From: Gary R Hook <ghook@amd.com>
To: Cfir Cohen <cfir@google.com>,
"Lendacky, Thomas" <Thomas.Lendacky@amd.com>,
"Hook, Gary" <Gary.Hook@amd.com>,
Herbert Xu <herbert@gondor.apana.org.au>,
David Rientjes <rientjes@google.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-crypto@vger.kernel.org" <linux-crypto@vger.kernel.org>,
"stable@vger.kernel.org" <stable@vger.kernel.org>
Subject: Re: [PATCH v2] crypto: ccp/gcm - use const time tag comparison.
Date: Tue, 2 Jul 2019 17:46:53 +0000 [thread overview]
Message-ID: <aa19bd59-7b76-b8ad-3f25-42efbfb7fd29@amd.com> (raw)
In-Reply-To: <20190702173256.50485-1-cfir@google.com>
On 7/2/19 12:32 PM, Cfir Cohen wrote:
> Avoid leaking GCM tag through timing side channel.
>
> Fixes: 36cf515b9bbe ("crypto: ccp - Enable support for AES GCM on v5 CCPs")
> Cc: <stable@vger.kernel.org> # v4.12+
> Signed-off-by: Cfir Cohen <cfir@google.com>
Acked-by: Gary R Hook <ghook@amd.com>
> ---
> drivers/crypto/ccp/ccp-ops.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/crypto/ccp/ccp-ops.c b/drivers/crypto/ccp/ccp-ops.c
> index db8de89d990f..633670220f6c 100644
> --- a/drivers/crypto/ccp/ccp-ops.c
> +++ b/drivers/crypto/ccp/ccp-ops.c
> @@ -840,7 +840,8 @@ 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);
> }
>
>
next prev parent reply other threads:[~2019-07-02 17:47 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-02 17:32 [PATCH v2] crypto: ccp/gcm - use const time tag comparison Cfir Cohen
2019-07-02 17:46 ` Gary R Hook [this message]
2019-07-18 5:41 ` Herbert Xu
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