[PATCH] ima: check return value of crypto_shash_final() in boot aggregate

[Daniel Hodges <hodgesd@meta.com>]

The return value of crypto_shash_final() is not checked in
ima_calc_boot_aggregate_tfm(). If the hash finalization fails, the
function returns success and a corrupted boot aggregate digest could
be used for IMA measurements.

Capture the return value and propagate any error to the caller.

Fixes: 76bb28f6126f ("ima: use new crypto_shash API instead of old crypto_hash")
Signed-off-by: Daniel Hodges <hodgesd@meta.com>
---
 security/integrity/ima/ima_crypto.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/security/integrity/ima/ima_crypto.c b/security/integrity/ima/ima_crypto.c
index 6f5696d999d0..8ae7821a65c2 100644
--- a/security/integrity/ima/ima_crypto.c
+++ b/security/integrity/ima/ima_crypto.c
@@ -825,21 +825,21 @@ static int ima_calc_boot_aggregate_tfm(char *digest, u16 alg_id,
 	 * non-SHA1 boot_aggregate digests to avoid ambiguity.
 	 */
 	if (alg_id != TPM_ALG_SHA1) {
 		for (i = TPM_PCR8; i < TPM_PCR10; i++) {
 			ima_pcrread(i, &d);
 			rc = crypto_shash_update(shash, d.digest,
 						crypto_shash_digestsize(tfm));
 		}
 	}
 	if (!rc)
-		crypto_shash_final(shash, digest);
+		rc = crypto_shash_final(shash, digest);
 	return rc;
 }
 
 int ima_calc_boot_aggregate(struct ima_digest_data *hash)
 {
 	struct crypto_shash *tfm;
 	u16 crypto_id, alg_id;
 	int rc, i, bank_idx = -1;
 
 	for (i = 0; i < ima_tpm_chip->nr_allocated_banks; i++) {
-- 
2.47.3