Messages in this thread Patch in this message | | | Date | Tue, 03 Jan 2012 14:30:09 -0800 | From | Greg KH <> | Subject | [51/67] net: bpf_jit: fix an off-one bug in x86_64 cond jump target |
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3.0-stable review patch. If anyone has any objections, please let me know.
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From: Markus Kötter <nepenthesdev@gmail.com>
[ Upstream commit a03ffcf873fe0f2565386ca8ef832144c42e67fa ]
x86 jump instruction size is 2 or 5 bytes (near/long jump), not 2 or 6 bytes.
In case a conditional jump is followed by a long jump, conditional jump target is one byte past the start of target instruction.
Signed-off-by: Markus Kötter <nepenthesdev@gmail.com> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> --- arch/x86/net/bpf_jit_comp.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -568,8 +568,8 @@ cond_branch: f_offset = addrs[i + filt break; } if (filter[i].jt != 0) { - if (filter[i].jf) - t_offset += is_near(f_offset) ? 2 : 6; + if (filter[i].jf && f_offset) + t_offset += is_near(f_offset) ? 2 : 5; EMIT_COND_JMP(t_op, t_offset); if (filter[i].jf) EMIT_JMP(f_offset);
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