Merge branch 'bpf-ptrs-beyond-pkt-end'

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Alexei Starovoitov says:

====================
v1->v2:
- removed set-but-unused variable.
- added Jiri's Tested-by.

In some cases LLVM uses the knowledge that branch is taken to optimze the code
which causes the verifier to reject valid programs.
Teach the verifier to recognize that
r1 = skb->data;
r1 += 10;
r2 = skb->data_end;
if (r1 > r2) {
  here r1 points beyond packet_end and subsequent
  if (r1 > r2) // always evaluates to "true".
}
====================

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

...

This commit is contained in:

Daniel Borkmann 2020-11-13 01:42:12 +01:00

parent c36538798f cb62d34019

commit 0a58a65cc0

5 changed files with 245 additions and 23 deletions

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2

include/linux/bpf_verifier.h

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129

kernel/bpf/verifier.c

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41

tools/testing/selftests/bpf/prog_tests/test_skb_pkt_end.c

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54

tools/testing/selftests/bpf/progs/skb_pkt_end.c

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42

tools/testing/selftests/bpf/verifier/ctx_skb.c

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