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| author | Paolo Abeni <pabeni@redhat.com> | 2018-12-21 19:03:13 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2018-12-21 19:24:54 +0100 |
| commit | e94e50bd88f7ed2f2d40c32c06efd61c36c33ec8 (patch) | |
| tree | 1f55d0dc8ed86a0de8756571386ae6a9922bcbac | |
| parent | bpf: fix segfault in test_verifier selftest (diff) | |
| download | linux-e94e50bd88f7ed2f2d40c32c06efd61c36c33ec8.tar.xz linux-e94e50bd88f7ed2f2d40c32c06efd61c36c33ec8.zip | |
net: fix possible user-after-free in skb_ext_add()
On cow we can free the old extension: we must avoid dereferencing
such extension after skb_ext_maybe_cow(). Since 'new' contents
are always equal to 'old' after the copy, we can fix the above
accessing the relevant data using 'new'.
Fixes: df5042f4c5b9 ("sk_buff: add skb extension infrastructure")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Acked-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/core/skbuff.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/net/core/skbuff.c b/net/core/skbuff.c index cb0bf4215745..e1d88762f659 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -5666,13 +5666,13 @@ void *skb_ext_add(struct sk_buff *skb, enum skb_ext_id id) if (!new) return NULL; - if (__skb_ext_exist(old, id)) { + if (__skb_ext_exist(new, id)) { if (old != new) skb->extensions = new; goto set_active; } - newoff = old->chunks; + newoff = new->chunks; } else { newoff = SKB_EXT_CHUNKSIZEOF(*new); |