diff mbox series

[net-next,1/5] netfilter: nft_redir: use `struct nf_nat_range2` throughout and deduplicate eval call-backs

Message ID 20230322210802.6743-2-fw@strlen.de (mailing list archive)
State Accepted
Commit 6f56ad1b92328997e1b1792047099df6f8d7acb5
Delegated to: Netdev Maintainers
Headers show
Series [net-next,1/5] netfilter: nft_redir: use `struct nf_nat_range2` throughout and deduplicate eval call-backs | expand

Checks

Context Check Description
netdev/series_format success Pull request is its own cover letter
netdev/tree_selection success Clearly marked for net-next, async
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 18 this patch: 18
netdev/cc_maintainers warning 3 maintainers not CCed: kadlec@netfilter.org coreteam@netfilter.org pablo@netfilter.org
netdev/build_clang success Errors and warnings before: 18 this patch: 18
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 18 this patch: 18
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 287 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Florian Westphal March 22, 2023, 9:07 p.m. UTC 
From: Jeremy Sowden <jeremy@azazel.net>

`nf_nat_redirect_ipv4` takes a `struct nf_nat_ipv4_multi_range_compat`,
but converts it internally to a `struct nf_nat_range2`.  Change the
function to take the latter, factor out the code now shared with
`nf_nat_redirect_ipv6`, move the conversion to the xt_REDIRECT module,
and update the ipv4 range initialization in the nft_redir module.

Replace a bare hex constant for 127.0.0.1 with a macro.

Remove `WARN_ON`.  `nf_nat_setup_info` calls `nf_ct_is_confirmed`:

	/* Can't setup nat info for confirmed ct. */
	if (nf_ct_is_confirmed(ct))
		return NF_ACCEPT;

This means that `ct` cannot be null or the kernel will crash, and
implies that `ctinfo` is `IP_CT_NEW` or `IP_CT_RELATED`.

nft_redir has separate ipv4 and ipv6 call-backs which share much of
their code, and an inet one switch containing a switch that calls one of
the others based on the family of the packet.  Merge the ipv4 and ipv6
ones into the inet one in order to get rid of the duplicate code.

Const-qualify the `priv` pointer since we don't need to write through
it.

Assign `priv->flags` to the range instead of OR-ing it in.

Set the `NF_NAT_RANGE_PROTO_SPECIFIED` flag once during init, rather
than on every eval.

Signed-off-by: Jeremy Sowden <jeremy@azazel.net>
Signed-off-by: Florian Westphal <fw@strlen.de>
---
 include/net/netfilter/nf_nat_redirect.h |  3 +-
 net/netfilter/nf_nat_redirect.c         | 71 ++++++++++-----------
 net/netfilter/nft_redir.c               | 84 +++++++++----------------
 net/netfilter/xt_REDIRECT.c             | 10 ++-
 4 files changed, 72 insertions(+), 96 deletions(-)

Comments

patchwork-bot+netdevbpf@kernel.org March 24, 2023, 5 a.m. UTC | #1 
Hello:

This series was applied to netdev/net-next.git (main)
by Florian Westphal <fw@strlen.de>:

On Wed, 22 Mar 2023 22:07:58 +0100 you wrote:
> From: Jeremy Sowden <jeremy@azazel.net>
> 
> `nf_nat_redirect_ipv4` takes a `struct nf_nat_ipv4_multi_range_compat`,
> but converts it internally to a `struct nf_nat_range2`.  Change the
> function to take the latter, factor out the code now shared with
> `nf_nat_redirect_ipv6`, move the conversion to the xt_REDIRECT module,
> and update the ipv4 range initialization in the nft_redir module.
> 
> [...]

Here is the summary with links:
  - [net-next,1/5] netfilter: nft_redir: use `struct nf_nat_range2` throughout and deduplicate eval call-backs
    https://git.kernel.org/netdev/net-next/c/6f56ad1b9232
  - [net-next,2/5] netfilter: nft_masq: deduplicate eval call-backs
    https://git.kernel.org/netdev/net-next/c/f6ca5d5ed7ec
  - [net-next,3/5] netfilter: xtables: disable 32bit compat interface by default
    https://git.kernel.org/netdev/net-next/c/bde7170a04d6
  - [net-next,4/5] xtables: move icmp/icmpv6 logic to xt_tcpudp
    https://git.kernel.org/netdev/net-next/c/36ce9982ef2f
  - [net-next,5/5] netfilter: keep conntrack reference until IPsecv6 policy checks are done
    https://git.kernel.org/netdev/net-next/c/b0e214d21203

You are awesome, thank you!
diff mbox series

Patch

diff --git a/include/net/netfilter/nf_nat_redirect.h b/include/net/netfilter/nf_nat_redirect.h
index 2418653a66db..279380de904c 100644
--- a/include/net/netfilter/nf_nat_redirect.h
+++ b/include/net/netfilter/nf_nat_redirect.h
@@ -6,8 +6,7 @@ 
 #include <uapi/linux/netfilter/nf_nat.h>
 
 unsigned int
-nf_nat_redirect_ipv4(struct sk_buff *skb,
-		     const struct nf_nat_ipv4_multi_range_compat *mr,
+nf_nat_redirect_ipv4(struct sk_buff *skb, const struct nf_nat_range2 *range,
 		     unsigned int hooknum);
 unsigned int
 nf_nat_redirect_ipv6(struct sk_buff *skb, const struct nf_nat_range2 *range,
diff --git a/net/netfilter/nf_nat_redirect.c b/net/netfilter/nf_nat_redirect.c
index f91579c821e9..6616ba5d0b04 100644
--- a/net/netfilter/nf_nat_redirect.c
+++ b/net/netfilter/nf_nat_redirect.c
@@ -10,6 +10,7 @@ 
 
 #include <linux/if.h>
 #include <linux/inetdevice.h>
+#include <linux/in.h>
 #include <linux/ip.h>
 #include <linux/kernel.h>
 #include <linux/netdevice.h>
@@ -24,54 +25,56 @@ 
 #include <net/netfilter/nf_nat.h>
 #include <net/netfilter/nf_nat_redirect.h>
 
+static unsigned int
+nf_nat_redirect(struct sk_buff *skb, const struct nf_nat_range2 *range,
+		const union nf_inet_addr *newdst)
+{
+	struct nf_nat_range2 newrange;
+	enum ip_conntrack_info ctinfo;
+	struct nf_conn *ct;
+
+	ct = nf_ct_get(skb, &ctinfo);
+
+	memset(&newrange, 0, sizeof(newrange));
+
+	newrange.flags		= range->flags | NF_NAT_RANGE_MAP_IPS;
+	newrange.min_addr	= *newdst;
+	newrange.max_addr	= *newdst;
+	newrange.min_proto	= range->min_proto;
+	newrange.max_proto	= range->max_proto;
+
+	return nf_nat_setup_info(ct, &newrange, NF_NAT_MANIP_DST);
+}
+
 unsigned int
-nf_nat_redirect_ipv4(struct sk_buff *skb,
-		     const struct nf_nat_ipv4_multi_range_compat *mr,
+nf_nat_redirect_ipv4(struct sk_buff *skb, const struct nf_nat_range2 *range,
 		     unsigned int hooknum)
 {
-	struct nf_conn *ct;
-	enum ip_conntrack_info ctinfo;
-	__be32 newdst;
-	struct nf_nat_range2 newrange;
+	union nf_inet_addr newdst = {};
 
 	WARN_ON(hooknum != NF_INET_PRE_ROUTING &&
 		hooknum != NF_INET_LOCAL_OUT);
 
-	ct = nf_ct_get(skb, &ctinfo);
-	WARN_ON(!(ct && (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED)));
-
 	/* Local packets: make them go to loopback */
 	if (hooknum == NF_INET_LOCAL_OUT) {
-		newdst = htonl(0x7F000001);
+		newdst.ip = htonl(INADDR_LOOPBACK);
 	} else {
 		const struct in_device *indev;
 
-		newdst = 0;
-
 		indev = __in_dev_get_rcu(skb->dev);
 		if (indev) {
 			const struct in_ifaddr *ifa;
 
 			ifa = rcu_dereference(indev->ifa_list);
 			if (ifa)
-				newdst = ifa->ifa_local;
+				newdst.ip = ifa->ifa_local;
 		}
 
-		if (!newdst)
+		if (!newdst.ip)
 			return NF_DROP;
 	}
 
-	/* Transfer from original range. */
-	memset(&newrange.min_addr, 0, sizeof(newrange.min_addr));
-	memset(&newrange.max_addr, 0, sizeof(newrange.max_addr));
-	newrange.flags	     = mr->range[0].flags | NF_NAT_RANGE_MAP_IPS;
-	newrange.min_addr.ip = newdst;
-	newrange.max_addr.ip = newdst;
-	newrange.min_proto   = mr->range[0].min;
-	newrange.max_proto   = mr->range[0].max;
-
-	/* Hand modified range to generic setup. */
-	return nf_nat_setup_info(ct, &newrange, NF_NAT_MANIP_DST);
+	return nf_nat_redirect(skb, range, &newdst);
 }
 EXPORT_SYMBOL_GPL(nf_nat_redirect_ipv4);
 
@@ -81,14 +84,10 @@  unsigned int
 nf_nat_redirect_ipv6(struct sk_buff *skb, const struct nf_nat_range2 *range,
 		     unsigned int hooknum)
 {
-	struct nf_nat_range2 newrange;
-	struct in6_addr newdst;
-	enum ip_conntrack_info ctinfo;
-	struct nf_conn *ct;
+	union nf_inet_addr newdst = {};
 
-	ct = nf_ct_get(skb, &ctinfo);
 	if (hooknum == NF_INET_LOCAL_OUT) {
-		newdst = loopback_addr;
+		newdst.in6 = loopback_addr;
 	} else {
 		struct inet6_dev *idev;
 		struct inet6_ifaddr *ifa;
@@ -98,7 +97,7 @@  nf_nat_redirect_ipv6(struct sk_buff *skb, const struct nf_nat_range2 *range,
 		if (idev != NULL) {
 			read_lock_bh(&idev->lock);
 			list_for_each_entry(ifa, &idev->addr_list, if_list) {
-				newdst = ifa->addr;
+				newdst.in6 = ifa->addr;
 				addr = true;
 				break;
 			}
@@ -109,12 +108,6 @@  nf_nat_redirect_ipv6(struct sk_buff *skb, const struct nf_nat_range2 *range,
 			return NF_DROP;
 	}
 
-	newrange.flags		= range->flags | NF_NAT_RANGE_MAP_IPS;
-	newrange.min_addr.in6	= newdst;
-	newrange.max_addr.in6	= newdst;
-	newrange.min_proto	= range->min_proto;
-	newrange.max_proto	= range->max_proto;
-
-	return nf_nat_setup_info(ct, &newrange, NF_NAT_MANIP_DST);
+	return nf_nat_redirect(skb, range, &newdst);
 }
 EXPORT_SYMBOL_GPL(nf_nat_redirect_ipv6);
diff --git a/net/netfilter/nft_redir.c b/net/netfilter/nft_redir.c
index 67cec56bc84a..a70196ffcb1e 100644
--- a/net/netfilter/nft_redir.c
+++ b/net/netfilter/nft_redir.c
@@ -64,6 +64,8 @@  static int nft_redir_init(const struct nft_ctx *ctx,
 		} else {
 			priv->sreg_proto_max = priv->sreg_proto_min;
 		}
+
+		priv->flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
 	}
 
 	if (tb[NFTA_REDIR_FLAGS]) {
@@ -99,25 +101,37 @@  static int nft_redir_dump(struct sk_buff *skb,
 	return -1;
 }
 
-static void nft_redir_ipv4_eval(const struct nft_expr *expr,
-				struct nft_regs *regs,
-				const struct nft_pktinfo *pkt)
+static void nft_redir_eval(const struct nft_expr *expr,
+			   struct nft_regs *regs,
+			   const struct nft_pktinfo *pkt)
 {
-	struct nft_redir *priv = nft_expr_priv(expr);
-	struct nf_nat_ipv4_multi_range_compat mr;
+	const struct nft_redir *priv = nft_expr_priv(expr);
+	struct nf_nat_range2 range;
 
-	memset(&mr, 0, sizeof(mr));
+	memset(&range, 0, sizeof(range));
+	range.flags = priv->flags;
 	if (priv->sreg_proto_min) {
-		mr.range[0].min.all = (__force __be16)nft_reg_load16(
-			&regs->data[priv->sreg_proto_min]);
-		mr.range[0].max.all = (__force __be16)nft_reg_load16(
-			&regs->data[priv->sreg_proto_max]);
-		mr.range[0].flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
+		range.min_proto.all = (__force __be16)
+			nft_reg_load16(&regs->data[priv->sreg_proto_min]);
+		range.max_proto.all = (__force __be16)
+			nft_reg_load16(&regs->data[priv->sreg_proto_max]);
 	}
 
-	mr.range[0].flags |= priv->flags;
-
-	regs->verdict.code = nf_nat_redirect_ipv4(pkt->skb, &mr, nft_hook(pkt));
+	switch (nft_pf(pkt)) {
+	case NFPROTO_IPV4:
+		regs->verdict.code = nf_nat_redirect_ipv4(pkt->skb, &range,
+							  nft_hook(pkt));
+		break;
+#ifdef CONFIG_NF_TABLES_IPV6
+	case NFPROTO_IPV6:
+		regs->verdict.code = nf_nat_redirect_ipv6(pkt->skb, &range,
+							  nft_hook(pkt));
+		break;
+#endif
+	default:
+		WARN_ON_ONCE(1);
+		break;
+	}
 }
 
 static void
@@ -130,7 +144,7 @@  static struct nft_expr_type nft_redir_ipv4_type;
 static const struct nft_expr_ops nft_redir_ipv4_ops = {
 	.type		= &nft_redir_ipv4_type,
 	.size		= NFT_EXPR_SIZE(sizeof(struct nft_redir)),
-	.eval		= nft_redir_ipv4_eval,
+	.eval		= nft_redir_eval,
 	.init		= nft_redir_init,
 	.destroy	= nft_redir_ipv4_destroy,
 	.dump		= nft_redir_dump,
@@ -148,28 +162,6 @@  static struct nft_expr_type nft_redir_ipv4_type __read_mostly = {
 };
 
 #ifdef CONFIG_NF_TABLES_IPV6
-static void nft_redir_ipv6_eval(const struct nft_expr *expr,
-				struct nft_regs *regs,
-				const struct nft_pktinfo *pkt)
-{
-	struct nft_redir *priv = nft_expr_priv(expr);
-	struct nf_nat_range2 range;
-
-	memset(&range, 0, sizeof(range));
-	if (priv->sreg_proto_min) {
-		range.min_proto.all = (__force __be16)nft_reg_load16(
-			&regs->data[priv->sreg_proto_min]);
-		range.max_proto.all = (__force __be16)nft_reg_load16(
-			&regs->data[priv->sreg_proto_max]);
-		range.flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
-	}
-
-	range.flags |= priv->flags;
-
-	regs->verdict.code =
-		nf_nat_redirect_ipv6(pkt->skb, &range, nft_hook(pkt));
-}
-
 static void
 nft_redir_ipv6_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
 {
@@ -180,7 +172,7 @@  static struct nft_expr_type nft_redir_ipv6_type;
 static const struct nft_expr_ops nft_redir_ipv6_ops = {
 	.type		= &nft_redir_ipv6_type,
 	.size		= NFT_EXPR_SIZE(sizeof(struct nft_redir)),
-	.eval		= nft_redir_ipv6_eval,
+	.eval		= nft_redir_eval,
 	.init		= nft_redir_init,
 	.destroy	= nft_redir_ipv6_destroy,
 	.dump		= nft_redir_dump,
@@ -199,20 +191,6 @@  static struct nft_expr_type nft_redir_ipv6_type __read_mostly = {
 #endif
 
 #ifdef CONFIG_NF_TABLES_INET
-static void nft_redir_inet_eval(const struct nft_expr *expr,
-				struct nft_regs *regs,
-				const struct nft_pktinfo *pkt)
-{
-	switch (nft_pf(pkt)) {
-	case NFPROTO_IPV4:
-		return nft_redir_ipv4_eval(expr, regs, pkt);
-	case NFPROTO_IPV6:
-		return nft_redir_ipv6_eval(expr, regs, pkt);
-	}
-
-	WARN_ON_ONCE(1);
-}
-
 static void
 nft_redir_inet_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
 {
@@ -223,7 +201,7 @@  static struct nft_expr_type nft_redir_inet_type;
 static const struct nft_expr_ops nft_redir_inet_ops = {
 	.type		= &nft_redir_inet_type,
 	.size		= NFT_EXPR_SIZE(sizeof(struct nft_redir)),
-	.eval		= nft_redir_inet_eval,
+	.eval		= nft_redir_eval,
 	.init		= nft_redir_init,
 	.destroy	= nft_redir_inet_destroy,
 	.dump		= nft_redir_dump,
diff --git a/net/netfilter/xt_REDIRECT.c b/net/netfilter/xt_REDIRECT.c
index 353ca7801251..ff66b56a3f97 100644
--- a/net/netfilter/xt_REDIRECT.c
+++ b/net/netfilter/xt_REDIRECT.c
@@ -46,7 +46,6 @@  static void redirect_tg_destroy(const struct xt_tgdtor_param *par)
 	nf_ct_netns_put(par->net, par->family);
 }
 
-/* FIXME: Take multiple ranges --RR */
 static int redirect_tg4_check(const struct xt_tgchk_param *par)
 {
 	const struct nf_nat_ipv4_multi_range_compat *mr = par->targinfo;
@@ -65,7 +64,14 @@  static int redirect_tg4_check(const struct xt_tgchk_param *par)
 static unsigned int
 redirect_tg4(struct sk_buff *skb, const struct xt_action_param *par)
 {
-	return nf_nat_redirect_ipv4(skb, par->targinfo, xt_hooknum(par));
+	const struct nf_nat_ipv4_multi_range_compat *mr = par->targinfo;
+	struct nf_nat_range2 range = {
+		.flags       = mr->range[0].flags,
+		.min_proto   = mr->range[0].min,
+		.max_proto   = mr->range[0].max,
+	};
+
+	return nf_nat_redirect_ipv4(skb, &range, xt_hooknum(par));
 }
 
 static struct xt_target redirect_tg_reg[] __read_mostly = {