x86 bpf_jit: fix a bug in emitting the 16-bit immediate operand of AND

[ Upstream commit 1d24fb3684f347226747c6b11ea426b7b992694e ]

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  <zhuangfeiran@ict.ac.cn>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index 5671752f8d9cbccb2c5fb708bca8780883d56e19..5a5b6e4dd7386586b5a9e8d5559b6b104f48d447 100644 (file)
--- 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 */
                                }