diff options
| author | Jason Wang <jasowang@redhat.com> | 2013-07-10 13:43:28 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-07-28 16:26:04 -0700 |
| commit | 7d3f3dc17115e360f599c97c1882f9362e8330a5 (patch) | |
| tree | e60c77a16f0776627714aad2376595d46f83729c | |
| parent | f4a9457edcc8dc2c09b9fe5c0cd4cb8381d9205a (diff) | |
macvtap: correctly linearize skb when zerocopy is used
[ Upstream commit 61d46bf979d5cd7c164709a80ad5676a35494aae ]
Userspace may produce vectors greater than MAX_SKB_FRAGS. When we try to
linearize parts of the skb to let the rest of iov to be fit in
the frags, we need count copylen into linear when calling macvtap_alloc_skb()
instead of partly counting it into data_len. Since this breaks
zerocopy_sg_from_iovec() since its inner counter assumes nr_frags should
be zero at beginning. This cause nr_frags to be increased wrongly without
setting the correct frags.
This bug were introduced from b92946e2919134ebe2a4083e4302236295ea2a73
(macvtap: zerocopy: validate vectors before building skb).
Cc: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/net/macvtap.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c index bc5bf4014f70..5151f06c59ca 100644 --- a/drivers/net/macvtap.c +++ b/drivers/net/macvtap.c @@ -656,6 +656,7 @@ static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m, int vnet_hdr_len = 0; int copylen = 0; bool zerocopy = false; + size_t linear; if (q->flags & IFF_VNET_HDR) { vnet_hdr_len = q->vnet_hdr_sz; @@ -710,11 +711,14 @@ static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m, copylen = vnet_hdr.hdr_len; if (!copylen) copylen = GOODCOPY_LEN; - } else + linear = copylen; + } else { copylen = len; + linear = vnet_hdr.hdr_len; + } skb = macvtap_alloc_skb(&q->sk, NET_IP_ALIGN, copylen, - vnet_hdr.hdr_len, noblock, &err); + linear, noblock, &err); if (!skb) goto err; |