diff options
| author | Felix Maurer <fmaurer@redhat.com> | 2022-02-09 16:55:26 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-03-02 11:42:48 +0100 |
| commit | d0caa7218d76b373d404545b4e63d72af338939f (patch) | |
| tree | 5deddd567668d875c2fb15c3ce0d0e5b04cdd2fc /net/core | |
| parent | 962b2a3188bfa5388756ffbc47dfa5ff59cb8011 (diff) | |
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')
| -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 7fa4283f2a8c..659a32802471 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -2730,6 +2730,9 @@ 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 { |