[PATCH 4.19 031/264] ima: Dont ignore errors from crypto_shash_update()

[Greg Kroah-Hartman]

From: Roberto Sassu <roberto.sassu@xxxxxxxxxx>

commit 60386b854008adc951c470067f90a2d85b5d520f upstream.

Errors returned by crypto_shash_update() are not checked in
ima_calc_boot_aggregate_tfm() and thus can be overwritten at the next
iteration of the loop. This patch adds a check after calling
crypto_shash_update() and returns immediately if the result is not zero.

Cc: stable@xxxxxxxxxxxxxxx
Fixes: 3323eec921efd ("integrity: IMA as an integrity service provider")
Signed-off-by: Roberto Sassu <roberto.sassu@xxxxxxxxxx>
Signed-off-by: Mimi Zohar <zohar@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 security/integrity/ima/ima_crypto.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/security/integrity/ima/ima_crypto.c
+++ b/security/integrity/ima/ima_crypto.c
@@ -682,6 +682,8 @@ static int ima_calc_boot_aggregate_tfm(c
 		ima_pcrread(i, pcr_i);
 		/* now accumulate with current aggregate */
 		rc = crypto_shash_update(shash, pcr_i, TPM_DIGEST_SIZE);
+		if (rc != 0)
+			return rc;
 	}
 	if (!rc)
 		crypto_shash_final(shash, digest);