Smack: handle zero-length security labels without panic
[platform/adaptation/renesas_rcar/renesas_kernel.git] / security / smack / smack_lsm.c
index b86825b..7bd0363 100644 (file)
@@ -923,7 +923,7 @@ static int smack_inode_setxattr(struct dentry *dentry, const char *name,
                rc = -EPERM;
 
        if (rc == 0 && check_import) {
-               skp = smk_import_entry(value, size);
+               skp = size ? smk_import_entry(value, size) : NULL;
                if (skp == NULL || (check_star &&
                    (skp == &smack_known_star || skp == &smack_known_web)))
                        rc = -EINVAL;
@@ -1026,18 +1026,31 @@ static int smack_inode_removexattr(struct dentry *dentry, const char *name)
        } else
                rc = cap_inode_removexattr(dentry, name);
 
+       if (rc != 0)
+               return rc;
+
        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;
+       rc = smk_curacc(smk_of_inode(dentry->d_inode), MAY_WRITE, &ad);
+       if (rc != 0)
+               return rc;
+
+       isp = dentry->d_inode->i_security;
+       /*
+        * Don't do anything special for these.
+        *      XATTR_NAME_SMACKIPIN
+        *      XATTR_NAME_SMACKIPOUT
+        *      XATTR_NAME_SMACKEXEC
+        */
+       if (strcmp(name, XATTR_NAME_SMACK) == 0)
                isp->smk_task = NULL;
+       else if (strcmp(name, XATTR_NAME_SMACKMMAP) == 0)
                isp->smk_mmap = NULL;
-       }
+       else if (strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0)
+               isp->smk_flags &= ~SMK_INODE_TRANSMUTE;
 
-       return rc;
+       return 0;
 }
 
 /**
@@ -1082,7 +1095,7 @@ static int smack_inode_getsecurity(const struct inode *inode,
        ssp = sock->sk->sk_security;
 
        if (strcmp(name, XATTR_SMACK_IPIN) == 0)
-               isp = ssp->smk_in;
+               isp = ssp->smk_in->smk_known;
        else if (strcmp(name, XATTR_SMACK_IPOUT) == 0)
                isp = ssp->smk_out->smk_known;
        else
@@ -1109,13 +1122,12 @@ static int smack_inode_getsecurity(const struct inode *inode,
 static int smack_inode_listsecurity(struct inode *inode, char *buffer,
                                    size_t buffer_size)
 {
-       int len = strlen(XATTR_NAME_SMACK);
+       int len = sizeof(XATTR_NAME_SMACK);
 
-       if (buffer != NULL && len <= buffer_size) {
+       if (buffer != NULL && len <= buffer_size)
                memcpy(buffer, XATTR_NAME_SMACK, len);
-               return len;
-       }
-       return -EINVAL;
+
+       return len;
 }
 
 /**
@@ -1449,19 +1461,32 @@ static int smack_file_receive(struct file *file)
 /**
  * smack_file_open - Smack dentry open processing
  * @file: the object
- * @cred: unused
+ * @cred: task credential
  *
  * Set the security blob in the file structure.
+ * Allow the open only if the task has read access. There are
+ * many read operations (e.g. fstat) that you can do with an
+ * fd even if you have the file open write-only.
  *
  * Returns 0
  */
 static int smack_file_open(struct file *file, const struct cred *cred)
 {
+       struct task_smack *tsp = cred->security;
        struct inode_smack *isp = file_inode(file)->i_security;
+       struct smk_audit_info ad;
+       int rc;
 
-       file->f_security = isp->smk_inode;
+       if (smack_privileged(CAP_MAC_OVERRIDE))
+               return 0;
 
-       return 0;
+       smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
+       smk_ad_setfield_u_fs_path(&ad, file->f_path);
+       rc = smk_access(tsp->smk_task, isp->smk_inode, MAY_READ, &ad);
+       if (rc == 0)
+               file->f_security = isp->smk_inode;
+
+       return rc;
 }
 
 /*
@@ -1846,7 +1871,7 @@ static int smack_sk_alloc_security(struct sock *sk, int family, gfp_t gfp_flags)
        if (ssp == NULL)
                return -ENOMEM;
 
-       ssp->smk_in = skp->smk_known;
+       ssp->smk_in = skp;
        ssp->smk_out = skp;
        ssp->smk_packet = NULL;
 
@@ -2086,7 +2111,7 @@ static int smk_ipv6_port_check(struct sock *sk, struct sockaddr_in6 *address,
 
        if (act == SMK_RECEIVING) {
                skp = smack_net_ambient;
-               object = ssp->smk_in;
+               object = ssp->smk_in->smk_known;
        } else {
                skp = ssp->smk_out;
                object = smack_net_ambient->smk_known;
@@ -2116,9 +2141,9 @@ static int smk_ipv6_port_check(struct sock *sk, struct sockaddr_in6 *address,
        list_for_each_entry(spp, &smk_ipv6_port_list, list) {
                if (spp->smk_port != port)
                        continue;
-               object = spp->smk_in;
+               object = spp->smk_in->smk_known;
                if (act == SMK_CONNECTING)
-                       ssp->smk_packet = spp->smk_out->smk_known;
+                       ssp->smk_packet = spp->smk_out;
                break;
        }
 
@@ -2182,7 +2207,7 @@ static int smack_inode_setsecurity(struct inode *inode, const char *name,
        ssp = sock->sk->sk_security;
 
        if (strcmp(name, XATTR_SMACK_IPIN) == 0)
-               ssp->smk_in = skp->smk_known;
+               ssp->smk_in = skp;
        else if (strcmp(name, XATTR_SMACK_IPOUT) == 0) {
                ssp->smk_out = skp;
                if (sock->sk->sk_family == PF_INET) {
@@ -3047,30 +3072,34 @@ static int smack_unix_stream_connect(struct sock *sock,
                                     struct sock *other, struct sock *newsk)
 {
        struct smack_known *skp;
+       struct smack_known *okp;
        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);
+               okp = osp->smk_out;
+#ifdef CONFIG_AUDIT
+               smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net);
+               smk_ad_setfield_u_net_sk(&ad, other);
+#endif
+               rc = smk_access(skp, okp->smk_known, MAY_WRITE, &ad);
+               if (rc == 0)
+                       rc = smk_access(okp, okp->smk_known, MAY_WRITE, NULL);
        }
 
        /*
         * 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;
+               nsp->smk_packet = ssp->smk_out;
+               ssp->smk_packet = osp->smk_out;
        }
 
        return rc;
@@ -3102,7 +3131,7 @@ static int smack_unix_may_send(struct socket *sock, struct socket *other)
                return 0;
 
        skp = ssp->smk_out;
-       return smk_access(skp, osp->smk_in, MAY_WRITE, &ad);
+       return smk_access(skp, osp->smk_in->smk_known, MAY_WRITE, &ad);
 }
 
 /**
@@ -3197,7 +3226,7 @@ static struct smack_known *smack_from_secattr(struct netlbl_lsm_secattr *sap,
                if (found)
                        return skp;
 
-               if (ssp != NULL && ssp->smk_in == smack_known_star.smk_known)
+               if (ssp != NULL && ssp->smk_in == &smack_known_star)
                        return &smack_known_web;
                return &smack_known_star;
        }
@@ -3316,7 +3345,7 @@ static int smack_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb)
                 * This is the simplist possible security model
                 * for networking.
                 */
-               rc = smk_access(skp, ssp->smk_in, MAY_WRITE, &ad);
+               rc = smk_access(skp, ssp->smk_in->smk_known, MAY_WRITE, &ad);
                if (rc != 0)
                        netlbl_skbuff_err(skb, rc, 0);
                break;
@@ -3351,7 +3380,7 @@ static int smack_socket_getpeersec_stream(struct socket *sock,
 
        ssp = sock->sk->sk_security;
        if (ssp->smk_packet != NULL) {
-               rcp = ssp->smk_packet;
+               rcp = ssp->smk_packet->smk_known;
                slen = strlen(rcp) + 1;
        }
 
@@ -3436,7 +3465,7 @@ static void smack_sock_graft(struct sock *sk, struct socket *parent)
                return;
 
        ssp = sk->sk_security;
-       ssp->smk_in = skp->smk_known;
+       ssp->smk_in = skp;
        ssp->smk_out = skp;
        /* cssp->smk_packet is already set in smack_inet_csk_clone() */
 }
@@ -3496,7 +3525,7 @@ static int smack_inet_conn_request(struct sock *sk, struct sk_buff *skb,
         * 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);
+       rc = smk_access(skp, ssp->smk_in->smk_known, MAY_WRITE, &ad);
        if (rc != 0)
                return rc;
 
@@ -3540,7 +3569,7 @@ static void smack_inet_csk_clone(struct sock *sk,
 
        if (req->peer_secid != 0) {
                skp = smack_from_secid(req->peer_secid);
-               ssp->smk_packet = skp->smk_known;
+               ssp->smk_packet = skp;
        } else
                ssp->smk_packet = NULL;
 }