Alexei Starovoitov b1977682a3 bpf: improve verifier packet range checks
llvm can optimize the 'if (ptr > data_end)' checks to be in the order
slightly different than the original C code which will confuse verifier.
Like:
if (ptr + 16 > data_end)
  return TC_ACT_SHOT;
// may be followed by
if (ptr + 14 > data_end)
  return TC_ACT_SHOT;
while llvm can see that 'ptr' is valid for all 16 bytes,
the verifier could not.
Fix verifier logic to account for such case and add a test.

Reported-by: Huapeng Zhou <hzhou@fb.com>
Fixes: 969bf05eb3ce ("bpf: direct packet access")
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-03-24 20:51:28 -07:00
..
2017-01-12 07:01:56 -07:00
2017-02-22 10:30:38 -08:00
2017-02-22 17:08:33 -08:00
2017-02-27 18:43:47 -08:00
2016-03-01 20:36:56 +01:00
2016-12-22 22:58:37 -05:00