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authorEric Dumazet <edumazet@google.com>2017-04-26 09:09:23 -0700
committerDavid S. Miller <davem@davemloft.net>2017-04-30 22:23:16 -0400
commitd1f496fd8f34a40458d0eda6be0655926559e546 (patch)
tree06b7b187db463b7e59a63e20498e5a57027399d1 /net
parentae3696c167cc04d32634c4af82f43b446c5176b0 (diff)
bpf: restore skb->sk before pskb_trim() call
While testing a fix [1] in ___pskb_trim(), addressing the WARN_ON_ONCE() in skb_try_coalesce() reported by Andrey, I found that we had an skb with skb->sk set but no skb->destructor. This invalidated heuristic found in commit 158f323b9868 ("net: adjust skb->truesize in pskb_expand_head()") and in cited patch. Considering the BUG_ON(skb->sk) we have in skb_orphan(), we should restrain the temporary setting to a minimal section. [1] https://patchwork.ozlabs.org/patch/755570/ net: adjust skb->truesize in ___pskb_trim() Fixes: 8f917bba0042 ("bpf: pass sk to helper functions") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Willem de Bruijn <willemb@google.com> Cc: Andrey Konovalov <andreyknvl@google.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/core/filter.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/net/core/filter.c b/net/core/filter.c
index 9a37860a80fc..a253a6197e6b 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -98,8 +98,8 @@ int sk_filter_trim_cap(struct sock *sk, struct sk_buff *skb, unsigned int cap)
skb->sk = sk;
pkt_len = bpf_prog_run_save_cb(filter->prog, skb);
- err = pkt_len ? pskb_trim(skb, max(cap, pkt_len)) : -EPERM;
skb->sk = save_sk;
+ err = pkt_len ? pskb_trim(skb, max(cap, pkt_len)) : -EPERM;
}
rcu_read_unlock();