diff options
| author | Eric Dumazet <edumazet@google.com> | 2018-01-29 02:48:59 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-01-31 12:55:57 +0100 |
| commit | 4606077802f2c6ef7aff5185d9f7d99a50784ffd (patch) | |
| tree | 328f8d08adf0c402cbf230f32857a55d94a13faf /kernel | |
| parent | 5cb917aa1f1e03df9a4c29b363e3900d73508fa8 (diff) | |
bpf: fix divides by zero
[ upstream commit c366287ebd698ef5e3de300d90cd62ee9ee7373e ]
Divides by zero are not nice, lets avoid them if possible.
Also do_div() seems not needed when dealing with 32bit operands,
but this seems a minor detail.
Fixes: bd4cf0ed331a ("net: filter: rework/optimize internal BPF interpreter's instruction set")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel')
| -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 64c4b13952f0..879ca844ba1d 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -642,7 +642,7 @@ select_insn: DST = tmp; CONT; ALU_MOD_X: - if (unlikely(SRC == 0)) + if (unlikely((u32)SRC == 0)) return 0; tmp = (u32) DST; DST = do_div(tmp, (u32) SRC); @@ -661,7 +661,7 @@ select_insn: DST = div64_u64(DST, SRC); CONT; ALU_DIV_X: - if (unlikely(SRC == 0)) + if (unlikely((u32)SRC == 0)) return 0; tmp = (u32) DST; do_div(tmp, (u32) SRC); |