bpf: sockmap, error path can not release psock in multi-map case

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The current code, in the error path of sock_hash_ctx_update_elem,
checks if the sock has a psock in the user data and if so decrements
the reference count of the psock. However, if the error happens early
in the error path we may have never incremented the psock reference
count and if the psock exists because the sock is in another map then
we may inadvertently decrement the reference count.

Fix this by making the error path only call smap_release_sock if the
error happens after the increment.

Reported-by: syzbot+d464d2c20c717ef5a6a8@syzkaller.appspotmail.com
Fixes: 8111038444 ("bpf: sockmap, add hash map support")
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

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John Fastabend 2018-07-05 08:05:56 -07:00 • committed by Alexei Starovoitov

parent c48424d993

commit 547b3aa451

1 changed files with 6 additions and 11 deletions

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kernel/bpf/sockmap.c

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