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Commit 538a5a07 authored by Cfir Cohen's avatar Cfir Cohen Committed by Herbert Xu
Browse files

crypto: ccp/gcm - use const time tag comparison. 



Avoid leaking GCM tag through timing side channel.

Fixes: 36cf515b ("crypto: ccp - Enable support for AES GCM on v5 CCPs")
Cc: <stable@vger.kernel.org> # v4.12+
Signed-off-by: default avatarCfir Cohen <cfir@google.com>
Acked-by: default avatarGary R Hook <ghook@amd.com>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent 20e833dc

drivers/crypto/ccp/ccp-ops.c

+2 −1
Original line number Diff line number Diff line
@@ -850,7 +850,8 @@ static int ccp_run_aes_gcm_cmd(struct ccp_cmd_queue *cmd_q, 
		if (ret)

			goto e_tag;



		ret = memcmp(tag.address, final_wa.address, AES_BLOCK_SIZE);

		ret = crypto_memneq(tag.address, final_wa.address,

				    AES_BLOCK_SIZE) ? -EBADMSG : 0;

		ccp_dm_free(&tag);

	}