In xdp_linearize_page, when reading the following buffers from the ring,
we forget to check the received length with the true allocate size. This
can lead to an out-of-bound read. This commit adds that missing check.
Fixes: 4941d472bf95 ("virtio-net: do not reset during XDP set")
Signed-off-by: Bui Quang Minh <[email protected]>
---
drivers/net/virtio_net.c | 27 ++++++++++++++++++++++-----
1 file changed, 22 insertions(+), 5 deletions(-)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index e53ba600605a..2a130a3e50ac 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -1797,7 +1797,8 @@ static unsigned int virtnet_get_headroom(struct
virtnet_info *vi)
* across multiple buffers (num_buf > 1), and we make sure buffers
* have enough headroom.
*/
-static struct page *xdp_linearize_page(struct receive_queue *rq,
+static struct page *xdp_linearize_page(struct net_device *dev,
+ struct receive_queue *rq,
int *num_buf,
struct page *p,
int offset,
@@ -1818,17 +1819,33 @@ static struct page *xdp_linearize_page(struct
receive_queue *rq,
page_off += *len;
while (--*num_buf) {
- unsigned int buflen;
+ unsigned int headroom, tailroom, room;
+ unsigned int truesize, buflen;
void *buf;
+ void *ctx;
int off;
- buf = virtnet_rq_get_buf(rq, &buflen, NULL);
+ buf = virtnet_rq_get_buf(rq, &buflen, &ctx);
if (unlikely(!buf))
goto err_buf;
p = virt_to_head_page(buf);
off = buf - page_address(p);
+ truesize = mergeable_ctx_to_truesize(ctx);
+ headroom = mergeable_ctx_to_headroom(ctx);
+ tailroom = headroom ? sizeof(struct skb_shared_info) : 0;
+ room = SKB_DATA_ALIGN(headroom + tailroom);
+
+ if (unlikely(buflen > truesize - room)) {
+ put_page(p);
+ pr_debug("%s: rx error: len %u exceeds truesize %lu\n",
+ dev->name, buflen,
+ (unsigned long)(truesize - room));
+ DEV_STATS_INC(dev, rx_length_errors);
+ goto err_buf;
+ }
+
/* guard against a misconfigured or uncooperative backend that
* is sending packet larger than the MTU.
*/
@@ -1917,7 +1934,7 @@ static struct sk_buff *receive_small_xdp(struct
net_device *dev,
headroom = vi->hdr_len + header_offset;
buflen = SKB_DATA_ALIGN(GOOD_PACKET_LEN + headroom) +
SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
- xdp_page = xdp_linearize_page(rq, &num_buf, page,
+ xdp_page = xdp_linearize_page(dev, rq, &num_buf, page,
offset, header_offset,
&tlen);
if (!xdp_page)
@@ -2252,7 +2269,7 @@ static void *mergeable_xdp_get_buf(struct virtnet_info
*vi,
*/
if (!xdp_prog->aux->xdp_has_frags) {
/* linearize data for XDP */
- xdp_page = xdp_linearize_page(rq, num_buf,
+ xdp_page = xdp_linearize_page(vi->dev, rq, num_buf,
*page, offset,
XDP_PACKET_HEADROOM,
len);
--
2.43.0
