diff options
author | Jason Wang <jasowang@redhat.com> | 2013-07-10 01:43:28 -0400 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2013-07-10 21:45:52 -0400 |
commit | 61d46bf979d5cd7c164709a80ad5676a35494aae (patch) | |
tree | c7054c34dacaa95f2e4b63c61baf8227deab7581 | |
parent | 3dd5c3308e8b671e8e8882ba972f51cefbe9fd0d (diff) |
macvtap: correctly linearize skb when zerocopy is used
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>
-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 f2c4a3b218fc..876c72246ae9 100644 --- a/drivers/net/macvtap.c +++ b/drivers/net/macvtap.c | |||
@@ -712,6 +712,7 @@ static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m, | |||
712 | int vnet_hdr_len = 0; | 712 | int vnet_hdr_len = 0; |
713 | int copylen = 0; | 713 | int copylen = 0; |
714 | bool zerocopy = false; | 714 | bool zerocopy = false; |
715 | size_t linear; | ||
715 | 716 | ||
716 | if (q->flags & IFF_VNET_HDR) { | 717 | if (q->flags & IFF_VNET_HDR) { |
717 | vnet_hdr_len = q->vnet_hdr_sz; | 718 | vnet_hdr_len = q->vnet_hdr_sz; |
@@ -766,11 +767,14 @@ static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m, | |||
766 | copylen = vnet_hdr.hdr_len; | 767 | copylen = vnet_hdr.hdr_len; |
767 | if (!copylen) | 768 | if (!copylen) |
768 | copylen = GOODCOPY_LEN; | 769 | copylen = GOODCOPY_LEN; |
769 | } else | 770 | linear = copylen; |
771 | } else { | ||
770 | copylen = len; | 772 | copylen = len; |
773 | linear = vnet_hdr.hdr_len; | ||
774 | } | ||
771 | 775 | ||
772 | skb = macvtap_alloc_skb(&q->sk, NET_IP_ALIGN, copylen, | 776 | skb = macvtap_alloc_skb(&q->sk, NET_IP_ALIGN, copylen, |
773 | vnet_hdr.hdr_len, noblock, &err); | 777 | linear, noblock, &err); |
774 | if (!skb) | 778 | if (!skb) |
775 | goto err; | 779 | goto err; |
776 | 780 | ||