Linux Virtualization - Jun 2020 - Patch "crypto: virtio: Fix src/dst scatterlist calculation in __virtio_crypto_skcipher_do_req()" has been added to the 5.6-stable tree

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

    crypto: virtio: Fix src/dst scatterlist calculation in
__virtio_crypto_skcipher_do_req()

to the 5.6-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-virtio-fix-src-dst-scatterlist-calculation-in-__virtio_crypto_skcipher_do_req.patch
and it can be found in the queue-5.6 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable at vger.kernel.org> know about it.

>From b02989f37fc5e865ceeee9070907e4493b3a21e2 Mon Sep 17 00:00:00 2001
From: "Longpeng(Mike)" <longpeng2 at huawei.com>
Date: Tue, 2 Jun 2020 15:04:59 +0800
Subject: crypto: virtio: Fix src/dst scatterlist calculation in
__virtio_crypto_skcipher_do_req()

From: Longpeng(Mike) <longpeng2 at huawei.com>

commit b02989f37fc5e865ceeee9070907e4493b3a21e2 upstream.

The system will crash when the users insmod crypto/tcrypt.ko with mode=38
( testing "cts(cbc(aes))" ).

Usually the next entry of one sg will be @sg@ + 1, but if this sg element
is part of a chained scatterlist, it could jump to the start of a new
scatterlist array. Fix it by sg_next() on calculation of src/dst
scatterlist.

Fixes: dbaf0624ffa5 ("crypto: add virtio-crypto driver")
Reported-by: LABBE Corentin <clabbe at baylibre.com>
Cc: Herbert Xu <herbert at gondor.apana.org.au>
Cc: "Michael S. Tsirkin" <mst at redhat.com>
Cc: Jason Wang <jasowang at redhat.com>
Cc: "David S. Miller" <davem at davemloft.net>
Cc: virtualization at lists.linux-foundation.org
Cc: linux-kernel at vger.kernel.org
Cc: stable at vger.kernel.org
Link: https://lore.kernel.org/r/20200123101000.GB24255 at Red
Signed-off-by: Gonglei <arei.gonglei at huawei.com>
Signed-off-by: Longpeng(Mike) <longpeng2 at huawei.com>
Link: https://lore.kernel.org/r/20200602070501.2023-2-longpeng2 at huawei.com
Signed-off-by: Michael S. Tsirkin <mst at redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>

---
 drivers/crypto/virtio/virtio_crypto_algs.c |   15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

--- a/drivers/crypto/virtio/virtio_crypto_algs.c
+++ b/drivers/crypto/virtio/virtio_crypto_algs.c
@@ -350,13 +350,18 @@ __virtio_crypto_skcipher_do_req(struct v
 	int err;
 	unsigned long flags;
 	struct scatterlist outhdr, iv_sg, status_sg, **sgs;
-	int i;
 	u64 dst_len;
 	unsigned int num_out = 0, num_in = 0;
 	int sg_total;
 	uint8_t *iv;
+	struct scatterlist *sg;
 
 	src_nents = sg_nents_for_len(req->src, req->cryptlen);
+	if (src_nents < 0) {
+		pr_err("Invalid number of src SG.\n");
+		return src_nents;
+	}
+
 	dst_nents = sg_nents(req->dst);
 
 	pr_debug("virtio_crypto: Number of sgs (src_nents: %d, dst_nents:
%d)\n",
@@ -443,12 +448,12 @@ __virtio_crypto_skcipher_do_req(struct v
 	vc_sym_req->iv = iv;
 
 	/* Source data */
-	for (i = 0; i < src_nents; i++)
-		sgs[num_out++] = &req->src[i];
+	for (sg = req->src; src_nents; sg = sg_next(sg), src_nents--)
+		sgs[num_out++] = sg;
 
 	/* Destination data */
-	for (i = 0; i < dst_nents; i++)
-		sgs[num_out + num_in++] = &req->dst[i];
+	for (sg = req->dst; sg; sg = sg_next(sg))
+		sgs[num_out + num_in++] = sg;
 
 	/* Status */
 	sg_init_one(&status_sg, &vc_req->status,
sizeof(vc_req->status));


Patches currently in stable-queue which might be from longpeng2 at huawei.com
are

queue-5.6/crypto-virtio-fix-src-dst-scatterlist-calculation-in-__virtio_crypto_skcipher_do_req.patch
queue-5.6/crypto-virtio-fix-dest-length-calculation-in-__virtio_crypto_skcipher_do_req.patch
queue-5.6/crypto-virtio-fix-use-after-free-in-virtio_crypto_skcipher_finalize_req.patch