Received-SPF: softfail (google.com: domain of transitioning linux-crypto-owner@vger.kernel.org does not designate 23.128.96.19 as permitted sender) client-ip=23.128.96.19;
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 19/19] crypto: sun8i-ce: do not fallback if cryptlen is less than sg length
Date:   Thu, 17 Mar 2022 20:56:05 +0000
Message-Id: <20220317205605.3924836-20-clabbe@baylibre.com>
In-Reply-To: <20220317205605.3924836-1-clabbe@baylibre.com>
References: <20220317205605.3924836-1-clabbe@baylibre.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

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>
---
 drivers/crypto/allwinner/sun8i-ce/sun8i-ce-cipher.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/crypto/allwinner/sun8i-ce/sun8i-ce-cipher.c b/drivers/crypto/allwinner/sun8i-ce/sun8i-ce-cipher.c
index 315a62e424d6..74b4e910a38d 100644
--- a/drivers/crypto/allwinner/sun8i-ce/sun8i-ce-cipher.c
+++ b/drivers/crypto/allwinner/sun8i-ce/sun8i-ce-cipher.c
@@ -27,6 +27,7 @@ static int sun8i_ce_cipher_need_fallback(struct skcipher_request *areq)
 	struct scatterlist *sg;
 	struct skcipher_alg *alg = crypto_skcipher_alg(tfm);
 	struct sun8i_ce_alg_template *algt;
+	unsigned int todo, len;
 
 	algt = container_of(alg, struct sun8i_ce_alg_template, alg.skcipher);
 
@@ -51,28 +52,35 @@ static int sun8i_ce_cipher_need_fallback(struct skcipher_request *areq)
 		return true;
 	}
 
+	len = areq->cryptlen;
 	sg = areq->src;
 	while (sg) {
 		if (!IS_ALIGNED(sg->offset, sizeof(u32))) {
 			algt->stat_fb_srcali++;
 			return true;
 		}
-		if (sg->length % 4) {
+		todo = min(len, sg->length);
+		if (todo % 4) {
 			algt->stat_fb_srclen++;
 			return true;
 		}
+		len -= todo;
 		sg = sg_next(sg);
 	}
+
+	len = areq->cryptlen;
 	sg = areq->dst;
 	while (sg) {
 		if (!IS_ALIGNED(sg->offset, sizeof(u32))) {
 			algt->stat_fb_dstali++;
 			return true;
 		}
-		if (sg->length % 4) {
+		todo = min(len, sg->length);
+		if (todo % 4) {
 			algt->stat_fb_dstlen++;
 			return true;
 		}
+		len -= todo;
 		sg = sg_next(sg);
 	}
 	return false;
-- 
2.34.1