| From: Willem de Bruijn <willemb@google.com> |
| Date: Thu, 17 May 2018 13:13:29 -0400 |
| Subject: net: test tailroom before appending to linear skb |
| |
| commit 113f99c3358564a0647d444c2ae34e8b1abfd5b9 upstream. |
| |
| Device features may change during transmission. In particular with |
| corking, a device may toggle scatter-gather in between allocating |
| and writing to an skb. |
| |
| Do not unconditionally assume that !NETIF_F_SG at write time implies |
| that the same held at alloc time and thus the skb has sufficient |
| tailroom. |
| |
| This issue predates git history. |
| |
| Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") |
| Reported-by: Eric Dumazet <edumazet@google.com> |
| Signed-off-by: Willem de Bruijn <willemb@google.com> |
| Reviewed-by: Eric Dumazet <edumazet@google.com> |
| Signed-off-by: David S. Miller <davem@davemloft.net> |
| Signed-off-by: Ben Hutchings <ben@decadent.org.uk> |
| --- |
| net/ipv4/ip_output.c | 3 ++- |
| net/ipv6/ip6_output.c | 3 ++- |
| 2 files changed, 4 insertions(+), 2 deletions(-) |
| |
| --- a/net/ipv4/ip_output.c |
| +++ b/net/ipv4/ip_output.c |
| @@ -1025,7 +1025,8 @@ alloc_new_skb: |
| if (copy > length) |
| copy = length; |
| |
| - if (!(rt->dst.dev->features&NETIF_F_SG)) { |
| + if (!(rt->dst.dev->features&NETIF_F_SG) && |
| + skb_tailroom(skb) >= copy) { |
| unsigned int off; |
| |
| off = skb->len; |
| --- a/net/ipv6/ip6_output.c |
| +++ b/net/ipv6/ip6_output.c |
| @@ -1453,7 +1453,8 @@ alloc_new_skb: |
| if (copy > length) |
| copy = length; |
| |
| - if (!(rt->dst.dev->features&NETIF_F_SG)) { |
| + if (!(rt->dst.dev->features&NETIF_F_SG) && |
| + skb_tailroom(skb) >= copy) { |
| unsigned int off; |
| |
| off = skb->len; |