process_buffer_measurement() currently only measures the input buffer. When the buffer being measured is too large, it may result in bloated IMA logs.
Introduce a boolean parameter measure_buf_hash to support measuring hash of a buffer, which would be much smaller, instead of the buffer itself. Signed-off-by: Tushar Sugandhi <[email protected]> --- 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, 32 insertions(+), 7 deletions(-) diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h index 83ed57147e68..ba332de8ed0b 100644 --- a/security/integrity/ima/ima.h +++ b/security/integrity/ima/ima.h @@ -267,7 +267,8 @@ void ima_store_measurement(struct integrity_iint_cache *iint, struct file *file, struct ima_template_desc *template_desc); int 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 measure_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 372d16382960..20adffe5bf58 100644 --- a/security/integrity/ima/ima_appraise.c +++ b/security/integrity/ima/ima_appraise.c @@ -336,7 +336,7 @@ 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 1c68c500c26f..a74095793936 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 0979a62a9257..52cbbc1f7ea2 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -733,17 +733,21 @@ int ima_load_data(enum kernel_load_data_id id) * @func: IMA hook * @pcr: pcr to extend the measurement * @func_data: private data specific to @func, can be NULL. + * @measure_buf_hash: if set to true - will measure hash of the buf, + * instead of buf * * Based on policy, the buffer is measured into the ima log. */ int 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 measure_buf_hash) { int ret = 0; const char *audit_cause = "ENOMEM"; struct ima_template_entry *entry = NULL; struct integrity_iint_cache iint = {}; + struct integrity_iint_cache digest_iint = {}; struct ima_event_data event_data = {.iint = &iint, .filename = eventname, .buf = buf, @@ -752,7 +756,7 @@ int process_buffer_measurement(struct inode *inode, const void *buf, int size, struct { struct ima_digest_data hdr; char digest[IMA_MAX_DIGEST_SIZE]; - } hash = {}; + } hash = {}, digest_hash = {}; int violation = 0; int action = 0; u32 secid; @@ -801,6 +805,24 @@ int process_buffer_measurement(struct inode *inode, const void *buf, int size, goto out; } + if (measure_buf_hash) { + digest_iint.ima_hash = &digest_hash.hdr; + digest_iint.ima_hash->algo = ima_hash_algo; + digest_iint.ima_hash->length = hash_digest_size[ima_hash_algo]; + + ret = ima_calc_buffer_hash(hash.hdr.digest, + iint.ima_hash->length, + digest_iint.ima_hash); + if (ret < 0) { + audit_cause = "digest_hashing_error"; + goto out; + } + + event_data.iint = &digest_iint; + event_data.buf = hash.hdr.digest; + event_data.buf_len = iint.ima_hash->length; + } + ret = ima_alloc_init_template(&event_data, &entry, template); if (ret < 0) { audit_cause = "alloc_entry"; @@ -842,7 +864,8 @@ 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 69a8626a35c0..c2f2ad34f9b7 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); } -- 2.17.1 -- dm-devel mailing list [email protected] https://www.redhat.com/mailman/listinfo/dm-devel
