From 291af651b350817f7f1cbe308faaf7fa7af2a92c Mon Sep 17 00:00:00 2001 From: Tushar Sugandhi Date: Thu, 7 Jan 2021 20:07:02 -0800 Subject: [PATCH] IMA: add support to measure buffer data hash The original IMA buffer data measurement sizes were small (e.g. boot command line), but the new buffer data measurement use cases have data sizes that are a lot larger. Just as IMA measures the file data hash, not the file data, IMA should similarly support the option for measuring buffer data hash. Introduce a boolean parameter to support measuring buffer data hash, which would be much smaller, instead of the buffer itself. Signed-off-by: Tushar Sugandhi Reviewed-by: Tyler Hicks Signed-off-by: Mimi Zohar --- security/integrity/ima/ima.h | 3 ++- security/integrity/ima/ima_appraise.c | 2 +- security/integrity/ima/ima_asymmetric_keys.c | 2 +- security/integrity/ima/ima_main.c | 29 +++++++++++++++++++++++----- security/integrity/ima/ima_queue_keys.c | 3 ++- 5 files changed, 30 insertions(+), 9 deletions(-) diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h index e5622ce..0b46345 100644 --- a/security/integrity/ima/ima.h +++ b/security/integrity/ima/ima.h @@ -268,7 +268,8 @@ void ima_store_measurement(struct integrity_iint_cache *iint, struct file *file, struct ima_template_desc *template_desc); void process_buffer_measurement(struct inode *inode, const void *buf, int size, const char *eventname, enum ima_hooks func, - int pcr, const char *func_data); + int pcr, const char *func_data, + bool buf_hash); void ima_audit_measurement(struct integrity_iint_cache *iint, const unsigned char *filename); int ima_alloc_init_template(struct ima_event_data *event_data, diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c index 8361941..46ffa38 100644 --- a/security/integrity/ima/ima_appraise.c +++ b/security/integrity/ima/ima_appraise.c @@ -352,7 +352,7 @@ int ima_check_blacklist(struct integrity_iint_cache *iint, if ((rc == -EPERM) && (iint->flags & IMA_MEASURE)) process_buffer_measurement(NULL, digest, digestsize, "blacklisted-hash", NONE, - pcr, NULL); + pcr, NULL, false); } return rc; diff --git a/security/integrity/ima/ima_asymmetric_keys.c b/security/integrity/ima/ima_asymmetric_keys.c index 1c68c50..a740957 100644 --- a/security/integrity/ima/ima_asymmetric_keys.c +++ b/security/integrity/ima/ima_asymmetric_keys.c @@ -60,5 +60,5 @@ void ima_post_key_create_or_update(struct key *keyring, struct key *key, */ process_buffer_measurement(NULL, payload, payload_len, keyring->description, KEY_CHECK, 0, - keyring->description); + keyring->description, false); } diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c index 0c64569..250e521 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -809,7 +809,7 @@ int ima_post_load_data(char *buf, loff_t size, } /* - * process_buffer_measurement - Measure the buffer to ima log. + * process_buffer_measurement - Measure the buffer or the buffer data hash * @inode: inode associated with the object being measured (NULL for KEY_CHECK) * @buf: pointer to the buffer that needs to be added to the log. * @size: size of buffer(in bytes). @@ -817,12 +817,14 @@ int ima_post_load_data(char *buf, loff_t size, * @func: IMA hook * @pcr: pcr to extend the measurement * @func_data: func specific data, may be NULL + * @buf_hash: measure buffer data hash * - * Based on policy, the buffer is measured into the ima log. + * Based on policy, either the buffer data or buffer data hash is measured */ void process_buffer_measurement(struct inode *inode, const void *buf, int size, const char *eventname, enum ima_hooks func, - int pcr, const char *func_data) + int pcr, const char *func_data, + bool buf_hash) { int ret = 0; const char *audit_cause = "ENOMEM"; @@ -837,6 +839,8 @@ void process_buffer_measurement(struct inode *inode, const void *buf, int size, struct ima_digest_data hdr; char digest[IMA_MAX_DIGEST_SIZE]; } hash = {}; + char digest_hash[IMA_MAX_DIGEST_SIZE]; + int digest_hash_len = hash_digest_size[ima_hash_algo]; int violation = 0; int action = 0; u32 secid; @@ -879,13 +883,27 @@ void process_buffer_measurement(struct inode *inode, const void *buf, int size, goto out; } + if (buf_hash) { + memcpy(digest_hash, hash.hdr.digest, digest_hash_len); + + ret = ima_calc_buffer_hash(digest_hash, digest_hash_len, + iint.ima_hash); + if (ret < 0) { + audit_cause = "hashing_error"; + goto out; + } + + event_data.buf = digest_hash; + event_data.buf_len = digest_hash_len; + } + ret = ima_alloc_init_template(&event_data, &entry, template); if (ret < 0) { audit_cause = "alloc_entry"; goto out; } - ret = ima_store_template(entry, violation, NULL, buf, pcr); + ret = ima_store_template(entry, violation, NULL, event_data.buf, pcr); if (ret < 0) { audit_cause = "store_entry"; ima_free_template_entry(entry); @@ -920,7 +938,8 @@ void ima_kexec_cmdline(int kernel_fd, const void *buf, int size) return; process_buffer_measurement(file_inode(f.file), buf, size, - "kexec-cmdline", KEXEC_CMDLINE, 0, NULL); + "kexec-cmdline", KEXEC_CMDLINE, 0, NULL, + false); fdput(f); } diff --git a/security/integrity/ima/ima_queue_keys.c b/security/integrity/ima/ima_queue_keys.c index 69a8626..c2f2ad3 100644 --- a/security/integrity/ima/ima_queue_keys.c +++ b/security/integrity/ima/ima_queue_keys.c @@ -162,7 +162,8 @@ void ima_process_queued_keys(void) entry->payload_len, entry->keyring_name, KEY_CHECK, 0, - entry->keyring_name); + entry->keyring_name, + false); list_del(&entry->list); ima_free_key_entry(entry); } -- 2.7.4