2021-05-21 09:20:07

by Thara Gopinath

Subject: [PATCH] crypto: qce: skcipher: Fix incorrect sg count for dma transfers

Use the sg count returned by dma_map_sg to call into
dmaengine_prep_slave_sg rather than using the original sg count. dma_map_sg
can merge consecutive sglist entries, thus making the original sg count
wrong. This is a fix for memory coruption issues observed while testing
encryption/decryption of large messages using libkcapi framework.

Patch has been tested further by running full suite of tcrypt.ko tests
including fuzz tests.

Signed-off-by: Thara Gopinath <[email protected]>
---
drivers/crypto/qce/skcipher.c | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/drivers/crypto/qce/skcipher.c b/drivers/crypto/qce/skcipher.c
index c0a0d8c4fce1..259418479227 100644
--- a/drivers/crypto/qce/skcipher.c
+++ b/drivers/crypto/qce/skcipher.c
@@ -72,7 +72,7 @@ qce_skcipher_async_req_handle(struct crypto_async_request *async_req)
struct scatterlist *sg;
bool diff_dst;
gfp_t gfp;
- int ret;
+ int dst_nents, src_nents, ret;

rctx->iv = req->iv;
rctx->ivsize = crypto_skcipher_ivsize(skcipher);
@@ -123,21 +123,22 @@ qce_skcipher_async_req_handle(struct crypto_async_request *async_req)
sg_mark_end(sg);
rctx->dst_sg = rctx->dst_tbl.sgl;

- ret = dma_map_sg(qce->dev, rctx->dst_sg, rctx->dst_nents, dir_dst);
- if (ret < 0)
+ dst_nents = dma_map_sg(qce->dev, rctx->dst_sg, rctx->dst_nents, dir_dst);
+ if (dst_nents < 0)
goto error_free;

if (diff_dst) {
- ret = dma_map_sg(qce->dev, req->src, rctx->src_nents, dir_src);
- if (ret < 0)
+ src_nents = dma_map_sg(qce->dev, req->src, rctx->src_nents, dir_src);
+ if (src_nents < 0)
goto error_unmap_dst;
rctx->src_sg = req->src;
} else {
rctx->src_sg = rctx->dst_sg;
+ src_nents = dst_nents - 1;
}

- ret = qce_dma_prep_sgs(&qce->dma, rctx->src_sg, rctx->src_nents,
- rctx->dst_sg, rctx->dst_nents,
+ ret = qce_dma_prep_sgs(&qce->dma, rctx->src_sg, src_nents,
+ rctx->dst_sg, dst_nents,
qce_skcipher_done, async_req);
if (ret)
goto error_unmap_src;
--
2.25.1

2021-05-28 07:44:02

by Herbert Xu

Subject: Re: [PATCH] crypto: qce: skcipher: Fix incorrect sg count for dma transfers

On Thu, May 20, 2021 at 10:20:23PM -0400, Thara Gopinath wrote:
> Use the sg count returned by dma_map_sg to call into
> dmaengine_prep_slave_sg rather than using the original sg count. dma_map_sg
> can merge consecutive sglist entries, thus making the original sg count
> wrong. This is a fix for memory coruption issues observed while testing
> encryption/decryption of large messages using libkcapi framework.
>
> Patch has been tested further by running full suite of tcrypt.ko tests
> including fuzz tests.
>
> Signed-off-by: Thara Gopinath <[email protected]>
> ---
> drivers/crypto/qce/skcipher.c | 15 ++++++++-------
> 1 file changed, 8 insertions(+), 7 deletions(-)

Patch applied. Thanks.
--
Email: Herbert Xu <[email protected]>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt