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| author | Willem de Bruijn <willemb@google.com> | 2016-03-08 15:18:54 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-04-20 15:45:11 +0900 |
| commit | 866fdf66d246e453072a7e004c60f6c9c6c0f4bc (patch) | |
| tree | b12a275f566c4f07e12def25db34d30f0dc8964c /drivers/net | |
| parent | 79ad48ee3ce1c3ab186465a6e741cb38a1f0d748 (diff) | |
| download | lwn-866fdf66d246e453072a7e004c60f6c9c6c0f4bc.tar.gz lwn-866fdf66d246e453072a7e004c60f6c9c6c0f4bc.zip | |
macvtap: always pass ethernet header in linear
[ Upstream commit 8e2ad4113ce4671686740f808ff2795395c39eef ]
The stack expects link layer headers in the skb linear section.
Macvtap can create skbs with llheader in frags in edge cases:
when (IFF_VNET_HDR is off or vnet_hdr.hdr_len < ETH_HLEN) and
prepad + len > PAGE_SIZE and vnet_hdr.flags has no or bad csum.
Add checks to ensure linear is always at least ETH_HLEN.
At this point, len is already ensured to be >= ETH_HLEN.
For backwards compatiblity, rounds up short vnet_hdr.hdr_len.
This differs from tap and packet, which return an error.
Fixes b9fb9ee07e67 ("macvtap: add GSO/csum offload support")
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/net')
| -rw-r--r-- | drivers/net/macvtap.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c index d636d051fac8..95394edd1ed5 100644 --- a/drivers/net/macvtap.c +++ b/drivers/net/macvtap.c @@ -760,6 +760,8 @@ static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m, macvtap16_to_cpu(q, vnet_hdr.hdr_len) : GOODCOPY_LEN; if (copylen > good_linear) copylen = good_linear; + else if (copylen < ETH_HLEN) + copylen = ETH_HLEN; linear = copylen; i = *from; iov_iter_advance(&i, copylen); @@ -769,10 +771,11 @@ static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m, if (!zerocopy) { copylen = len; - if (macvtap16_to_cpu(q, vnet_hdr.hdr_len) > good_linear) + linear = macvtap16_to_cpu(q, vnet_hdr.hdr_len); + if (linear > good_linear) linear = good_linear; - else - linear = macvtap16_to_cpu(q, vnet_hdr.hdr_len); + else if (linear < ETH_HLEN) + linear = ETH_HLEN; } skb = macvtap_alloc_skb(&q->sk, MACVTAP_RESERVE, copylen, |