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| author | Jason Wang <jasowang@redhat.com> | 2013-07-10 13:43:28 +0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2013-07-10 18:45:52 -0700 |
| commit | 61d46bf979d5cd7c164709a80ad5676a35494aae (patch) | |
| tree | c7054c34dacaa95f2e4b63c61baf8227deab7581 | |
| parent | 3dd5c3308e8b671e8e8882ba972f51cefbe9fd0d (diff) | |
| download | linux-61d46bf979d5cd7c164709a80ad5676a35494aae.tar.gz linux-61d46bf979d5cd7c164709a80ad5676a35494aae.tar.bz2 linux-61d46bf979d5cd7c164709a80ad5676a35494aae.zip | |
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, 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; @@ -766,11 +767,14 @@ 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; |