Re: [PATCH] net: bpf_jit: fix BPF_S_ALU_AND_K compilation
From: Eric Dumazet <hidden>
Date: 2012-03-31 10:23:12
Also in:
lkml, stable
On Sat, 2012-03-31 at 20:52 +1100, Indan Zupancic wrote:
quoted hunk ↗ jump to hunk
Hello, Finally, after much searching I found one little bug. [PATCH] net: bpf_jit: fix BPF_S_ALU_AND_K compilation Small typo resulted in bad code generation for certain values of K for the BPF_S_ALU_AND_K instruction. Signed-off-by: Indan Zupancic <redacted> ---diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index 7c1b765..28bc807 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c@@ -289,7 +289,7 @@ void bpf_jit_compile(struct sk_filter *fp) EMIT2(0x24, K & 0xFF); /* and imm8,%al */ } else if (K >= 0xFFFF0000) { EMIT2(0x66, 0x25); /* and imm16,%ax */ - EMIT2(K, 2); + EMIT(K, 2); } else { EMIT1_off32(0x25, K); /* and imm32,%eax */ }
Thanks but it was already fixed.
commit 1d24fb3684f347226747c6b11ea426b7b992694e
Author: zhuangfeiran@ict.ac.cn [off-list ref]
Date: Wed Mar 28 23:27:00 2012 +0000
x86 bpf_jit: fix a bug in emitting the 16-bit immediate operand of AND
When K >= 0xFFFF0000, AND needs the two least significant bytes of K as
its operand, but EMIT2() gives it the least significant byte of K and
0x2. EMIT() should be used here to replace EMIT2().
Signed-off-by: Feiran Zhuang [off-list ref]
Acked-by: Eric Dumazet [off-list ref]
Signed-off-by: David S. Miller [off-list ref]