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bpf: fix divides by zero
[ upstream commitc366287ebd
] 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:bd4cf0ed33
("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>
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parent
5cb917aa1f
commit
4606077802
1 changed files with 2 additions and 2 deletions
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@ -642,7 +642,7 @@ static unsigned int __bpf_prog_run(void *ctx, const struct bpf_insn *insn)
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DST = tmp;
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DST = tmp;
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CONT;
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CONT;
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ALU_MOD_X:
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ALU_MOD_X:
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if (unlikely(SRC == 0))
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if (unlikely((u32)SRC == 0))
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return 0;
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return 0;
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tmp = (u32) DST;
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tmp = (u32) DST;
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DST = do_div(tmp, (u32) SRC);
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DST = do_div(tmp, (u32) SRC);
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@ -661,7 +661,7 @@ static unsigned int __bpf_prog_run(void *ctx, const struct bpf_insn *insn)
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DST = div64_u64(DST, SRC);
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DST = div64_u64(DST, SRC);
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CONT;
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CONT;
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ALU_DIV_X:
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ALU_DIV_X:
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if (unlikely(SRC == 0))
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if (unlikely((u32)SRC == 0))
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return 0;
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return 0;
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tmp = (u32) DST;
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tmp = (u32) DST;
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do_div(tmp, (u32) SRC);
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do_div(tmp, (u32) SRC);
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