* [PATCH v2] crypto: ccp/gcm - use const time tag comparison.
@ 2019-07-02 17:32 Cfir Cohen
2019-07-02 17:46 ` Gary R Hook
2019-07-18 5:41 ` Herbert Xu
0 siblings, 2 replies; 3+ messages in thread
From: Cfir Cohen @ 2019-07-02 17:32 UTC (permalink / raw)
To: Tom Lendacky, Gary Hook, Herbert Xu, David Rientjes
Cc: linux-kernel, linux-crypto, Cfir Cohen, stable
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>
---
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);
}
--
2.22.0.410.gd8fdbe21b5-goog
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH v2] crypto: ccp/gcm - use const time tag comparison.
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
2019-07-18 5:41 ` Herbert Xu
1 sibling, 0 replies; 3+ messages in thread
From: Gary R Hook @ 2019-07-02 17:46 UTC (permalink / raw)
To: Cfir Cohen, Lendacky, Thomas, Hook, Gary, Herbert Xu,
David Rientjes
Cc: linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org,
stable@vger.kernel.org
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);
> }
>
>
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH v2] crypto: ccp/gcm - use const time tag comparison.
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
@ 2019-07-18 5:41 ` Herbert Xu
1 sibling, 0 replies; 3+ messages in thread
From: Herbert Xu @ 2019-07-18 5:41 UTC (permalink / raw)
To: Cfir Cohen
Cc: Tom Lendacky, Gary Hook, David Rientjes, linux-kernel,
linux-crypto, stable
On Tue, Jul 02, 2019 at 10:32:56AM -0700, 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>
> ---
> drivers/crypto/ccp/ccp-ops.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
Patch applied. Thanks.
--
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
^ permalink raw reply [flat|nested] 3+ messages in thread
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