net: filter: fix SKF_AD_PKTTYPE extension on big-endian
BPF classic->internal converter broke SKF_AD_PKTTYPE extension, since
pkt_type_offset() was failing to find skb->pkt_type field which is defined as:
__u8 pkt_type:3,
fclone:2,
ipvs_property:1,
peeked:1,
nf_trace:1;
Fix it by searching for 3 most significant bits and shift them by 5 at run-time
Fixes: bd4cf0ed331a ("net: filter: rework/optimize internal BPF interpreter's instruction set")
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Acked-by: Daniel Borkmann <dborkman@redhat.com>
Tested-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/filter.c b/net/core/filter.c
index 4aec7b9..ab3c74e 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -578,7 +578,11 @@
* to make sure its still a 3bit field starting at a byte boundary;
* taken from arch/x86/net/bpf_jit_comp.c.
*/
+#ifdef __BIG_ENDIAN_BITFIELD
+#define PKT_TYPE_MAX (7 << 5)
+#else
#define PKT_TYPE_MAX 7
+#endif
static unsigned int pkt_type_offset(void)
{
struct sk_buff skb_probe = { .pkt_type = ~0, };
@@ -685,6 +689,13 @@
insn->code = BPF_ALU | BPF_AND | BPF_K;
insn->a_reg = A_REG;
insn->imm = PKT_TYPE_MAX;
+#ifdef __BIG_ENDIAN_BITFIELD
+ insn++;
+
+ insn->code = BPF_ALU | BPF_RSH | BPF_K;
+ insn->a_reg = A_REG;
+ insn->imm = 5;
+#endif
break;
case SKF_AD_OFF + SKF_AD_IFINDEX: