Patch "crypto: qce: skcipher: Fix incorrect sg count for dma transfers" has been added to the 5.12-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    crypto: qce: skcipher: Fix incorrect sg count for dma transfers

to the 5.12-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     crypto-qce-skcipher-fix-incorrect-sg-count-for-dma-t.patch
and it can be found in the queue-5.12 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 1a28aa9626486c25f1adc4e2f40d1235a981fc28
Author: Thara Gopinath <thara.gopinath@xxxxxxxxxx>
Date:   Thu May 20 22:20:23 2021 -0400

    crypto: qce: skcipher: Fix incorrect sg count for dma transfers
    
    [ Upstream commit 1339a7c3ba05137a2d2fe75f602311bbfc6fab33 ]
    
    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 <thara.gopinath@xxxxxxxxxx>
    Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/crypto/qce/skcipher.c b/drivers/crypto/qce/skcipher.c
index a2d3da0ad95f..5a6559131eac 100644
--- a/drivers/crypto/qce/skcipher.c
+++ b/drivers/crypto/qce/skcipher.c
@@ -71,7 +71,7 @@ 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);
@@ -122,21 +122,22 @@ 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;