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| author | Felix Maurer <fmaurer@redhat.com> | 2022-02-09 18:55:26 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-03-02 13:47:55 +0300 |
| commit | 5d75e374eb7700fff1aaa98899fb6b25a9bbb87a (patch) | |
| tree | 8f4605dc81e1fe53997e8e2c17ca867b92974992 /net/core/filter.c | |
| parent | 719d1c2524c89ada78c4c9202641c1d9e942a322 (diff) | |
| download | linux-5d75e374eb7700fff1aaa98899fb6b25a9bbb87a.tar.xz | |
bpf: Do not try bpf_msg_push_data with len 0
commit 4a11678f683814df82fca9018d964771e02d7e6d upstream.
If bpf_msg_push_data() is called with len 0 (as it happens during
selftests/bpf/test_sockmap), we do not need to do anything and can
return early.
Calling bpf_msg_push_data() with len 0 previously lead to a wrong ENOMEM
error: we later called get_order(copy + len); if len was 0, copy + len
was also often 0 and get_order() returned some undefined value (at the
moment 52). alloc_pages() caught that and failed, but then bpf_msg_push_data()
returned ENOMEM. This was wrong because we are most probably not out of
memory and actually do not need any additional memory.
Fixes: 6fff607e2f14b ("bpf: sk_msg program helper bpf_msg_push_data")
Signed-off-by: Felix Maurer <fmaurer@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/df69012695c7094ccb1943ca02b4920db3537466.1644421921.git.fmaurer@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net/core/filter.c')
| -rw-r--r-- | net/core/filter.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/net/core/filter.c b/net/core/filter.c index f207e4782bd0..76e406965b6f 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -2711,6 +2711,9 @@ BPF_CALL_4(bpf_msg_push_data, struct sk_msg *, msg, u32, start, if (unlikely(flags)) return -EINVAL; + if (unlikely(len == 0)) + return 0; + /* First find the starting scatterlist element */ i = msg->sg.start; do { |