From b4fe0ec86dae91abfa9f932cd0e2e9d50e336c8b Mon Sep 17 00:00:00 2001 From: Markos Chandras Date: Mon, 23 Jun 2014 10:38:58 +0100 Subject: [PATCH] MIPS: bpf: Fix PKT_TYPE case for big-endian cores The skb->pkt_type field is defined as follows: u8 pkt_type:3, fclone:2, ipvs_property:1, peeked:1, nf_trace:1 resulting to the following layout in big-endian systems [pkt_type][fclone][ipvs_propery][peeked][nf_trace] ^ ^ | | LSB MSB As a result, the existing code did not work because it was trying to match pkt_type == 7 whereas in reality it is 7<<5 on big-endian systems. This has been fixed in the interpreter in 0dcceabb0c1bf2d4c12a748df9933fad303072a7 "net: filter: fix SKF_AD_PKTTYPE extension on big-endian" The fix is to look for 7<<5 on big-endian systems for the pkt_type field, and shift by 5 so the packet type will be at the lower 3 bits of the A register. Signed-off-by: Markos Chandras Cc: David S. Miller Cc: Daniel Borkmann Cc: Alexei Starovoitov Cc: netdev@vger.kernel.org Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/7132/ Signed-off-by: Ralf Baechle --- arch/mips/net/bpf_jit.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/arch/mips/net/bpf_jit.c b/arch/mips/net/bpf_jit.c index 9476e7f061a1..4505e2e6ab53 100644 --- a/arch/mips/net/bpf_jit.c +++ b/arch/mips/net/bpf_jit.c @@ -751,13 +751,17 @@ static u64 jit_get_skb_w(struct sk_buff *skb, unsigned offset) return (u64)err << 32 | ntohl(ret); } -#define PKT_TYPE_MAX 7 +#ifdef __BIG_ENDIAN_BITFIELD +#define PKT_TYPE_MAX (7 << 5) +#else +#define PKT_TYPE_MAX 7 +#endif static int pkt_type_offset(void) { struct sk_buff skb_probe = { .pkt_type = ~0, }; - char *ct = (char *)&skb_probe; + u8 *ct = (u8 *)&skb_probe; unsigned int off; for (off = 0; off < sizeof(struct sk_buff); off++) { @@ -1320,6 +1324,10 @@ jmp_cmp: emit_load_byte(r_tmp, r_skb, off, ctx); /* Keep only the last 3 bits */ emit_andi(r_A, r_tmp, PKT_TYPE_MAX, ctx); +#ifdef __BIG_ENDIAN_BITFIELD + /* Get the actual packet type to the lower 3 bits */ + emit_srl(r_A, r_A, 5, ctx); +#endif break; case BPF_ANC | SKF_AD_QUEUE: ctx->flags |= SEEN_SKB | SEEN_A;