On 6/21/24 3:44 PM, Mimi Zohar wrote:
Hi Samasth,
On Thu, 2024-06-20 at 12:46 -0700, Samasth Norway Ananda wrote:
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.
The original 'ima' template ("d|n") digest is not prefixed with the digest
algorithm, since it is hard coded to sha1. ima_eventdigest_init() intentionally
calls ima_eventdigest_init_common() with HASH_ALGO__LAST. To avoid ...
Fixes: 9fab303a2cb3 ("ima: fix violation measurement list record")
Signed-off-by: Samasth Norway Ananda <samasth.norway.ananda@xxxxxxxxxx>
---
security/integrity/ima/ima_template_lib.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/security/integrity/ima/ima_template_lib.c b/security/integrity/ima/ima_template_lib.c
index 4183956c53af..14c000fe8312 100644
--- a/security/integrity/ima/ima_template_lib.c
+++ b/security/integrity/ima/ima_template_lib.c
@@ -320,13 +320,17 @@ static int ima_eventdigest_init_common(const u8 *digest, u32 digestsize,
if (digest)
Please add a brace after "digest" and before "else".
Refer to the section titled "3) Placing Braces and Spaces" in "
https://www.kernel.org/doc/html/v4.10/process/coding-style.html.
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.
*/
Please update the comment to reflect the case when the hash algorithm isn't
specified.
- 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);
Please fix the other scripts/checkpatch.pl complaints.
Thanks for correcting me Mimi. I should have checked that before
sending. I will make the changes and send a v2 of the patch.
thanks,
Mimi
