);
        smk_insert_entry(&smack_known_web);
}

/**
 * smack_init - initialize the smack system
 *
 * Returns 0
 */
static __init int smack_init(void)
{
        struct cred *cred;
        struct task_smack *tsp;

        if (!security_module_enable(&smack_ops))
                return 0;

        tsp = new_task_smack(&smack_known_floor, &smack_known_floor,
                                GFP_KERNEL);
        if (tsp == NULL)
                return -ENOMEM;

        printk(KERN_INFO "Smack:  Initializing.\n");

        /*
         * Set the security state for the initial task.
         */
        cred = (struct cred *) current->cred;
        cred->security = tsp;

        /* initialize the smack_known_list */
        init_smack_known_list();

        /*
         * Register with LSM
         */
        if (register_security(&smack_ops))
                panic("smack: Unable to register with kernel.\n");

        return 0;
}

/*
 * Smack requires early initialization in order to label
 * all processes and objects when they are created.
 */
security_initcall(smack_init);