diff options
| author | Yonghong Song <yhs@fb.com> | 2017-04-30 05:52:42 (GMT) |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-05-14 12:00:20 (GMT) |
| commit | 7bca0a9702edfc8d0e7e46f984ca422ffdbe0498 (patch) | |
| tree | 0ba7e16e8d344286ab284b4c4e5cc83a3c81e46f /lib | |
| parent | f3235cbd5be15aa084d5561c2eb8492ed68cd7e5 (diff) | |
| download | linux-7bca0a9702edfc8d0e7e46f984ca422ffdbe0498.tar.xz | |
bpf: enhance verifier to understand stack pointer arithmetic
[ Upstream commit 332270fdc8b6fba07d059a9ad44df9e1a2ad4529 ]
llvm 4.0 and above generates the code like below:
....
440: (b7) r1 = 15
441: (05) goto pc+73
515: (79) r6 = *(u64 *)(r10 -152)
516: (bf) r7 = r10
517: (07) r7 += -112
518: (bf) r2 = r7
519: (0f) r2 += r1
520: (71) r1 = *(u8 *)(r8 +0)
521: (73) *(u8 *)(r2 +45) = r1
....
and the verifier complains "R2 invalid mem access 'inv'" for insn #521.
This is because verifier marks register r2 as unknown value after #519
where r2 is a stack pointer and r1 holds a constant value.
Teach verifier to recognize "stack_ptr + imm" and
"stack_ptr + reg with const val" as valid stack_ptr with new offset.
Signed-off-by: Yonghong Song <yhs@fb.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'lib')
0 files changed, 0 insertions, 0 deletions