From: Roberto Sassu <roberto.sassu@xxxxxxxxxx> Introduce ima_digest_cache_load_verified_usage() to retrieve the verified usage from the digest cache returned from the lookup of the digest calculated by IMA on a file being accessed. Verified usage cannot be loaded from the digest cache returned by digest_cache_get() since the latter might return a directory digest cache, which does not contain any verification data (only set to digest cache populated from a file). Signed-off-by: Roberto Sassu <roberto.sassu@xxxxxxxxxx> --- security/integrity/ima/ima_digest_cache.c | 37 +++++++++++++++++++++++ security/integrity/ima/ima_digest_cache.h | 9 ++++++ 2 files changed, 46 insertions(+) diff --git a/security/integrity/ima/ima_digest_cache.c b/security/integrity/ima/ima_digest_cache.c index baa3faae77d2..bb8a9a9aa933 100644 --- a/security/integrity/ima/ima_digest_cache.c +++ b/security/integrity/ima/ima_digest_cache.c @@ -82,3 +82,40 @@ void ima_digest_cache_store_verified_usage(struct file *file, pr_debug("Cannot set verified usage for %s, ret: %d, ignoring\n", file_dentry(file)->d_name.name, rc); } + +/** + * ima_digest_cache_load_verified_usage - Load verified usage from digest cache + * @dentry: Dentry of the inode for which the digest cache will be used + * @iint: Inode integrity metadata + * + * Load digest cache verified usage from the digest cache returned by + * digest_cache_lookup(), containing the file digest calculated by IMA (if the + * digest is found). + * + * Return: Verified usage if digest is found in digest cache, zero otherwise. + */ +u64 ima_digest_cache_load_verified_usage(struct dentry *dentry, + struct ima_iint_cache *iint) +{ + void *verified_usage_ptr; + uintptr_t found_cache_ptr; + struct digest_cache *found_cache; + + if (!iint->digest_cache) + return 0ULL; + + /* Do lookup to identify digest cache verification data is read from. */ + found_cache_ptr = digest_cache_lookup(dentry, iint->digest_cache, + iint->ima_hash->digest, + iint->ima_hash->algo); + if (!found_cache_ptr) + return 0ULL; + + found_cache = (struct digest_cache *)found_cache_ptr; + + verified_usage_ptr = digest_cache_verif_get(found_cache, "ima"); + if (!verified_usage_ptr) + return 0ULL; + + return *(u64 *)verified_usage_ptr; +} diff --git a/security/integrity/ima/ima_digest_cache.h b/security/integrity/ima/ima_digest_cache.h index 1544dc798631..41a37630b1f7 100644 --- a/security/integrity/ima/ima_digest_cache.h +++ b/security/integrity/ima/ima_digest_cache.h @@ -14,6 +14,8 @@ bool ima_digest_cache_get_check(struct dentry *dentry, struct ima_iint_cache *iint); void ima_digest_cache_store_verified_usage(struct file *file, struct ima_iint_cache *iint); +u64 ima_digest_cache_load_verified_usage(struct dentry *dentry, + struct ima_iint_cache *iint); #else static inline bool ima_digest_cache_get_check(struct dentry *dentry, struct ima_iint_cache *iint) @@ -26,4 +28,11 @@ ima_digest_cache_store_verified_usage(struct file *file, struct ima_iint_cache *iint) { } +static inline u64 +ima_digest_cache_load_verified_usage(struct dentry *dentry, + struct ima_iint_cache *iint) +{ + return 0ULL; +} + #endif /* CONFIG_INTEGRITY_DIGEST_CACHE */ -- 2.34.1