ebpf: emit correct src_reg for conditional jumps
Instead of always emitting BPF_REG_X, let's emit BPF_REG_X only when the source actually is BPF_X. This causes programs generated by the classic converter to not be importable via bpf(), as the eBPF verifier checks that the src_reg is correct or 0. While not a problem yet, this will be a problem when BPF_PROG_DUMP lands, and we can potentially dump and re-import programs generated by the converter. Signed-off-by: Tycho Andersen <tycho.andersen@canonical.com> CC: Alexei Starovoitov <ast@kernel.org> CC: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
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@ -478,9 +478,9 @@ do_pass:
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bpf_src = BPF_X;
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} else {
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insn->dst_reg = BPF_REG_A;
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insn->src_reg = BPF_REG_X;
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insn->imm = fp->k;
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bpf_src = BPF_SRC(fp->code);
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insn->src_reg = bpf_src == BPF_X ? BPF_REG_X : 0;
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}
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/* Common case where 'jump_false' is next insn. */
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