powerpc: bpf: Use correct mask while accessing the VLAN tag

To get a full tag (and not just a VID) we should access the TCI
except the VLAN_TAG_PRESENT field (which means that 802.1q header
is present). Also ensure that the VLAN_TAG_PRESENT stay on its place

Signed-off-by: Denis Kirjanov <kda@linux-powerpc.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 1 deletions

diff --git a/arch/powerpc/net/bpf_jit_comp.c b/arch/powerpc/net/bpf_jit_comp.c
index 6dcdadefd8d0..892167b0a4bc 100644
--- a/arch/powerpc/net/bpf_jit_comp.c
+++ b/arch/powerpc/net/bpf_jit_comp.c
@@ -390,10 +390,12 @@ static int bpf_jit_build_body(struct sk_filter *fp, u32 *image,
                 case BPF_ANC | SKF_AD_VLAN_TAG:
                 case BPF_ANC | SKF_AD_VLAN_TAG_PRESENT:
                         BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_tci) != 2);
+                        BUILD_BUG_ON(VLAN_TAG_PRESENT != 0x1000);
+
                         PPC_LHZ_OFFS(r_A, r_skb, offsetof(struct sk_buff,
                                                           vlan_tci));
                         if (code == (BPF_ANC | SKF_AD_VLAN_TAG))
-                                PPC_ANDI(r_A, r_A, VLAN_VID_MASK);
+                                PPC_ANDI(r_A, r_A, ~VLAN_TAG_PRESENT);
                         else
                                 PPC_ANDI(r_A, r_A, VLAN_TAG_PRESENT);
                         break;