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| author | Eric Dumazet <edumazet@google.com> | 2014-05-16 11:34:37 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-05-31 13:20:38 -0700 |
| commit | d83924d7681e7048d639debb614bdd1d9183d201 (patch) | |
| tree | 9c7160a7e6d791bdf5bc923f2cd5d0578293c1fa /net | |
| parent | 2132c5ea87fe6061762813b4f84b3846347de09c (diff) | |
| download | lwn-d83924d7681e7048d639debb614bdd1d9183d201.tar.gz lwn-d83924d7681e7048d639debb614bdd1d9183d201.zip | |
net: gro: make sure skb->cb[] initial content has not to be zero
[ Upstream commit 29e98242783ed3ba569797846a606ba66f781625 ]
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net')
| -rw-r--r-- | net/core/dev.c | 1 | ||||
| -rw-r--r-- | net/core/skbuff.c | 4 |
2 files changed, 3 insertions, 2 deletions
diff --git a/net/core/dev.c b/net/core/dev.c index 6de84014f3e0..62d29d94dbbf 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -3944,6 +3944,7 @@ 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 31d7cd79ff84..e5ae776ee9b4 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; |