Merge tag 'nf-23-09-06' of https://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf

Florian Westphal says:

====================
netfilter updates for net

This PR contains nf_tables updates for your *net* tree.
This time almost all fixes are for old bugs:

First patch fixes a 4-byte stack OOB write, from myself.
This was broken ever since nftables was switches from 128 to 32bit
register addressing in v4.1.

2nd patch fixes an out-of-bounds read.
This has been broken ever since xt_osf got added in 2.6.31, the bug
was then just moved around during refactoring, from Wander Lairson Costa.

3rd patch adds a missing enum description, from Phil Sutter.

4th patch fixes a UaF inftables that occurs when userspace adds
elements with a timeout so small that expiration happens while the
transaction is still in progress.  Fix from Pablo Neira Ayuso.

Patch 5 fixes a memory out of bounds access, this was
broken since v4.20. Patch from Kyle Zeng and Jozsef Kadlecsik.

Patch 6 fixes another bogus memory access when building audit
record. Bug added in the previous pull request, fix from Pablo.

netfilter pull request 2023-09-06

* tag 'nf-23-09-06' of https://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf:
  netfilter: nf_tables: Unbreak audit log reset
  netfilter: ipset: add the missing IP_SET_HASH_WITH_NET0 macro for ip_set_hash_netportnet.c
  netfilter: nft_set_rbtree: skip sync GC for new elements in this transaction
  netfilter: nf_tables: uapi: Describe NFTA_RULE_CHAIN_ID
  netfilter: nfnetlink_osf: avoid OOB read
  netfilter: nftables: exthdr: fix 4-byte stack OOB write
====================

Link: https://lore.kernel.org/r/20230906162525.11079-1-fw@strlen.deSigned-off-by: Paolo Abeni <pabeni@redhat.com>

include/uapi/linux/netfilter/nf_tables.h

@@ -263,6 +263,7 @@ enum nft_chain_attributes {
  * @NFTA_RULE_USERDATA: user data (NLA_BINARY, NFT_USERDATA_MAXLEN)
  * @NFTA_RULE_ID: uniquely identifies a rule in a transaction (NLA_U32)
  * @NFTA_RULE_POSITION_ID: transaction unique identifier of the previous rule (NLA_U32)
+ * @NFTA_RULE_CHAIN_ID: add the rule to chain by ID, alternative to @NFTA_RULE_CHAIN (NLA_U32)
  */
 enum nft_rule_attributes {
 	NFTA_RULE_UNSPEC,

net/netfilter/ipset/ip_set_hash_netportnet.c

@@ -36,6 +36,7 @@ MODULE_ALIAS("ip_set_hash:net,port,net");
 #define IP_SET_HASH_WITH_PROTO
 #define IP_SET_HASH_WITH_NETS
 #define IPSET_NET_COUNT 2
+#define IP_SET_HASH_WITH_NET0
 
 /* IPv4 variant */
 

net/netfilter/nf_tables_api.c

@@ -3480,6 +3480,10 @@ static int __nf_tables_dump_rules(struct sk_buff *skb,
 cont_skip:
 		(*idx)++;
 	}
+
+	if (reset && *idx)
+		audit_log_rule_reset(table, cb->seq, *idx);
+
 	return 0;
 }
 
@@ -3540,9 +3544,6 @@ static int nf_tables_dump_rules(struct sk_buff *skb,
 done:
 	rcu_read_unlock();
 
-	if (reset && idx > cb->args[0])
-		audit_log_rule_reset(table, cb->seq, idx - cb->args[0]);
-
 	cb->args[0] = idx;
 	return skb->len;
 }
@@ -5760,8 +5761,6 @@ static int nf_tables_dump_set(struct sk_buff *skb, struct netlink_callback *cb)
 	if (!args.iter.err && args.iter.count == cb->args[0])
 		args.iter.err = nft_set_catchall_dump(net, skb, set,
 						      reset, cb->seq);
-	rcu_read_unlock();
-
 	nla_nest_end(skb, nest);
 	nlmsg_end(skb, nlh);
 
@@ -5769,6 +5768,8 @@ static int nf_tables_dump_set(struct sk_buff *skb, struct netlink_callback *cb)
 		audit_log_nft_set_reset(table, cb->seq,
 					args.iter.count - args.iter.skip);
 
+	rcu_read_unlock();
+
 	if (args.iter.err && args.iter.err != -EMSGSIZE)
 		return args.iter.err;
 	if (args.iter.count == cb->args[0])

net/netfilter/nfnetlink_osf.c

@@ -315,6 +315,14 @@ static int nfnl_osf_add_callback(struct sk_buff *skb,
 
 	f = nla_data(osf_attrs[OSF_ATTR_FINGER]);
 
+	if (f->opt_num > ARRAY_SIZE(f->opt))
+		return -EINVAL;
+
+	if (!memchr(f->genre, 0, MAXGENRELEN) ||
+	    !memchr(f->subtype, 0, MAXGENRELEN) ||
+	    !memchr(f->version, 0, MAXGENRELEN))
+		return -EINVAL;
+
 	kf = kmalloc(sizeof(struct nf_osf_finger), GFP_KERNEL);
 	if (!kf)
 		return -ENOMEM;

net/netfilter/nft_exthdr.c

@@ -35,6 +35,14 @@ static unsigned int optlen(const u8 *opt, unsigned int offset)
 		return opt[offset + 1];
 }
 
+static int nft_skb_copy_to_reg(const struct sk_buff *skb, int offset, u32 *dest, unsigned int len)
+{
+	if (len % NFT_REG32_SIZE)
+		dest[len / NFT_REG32_SIZE] = 0;
+
+	return skb_copy_bits(skb, offset, dest, len);
+}
+
 static void nft_exthdr_ipv6_eval(const struct nft_expr *expr,
 				 struct nft_regs *regs,
 				 const struct nft_pktinfo *pkt)
@@ -56,8 +64,7 @@ static void nft_exthdr_ipv6_eval(const struct nft_expr *expr,
 	}
 	offset += priv->offset;
 
-	dest[priv->len / NFT_REG32_SIZE] = 0;
-	if (skb_copy_bits(pkt->skb, offset, dest, priv->len) < 0)
+	if (nft_skb_copy_to_reg(pkt->skb, offset, dest, priv->len) < 0)
 		goto err;
 	return;
 err:
@@ -153,8 +160,7 @@ static void nft_exthdr_ipv4_eval(const struct nft_expr *expr,
 	}
 	offset += priv->offset;
 
-	dest[priv->len / NFT_REG32_SIZE] = 0;
-	if (skb_copy_bits(pkt->skb, offset, dest, priv->len) < 0)
+	if (nft_skb_copy_to_reg(pkt->skb, offset, dest, priv->len) < 0)
 		goto err;
 	return;
 err:
@@ -210,6 +216,7 @@ static void nft_exthdr_tcp_eval(const struct nft_expr *expr,
 		if (priv->flags & NFT_EXTHDR_F_PRESENT) {
 			*dest = 1;
 		} else {
+			if (priv->len % NFT_REG32_SIZE)
 				dest[priv->len / NFT_REG32_SIZE] = 0;
 			memcpy(dest, opt + offset, priv->len);
 		}
@@ -388,8 +395,7 @@ static void nft_exthdr_sctp_eval(const struct nft_expr *expr,
 			    offset + ntohs(sch->length) > pkt->skb->len)
 				break;
 
-			dest[priv->len / NFT_REG32_SIZE] = 0;
-			if (skb_copy_bits(pkt->skb, offset + priv->offset,
+			if (nft_skb_copy_to_reg(pkt->skb, offset + priv->offset,
 						dest, priv->len) < 0)
 				break;
 			return;

net/netfilter/nft_set_rbtree.c

@@ -312,6 +312,7 @@ static int __nft_rbtree_insert(const struct net *net, const struct nft_set *set,
 	struct nft_rbtree_elem *rbe, *rbe_le = NULL, *rbe_ge = NULL;
 	struct rb_node *node, *next, *parent, **p, *first = NULL;
 	struct nft_rbtree *priv = nft_set_priv(set);
+	u8 cur_genmask = nft_genmask_cur(net);
 	u8 genmask = nft_genmask_next(net);
 	int d, err;
 
@@ -357,8 +358,11 @@ static int __nft_rbtree_insert(const struct net *net, const struct nft_set *set,
 		if (!nft_set_elem_active(&rbe->ext, genmask))
 			continue;
 
-		/* perform garbage collection to avoid bogus overlap reports. */
-		if (nft_set_elem_expired(&rbe->ext)) {
+		/* perform garbage collection to avoid bogus overlap reports
+		 * but skip new elements in this transaction.
+		 */
+		if (nft_set_elem_expired(&rbe->ext) &&
+		    nft_set_elem_active(&rbe->ext, cur_genmask)) {
 			err = nft_rbtree_gc_elem(set, priv, rbe, genmask);
 			if (err < 0)
 				return err;