linux-kernel - [PATCH 15/19] crypto: sun8i-ss: do not fallback if cryptlen is less than sg length

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Date:   Thu, 17 Mar 2022 20:56:01 +0000
From:   Corentin Labbe <clabbe@...libre.com>
To:     herbert@...dor.apana.org.au, jernej.skrabec@...il.com,
        samuel@...lland.org, wens@...e.org
Cc:     linux-arm-kernel@...ts.infradead.org, linux-crypto@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-sunxi@...ts.linux.dev,
        Corentin Labbe <clabbe@...libre.com>
Subject: [PATCH 15/19] crypto: sun8i-ss: do not fallback if cryptlen is less than sg length

The sg length could be more than remaining data on it.
So check the length requirement against the minimum between those two
values.

Signed-off-by: Corentin Labbe <clabbe@...libre.com>
---
 .../allwinner/sun8i-ss/sun8i-ss-cipher.c      | 19 +++++++++----------
 1 file changed, 9 insertions(+), 10 deletions(-)

diff --git a/drivers/crypto/allwinner/sun8i-ss/sun8i-ss-cipher.c b/drivers/crypto/allwinner/sun8i-ss/sun8i-ss-cipher.c
index 7f1940c6cc41..5bb950182026 100644
--- a/drivers/crypto/allwinner/sun8i-ss/sun8i-ss-cipher.c
+++ b/drivers/crypto/allwinner/sun8i-ss/sun8i-ss-cipher.c
@@ -28,6 +28,7 @@ static bool sun8i_ss_need_fallback(struct skcipher_request *areq)
 	struct scatterlist *in_sg = areq->src;
 	struct scatterlist *out_sg = areq->dst;
 	struct scatterlist *sg;
+	unsigned int todo, len;
 
 	if (areq->cryptlen == 0 || areq->cryptlen % 16) {
 		algt->stat_fb_len++;
@@ -40,13 +41,11 @@ static bool sun8i_ss_need_fallback(struct skcipher_request *areq)
 		return true;
 	}
 
+	len = areq->cryptlen;
 	sg = areq->src;
 	while (sg) {
-		if ((sg->length % 16) != 0) {
-			algt->stat_fb_sglen++;
-			return true;
-		}
-		if ((sg_dma_len(sg) % 16) != 0) {
+		todo = min(len, sg->length);
+		if ((todo % 16) != 0) {
 			algt->stat_fb_sglen++;
 			return true;
 		}
@@ -54,15 +53,14 @@ static bool sun8i_ss_need_fallback(struct skcipher_request *areq)
 			algt->stat_fb_align++;
 			return true;
 		}
+		len -= todo;
 		sg = sg_next(sg);
 	}
+	len = areq->cryptlen;
 	sg = areq->dst;
 	while (sg) {
-		if ((sg->length % 16) != 0) {
-			algt->stat_fb_sglen++;
-			return true;
-		}
-		if ((sg_dma_len(sg) % 16) != 0) {
+		todo = min(len, sg->length);
+		if ((todo % 16) != 0) {
 			algt->stat_fb_sglen++;
 			return true;
 		}
@@ -70,6 +68,7 @@ static bool sun8i_ss_need_fallback(struct skcipher_request *areq)
 			algt->stat_fb_align++;
 			return true;
 		}
+		len -= todo;
 		sg = sg_next(sg);
 	}
 
-- 
2.34.1