ima: provide support for arbitrary hash algorithms

In preparation of supporting more hash algorithms with larger hash sizes
needed for signature verification, this patch replaces the 20 byte sized
digest, with a more flexible structure.  The new structure includes the
hash algorithm, digest size, and digest.

Changelog:
- recalculate filedata hash for the measurement list, if the signature
  hash digest size is greater than 20 bytes.
- use generic HASH_ALGO_
- make ima_calc_file_hash static
- scripts lindent and checkpatch fixes

Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>

diff --git a/crypto/asymmetric_keys/x509_parser.h b/crypto/asymmetric_keys/x509_parser.h
index 04c81bd..87d9cc2 100644 (file)
--- a/crypto/asymmetric_keys/x509_parser.h
+++ b/crypto/asymmetric_keys/x509_parser.h
@@ -21,8 +21,6 @@ struct x509_certificate {
        char            *authority;             /* Authority key fingerprint as hex */
        struct tm       valid_from;
        struct tm       valid_to;
-       enum pkey_algo  pkey_algo : 8;          /* Public key algorithm */
-       enum hash_algo sig_hash_algo : 8;       /* Signature hash algorithm */
        const void      *tbs;                   /* Signed data */
        unsigned        tbs_size;               /* Size of signed data */
        unsigned        raw_sig_size;           /* Size of sigature */

diff --git a/crypto/asymmetric_keys/x509_public_key.c b/crypto/asymmetric_keys/x509_public_key.c
index 0a6bfad..f83300b 100644 (file)
--- a/crypto/asymmetric_keys/x509_public_key.c
+++ b/crypto/asymmetric_keys/x509_public_key.c
@@ -213,7 +213,8 @@ static int x509_key_preparse(struct key_preparsed_payload *prep)
                 cert->valid_to.tm_year + 1900, cert->valid_to.tm_mon + 1,
                 cert->valid_to.tm_mday, cert->valid_to.tm_hour,
                 cert->valid_to.tm_min,  cert->valid_to.tm_sec);
-       pr_devel("Cert Signature: %s\n",
+       pr_devel("Cert Signature: %s + %s\n",
+                pkey_algo_name[cert->sig.pkey_algo],
                 hash_algo_name[cert->sig.pkey_hash_algo]);
 
        if (!cert->fingerprint) {

diff --git a/security/integrity/ima/Kconfig b/security/integrity/ima/Kconfig
index 39196ab..e6628e7 100644 (file)
--- a/security/integrity/ima/Kconfig
+++ b/security/integrity/ima/Kconfig
@@ -9,6 +9,7 @@ config IMA
        select CRYPTO_HMAC
        select CRYPTO_MD5
        select CRYPTO_SHA1
+       select CRYPTO_HASH_INFO
        select TCG_TPM if HAS_IOMEM && !UML
        select TCG_TIS if TCG_TPM && X86
        select TCG_IBMVTPM if TCG_TPM && PPC64

diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index b3dd616..eb86032 100644 (file)
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -39,7 +39,7 @@ enum tpm_pcrs { TPM_PCR0 = 0, TPM_PCR8 = 8 };
 /* set during initialization */
 extern int ima_initialized;
 extern int ima_used_chip;
-extern char *ima_hash;
+extern int ima_hash_algo;
 extern int ima_appraise;
 
 /* IMA inode template definition */
@@ -70,8 +70,9 @@ void ima_fs_cleanup(void);
 int ima_inode_alloc(struct inode *inode);
 int ima_add_template_entry(struct ima_template_entry *entry, int violation,
                           const char *op, struct inode *inode);
-int ima_calc_file_hash(struct file *file, char *digest);
-int ima_calc_buffer_hash(const void *data, int len, char *digest);
+int ima_calc_file_hash(struct file *file, struct ima_digest_data *hash);
+int ima_calc_buffer_hash(const void *data, int len,
+                        struct ima_digest_data *hash);
 int ima_calc_boot_aggregate(char *digest);
 void ima_add_violation(struct inode *inode, const unsigned char *filename,
                       const char *op, const char *cause);

diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c
index 1c03e8f..e531fe2 100644 (file)
--- a/security/integrity/ima/ima_api.c
+++ b/security/integrity/ima/ima_api.c
@@ -44,6 +44,7 @@ int ima_store_template(struct ima_template_entry *entry,
        const char *op = "add_template_measure";
        const char *audit_cause = "hashing_error";
        int result;
+       struct ima_digest_data hash;
 
        memset(entry->digest, 0, sizeof(entry->digest));
        entry->template_name = IMA_TEMPLATE_NAME;
@@ -51,14 +52,14 @@ int ima_store_template(struct ima_template_entry *entry,
 
        if (!violation) {
                result = ima_calc_buffer_hash(&entry->template,
-                                               entry->template_len,
-                                               entry->digest);
+                                             entry->template_len, &hash);
                if (result < 0) {
                        integrity_audit_msg(AUDIT_INTEGRITY_PCR, inode,
                                            entry->template_name, op,
                                            audit_cause, result, 0);
                        return result;
                }
+               memcpy(entry->digest, hash.digest, hash.length);
        }
        result = ima_add_template_entry(entry, violation, op, inode);
        return result;
@@ -147,8 +148,9 @@ int ima_collect_measurement(struct integrity_iint_cache *iint,
        if (!(iint->flags & IMA_COLLECTED)) {
                u64 i_version = file_inode(file)->i_version;
 
-               iint->ima_xattr.type = IMA_XATTR_DIGEST;
-               result = ima_calc_file_hash(file, iint->ima_xattr.digest);
+               /* use default hash algorithm */
+               iint->ima_hash.algo = ima_hash_algo;
+               result = ima_calc_file_hash(file, &iint->ima_hash);
                if (!result) {
                        iint->version = i_version;
                        iint->flags |= IMA_COLLECTED;
@@ -196,7 +198,21 @@ void ima_store_measurement(struct integrity_iint_cache *iint,
                return;
        }
        memset(&entry->template, 0, sizeof(entry->template));
-       memcpy(entry->template.digest, iint->ima_xattr.digest, IMA_DIGEST_SIZE);
+       if (iint->ima_hash.algo != ima_hash_algo) {
+               struct ima_digest_data hash;
+
+               hash.algo = ima_hash_algo;
+               result = ima_calc_file_hash(file, &hash);
+               if (result)
+                       integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode,
+                                           filename, "collect_data", "failed",
+                                           result, 0);
+               else
+                       memcpy(entry->template.digest, hash.digest,
+                              hash.length);
+       } else
+               memcpy(entry->template.digest, iint->ima_hash.digest,
+                      iint->ima_hash.length);
        strcpy(entry->template.file_name,
               (strlen(filename) > IMA_EVENT_NAME_LEN_MAX) ?
               file->f_dentry->d_name.name : filename);
@@ -212,14 +228,14 @@ void ima_audit_measurement(struct integrity_iint_cache *iint,
                           const unsigned char *filename)
 {
        struct audit_buffer *ab;
-       char hash[(IMA_DIGEST_SIZE * 2) + 1];
+       char hash[(iint->ima_hash.length * 2) + 1];
        int i;
 
        if (iint->flags & IMA_AUDITED)
                return;
 
-       for (i = 0; i < IMA_DIGEST_SIZE; i++)
-               hex_byte_pack(hash + (i * 2), iint->ima_xattr.digest[i]);
+       for (i = 0; i < iint->ima_hash.length; i++)
+               hex_byte_pack(hash + (i * 2), iint->ima_hash.digest[i]);
        hash[i * 2] = '\0';
 
        ab = audit_log_start(current->audit_context, GFP_KERNEL,

diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c
index e3230d6..3833b0f 100644 (file)
--- a/security/integrity/ima/ima_appraise.c
+++ b/security/integrity/ima/ima_appraise.c
@@ -43,12 +43,12 @@ int ima_must_appraise(struct inode *inode, int mask, enum ima_hooks func)
 }
 
 static int ima_fix_xattr(struct dentry *dentry,
-                         struct integrity_iint_cache *iint)
+                        struct integrity_iint_cache *iint)
 {
-       iint->ima_xattr.type = IMA_XATTR_DIGEST;
+       iint->ima_hash.type = IMA_XATTR_DIGEST;
        return __vfs_setxattr_noperm(dentry, XATTR_NAME_IMA,
-                                    (u8 *)&iint->ima_xattr,
-                                     sizeof(iint->ima_xattr), 0);
+                                    &iint->ima_hash.type,
+                                    1 + iint->ima_hash.length, 0);
 }
 
 /* Return specific func appraised cached result */
@@ -159,8 +159,12 @@ int ima_appraise_measurement(int func, struct integrity_iint_cache *iint,
                        status = INTEGRITY_FAIL;
                        break;
                }
-               rc = memcmp(xattr_value->digest, iint->ima_xattr.digest,
-                           IMA_DIGEST_SIZE);
+               if (rc - 1 == iint->ima_hash.length)
+                       rc = memcmp(xattr_value->digest,
+                                   iint->ima_hash.digest,
+                                   iint->ima_hash.length);
+               else
+                       rc = -EINVAL;
                if (rc) {
                        cause = "invalid-hash";
                        status = INTEGRITY_FAIL;
@@ -172,8 +176,8 @@ int ima_appraise_measurement(int func, struct integrity_iint_cache *iint,
                iint->flags |= IMA_DIGSIG;
                rc = integrity_digsig_verify(INTEGRITY_KEYRING_IMA,
                                             xattr_value->digest, rc - 1,
-                                            iint->ima_xattr.digest,
-                                            IMA_DIGEST_SIZE);
+                                            iint->ima_hash.digest,
+                                            iint->ima_hash.length);
                if (rc == -EOPNOTSUPP) {
                        status = INTEGRITY_UNKNOWN;
                } else if (rc) {

diff --git a/security/integrity/ima/ima_crypto.c b/security/integrity/ima/ima_crypto.c
index a02e079..2fd1786 100644 (file)
--- a/security/integrity/ima/ima_crypto.c
+++ b/security/integrity/ima/ima_crypto.c
@@ -20,6 +20,7 @@
 #include <linux/err.h>
 #include <linux/slab.h>
 #include <crypto/hash.h>
+#include <crypto/hash_info.h>
 #include "ima.h"
 
 static struct crypto_shash *ima_shash_tfm;
@@ -28,10 +29,11 @@ int ima_init_crypto(void)
 {
        long rc;
 
-       ima_shash_tfm = crypto_alloc_shash(ima_hash, 0, 0);
+       ima_shash_tfm = crypto_alloc_shash(hash_algo_name[ima_hash_algo], 0, 0);
        if (IS_ERR(ima_shash_tfm)) {
                rc = PTR_ERR(ima_shash_tfm);
-               pr_err("Can not allocate %s (reason: %ld)\n", ima_hash, rc);
+               pr_err("Can not allocate %s (reason: %ld)\n",
+                      hash_algo_name[ima_hash_algo], rc);
                return rc;
        }
        return 0;
@@ -40,17 +42,19 @@ int ima_init_crypto(void)
 /*
  * Calculate the MD5/SHA1 file digest
  */
-int ima_calc_file_hash(struct file *file, char *digest)
+static int ima_calc_file_hash_tfm(struct file *file,
+                                 struct ima_digest_data *hash,
+                                 struct crypto_shash *tfm)
 {
        loff_t i_size, offset = 0;
        char *rbuf;
        int rc, read = 0;
        struct {
                struct shash_desc shash;
-               char ctx[crypto_shash_descsize(ima_shash_tfm)];
+               char ctx[crypto_shash_descsize(tfm)];
        } desc;
 
-       desc.shash.tfm = ima_shash_tfm;
+       desc.shash.tfm = tfm;
        desc.shash.flags = 0;
 
        rc = crypto_shash_init(&desc.shash);
@@ -85,17 +89,42 @@ int ima_calc_file_hash(struct file *file, char *digest)
        }
        kfree(rbuf);
        if (!rc)
-               rc = crypto_shash_final(&desc.shash, digest);
+               rc = crypto_shash_final(&desc.shash, hash->digest);
        if (read)
                file->f_mode &= ~FMODE_READ;
 out:
        return rc;
 }
 
+int ima_calc_file_hash(struct file *file, struct ima_digest_data *hash)
+{
+       struct crypto_shash *tfm = ima_shash_tfm;
+       int rc;
+
+       if (hash->algo != ima_hash_algo && hash->algo < HASH_ALGO__LAST) {
+               tfm = crypto_alloc_shash(hash_algo_name[hash->algo], 0, 0);
+               if (IS_ERR(tfm)) {
+                       rc = PTR_ERR(tfm);
+                       pr_err("Can not allocate %s (reason: %d)\n",
+                              hash_algo_name[hash->algo], rc);
+                       return rc;
+               }
+       }
+
+       hash->length = crypto_shash_digestsize(tfm);
+
+       rc = ima_calc_file_hash_tfm(file, hash, tfm);
+
+       if (tfm != ima_shash_tfm)
+               crypto_free_shash(tfm);
+
+       return rc;
+}
+
 /*
  * Calculate the hash of a given buffer
  */
-int ima_calc_buffer_hash(const void *data, int len, char *digest)
+int ima_calc_buffer_hash(const void *buf, int len, struct ima_digest_data *hash)
 {
        struct {
                struct shash_desc shash;
@@ -105,7 +134,11 @@ int ima_calc_buffer_hash(const void *data, int len, char *digest)
        desc.shash.tfm = ima_shash_tfm;
        desc.shash.flags = 0;
 
-       return crypto_shash_digest(&desc.shash, data, len, digest);
+       /* this function uses default algo */
+       hash->algo = ima_hash_algo;
+       hash->length = crypto_shash_digestsize(ima_shash_tfm);
+
+       return crypto_shash_digest(&desc.shash, buf, len, hash->digest);
 }
 
 static void __init ima_pcrread(int idx, u8 *pcr)

diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 0f359df..7708c21 100644 (file)
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -24,6 +24,7 @@
 #include <linux/slab.h>
 #include <linux/xattr.h>
 #include <linux/ima.h>
+#include <crypto/hash_info.h>
 
 #include "ima.h"
 
@@ -35,11 +36,12 @@ int ima_appraise = IMA_APPRAISE_ENFORCE;
 int ima_appraise;
 #endif
 
-char *ima_hash = "sha1";
+int ima_hash_algo = HASH_ALGO_SHA1;
+
 static int __init hash_setup(char *str)
 {
        if (strncmp(str, "md5", 3) == 0)
-               ima_hash = "md5";
+               ima_hash_algo = HASH_ALGO_MD5;
        return 1;
 }
 __setup("ima_hash=", hash_setup);

diff --git a/security/integrity/integrity.h b/security/integrity/integrity.h
index f867316..0b02ea8 100644 (file)
--- a/security/integrity/integrity.h
+++ b/security/integrity/integrity.h
@@ -59,20 +59,29 @@ enum evm_ima_xattr_type {
 struct evm_ima_xattr_data {
        u8 type;
        u8 digest[SHA1_DIGEST_SIZE];
-}  __attribute__((packed));
+} __packed;
+
+#define IMA_MAX_DIGEST_SIZE    64
+
+struct ima_digest_data {
+       u8 algo;
+       u8 length;
+       u8 type;
+       u8 digest[IMA_MAX_DIGEST_SIZE];
+} __packed;
 
 /* integrity data associated with an inode */
 struct integrity_iint_cache {
-       struct rb_node rb_node; /* rooted in integrity_iint_tree */
+       struct rb_node rb_node; /* rooted in integrity_iint_tree */
        struct inode *inode;    /* back pointer to inode in question */
        u64 version;            /* track inode changes */
        unsigned long flags;
-       struct evm_ima_xattr_data ima_xattr;
        enum integrity_status ima_file_status:4;
        enum integrity_status ima_mmap_status:4;
        enum integrity_status ima_bprm_status:4;
        enum integrity_status ima_module_status:4;
        enum integrity_status evm_status:4;
+       struct ima_digest_data ima_hash;
 };
 
 /* rbtree tree calls to lookup, insert, delete