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

[ Upstream commit 1d24fb36 ]

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>

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 */
 				}