Merge tag 'nf-24-10-31' of git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf

Pablo Neira Ayuso says:

====================
The following patchset contains Netfilter fixes for net:

1) Remove unused parameters in conntrack_dump_flush.c used by
   selftests, from Liu Jing.

2) Fix possible UaF when removing xtables module via getsockopt()
   interface, from Dong Chenchen.

3) Fix potential crash in nf_send_reset6() reported by syzkaller.
   From Eric Dumazet

4) Validate offset and length before calling skb_checksum()
   in nft_payload, otherwise hitting BUG() is possible.

netfilter pull request 24-10-31

* tag 'nf-24-10-31' of git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf:
  netfilter: nft_payload: sanitize offset and length before calling skb_checksum()
  netfilter: nf_reject_ipv6: fix potential crash in nf_send_reset6()
  netfilter: Fix use-after-free in get_info()
  selftests: netfilter: remove unused parameter
====================

Link: https://patch.msgid.link/
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

4 files changed, 14 insertions, 12 deletions

diff --git a/net/ipv6/netfilter/nf_reject_ipv6.c b/net/ipv6/netfilter/nf_reject_ipv6.c
index 7db0437140bf..9ae2b2725bf9 100644
--- a/net/ipv6/netfilter/nf_reject_ipv6.c
+++ b/net/ipv6/netfilter/nf_reject_ipv6.c
@@ -268,12 +268,12 @@ static int nf_reject6_fill_skb_dst(struct sk_buff *skb_in)
 void nf_send_reset6(struct net *net, struct sock *sk, struct sk_buff *oldskb,
 		    int hook)
 {
-	struct sk_buff *nskb;
-	struct tcphdr _otcph;
-	const struct tcphdr *otcph;
-	unsigned int otcplen, hh_len;
 	const struct ipv6hdr *oip6h = ipv6_hdr(oldskb);
 	struct dst_entry *dst = NULL;
+	const struct tcphdr *otcph;
+	struct sk_buff *nskb;
+	struct tcphdr _otcph;
+	unsigned int otcplen;
 	struct flowi6 fl6;
 
 	if ((!(ipv6_addr_type(&oip6h->saddr) & IPV6_ADDR_UNICAST)) ||
@@ -312,9 +312,8 @@ void nf_send_reset6(struct net *net, struct sock *sk, struct sk_buff *oldskb,
 	if (IS_ERR(dst))
 		return;
 
-	hh_len = (dst->dev->hard_header_len + 15)&~15;
-	nskb = alloc_skb(hh_len + 15 + dst->header_len + sizeof(struct ipv6hdr)
-			 + sizeof(struct tcphdr) + dst->trailer_len,
+	nskb = alloc_skb(LL_MAX_HEADER + sizeof(struct ipv6hdr) +
+			 sizeof(struct tcphdr) + dst->trailer_len,
 			 GFP_ATOMIC);
 
 	if (!nskb) {
@@ -327,7 +326,7 @@ void nf_send_reset6(struct net *net, struct sock *sk, struct sk_buff *oldskb,
 
 	nskb->mark = fl6.flowi6_mark;
 
-	skb_reserve(nskb, hh_len + dst->header_len);
+	skb_reserve(nskb, LL_MAX_HEADER);
 	nf_reject_ip6hdr_put(nskb, oldskb, IPPROTO_TCP, ip6_dst_hoplimit(dst));
 	nf_reject_ip6_tcphdr_put(nskb, oldskb, otcph, otcplen);
 
diff --git a/net/netfilter/nft_payload.c b/net/netfilter/nft_payload.c
index 330609a76fb2..7dfc5343dae4 100644
--- a/net/netfilter/nft_payload.c
+++ b/net/netfilter/nft_payload.c
@@ -904,6 +904,9 @@ static void nft_payload_set_eval(const struct nft_expr *expr,
 	    ((priv->base != NFT_PAYLOAD_TRANSPORT_HEADER &&
 	      priv->base != NFT_PAYLOAD_INNER_HEADER) ||
 	     skb->ip_summed != CHECKSUM_PARTIAL)) {
+		if (offset + priv->len > skb->len)
+			goto err;
+
 		fsum = skb_checksum(skb, offset, priv->len, 0);
 		tsum = csum_partial(src, priv->len, 0);
 
diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c
index da5d929c7c85..709840612f0d 100644
--- a/net/netfilter/x_tables.c
+++ b/net/netfilter/x_tables.c
@@ -1269,7 +1269,7 @@ struct xt_table *xt_find_table_lock(struct net *net, u_int8_t af,
 
 	/* and once again: */
 	list_for_each_entry(t, &xt_net->tables[af], list)
-		if (strcmp(t->name, name) == 0)
+		if (strcmp(t->name, name) == 0 && owner == t->me)
 			return t;
 
 	module_put(owner);
diff --git a/tools/testing/selftests/net/netfilter/conntrack_dump_flush.c b/tools/testing/selftests/net/netfilter/conntrack_dump_flush.c
index dc056fec993b..254ff03297f0 100644
--- a/tools/testing/selftests/net/netfilter/conntrack_dump_flush.c
+++ b/tools/testing/selftests/net/netfilter/conntrack_dump_flush.c
@@ -98,7 +98,7 @@ static int conntrack_data_insert(struct mnl_socket *sock, struct nlmsghdr *nlh,
 	char buf[MNL_SOCKET_BUFFER_SIZE];
 	struct nlmsghdr *rplnlh;
 	unsigned int portid;
-	int err, ret;
+	int ret;
 
 	portid = mnl_socket_get_portid(sock);
 
@@ -217,7 +217,7 @@ static int conntracK_count_zone(struct mnl_socket *sock, uint16_t zone)
 	struct nfgenmsg *nfh;
 	struct nlattr *nest;
 	unsigned int portid;
-	int err, ret;
+	int ret;
 
 	portid = mnl_socket_get_portid(sock);
 
@@ -264,7 +264,7 @@ static int conntrack_flush_zone(struct mnl_socket *sock, uint16_t zone)
 	struct nfgenmsg *nfh;
 	struct nlattr *nest;
 	unsigned int portid;
-	int err, ret;
+	int ret;
 
 	portid = mnl_socket_get_portid(sock);