diff mbox series

[v2] ima: fix buffer overrun in ima_eventdigest_init_common

Message ID 20240807172713.1692608-1-samasth.norway.ananda@oracle.com (mailing list archive)
State New
Headers show
Series [v2] ima: fix buffer overrun in ima_eventdigest_init_common | expand

Commit Message

Samasth Norway Ananda Aug. 7, 2024, 5:27 p.m. UTC
Function ima_eventdigest_init() can call ima_eventdigest_init_common()
with HASH_ALGO__LAST which is then used to access the array
hash_digest_size[] leading to buffer overrun. Have a conditional
statement to handle this.

Fixes: 9fab303a2cb3 ("ima: fix violation measurement list record")
Signed-off-by: Samasth Norway Ananda <samasth.norway.ananda@oracle.com>
---
 security/integrity/ima/ima_template_lib.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

Comments

Mimi Zohar Aug. 8, 2024, 11:46 p.m. UTC | #1
Hi Samasth,

On Wed, 2024-08-07 at 10:27 -0700, Samasth Norway Ananda wrote:
> Function ima_eventdigest_init() can call ima_eventdigest_init_common()

"can call" -> "calls"

> with HASH_ALGO__LAST which is then used to access the array
> hash_digest_size[] leading to buffer overrun. Have a conditional
> statement to handle this.
> 
> Fixes: 9fab303a2cb3 ("ima: fix violation measurement list record")
> Signed-off-by: Samasth Norway Ananda <samasth.norway.ananda@oracle.com>

Thanks, Samasth for fixing the patch. It's now queued in next-integrity with the
change above.

thanks,

Mimi
diff mbox series

Patch

diff --git a/security/integrity/ima/ima_template_lib.c b/security/integrity/ima/ima_template_lib.c
index 4183956c53af..0e627eac9c33 100644
--- a/security/integrity/ima/ima_template_lib.c
+++ b/security/integrity/ima/ima_template_lib.c
@@ -318,15 +318,21 @@  static int ima_eventdigest_init_common(const u8 *digest, u32 digestsize,
 				      hash_algo_name[hash_algo]);
 	}
 
-	if (digest)
+	if (digest) {
 		memcpy(buffer + offset, digest, digestsize);
-	else
+	} else {
 		/*
 		 * If digest is NULL, the event being recorded is a violation.
 		 * Make room for the digest by increasing the offset by the
-		 * hash algorithm digest size.
+		 * hash algorithm digest size. If the hash algorithm is not
+		 * specified increase the offset by IMA_DIGEST_SIZE which
+		 * fits SHA1 or MD5
 		 */
-		offset += hash_digest_size[hash_algo];
+		if (hash_algo < HASH_ALGO__LAST)
+			offset += hash_digest_size[hash_algo];
+		else
+			offset += IMA_DIGEST_SIZE;
+	}
 
 	return ima_write_template_field_data(buffer, offset + digestsize,
 					     fmt, field_data);