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| author | Yonghong Song <yhs@fb.com> | 2023-04-06 19:45:05 +0300 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2023-04-07 01:26:08 +0300 |
| commit | 953d9f5beaf75e88c69a13d70ce424cd606a29f5 (patch) | |
| tree | 2c3b22c17cf94f504e60fc5659a5066a34c58d12 /tools | |
| parent | aec08d677b4d0adeb7412fa98547cf07bfce6fea (diff) | |
| download | linux-953d9f5beaf75e88c69a13d70ce424cd606a29f5.tar.xz | |
bpf: Improve handling of pattern '<const> <cond_op> <non_const>' in verifier
Currently, the verifier does not handle '<const> <cond_op> <non_const>' well.
For example,
...
10: (79) r1 = *(u64 *)(r10 -16) ; R1_w=scalar() R10=fp0
11: (b7) r2 = 0 ; R2_w=0
12: (2d) if r2 > r1 goto pc+2
13: (b7) r0 = 0
14: (95) exit
15: (65) if r1 s> 0x1 goto pc+3
16: (0f) r0 += r1
...
At insn 12, verifier decides both true and false branch are possible, but
actually only false branch is possible.
Currently, the verifier already supports patterns '<non_const> <cond_op> <const>.
Add support for patterns '<const> <cond_op> <non_const>' in a similar way.
Also fix selftest 'verifier_bounds_mix_sign_unsign/bounds checks mixing signed and unsigned, variant 10'
due to this change.
Signed-off-by: Yonghong Song <yhs@fb.com>
Acked-by: Dave Marchevsky <davemarchevsky@fb.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230406164505.1046801-1-yhs@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/testing/selftests/bpf/progs/verifier_bounds_mix_sign_unsign.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/tools/testing/selftests/bpf/progs/verifier_bounds_mix_sign_unsign.c b/tools/testing/selftests/bpf/progs/verifier_bounds_mix_sign_unsign.c index 91a66357896a..4f40144748a5 100644 --- a/tools/testing/selftests/bpf/progs/verifier_bounds_mix_sign_unsign.c +++ b/tools/testing/selftests/bpf/progs/verifier_bounds_mix_sign_unsign.c @@ -354,7 +354,7 @@ __naked void signed_and_unsigned_variant_10(void) call %[bpf_map_lookup_elem]; \ if r0 == 0 goto l0_%=; \ r1 = *(u64*)(r10 - 16); \ - r2 = 0; \ + r2 = -1; \ if r2 > r1 goto l1_%=; \ r0 = 0; \ exit; \ |