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| author | Eric Dumazet <edumazet@google.com> | 2018-01-13 02:43:23 +0100 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2018-01-14 18:03:43 +0100 |
| commit | c366287ebd698ef5e3de300d90cd62ee9ee7373e (patch) | |
| tree | db24f872f9e1d05b43387b4480914ad8f5ee78b7 /kernel | |
| parent | Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf (diff) | |
| download | linux-c366287ebd698ef5e3de300d90cd62ee9ee7373e.tar.xz linux-c366287ebd698ef5e3de300d90cd62ee9ee7373e.zip | |
bpf: fix divides by zero
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>
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 51ec2dda7f08..7949e8b8f94e 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -956,7 +956,7 @@ 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); @@ -975,7 +975,7 @@ 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); |