From: Liping Zhang zlpnobody@gmail.com
Currently, there are two different methods to store an u16 integer to the u32 data register. For example: u32 *dest = ®s->data[priv->dreg]; 1. *dest = 0; *(u16 *) dest = val_u16; 2. *dest = val_u16;
For method 1, the u16 value will be stored like this, either in big-endian or little-endian system: 0 15 31 +-+-+-+-+-+-+-+-+-+-+-+-+ | Value | 0 | +-+-+-+-+-+-+-+-+-+-+-+-+
For method 2, in little-endian system, the u16 value will be the same as listed above. But in big-endian system, the u16 value will be stored like this: 0 15 31 +-+-+-+-+-+-+-+-+-+-+-+-+ | 0 | Value | +-+-+-+-+-+-+-+-+-+-+-+-+
So later we use "memcmp(®s->data[priv->sreg], data, 2);" to do compare in nft_cmp, nft_lookup expr ..., method 2 will get the wrong result in big-endian system, as 0~15 bits will always be zero.
For the similar reason, when loading an u16 value from the u32 data register, we should use "*(u16 *) sreg;" instead of "(u16)*sreg;", the 2nd method will get the wrong value in the big-endian system.
So introduce some wrapper functions to store/load an u8 or u16 integer to/from the u32 data register, and use them in the right place.
This is OpenWrts backport of upstream commit 10596608c4d62cb8c1c2b806debcbd32fe657e71 "netfilter: nf_tables: fix mismatch in big-endian system", the upstream commit does not work right off.
Signed-off-by: Liping Zhang zlpnobody@gmail.com Signed-off-by: Pablo Neira Ayuso pablo@netfilter.org --- include/net/netfilter/nf_tables.h | 29 ++++++++++++++++++++ net/ipv4/netfilter/nft_masq_ipv4.c | 8 +++--- net/ipv4/netfilter/nft_redir_ipv4.c | 8 +++--- net/ipv6/netfilter/nft_masq_ipv6.c | 8 +++--- net/ipv6/netfilter/nft_redir_ipv6.c | 8 +++--- net/netfilter/nft_ct.c | 10 +++---- net/netfilter/nft_meta.c | 42 +++++++++++++++-------------- net/netfilter/nft_nat.c | 8 +++--- 8 files changed, 76 insertions(+), 45 deletions(-)
diff --git a/include/net/netfilter/nf_tables.h b/include/net/netfilter/nf_tables.h index b02af0bf5777..66f6b84df287 100644 --- a/include/net/netfilter/nf_tables.h +++ b/include/net/netfilter/nf_tables.h @@ -87,6 +87,35 @@ struct nft_regs { }; };
+/* Store/load an u16 or u8 integer to/from the u32 data register. + * + * Note, when using concatenations, register allocation happens at 32-bit + * level. So for store instruction, pad the rest part with zero to avoid + * garbage values. + */ + +static inline void nft_reg_store16(u32 *dreg, u16 val) +{ + *dreg = 0; + *(u16 *)dreg = val; +} + +static inline void nft_reg_store8(u32 *dreg, u8 val) +{ + *dreg = 0; + *(u8 *)dreg = val; +} + +static inline u16 nft_reg_load16(u32 *sreg) +{ + return *(u16 *)sreg; +} + +static inline u8 nft_reg_load8(u32 *sreg) +{ + return *(u8 *)sreg; +} + static inline void nft_data_copy(u32 *dst, const struct nft_data *src, unsigned int len) { diff --git a/net/ipv4/netfilter/nft_masq_ipv4.c b/net/ipv4/netfilter/nft_masq_ipv4.c index 51ced81b616c..dc3628a396ec 100644 --- a/net/ipv4/netfilter/nft_masq_ipv4.c +++ b/net/ipv4/netfilter/nft_masq_ipv4.c @@ -26,10 +26,10 @@ static void nft_masq_ipv4_eval(const struct nft_expr *expr, memset(&range, 0, sizeof(range)); range.flags = priv->flags; if (priv->sreg_proto_min) { - range.min_proto.all = - *(__be16 *)®s->data[priv->sreg_proto_min]; - range.max_proto.all = - *(__be16 *)®s->data[priv->sreg_proto_max]; + range.min_proto.all = (__force __be16)nft_reg_load16( + ®s->data[priv->sreg_proto_min]); + range.max_proto.all = (__force __be16)nft_reg_load16( + ®s->data[priv->sreg_proto_max]); } regs->verdict.code = nf_nat_masquerade_ipv4(pkt->skb, pkt->hook, &range, pkt->out); diff --git a/net/ipv4/netfilter/nft_redir_ipv4.c b/net/ipv4/netfilter/nft_redir_ipv4.c index c09d4381427e..f760524e1353 100644 --- a/net/ipv4/netfilter/nft_redir_ipv4.c +++ b/net/ipv4/netfilter/nft_redir_ipv4.c @@ -26,10 +26,10 @@ static void nft_redir_ipv4_eval(const struct nft_expr *expr,
memset(&mr, 0, sizeof(mr)); if (priv->sreg_proto_min) { - mr.range[0].min.all = - *(__be16 *)®s->data[priv->sreg_proto_min]; - mr.range[0].max.all = - *(__be16 *)®s->data[priv->sreg_proto_max]; + mr.range[0].min.all = (__force __be16)nft_reg_load16( + ®s->data[priv->sreg_proto_min]); + mr.range[0].max.all = (__force __be16)nft_reg_load16( + ®s->data[priv->sreg_proto_max]); mr.range[0].flags |= NF_NAT_RANGE_PROTO_SPECIFIED; }
diff --git a/net/ipv6/netfilter/nft_masq_ipv6.c b/net/ipv6/netfilter/nft_masq_ipv6.c index 9597ffb74077..b74a420050c4 100644 --- a/net/ipv6/netfilter/nft_masq_ipv6.c +++ b/net/ipv6/netfilter/nft_masq_ipv6.c @@ -27,10 +27,10 @@ static void nft_masq_ipv6_eval(const struct nft_expr *expr, memset(&range, 0, sizeof(range)); range.flags = priv->flags; if (priv->sreg_proto_min) { - range.min_proto.all = - *(__be16 *)®s->data[priv->sreg_proto_min]; - range.max_proto.all = - *(__be16 *)®s->data[priv->sreg_proto_max]; + range.min_proto.all = (__force __be16)nft_reg_load16( + ®s->data[priv->sreg_proto_min]); + range.max_proto.all = (__force __be16)nft_reg_load16( + ®s->data[priv->sreg_proto_max]); } regs->verdict.code = nf_nat_masquerade_ipv6(pkt->skb, &range, pkt->out); } diff --git a/net/ipv6/netfilter/nft_redir_ipv6.c b/net/ipv6/netfilter/nft_redir_ipv6.c index aca44e89a881..7ef58e493fca 100644 --- a/net/ipv6/netfilter/nft_redir_ipv6.c +++ b/net/ipv6/netfilter/nft_redir_ipv6.c @@ -26,10 +26,10 @@ static void nft_redir_ipv6_eval(const struct nft_expr *expr,
memset(&range, 0, sizeof(range)); if (priv->sreg_proto_min) { - range.min_proto.all = - *(__be16 *)®s->data[priv->sreg_proto_min], - range.max_proto.all = - *(__be16 *)®s->data[priv->sreg_proto_max], + range.min_proto.all = (__force __be16)nft_reg_load16( + ®s->data[priv->sreg_proto_min]); + range.max_proto.all = (__force __be16)nft_reg_load16( + ®s->data[priv->sreg_proto_max]); range.flags |= NF_NAT_RANGE_PROTO_SPECIFIED; }
diff --git a/net/netfilter/nft_ct.c b/net/netfilter/nft_ct.c index d7b0d171172a..2b9fda71fa8b 100644 --- a/net/netfilter/nft_ct.c +++ b/net/netfilter/nft_ct.c @@ -77,7 +77,7 @@ static void nft_ct_get_eval(const struct nft_expr *expr,
switch (priv->key) { case NFT_CT_DIRECTION: - *dest = CTINFO2DIR(ctinfo); + nft_reg_store8(dest, CTINFO2DIR(ctinfo)); return; case NFT_CT_STATUS: *dest = ct->status; @@ -129,10 +129,10 @@ static void nft_ct_get_eval(const struct nft_expr *expr, return; } case NFT_CT_L3PROTOCOL: - *dest = nf_ct_l3num(ct); + nft_reg_store8(dest, nf_ct_l3num(ct)); return; case NFT_CT_PROTOCOL: - *dest = nf_ct_protonum(ct); + nft_reg_store8(dest, nf_ct_protonum(ct)); return; default: break; @@ -149,10 +149,10 @@ static void nft_ct_get_eval(const struct nft_expr *expr, nf_ct_l3num(ct) == NFPROTO_IPV4 ? 4 : 16); return; case NFT_CT_PROTO_SRC: - *dest = (__force __u16)tuple->src.u.all; + nft_reg_store16(dest, (__force u16)tuple->src.u.all); return; case NFT_CT_PROTO_DST: - *dest = (__force __u16)tuple->dst.u.all; + nft_reg_store16(dest, (__force u16)tuple->dst.u.all); return; default: break; diff --git a/net/netfilter/nft_meta.c b/net/netfilter/nft_meta.c index 7c3395513ff0..cec8dc0e5e6f 100644 --- a/net/netfilter/nft_meta.c +++ b/net/netfilter/nft_meta.c @@ -45,16 +45,15 @@ void nft_meta_get_eval(const struct nft_expr *expr, *dest = skb->len; break; case NFT_META_PROTOCOL: - *dest = 0; - *(__be16 *)dest = skb->protocol; + nft_reg_store16(dest, (__force u16)skb->protocol); break; case NFT_META_NFPROTO: - *dest = pkt->pf; + nft_reg_store8(dest, pkt->pf); break; case NFT_META_L4PROTO: if (!pkt->tprot_set) goto err; - *dest = pkt->tprot; + nft_reg_store8(dest, pkt->tprot); break; case NFT_META_PRIORITY: *dest = skb->priority; @@ -85,14 +84,12 @@ void nft_meta_get_eval(const struct nft_expr *expr, case NFT_META_IIFTYPE: if (in == NULL) goto err; - *dest = 0; - *(u16 *)dest = in->type; + nft_reg_store16(dest, in->type); break; case NFT_META_OIFTYPE: if (out == NULL) goto err; - *dest = 0; - *(u16 *)dest = out->type; + nft_reg_store16(dest, out->type); break; case NFT_META_SKUID: sk = skb_to_full_sk(skb); @@ -142,22 +139,22 @@ void nft_meta_get_eval(const struct nft_expr *expr, #endif case NFT_META_PKTTYPE: if (skb->pkt_type != PACKET_LOOPBACK) { - *dest = skb->pkt_type; + nft_reg_store8(dest, skb->pkt_type); break; }
switch (pkt->pf) { case NFPROTO_IPV4: if (ipv4_is_multicast(ip_hdr(skb)->daddr)) - *dest = PACKET_MULTICAST; + nft_reg_store8(dest, PACKET_MULTICAST); else - *dest = PACKET_BROADCAST; + nft_reg_store8(dest, PACKET_BROADCAST); break; case NFPROTO_IPV6: if (ipv6_hdr(skb)->daddr.s6_addr[0] == 0xFF) - *dest = PACKET_MULTICAST; + nft_reg_store8(dest, PACKET_MULTICAST); else - *dest = PACKET_BROADCAST; + nft_reg_store8(dest, PACKET_BROADCAST); break; case NFPROTO_NETDEV: switch (skb->protocol) { @@ -171,14 +168,14 @@ void nft_meta_get_eval(const struct nft_expr *expr, goto err;
if (ipv4_is_multicast(iph->daddr)) - *dest = PACKET_MULTICAST; + nft_reg_store8(dest, PACKET_MULTICAST); else - *dest = PACKET_BROADCAST; + nft_reg_store8(dest, PACKET_BROADCAST);
break; } case htons(ETH_P_IPV6): - *dest = PACKET_MULTICAST; + nft_reg_store8(dest, PACKET_MULTICAST); break; default: WARN_ON_ONCE(1); @@ -233,7 +230,9 @@ void nft_meta_set_eval(const struct nft_expr *expr, { const struct nft_meta *meta = nft_expr_priv(expr); struct sk_buff *skb = pkt->skb; - u32 value = regs->data[meta->sreg]; + u32 *sreg = ®s->data[meta->sreg]; + u32 value = *sreg; + u8 pkt_type;
switch (meta->key) { case NFT_META_MARK: @@ -243,9 +242,12 @@ void nft_meta_set_eval(const struct nft_expr *expr, skb->priority = value; break; case NFT_META_PKTTYPE: - if (skb->pkt_type != value && - skb_pkt_type_ok(value) && skb_pkt_type_ok(skb->pkt_type)) - skb->pkt_type = value; + pkt_type = nft_reg_load8(sreg); + + if (skb->pkt_type != pkt_type && + skb_pkt_type_ok(pkt_type) && + skb_pkt_type_ok(skb->pkt_type)) + skb->pkt_type = pkt_type; break; case NFT_META_NFTRACE: skb->nf_trace = !!value; diff --git a/net/netfilter/nft_nat.c b/net/netfilter/nft_nat.c index ee2d71753746..4c48e9bb21e2 100644 --- a/net/netfilter/nft_nat.c +++ b/net/netfilter/nft_nat.c @@ -65,10 +65,10 @@ static void nft_nat_eval(const struct nft_expr *expr, }
if (priv->sreg_proto_min) { - range.min_proto.all = - *(__be16 *)®s->data[priv->sreg_proto_min]; - range.max_proto.all = - *(__be16 *)®s->data[priv->sreg_proto_max]; + range.min_proto.all = (__force __be16)nft_reg_load16( + ®s->data[priv->sreg_proto_min]); + range.max_proto.all = (__force __be16)nft_reg_load16( + ®s->data[priv->sreg_proto_max]); range.flags |= NF_NAT_RANGE_PROTO_SPECIFIED; }