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 <[email protected]>
---
 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)
                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.
                 */
-               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);
-- 
2.45.2


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