| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.9 02/96] net: test tailroom before appending to linear skb | Date | Thu, 24 May 2018 11:37:45 +0200 |
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4.9-stable review patch. If anyone has any objections, please let me know.
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From: Willem de Bruijn <willemb@google.com>
[ Upstream commit 113f99c3358564a0647d444c2ae34e8b1abfd5b9 ]
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: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- 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 @@ -1076,7 +1076,8 @@ 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 @@ -1545,7 +1545,8 @@ 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;
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