diff mbox

crypto: ccm - move cbcmac input off the stack

Message ID 1488209456-7653-1-git-send-email-ard.biesheuvel@linaro.org
State Accepted
Commit 3b30460c5b0ed762be75a004e924ec3f8711e032
Headers show

Commit Message

Ard Biesheuvel Feb. 27, 2017, 3:30 p.m. UTC
Commit f15f05b0a5de ("crypto: ccm - switch to separate cbcmac driver")
refactored the CCM driver to allow separate implementations of the
underlying MAC to be provided by a platform. However, in doing so, it
moved some data from the linear region to the stack, which violates the
SG constraints when the stack is virtually mapped.

So move idata/odata back to the request ctx struct, of which we can
reasonably expect that it has been allocated using kmalloc() et al.

Reported-by: Johannes Berg <johannes@sipsolutions.net>
Fixes: f15f05b0a5de ("crypto: ccm - switch to separate cbcmac driver")
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

---
 crypto/ccm.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

-- 
2.7.4

Comments

Johannes Berg Feb. 27, 2017, 4:04 p.m. UTC | #1
On Mon, 2017-02-27 at 15:30 +0000, Ard Biesheuvel wrote:
> Commit f15f05b0a5de ("crypto: ccm - switch to separate cbcmac

> driver")

> refactored the CCM driver to allow separate implementations of the

> underlying MAC to be provided by a platform. However, in doing so, it

> moved some data from the linear region to the stack, which violates

> the

> SG constraints when the stack is virtually mapped.

> 

> So move idata/odata back to the request ctx struct, of which we can

> reasonably expect that it has been allocated using kmalloc() et al.

> 

> Reported-by: Johannes Berg <johannes@sipsolutions.net>

> Fixes: f15f05b0a5de ("crypto: ccm - switch to separate cbcmac

> driver")

> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>


Tested-by: Johannes Berg <johannes@sipsolutions.net>


Thanks for the quick fix!

johannes
Herbert Xu Feb. 28, 2017, 9:33 a.m. UTC | #2
On Mon, Feb 27, 2017 at 03:30:56PM +0000, Ard Biesheuvel wrote:
> Commit f15f05b0a5de ("crypto: ccm - switch to separate cbcmac driver")

> refactored the CCM driver to allow separate implementations of the

> underlying MAC to be provided by a platform. However, in doing so, it

> moved some data from the linear region to the stack, which violates the

> SG constraints when the stack is virtually mapped.

> 

> So move idata/odata back to the request ctx struct, of which we can

> reasonably expect that it has been allocated using kmalloc() et al.

> 

> Reported-by: Johannes Berg <johannes@sipsolutions.net>

> Fixes: f15f05b0a5de ("crypto: ccm - switch to separate cbcmac driver")

> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>


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
diff mbox

Patch

diff --git a/crypto/ccm.c b/crypto/ccm.c
index 442848807a52..1ce37ae0ce56 100644
--- a/crypto/ccm.c
+++ b/crypto/ccm.c
@@ -45,6 +45,7 @@  struct crypto_rfc4309_req_ctx {
 
 struct crypto_ccm_req_priv_ctx {
 	u8 odata[16];
+	u8 idata[16];
 	u8 auth_tag[16];
 	u32 flags;
 	struct scatterlist src[3];
@@ -183,8 +184,8 @@  static int crypto_ccm_auth(struct aead_request *req, struct scatterlist *plain,
 	AHASH_REQUEST_ON_STACK(ahreq, ctx->mac);
 	unsigned int assoclen = req->assoclen;
 	struct scatterlist sg[3];
-	u8 odata[16];
-	u8 idata[16];
+	u8 *odata = pctx->odata;
+	u8 *idata = pctx->idata;
 	int ilen, err;
 
 	/* format control data for input */