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authorEric Dumazet <edumazet@google.com>2014-05-16 22:34:37 +0400
committerDavid S. Miller <davem@davemloft.net>2014-05-17 01:24:54 +0400
commit29e98242783ed3ba569797846a606ba66f781625 (patch)
tree2d71da0d89ef9f62a4d244fc8d8a92d3f81a802c
parent22fb22eaebf4d16987f3fd9c3484c436ee0badf2 (diff)
downloadlinux-29e98242783ed3ba569797846a606ba66f781625.tar.xz
net: gro: make sure skb->cb[] initial content has not to be zero
Starting from linux-3.13, GRO attempts to build full size skbs. Problem is the commit assumed one particular field in skb->cb[] was clean, but it is not the case on some stacked devices. Timo reported a crash in case traffic is decrypted before reaching a GRE device. Fix this by initializing NAPI_GRO_CB(skb)->last at the right place, this also removes one conditional. Thanks a lot to Timo for providing full reports and bisecting this. Fixes: 8a29111c7ca6 ("net: gro: allow to build full sized skb") Bisected-by: Timo Teras <timo.teras@iki.fi> Signed-off-by: Eric Dumazet <edumazet@google.com> Tested-by: Timo Teräs <timo.teras@iki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/core/dev.c1
-rw-r--r--net/core/skbuff.c4
2 files changed, 3 insertions, 2 deletions
diff --git a/net/core/dev.c b/net/core/dev.c
index 6da649bde4f7..ed928e846559 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3951,6 +3951,7 @@ static enum gro_result dev_gro_receive(struct napi_struct *napi, struct sk_buff
}
NAPI_GRO_CB(skb)->count = 1;
NAPI_GRO_CB(skb)->age = jiffies;
+ NAPI_GRO_CB(skb)->last = skb;
skb_shinfo(skb)->gso_size = skb_gro_len(skb);
skb->next = napi->gro_list;
napi->gro_list = skb;
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 1b62343f5837..8383b2bddeb9 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -3076,7 +3076,7 @@ int skb_gro_receive(struct sk_buff **head, struct sk_buff *skb)
if (unlikely(p->len + len >= 65536))
return -E2BIG;
- lp = NAPI_GRO_CB(p)->last ?: p;
+ lp = NAPI_GRO_CB(p)->last;
pinfo = skb_shinfo(lp);
if (headlen <= offset) {
@@ -3192,7 +3192,7 @@ merge:
__skb_pull(skb, offset);
- if (!NAPI_GRO_CB(p)->last)
+ if (NAPI_GRO_CB(p)->last == p)
skb_shinfo(p)->frag_list = skb;
else
NAPI_GRO_CB(p)->last->next = skb;