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authorTycho Andersen <[email protected]>2015-09-10 18:25:07 -0600
committerDavid S. Miller <[email protected]>2015-09-11 14:52:41 -0700
commit19539ce783dd27768d4f7f3b753152bf983db65b (patch)
tree9b60e9e3326ed629ada5b85bbfbdb018550eb223
parent1853c949646005b5959c483becde86608f548f24 (diff)
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 <[email protected]> CC: Alexei Starovoitov <[email protected]> CC: Daniel Borkmann <[email protected]> Acked-by: Daniel Borkmann <[email protected]> Signed-off-by: David S. Miller <[email protected]>
-rw-r--r--net/core/filter.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/net/core/filter.c b/net/core/filter.c
index 13079f03902e..05a04ea87172 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -478,9 +478,9 @@ do_pass:
bpf_src = BPF_X;
} else {
insn->dst_reg = BPF_REG_A;
- insn->src_reg = BPF_REG_X;
insn->imm = fp->k;
bpf_src = BPF_SRC(fp->code);
+ insn->src_reg = bpf_src == BPF_X ? BPF_REG_X : 0;
}
/* Common case where 'jump_false' is next insn. */