From c7c8bb237fdbff932b5e431aebee5ce862ea07d1 Mon Sep 17 00:00:00 2001 From: Dmitry Kasatkin Date: Thu, 25 Apr 2013 10:43:56 +0300 Subject: 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 Signed-off-by: Mimi Zohar --- security/integrity/ima/Kconfig | 1 + security/integrity/ima/ima.h | 7 ++--- security/integrity/ima/ima_api.c | 32 +++++++++++++++++------ security/integrity/ima/ima_appraise.c | 20 ++++++++------ security/integrity/ima/ima_crypto.c | 49 +++++++++++++++++++++++++++++------ security/integrity/ima/ima_main.c | 6 +++-- security/integrity/integrity.h | 15 ++++++++--- 7 files changed, 98 insertions(+), 32 deletions(-) (limited to 'security') diff --git a/security/integrity/ima/Kconfig b/security/integrity/ima/Kconfig index 39196abaff0d..e6628e783df1 100644 --- 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 b3dd616560f7..eb86032f4f1e 100644 --- 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 1c03e8f1e0e1..e531fe22e582 100644 --- 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 e3230d6a8d96..3833b0fa7108 100644 --- 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 a02e0791cf15..2fd178651467 100644 --- a/security/integrity/ima/ima_crypto.c +++ b/security/integrity/ima/ima_crypto.c @@ -20,6 +20,7 @@ #include #include #include +#include #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 0f359df6344c..7708c2120d9c 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -24,6 +24,7 @@ #include #include #include +#include #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 f86731649f54..0b02ea868e30 100644 --- 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 -- cgit v1.2.3