crypto: DRBG - initialize SGL only once

Commit Message

Stephan Mueller March 22, 2017, 2:26 p.m. UTC

An SGL to be initialized only once even when its buffers are written
to several times.

Signed-off-by: Stephan Mueller <[e-mail]>
---
 crypto/drbg.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

Comments

Herbert Xu March 24, 2017, 2:15 p.m. UTC | #1

On Wed, Mar 22, 2017 at 03:26:36PM +0100, Stephan Müller wrote:
> An SGL to be initialized only once even when its buffers are written
> to several times.
> 
> Signed-off-by: Stephan Mueller <[e-mail]>

Patch applied.  Thanks.

Patch

diff --git a/crypto/drbg.c b/crypto/drbg.c
index 8a4d98b..fa749f4 100644
--- a/crypto/drbg.c
+++ b/crypto/drbg.c
@@ -1749,17 +1749,16 @@  static int drbg_kcapi_sym_ctr(struct drbg_state *drbg,
 			      u8 *inbuf, u32 inlen,
 			      u8 *outbuf, u32 outlen)
 {
-	struct scatterlist sg_in;
+	struct scatterlist sg_in, sg_out;
 	int ret;
 
 	sg_init_one(&sg_in, inbuf, inlen);
+	sg_init_one(&sg_out, drbg->outscratchpad, DRBG_OUTSCRATCHLEN);
 
 	while (outlen) {
 		u32 cryptlen = min3(inlen, outlen, (u32)DRBG_OUTSCRATCHLEN);
-		struct scatterlist sg_out;
 
 		/* Output buffer may not be valid for SGL, use scratchpad */
-		sg_init_one(&sg_out, drbg->outscratchpad, cryptlen);
 		skcipher_request_set_crypt(drbg->ctr_req, &sg_in, &sg_out,
 					   cryptlen, drbg->V);
 		ret = crypto_skcipher_encrypt(drbg->ctr_req);