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authorEric Dumazet <edumazet@google.com>2018-01-30 03:37:44 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-02-03 17:04:24 +0100
commitb72ba2a0d82447538c7c977ccb3f2b31b19b7767 (patch)
tree8662d863cfbfa721030de712d1004d5b61b78c2a /kernel
parent96d9b2338bed553c37f759127d8d18c857449ceb (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.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index c40e25e63bb0..eb52d11fdaa7 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -444,7 +444,7 @@ 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);
@@ -463,7 +463,7 @@ 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);