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324 lines
9.8 KiB
324 lines
9.8 KiB
![]()
7 years ago
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From 0bc01df3df7a88258148518eb9ce7f88c16a6106 Mon Sep 17 00:00:00 2001
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From: Liping Zhang <zlpnobody@gmail.com>
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Date: Wed, 8 Mar 2017 22:54:18 +0800
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Subject: netfilter: nf_tables: fix mismatch in big-endian system
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Currently, there are two different methods to store an u16 integer to
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the u32 data register. For example:
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u32 *dest = ®s->data[priv->dreg];
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1. *dest = 0; *(u16 *) dest = val_u16;
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2. *dest = val_u16;
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For method 1, the u16 value will be stored like this, either in
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big-endian or little-endian system:
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0 15 31
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+-+-+-+-+-+-+-+-+-+-+-+-+
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| Value | 0 |
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+-+-+-+-+-+-+-+-+-+-+-+-+
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For method 2, in little-endian system, the u16 value will be the same
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as listed above. But in big-endian system, the u16 value will be stored
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like this:
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0 15 31
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+-+-+-+-+-+-+-+-+-+-+-+-+
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| 0 | Value |
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+-+-+-+-+-+-+-+-+-+-+-+-+
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So later we use "memcmp(®s->data[priv->sreg], data, 2);" to do
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compare in nft_cmp, nft_lookup expr ..., method 2 will get the wrong
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result in big-endian system, as 0~15 bits will always be zero.
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For the similar reason, when loading an u16 value from the u32 data
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register, we should use "*(u16 *) sreg;" instead of "(u16)*sreg;",
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the 2nd method will get the wrong value in the big-endian system.
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So introduce some wrapper functions to store/load an u8 or u16
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integer to/from the u32 data register, and use them in the right
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place.
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Signed-off-by: Liping Zhang <zlpnobody@gmail.com>
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Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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---
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include/net/netfilter/nf_tables.h | 29 +++++++++++++++++++++++++
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net/ipv4/netfilter/nft_masq_ipv4.c | 8 +++----
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net/ipv4/netfilter/nft_redir_ipv4.c | 8 +++----
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net/ipv6/netfilter/nft_masq_ipv6.c | 8 +++----
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net/ipv6/netfilter/nft_redir_ipv6.c | 8 +++----
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net/netfilter/nft_ct.c | 10 ++++-----
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net/netfilter/nft_meta.c | 42 +++++++++++++++++++------------------
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net/netfilter/nft_nat.c | 8 +++----
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8 files changed, 76 insertions(+), 45 deletions(-)
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--- a/include/net/netfilter/nf_tables.h
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+++ b/include/net/netfilter/nf_tables.h
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@@ -87,6 +87,35 @@ struct nft_regs {
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};
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};
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+/* Store/load an u16 or u8 integer to/from the u32 data register.
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+ *
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+ * Note, when using concatenations, register allocation happens at 32-bit
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+ * level. So for store instruction, pad the rest part with zero to avoid
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+ * garbage values.
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+ */
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+
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+static inline void nft_reg_store16(u32 *dreg, u16 val)
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+{
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+ *dreg = 0;
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+ *(u16 *)dreg = val;
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+}
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+
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+static inline void nft_reg_store8(u32 *dreg, u8 val)
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+{
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+ *dreg = 0;
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+ *(u8 *)dreg = val;
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+}
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+
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+static inline u16 nft_reg_load16(u32 *sreg)
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+{
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+ return *(u16 *)sreg;
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+}
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+
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+static inline u8 nft_reg_load8(u32 *sreg)
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+{
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+ return *(u8 *)sreg;
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+}
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+
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static inline void nft_data_copy(u32 *dst, const struct nft_data *src,
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unsigned int len)
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{
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--- a/net/ipv4/netfilter/nft_masq_ipv4.c
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+++ b/net/ipv4/netfilter/nft_masq_ipv4.c
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@@ -26,10 +26,10 @@ static void nft_masq_ipv4_eval(const str
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memset(&range, 0, sizeof(range));
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range.flags = priv->flags;
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if (priv->sreg_proto_min) {
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- range.min_proto.all =
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- *(__be16 *)®s->data[priv->sreg_proto_min];
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- range.max_proto.all =
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- *(__be16 *)®s->data[priv->sreg_proto_max];
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+ range.min_proto.all = (__force __be16)nft_reg_load16(
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+ ®s->data[priv->sreg_proto_min]);
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+ range.max_proto.all = (__force __be16)nft_reg_load16(
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+ ®s->data[priv->sreg_proto_max]);
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}
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regs->verdict.code = nf_nat_masquerade_ipv4(pkt->skb, pkt->hook,
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&range, pkt->out);
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--- a/net/ipv4/netfilter/nft_redir_ipv4.c
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+++ b/net/ipv4/netfilter/nft_redir_ipv4.c
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@@ -26,10 +26,10 @@ static void nft_redir_ipv4_eval(const st
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memset(&mr, 0, sizeof(mr));
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if (priv->sreg_proto_min) {
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- mr.range[0].min.all =
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- *(__be16 *)®s->data[priv->sreg_proto_min];
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- mr.range[0].max.all =
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- *(__be16 *)®s->data[priv->sreg_proto_max];
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+ mr.range[0].min.all = (__force __be16)nft_reg_load16(
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+ ®s->data[priv->sreg_proto_min]);
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+ mr.range[0].max.all = (__force __be16)nft_reg_load16(
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+ ®s->data[priv->sreg_proto_max]);
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mr.range[0].flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
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}
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--- a/net/ipv6/netfilter/nft_masq_ipv6.c
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+++ b/net/ipv6/netfilter/nft_masq_ipv6.c
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@@ -27,10 +27,10 @@ static void nft_masq_ipv6_eval(const str
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memset(&range, 0, sizeof(range));
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range.flags = priv->flags;
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if (priv->sreg_proto_min) {
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- range.min_proto.all =
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- *(__be16 *)®s->data[priv->sreg_proto_min];
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- range.max_proto.all =
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- *(__be16 *)®s->data[priv->sreg_proto_max];
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+ range.min_proto.all = (__force __be16)nft_reg_load16(
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+ ®s->data[priv->sreg_proto_min]);
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+ range.max_proto.all = (__force __be16)nft_reg_load16(
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+ ®s->data[priv->sreg_proto_max]);
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}
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regs->verdict.code = nf_nat_masquerade_ipv6(pkt->skb, &range, pkt->out);
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}
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--- a/net/ipv6/netfilter/nft_redir_ipv6.c
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+++ b/net/ipv6/netfilter/nft_redir_ipv6.c
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@@ -26,10 +26,10 @@ static void nft_redir_ipv6_eval(const st
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memset(&range, 0, sizeof(range));
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if (priv->sreg_proto_min) {
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- range.min_proto.all =
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- *(__be16 *)®s->data[priv->sreg_proto_min],
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- range.max_proto.all =
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- *(__be16 *)®s->data[priv->sreg_proto_max],
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+ range.min_proto.all = (__force __be16)nft_reg_load16(
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+ ®s->data[priv->sreg_proto_min]);
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+ range.max_proto.all = (__force __be16)nft_reg_load16(
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+ ®s->data[priv->sreg_proto_max]);
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range.flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
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}
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--- a/net/netfilter/nft_ct.c
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+++ b/net/netfilter/nft_ct.c
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@@ -77,7 +77,7 @@ static void nft_ct_get_eval(const struct
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switch (priv->key) {
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case NFT_CT_DIRECTION:
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- *dest = CTINFO2DIR(ctinfo);
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+ nft_reg_store8(dest, CTINFO2DIR(ctinfo));
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return;
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case NFT_CT_STATUS:
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*dest = ct->status;
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@@ -129,10 +129,10 @@ static void nft_ct_get_eval(const struct
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return;
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}
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case NFT_CT_L3PROTOCOL:
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- *dest = nf_ct_l3num(ct);
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+ nft_reg_store8(dest, nf_ct_l3num(ct));
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return;
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case NFT_CT_PROTOCOL:
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- *dest = nf_ct_protonum(ct);
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+ nft_reg_store8(dest, nf_ct_protonum(ct));
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return;
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default:
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break;
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@@ -149,10 +149,10 @@ static void nft_ct_get_eval(const struct
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nf_ct_l3num(ct) == NFPROTO_IPV4 ? 4 : 16);
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return;
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case NFT_CT_PROTO_SRC:
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- *dest = (__force __u16)tuple->src.u.all;
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+ nft_reg_store16(dest, (__force u16)tuple->src.u.all);
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return;
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case NFT_CT_PROTO_DST:
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- *dest = (__force __u16)tuple->dst.u.all;
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+ nft_reg_store16(dest, (__force u16)tuple->dst.u.all);
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return;
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default:
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break;
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--- a/net/netfilter/nft_meta.c
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+++ b/net/netfilter/nft_meta.c
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@@ -45,16 +45,15 @@ void nft_meta_get_eval(const struct nft_
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*dest = skb->len;
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break;
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case NFT_META_PROTOCOL:
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- *dest = 0;
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- *(__be16 *)dest = skb->protocol;
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+ nft_reg_store16(dest, (__force u16)skb->protocol);
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break;
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case NFT_META_NFPROTO:
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- *dest = pkt->pf;
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+ nft_reg_store8(dest, pkt->pf);
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break;
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case NFT_META_L4PROTO:
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if (!pkt->tprot_set)
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goto err;
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- *dest = pkt->tprot;
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+ nft_reg_store8(dest, pkt->tprot);
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break;
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case NFT_META_PRIORITY:
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*dest = skb->priority;
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@@ -85,14 +84,12 @@ void nft_meta_get_eval(const struct nft_
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case NFT_META_IIFTYPE:
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if (in == NULL)
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goto err;
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- *dest = 0;
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- *(u16 *)dest = in->type;
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+ nft_reg_store16(dest, in->type);
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break;
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case NFT_META_OIFTYPE:
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if (out == NULL)
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goto err;
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- *dest = 0;
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- *(u16 *)dest = out->type;
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+ nft_reg_store16(dest, out->type);
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break;
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case NFT_META_SKUID:
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sk = skb_to_full_sk(skb);
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@@ -142,22 +139,22 @@ void nft_meta_get_eval(const struct nft_
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#endif
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case NFT_META_PKTTYPE:
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if (skb->pkt_type != PACKET_LOOPBACK) {
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- *dest = skb->pkt_type;
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+ nft_reg_store8(dest, skb->pkt_type);
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break;
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}
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switch (pkt->pf) {
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case NFPROTO_IPV4:
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if (ipv4_is_multicast(ip_hdr(skb)->daddr))
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- *dest = PACKET_MULTICAST;
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+ nft_reg_store8(dest, PACKET_MULTICAST);
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else
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- *dest = PACKET_BROADCAST;
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+ nft_reg_store8(dest, PACKET_BROADCAST);
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break;
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case NFPROTO_IPV6:
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if (ipv6_hdr(skb)->daddr.s6_addr[0] == 0xFF)
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- *dest = PACKET_MULTICAST;
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+ nft_reg_store8(dest, PACKET_MULTICAST);
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else
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- *dest = PACKET_BROADCAST;
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+ nft_reg_store8(dest, PACKET_BROADCAST);
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break;
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case NFPROTO_NETDEV:
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switch (skb->protocol) {
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@@ -171,14 +168,14 @@ void nft_meta_get_eval(const struct nft_
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goto err;
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if (ipv4_is_multicast(iph->daddr))
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- *dest = PACKET_MULTICAST;
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+ nft_reg_store8(dest, PACKET_MULTICAST);
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else
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- *dest = PACKET_BROADCAST;
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+ nft_reg_store8(dest, PACKET_BROADCAST);
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break;
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}
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case htons(ETH_P_IPV6):
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- *dest = PACKET_MULTICAST;
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+ nft_reg_store8(dest, PACKET_MULTICAST);
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break;
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default:
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WARN_ON_ONCE(1);
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@@ -233,7 +230,9 @@ void nft_meta_set_eval(const struct nft_
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{
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const struct nft_meta *meta = nft_expr_priv(expr);
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struct sk_buff *skb = pkt->skb;
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- u32 value = regs->data[meta->sreg];
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+ u32 *sreg = ®s->data[meta->sreg];
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+ u32 value = *sreg;
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+ u8 pkt_type;
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switch (meta->key) {
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case NFT_META_MARK:
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@@ -243,9 +242,12 @@ void nft_meta_set_eval(const struct nft_
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skb->priority = value;
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break;
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case NFT_META_PKTTYPE:
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- if (skb->pkt_type != value &&
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- skb_pkt_type_ok(value) && skb_pkt_type_ok(skb->pkt_type))
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- skb->pkt_type = value;
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+ pkt_type = nft_reg_load8(sreg);
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+
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+ if (skb->pkt_type != pkt_type &&
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+ skb_pkt_type_ok(pkt_type) &&
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+ skb_pkt_type_ok(skb->pkt_type))
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+ skb->pkt_type = pkt_type;
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break;
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case NFT_META_NFTRACE:
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skb->nf_trace = !!value;
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--- a/net/netfilter/nft_nat.c
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+++ b/net/netfilter/nft_nat.c
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@@ -65,10 +65,10 @@ static void nft_nat_eval(const struct nf
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}
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if (priv->sreg_proto_min) {
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- range.min_proto.all =
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- *(__be16 *)®s->data[priv->sreg_proto_min];
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- range.max_proto.all =
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- *(__be16 *)®s->data[priv->sreg_proto_max];
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+ range.min_proto.all = (__force __be16)nft_reg_load16(
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+ ®s->data[priv->sreg_proto_min]);
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+ range.max_proto.all = (__force __be16)nft_reg_load16(
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+ ®s->data[priv->sreg_proto_max]);
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range.flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
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}
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