diff options
| author | Eric Dumazet <edumazet@google.com> | 2018-01-29 00:36:44 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-01-31 14:03:50 +0100 |
| commit | 6eca013bef784aaf7be1a6262e3fe2de75476166 (patch) | |
| tree | 353fb0a5fb4f3c34a7873af56613214d33fbb479 /kernel | |
| parent | 3ea4247ec1b7efc423cf4f75450ebf5cffab9ed8 (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 aaa44244d498..2246115365d9 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -949,7 +949,7 @@ 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); @@ -968,7 +968,7 @@ 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); |