diff options
| author | Jiong Wang <jiong.wang@netronome.com> | 2019-06-25 17:41:50 +0100 |
|---|---|---|
| committer | Daniel Borkmann <daniel@iogearbox.net> | 2019-06-26 14:48:20 +0200 |
| commit | 75672dda27bd00109a84cd975c17949ad9c45663 (patch) | |
| tree | b133c5796f60d4f2407d98ff14fcd59937605038 /kernel/bpf/core.c | |
| parent | 6c6874f401e5a0caab3b6a0663169e1fb5e930bb (diff) | |
bpf: fix BPF_ALU32 | BPF_ARSH on BE arches
Yauheni reported the following code do not work correctly on BE arches:
ALU_ARSH_X:
DST = (u64) (u32) ((*(s32 *) &DST) >> SRC);
CONT;
ALU_ARSH_K:
DST = (u64) (u32) ((*(s32 *) &DST) >> IMM);
CONT;
and are causing failure of test_verifier test 'arsh32 on imm 2' on BE
arches.
The code is taking address and interpreting memory directly, so is not
endianness neutral. We should instead perform standard C type casting on
the variable. A u64 to s32 conversion will drop the high 32-bit and reserve
the low 32-bit as signed integer, this is all we want.
Fixes: 2dc6b100f928 ("bpf: interpreter support BPF_ALU | BPF_ARSH")
Reported-by: Yauheni Kaliuta <yauheni.kaliuta@redhat.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Diffstat (limited to 'kernel/bpf/core.c')
| -rw-r--r-- | kernel/bpf/core.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 080e2bb644cc..f2148db91439 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -1364,10 +1364,10 @@ select_insn: insn++; CONT; ALU_ARSH_X: - DST = (u64) (u32) ((*(s32 *) &DST) >> SRC); + DST = (u64) (u32) (((s32) DST) >> SRC); CONT; ALU_ARSH_K: - DST = (u64) (u32) ((*(s32 *) &DST) >> IMM); + DST = (u64) (u32) (((s32) DST) >> IMM); CONT; ALU64_ARSH_X: (*(s64 *) &DST) >>= SRC; |