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From:   Corentin Labbe <clabbe@baylibre.com>
To:     herbert@gondor.apana.org.au, jernej.skrabec@gmail.com,
        samuel@sholland.org, wens@csie.org
Cc:     linux-arm-kernel@lists.infradead.org, linux-crypto@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-sunxi@lists.linux.dev,
        Corentin Labbe <clabbe@baylibre.com>
Subject: [PATCH v2 15/19] crypto: sun8i-ss: do not fallback if cryptlen is less than sg length
Date:   Mon,  2 May 2022 20:19:25 +0000
Message-Id: <20220502201929.843194-16-clabbe@baylibre.com>
In-Reply-To: <20220502201929.843194-1-clabbe@baylibre.com>
References: <20220502201929.843194-1-clabbe@baylibre.com>
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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@baylibre.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);
 	}
 
-- 
2.35.1