diff mbox series

[v2,1/2] crypto: virtio: Fix src/dst scatterlist calculation in __virtio_crypto_skcipher_do_req()

Message ID 20200526031956.1897-2-longpeng2@huawei.com (mailing list archive)
State Superseded
Delegated to: Herbert Xu
Headers show
Series crypto: virtio: Fix two crash issue | expand

Commit Message

Longpeng(Mike) May 26, 2020, 3:19 a.m. UTC
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@baylibre.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Markus Elfring <Markus.Elfring@web.de>
Cc: virtualization@lists.linux-foundation.org
Cc: linux-kernel@vger.kernel.org
Cc: stable@vger.kernel.org
Message-Id: <20200123101000.GB24255@Red>
Signed-off-by: Gonglei <arei.gonglei@huawei.com>
Signed-off-by: Longpeng(Mike) <longpeng2@huawei.com>
---
 drivers/crypto/virtio/virtio_crypto_algs.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

Comments

Markus Elfring May 26, 2020, 7:03 a.m. UTC | #1
> Fix it by sg_next() on calculation of src/dst scatterlist.

Wording adjustment:
… by calling the function “sg_next” …


…
> +++ b/drivers/crypto/virtio/virtio_crypto_algs.c
> @@ -350,13 +350,18 @@ __virtio_crypto_skcipher_do_req(struct virtio_crypto_sym_request *vc_sym_req,>  	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);
…

I suggest to move the addition of such input parameter validation
to a separate update step.

Regards,
Markus
Longpeng(Mike) May 26, 2020, 7:21 a.m. UTC | #2
Hi Markus,

On 2020/5/26 15:03, Markus Elfring wrote:
>> Fix it by sg_next() on calculation of src/dst scatterlist.
> 
> Wording adjustment:
> … by calling the function “sg_next” …
> 
OK, thanks.

> 
> …
>> +++ b/drivers/crypto/virtio/virtio_crypto_algs.c
>> @@ -350,13 +350,18 @@ __virtio_crypto_skcipher_do_req(struct virtio_crypto_sym_request *vc_sym_req,
> …
>>  	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);
> …
> 
> I suggest to move the addition of such input parameter validation
> to a separate update step.
> 
Um...The 'src_nents' will be used as a loop condition, so validate it here is
needed ?

'''
 	/* 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;
'''

> Regards,
> Markus
>
Markus Elfring May 26, 2020, 8:25 a.m. UTC | #3
>> I suggest to move the addition of such input parameter validation
>> to a separate update step.
>>
> Um...The 'src_nents' will be used as a loop condition,
> so validate it here is needed ?

Would you prefer to add such checking as the first update in
another small patch series?

Regards,
Markus
Sasha Levin May 26, 2020, 2:11 p.m. UTC | #4
<20200123101000.GB24255@Red>
References: <20200526031956.1897-2-longpeng2@huawei.com>
<20200123101000.GB24255@Red>

Hi

[This is an automated email]

This commit has been processed because it contains a "Fixes:" tag
fixing commit: dbaf0624ffa5 ("crypto: add virtio-crypto driver").

The bot has tested the following trees: v5.6.14, v5.4.42, v4.19.124, v4.14.181.

v5.6.14: Build OK!
v5.4.42: Failed to apply! Possible dependencies:
    eee1d6fca0a0 ("crypto: virtio - switch to skcipher API")

v4.19.124: Failed to apply! Possible dependencies:
    eee1d6fca0a0 ("crypto: virtio - switch to skcipher API")

v4.14.181: Failed to apply! Possible dependencies:
    500e6807ce93 ("crypto: virtio - implement missing support for output IVs")
    67189375bb3a ("crypto: virtio - convert to new crypto engine API")
    d0d859bb87ac ("crypto: virtio - Register an algo only if it's supported")
    e02b8b43f55a ("crypto: virtio - pr_err() strings should end with newlines")
    eee1d6fca0a0 ("crypto: virtio - switch to skcipher API")


NOTE: The patch will not be queued to stable trees until it is upstream.

How should we proceed with this patch?
diff mbox series

Patch

diff --git a/drivers/crypto/virtio/virtio_crypto_algs.c b/drivers/crypto/virtio/virtio_crypto_algs.c
index fd045e64972a..5f8243563009 100644
--- 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 virtio_crypto_sym_request *vc_sym_req,
 	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",
@@ -442,12 +447,12 @@  __virtio_crypto_skcipher_do_req(struct virtio_crypto_sym_request *vc_sym_req,
 	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));