Merge branch 'raw-ping-fix-locking-in-proc-net-raw-icmp'

Kuniyuki Iwashima says:

====================
raw/ping: Fix locking in /proc/net/{raw,icmp}.

The first patch fixes a NULL deref for /proc/net/raw and second one fixes
the same issue for ping sockets.

The first patch also converts hlist_nulls to hlist, but this is because
the current code uses sk_nulls_for_each() for lockless readers, instead
of sk_nulls_for_each_rcu() which adds memory barrier, but raw sockets
does not use the nulls marker nor SLAB_TYPESAFE_BY_RCU in the first place.

OTOH, the ping sockets already uses sk_nulls_for_each_rcu(), and such
conversion can be posted later for net-next.
====================

Link: https://lore.kernel.org/r/20230403194959.48928-1-kuniyu@amazon.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

include/net/raw.h

@@ -37,7 +37,7 @@ int raw_rcv(struct sock *, struct sk_buff *);
 struct raw_hashinfo {
 	spinlock_t lock;
 
-	struct hlist_nulls_head ht[RAW_HTABLE_SIZE] ____cacheline_aligned;
+	struct hlist_head ht[RAW_HTABLE_SIZE] ____cacheline_aligned;
 };
 
 static inline u32 raw_hashfunc(const struct net *net, u32 proto)
@@ -51,7 +51,7 @@ static inline void raw_hashinfo_init(struct raw_hashinfo *hashinfo)
 
 	spin_lock_init(&hashinfo->lock);
 	for (i = 0; i < RAW_HTABLE_SIZE; i++)
-		INIT_HLIST_NULLS_HEAD(&hashinfo->ht[i], i);
+		INIT_HLIST_HEAD(&hashinfo->ht[i]);
 }
 
 #ifdef CONFIG_PROC_FS

net/ipv4/ping.c

@@ -1089,13 +1089,13 @@ static struct sock *ping_get_idx(struct seq_file *seq, loff_t pos)
 }
 
 void *ping_seq_start(struct seq_file *seq, loff_t *pos, sa_family_t family)
-	__acquires(RCU)
+	__acquires(ping_table.lock)
 {
 	struct ping_iter_state *state = seq->private;
 	state->bucket = 0;
 	state->family = family;
 
-	rcu_read_lock();
+	spin_lock(&ping_table.lock);
 
 	return *pos ? ping_get_idx(seq, *pos-1) : SEQ_START_TOKEN;
 }
@@ -1121,9 +1121,9 @@ void *ping_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 EXPORT_SYMBOL_GPL(ping_seq_next);
 
 void ping_seq_stop(struct seq_file *seq, void *v)
-	__releases(RCU)
+	__releases(ping_table.lock)
 {
-	rcu_read_unlock();
+	spin_unlock(&ping_table.lock);
 }
 EXPORT_SYMBOL_GPL(ping_seq_stop);
 

net/ipv4/raw.c

@@ -91,12 +91,12 @@ EXPORT_SYMBOL_GPL(raw_v4_hashinfo);
 int raw_hash_sk(struct sock *sk)
 {
 	struct raw_hashinfo *h = sk->sk_prot->h.raw_hash;
-	struct hlist_nulls_head *hlist;
+	struct hlist_head *hlist;
 
 	hlist = &h->ht[raw_hashfunc(sock_net(sk), inet_sk(sk)->inet_num)];
 
 	spin_lock(&h->lock);
-	__sk_nulls_add_node_rcu(sk, hlist);
+	sk_add_node_rcu(sk, hlist);
 	sock_set_flag(sk, SOCK_RCU_FREE);
 	spin_unlock(&h->lock);
 	sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
@@ -110,7 +110,7 @@ void raw_unhash_sk(struct sock *sk)
 	struct raw_hashinfo *h = sk->sk_prot->h.raw_hash;
 
 	spin_lock(&h->lock);
-	if (__sk_nulls_del_node_init_rcu(sk))
+	if (sk_del_node_init_rcu(sk))
 		sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
 	spin_unlock(&h->lock);
 }
@@ -163,16 +163,15 @@ static int icmp_filter(const struct sock *sk, const struct sk_buff *skb)
 static int raw_v4_input(struct net *net, struct sk_buff *skb,
 			const struct iphdr *iph, int hash)
 {
-	struct hlist_nulls_head *hlist;
-	struct hlist_nulls_node *hnode;
 	int sdif = inet_sdif(skb);
+	struct hlist_head *hlist;
 	int dif = inet_iif(skb);
 	int delivered = 0;
 	struct sock *sk;
 
 	hlist = &raw_v4_hashinfo.ht[hash];
 	rcu_read_lock();
-	sk_nulls_for_each(sk, hnode, hlist) {
+	sk_for_each_rcu(sk, hlist) {
 		if (!raw_v4_match(net, sk, iph->protocol,
 				  iph->saddr, iph->daddr, dif, sdif))
 			continue;
@@ -264,10 +263,9 @@ static void raw_err(struct sock *sk, struct sk_buff *skb, u32 info)
 void raw_icmp_error(struct sk_buff *skb, int protocol, u32 info)
 {
 	struct net *net = dev_net(skb->dev);
-	struct hlist_nulls_head *hlist;
-	struct hlist_nulls_node *hnode;
 	int dif = skb->dev->ifindex;
 	int sdif = inet_sdif(skb);
+	struct hlist_head *hlist;
 	const struct iphdr *iph;
 	struct sock *sk;
 	int hash;
@@ -276,7 +274,7 @@ void raw_icmp_error(struct sk_buff *skb, int protocol, u32 info)
 	hlist = &raw_v4_hashinfo.ht[hash];
 
 	rcu_read_lock();
-	sk_nulls_for_each(sk, hnode, hlist) {
+	sk_for_each_rcu(sk, hlist) {
 		iph = (const struct iphdr *)skb->data;
 		if (!raw_v4_match(net, sk, iph->protocol,
 				  iph->daddr, iph->saddr, dif, sdif))
@@ -950,14 +948,13 @@ static struct sock *raw_get_first(struct seq_file *seq, int bucket)
 {
 	struct raw_hashinfo *h = pde_data(file_inode(seq->file));
 	struct raw_iter_state *state = raw_seq_private(seq);
-	struct hlist_nulls_head *hlist;
-	struct hlist_nulls_node *hnode;
+	struct hlist_head *hlist;
 	struct sock *sk;
 
 	for (state->bucket = bucket; state->bucket < RAW_HTABLE_SIZE;
 			++state->bucket) {
 		hlist = &h->ht[state->bucket];
-		sk_nulls_for_each(sk, hnode, hlist) {
+		sk_for_each(sk, hlist) {
 			if (sock_net(sk) == seq_file_net(seq))
 				return sk;
 		}
@@ -970,7 +967,7 @@ static struct sock *raw_get_next(struct seq_file *seq, struct sock *sk)
 	struct raw_iter_state *state = raw_seq_private(seq);
 
 	do {
-		sk = sk_nulls_next(sk);
+		sk = sk_next(sk);
 	} while (sk && sock_net(sk) != seq_file_net(seq));
 
 	if (!sk)
@@ -989,9 +986,12 @@ static struct sock *raw_get_idx(struct seq_file *seq, loff_t pos)
 }
 
 void *raw_seq_start(struct seq_file *seq, loff_t *pos)
-	__acquires(RCU)
+	__acquires(&h->lock)
 {
-	rcu_read_lock();
+	struct raw_hashinfo *h = pde_data(file_inode(seq->file));
+
+	spin_lock(&h->lock);
+
 	return *pos ? raw_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
 }
 EXPORT_SYMBOL_GPL(raw_seq_start);
@@ -1010,9 +1010,11 @@ void *raw_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 EXPORT_SYMBOL_GPL(raw_seq_next);
 
 void raw_seq_stop(struct seq_file *seq, void *v)
-	__releases(RCU)
+	__releases(&h->lock)
 {
-	rcu_read_unlock();
+	struct raw_hashinfo *h = pde_data(file_inode(seq->file));
+
+	spin_unlock(&h->lock);
 }
 EXPORT_SYMBOL_GPL(raw_seq_stop);
 

net/ipv4/raw_diag.c

@@ -57,8 +57,7 @@ static bool raw_lookup(struct net *net, struct sock *sk,
 static struct sock *raw_sock_get(struct net *net, const struct inet_diag_req_v2 *r)
 {
 	struct raw_hashinfo *hashinfo = raw_get_hashinfo(r);
-	struct hlist_nulls_head *hlist;
-	struct hlist_nulls_node *hnode;
+	struct hlist_head *hlist;
 	struct sock *sk;
 	int slot;
 
@@ -68,7 +67,7 @@ static struct sock *raw_sock_get(struct net *net, const struct inet_diag_req_v2
 	rcu_read_lock();
 	for (slot = 0; slot < RAW_HTABLE_SIZE; slot++) {
 		hlist = &hashinfo->ht[slot];
-		sk_nulls_for_each(sk, hnode, hlist) {
+		sk_for_each_rcu(sk, hlist) {
 			if (raw_lookup(net, sk, r)) {
 				/*
 				 * Grab it and keep until we fill
@@ -142,9 +141,8 @@ static void raw_diag_dump(struct sk_buff *skb, struct netlink_callback *cb,
 	struct raw_hashinfo *hashinfo = raw_get_hashinfo(r);
 	struct net *net = sock_net(skb->sk);
 	struct inet_diag_dump_data *cb_data;
-	struct hlist_nulls_head *hlist;
-	struct hlist_nulls_node *hnode;
 	int num, s_num, slot, s_slot;
+	struct hlist_head *hlist;
 	struct sock *sk = NULL;
 	struct nlattr *bc;
 
@@ -161,7 +159,7 @@ static void raw_diag_dump(struct sk_buff *skb, struct netlink_callback *cb,
 		num = 0;
 
 		hlist = &hashinfo->ht[slot];
-		sk_nulls_for_each(sk, hnode, hlist) {
+		sk_for_each_rcu(sk, hlist) {
 			struct inet_sock *inet = inet_sk(sk);
 
 			if (!net_eq(sock_net(sk), net))

net/ipv6/raw.c

@@ -141,10 +141,9 @@ EXPORT_SYMBOL(rawv6_mh_filter_unregister);
 static bool ipv6_raw_deliver(struct sk_buff *skb, int nexthdr)
 {
 	struct net *net = dev_net(skb->dev);
-	struct hlist_nulls_head *hlist;
-	struct hlist_nulls_node *hnode;
 	const struct in6_addr *saddr;
 	const struct in6_addr *daddr;
+	struct hlist_head *hlist;
 	struct sock *sk;
 	bool delivered = false;
 	__u8 hash;
@@ -155,7 +154,7 @@ static bool ipv6_raw_deliver(struct sk_buff *skb, int nexthdr)
 	hash = raw_hashfunc(net, nexthdr);
 	hlist = &raw_v6_hashinfo.ht[hash];
 	rcu_read_lock();
-	sk_nulls_for_each(sk, hnode, hlist) {
+	sk_for_each_rcu(sk, hlist) {
 		int filtered;
 
 		if (!raw_v6_match(net, sk, nexthdr, daddr, saddr,
@@ -333,15 +332,14 @@ void raw6_icmp_error(struct sk_buff *skb, int nexthdr,
 		u8 type, u8 code, int inner_offset, __be32 info)
 {
 	struct net *net = dev_net(skb->dev);
-	struct hlist_nulls_head *hlist;
-	struct hlist_nulls_node *hnode;
+	struct hlist_head *hlist;
 	struct sock *sk;
 	int hash;
 
 	hash = raw_hashfunc(net, nexthdr);
 	hlist = &raw_v6_hashinfo.ht[hash];
 	rcu_read_lock();
-	sk_nulls_for_each(sk, hnode, hlist) {
+	sk_for_each_rcu(sk, hlist) {
 		/* Note: ipv6_hdr(skb) != skb->data */
 		const struct ipv6hdr *ip6h = (const struct ipv6hdr *)skb->data;