From: Willem de Bruijn <willemb@google.com>
Subject: net: test tailroom before appending to linear skb
Patch-mainline: v4.17-rc7
Git-commit: 113f99c3358564a0647d444c2ae34e8b1abfd5b9
References: git-fixes
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>
Acked-by: Denis Kirjanov <dkirjanov@suse.com>
---
net/ipv4/ip_output.c | 3 ++-
net/ipv6/ip6_output.c | 3 ++-
2 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index 41c5d8bdc768..c81916930652 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -1042,7 +1042,8 @@ static int __ip_append_data(struct sock *sk,
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;
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 42a97e490737..04729272dfb3 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -1484,7 +1484,8 @@ static int __ip6_append_data(struct sock *sk,
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;
--
2.12.3