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authorWillem de Bruijn <willemb@google.com>2016-03-08 15:18:54 -0500
committerDavid S. Miller <davem@davemloft.net>2016-03-11 14:45:21 -0500
commit8e2ad4113ce4671686740f808ff2795395c39eef (patch)
tree864a6adc34ad064f7c9ffae05e15776078c4224e /drivers/net/macvtap.c
parent8208d21bf309551686b7a76d19059ae182a956d0 (diff)
macvtap: always pass ethernet header in linear
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>
Diffstat (limited to 'drivers/net/macvtap.c')
-rw-r--r--drivers/net/macvtap.c9
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,