From d87f8bc47fbf012a7f115e311d0603d97e47c34c Mon Sep 17 00:00:00 2001 From: Sabrina Dubroca Date: Mon, 9 Mar 2026 11:32:43 +0100 Subject: xfrm: avoid RCU warnings around the per-netns netlink socket net->xfrm.nlsk is used in 2 types of contexts: - fully under RCU, with rcu_read_lock + rcu_dereference and a NULL check - in the netlink handlers, with requests coming from a userspace socket In the 2nd case, net->xfrm.nlsk is guaranteed to stay non-NULL and the object is alive, since we can't enter the netns destruction path while the user socket holds a reference on the netns. After adding the __rcu annotation to netns_xfrm.nlsk (which silences sparse warnings in the RCU users and __net_init code), we need to tell sparse that the 2nd case is safe. Add a helper for that. Signed-off-by: Sabrina Dubroca Reviewed-by: Simon Horman Signed-off-by: Steffen Klassert --- include/net/netns/xfrm.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/net') diff --git a/include/net/netns/xfrm.h b/include/net/netns/xfrm.h index 23dd647fe024..b73983a17e08 100644 --- a/include/net/netns/xfrm.h +++ b/include/net/netns/xfrm.h @@ -59,7 +59,7 @@ struct netns_xfrm { struct list_head inexact_bins; - struct sock *nlsk; + struct sock __rcu *nlsk; struct sock *nlsk_stash; u32 sysctl_aevent_etime; -- cgit v1.2.3 From 761fb8ec8778f0caf2bba5a41e3cff1ea86974f3 Mon Sep 17 00:00:00 2001 From: Luiz Augusto von Dentz Date: Tue, 17 Mar 2026 11:54:01 -0400 Subject: Bluetooth: L2CAP: Fix regressions caused by reusing ident This attempt to fix regressions caused by reusing ident which apparently is not handled well on certain stacks causing the stack to not respond to requests, so instead of simple returning the first unallocated id this stores the last used tx_ident and then attempt to use the next until all available ids are exausted and then cycle starting over to 1. Link: https://bugzilla.kernel.org/show_bug.cgi?id=221120 Link: https://bugzilla.kernel.org/show_bug.cgi?id=221177 Fixes: 6c3ea155e5ee ("Bluetooth: L2CAP: Fix not tracking outstanding TX ident") Signed-off-by: Luiz Augusto von Dentz Tested-by: Christian Eggers --- include/net/bluetooth/l2cap.h | 1 + net/bluetooth/l2cap_core.c | 29 ++++++++++++++++++++++++++--- 2 files changed, 27 insertions(+), 3 deletions(-) (limited to 'include/net') diff --git a/include/net/bluetooth/l2cap.h b/include/net/bluetooth/l2cap.h index 010f1a8fd15f..5172afee5494 100644 --- a/include/net/bluetooth/l2cap.h +++ b/include/net/bluetooth/l2cap.h @@ -658,6 +658,7 @@ struct l2cap_conn { struct sk_buff *rx_skb; __u32 rx_len; struct ida tx_ida; + __u8 tx_ident; struct sk_buff_head pending_rx; struct work_struct pending_rx_work; diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c index 30fd6848938e..3de3e3c8e966 100644 --- a/net/bluetooth/l2cap_core.c +++ b/net/bluetooth/l2cap_core.c @@ -926,16 +926,39 @@ int l2cap_chan_check_security(struct l2cap_chan *chan, bool initiator) static int l2cap_get_ident(struct l2cap_conn *conn) { + u8 max; + int ident; + /* LE link does not support tools like l2ping so use the full range */ if (conn->hcon->type == LE_LINK) - return ida_alloc_range(&conn->tx_ida, 1, 255, GFP_ATOMIC); - + max = 255; /* Get next available identificator. * 1 - 128 are used by kernel. * 129 - 199 are reserved. * 200 - 254 are used by utilities like l2ping, etc. */ - return ida_alloc_range(&conn->tx_ida, 1, 128, GFP_ATOMIC); + else + max = 128; + + /* Allocate ident using min as last used + 1 (cyclic) */ + ident = ida_alloc_range(&conn->tx_ida, READ_ONCE(conn->tx_ident) + 1, + max, GFP_ATOMIC); + /* Force min 1 to start over */ + if (ident <= 0) { + ident = ida_alloc_range(&conn->tx_ida, 1, max, GFP_ATOMIC); + if (ident <= 0) { + /* If all idents are in use, log an error, this is + * extremely unlikely to happen and would indicate a bug + * in the code that idents are not being freed properly. + */ + BT_ERR("Unable to allocate ident: %d", ident); + return 0; + } + } + + WRITE_ONCE(conn->tx_ident, ident); + + return ident; } static void l2cap_send_acl(struct l2cap_conn *conn, struct sk_buff *skb, -- cgit v1.2.3 From 4be7b99c253f0c85a255cc1db7127ba3232dfa30 Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima Date: Fri, 20 Mar 2026 07:23:00 +0000 Subject: ipv6: Don't remove permanent routes with exceptions from tb6_gc_hlist. The cited commit mechanically put fib6_remove_gc_list() just after every fib6_clean_expires() call. When a temporary route is promoted to a permanent route, there may already be exception routes tied to it. If fib6_remove_gc_list() removes the route from tb6_gc_hlist, such exception routes will no longer be aged. Let's replace fib6_remove_gc_list() with a new helper fib6_may_remove_gc_list() and use fib6_age_exceptions() there. Note that net->ipv6 is only compiled when CONFIG_IPV6 is enabled, so fib6_{add,remove,may_remove}_gc_list() are guarded. Fixes: 5eb902b8e719 ("net/ipv6: Remove expired routes with a separated list of routes.") Signed-off-by: Kuniyuki Iwashima Reviewed-by: David Ahern Link: https://patch.msgid.link/20260320072317.2561779-3-kuniyu@google.com Signed-off-by: Jakub Kicinski --- include/net/ip6_fib.h | 21 ++++++++++++++++++++- net/ipv6/addrconf.c | 4 ++-- net/ipv6/ip6_fib.c | 6 +++--- net/ipv6/route.c | 2 +- 4 files changed, 26 insertions(+), 7 deletions(-) (limited to 'include/net') diff --git a/include/net/ip6_fib.h b/include/net/ip6_fib.h index 88b0dd4d8e09..9f8b6814a96a 100644 --- a/include/net/ip6_fib.h +++ b/include/net/ip6_fib.h @@ -507,12 +507,14 @@ void fib6_rt_update(struct net *net, struct fib6_info *rt, void inet6_rt_notify(int event, struct fib6_info *rt, struct nl_info *info, unsigned int flags); +void fib6_age_exceptions(struct fib6_info *rt, struct fib6_gc_args *gc_args, + unsigned long now); void fib6_run_gc(unsigned long expires, struct net *net, bool force); - void fib6_gc_cleanup(void); int fib6_init(void); +#if IS_ENABLED(CONFIG_IPV6) /* Add the route to the gc list if it is not already there * * The callers should hold f6i->fib6_table->tb6_lock. @@ -545,6 +547,23 @@ static inline void fib6_remove_gc_list(struct fib6_info *f6i) hlist_del_init(&f6i->gc_link); } +static inline void fib6_may_remove_gc_list(struct net *net, + struct fib6_info *f6i) +{ + struct fib6_gc_args gc_args; + + if (hlist_unhashed(&f6i->gc_link)) + return; + + gc_args.timeout = READ_ONCE(net->ipv6.sysctl.ip6_rt_gc_interval); + gc_args.more = 0; + + rcu_read_lock(); + fib6_age_exceptions(f6i, &gc_args, jiffies); + rcu_read_unlock(); +} +#endif + struct ipv6_route_iter { struct seq_net_private p; struct fib6_walker w; diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index 0e55f139e05d..f4e23b543585 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -2862,7 +2862,7 @@ void addrconf_prefix_rcv(struct net_device *dev, u8 *opt, int len, bool sllao) fib6_add_gc_list(rt); } else { fib6_clean_expires(rt); - fib6_remove_gc_list(rt); + fib6_may_remove_gc_list(net, rt); } spin_unlock_bh(&table->tb6_lock); @@ -4840,7 +4840,7 @@ static int modify_prefix_route(struct net *net, struct inet6_ifaddr *ifp, if (!(flags & RTF_EXPIRES)) { fib6_clean_expires(f6i); - fib6_remove_gc_list(f6i); + fib6_may_remove_gc_list(net, f6i); } else { fib6_set_expires(f6i, expires); fib6_add_gc_list(f6i); diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c index fadfca49d6b1..dd26657b6a4a 100644 --- a/net/ipv6/ip6_fib.c +++ b/net/ipv6/ip6_fib.c @@ -1133,7 +1133,7 @@ static int fib6_add_rt2node(struct fib6_node *fn, struct fib6_info *rt, return -EEXIST; if (!(rt->fib6_flags & RTF_EXPIRES)) { fib6_clean_expires(iter); - fib6_remove_gc_list(iter); + fib6_may_remove_gc_list(info->nl_net, iter); } else { fib6_set_expires(iter, rt->expires); fib6_add_gc_list(iter); @@ -2348,8 +2348,8 @@ static void fib6_flush_trees(struct net *net) /* * Garbage collection */ -static void fib6_age_exceptions(struct fib6_info *rt, struct fib6_gc_args *gc_args, - unsigned long now) +void fib6_age_exceptions(struct fib6_info *rt, struct fib6_gc_args *gc_args, + unsigned long now) { bool may_expire = rt->fib6_flags & RTF_EXPIRES && rt->expires; int old_more = gc_args->more; diff --git a/net/ipv6/route.c b/net/ipv6/route.c index 08cd86f49bf9..cb521700cee7 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -1033,7 +1033,7 @@ int rt6_route_rcv(struct net_device *dev, u8 *opt, int len, if (!addrconf_finite_timeout(lifetime)) { fib6_clean_expires(rt); - fib6_remove_gc_list(rt); + fib6_may_remove_gc_list(net, rt); } else { fib6_set_expires(rt, jiffies + HZ * lifetime); fib6_add_gc_list(rt); -- cgit v1.2.3 From e537dd15d0d4ad989d56a1021290f0c674dd8b28 Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Thu, 19 Mar 2026 11:18:17 -0700 Subject: udp: Fix wildcard bind conflict check when using hash2 When binding a udp_sock to a local address and port, UDP uses two hashes (udptable->hash and udptable->hash2) for collision detection. The current code switches to "hash2" when hslot->count > 10. "hash2" is keyed by local address and local port. "hash" is keyed by local port only. The issue can be shown in the following bind sequence (pseudo code): bind(fd1, "[fd00::1]:8888") bind(fd2, "[fd00::2]:8888") bind(fd3, "[fd00::3]:8888") bind(fd4, "[fd00::4]:8888") bind(fd5, "[fd00::5]:8888") bind(fd6, "[fd00::6]:8888") bind(fd7, "[fd00::7]:8888") bind(fd8, "[fd00::8]:8888") bind(fd9, "[fd00::9]:8888") bind(fd10, "[fd00::10]:8888") /* Correctly return -EADDRINUSE because "hash" is used * instead of "hash2". udp_lib_lport_inuse() detects the * conflict. */ bind(fail_fd, "[::]:8888") /* After one more socket is bound to "[fd00::11]:8888", * hslot->count exceeds 10 and "hash2" is used instead. */ bind(fd11, "[fd00::11]:8888") bind(fail_fd, "[::]:8888") /* succeeds unexpectedly */ The same issue applies to the IPv4 wildcard address "0.0.0.0" and the IPv4-mapped wildcard address "::ffff:0.0.0.0". For example, if there are existing sockets bound to "192.168.1.[1-11]:8888", then binding "0.0.0.0:8888" or "[::ffff:0.0.0.0]:8888" can also miss the conflict when hslot->count > 10. TCP inet_csk_get_port() already has the correct check in inet_use_bhash2_on_bind(). Rename it to inet_use_hash2_on_bind() and move it to inet_hashtables.h so udp.c can reuse it in this fix. Fixes: 30fff9231fad ("udp: bind() optimisation") Reported-by: Andrew Onyshchuk Signed-off-by: Martin KaFai Lau Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20260319181817.1901357-1-martin.lau@linux.dev Signed-off-by: Jakub Kicinski --- include/net/inet_hashtables.h | 14 ++++++++++++++ net/ipv4/inet_connection_sock.c | 20 +++----------------- net/ipv4/udp.c | 2 +- 3 files changed, 18 insertions(+), 18 deletions(-) (limited to 'include/net') diff --git a/include/net/inet_hashtables.h b/include/net/inet_hashtables.h index 5a979dcab538..6d936e9f2fd3 100644 --- a/include/net/inet_hashtables.h +++ b/include/net/inet_hashtables.h @@ -264,6 +264,20 @@ inet_bhashfn_portaddr(const struct inet_hashinfo *hinfo, const struct sock *sk, return &hinfo->bhash2[hash & (hinfo->bhash_size - 1)]; } +static inline bool inet_use_hash2_on_bind(const struct sock *sk) +{ +#if IS_ENABLED(CONFIG_IPV6) + if (sk->sk_family == AF_INET6) { + if (ipv6_addr_any(&sk->sk_v6_rcv_saddr)) + return false; + + if (!ipv6_addr_v4mapped(&sk->sk_v6_rcv_saddr)) + return true; + } +#endif + return sk->sk_rcv_saddr != htonl(INADDR_ANY); +} + struct inet_bind_hashbucket * inet_bhash2_addr_any_hashbucket(const struct sock *sk, const struct net *net, int port); diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c index 5dfac6ce1110..e961936b6be7 100644 --- a/net/ipv4/inet_connection_sock.c +++ b/net/ipv4/inet_connection_sock.c @@ -154,20 +154,6 @@ bool inet_sk_get_local_port_range(const struct sock *sk, int *low, int *high) } EXPORT_SYMBOL(inet_sk_get_local_port_range); -static bool inet_use_bhash2_on_bind(const struct sock *sk) -{ -#if IS_ENABLED(CONFIG_IPV6) - if (sk->sk_family == AF_INET6) { - if (ipv6_addr_any(&sk->sk_v6_rcv_saddr)) - return false; - - if (!ipv6_addr_v4mapped(&sk->sk_v6_rcv_saddr)) - return true; - } -#endif - return sk->sk_rcv_saddr != htonl(INADDR_ANY); -} - static bool inet_bind_conflict(const struct sock *sk, struct sock *sk2, kuid_t uid, bool relax, bool reuseport_cb_ok, bool reuseport_ok) @@ -259,7 +245,7 @@ static int inet_csk_bind_conflict(const struct sock *sk, * checks separately because their spinlocks have to be acquired/released * independently of each other, to prevent possible deadlocks */ - if (inet_use_bhash2_on_bind(sk)) + if (inet_use_hash2_on_bind(sk)) return tb2 && inet_bhash2_conflict(sk, tb2, uid, relax, reuseport_cb_ok, reuseport_ok); @@ -376,7 +362,7 @@ other_parity_scan: head = &hinfo->bhash[inet_bhashfn(net, port, hinfo->bhash_size)]; spin_lock_bh(&head->lock); - if (inet_use_bhash2_on_bind(sk)) { + if (inet_use_hash2_on_bind(sk)) { if (inet_bhash2_addr_any_conflict(sk, port, l3mdev, relax, false)) goto next_port; } @@ -562,7 +548,7 @@ int inet_csk_get_port(struct sock *sk, unsigned short snum) check_bind_conflict = false; } - if (check_bind_conflict && inet_use_bhash2_on_bind(sk)) { + if (check_bind_conflict && inet_use_hash2_on_bind(sk)) { if (inet_bhash2_addr_any_conflict(sk, port, l3mdev, true, true)) goto fail_unlock; } diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index b60fad393e18..cb99a3c27053 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -287,7 +287,7 @@ int udp_lib_get_port(struct sock *sk, unsigned short snum, } else { hslot = udp_hashslot(udptable, net, snum); spin_lock_bh(&hslot->lock); - if (hslot->count > 10) { + if (inet_use_hash2_on_bind(sk) && hslot->count > 10) { int exist; unsigned int slot2 = udp_sk(sk)->udp_portaddr_hash ^ snum; -- cgit v1.2.3 From 815980fe6dbb01ad4007e8b260a45617f598b76d Mon Sep 17 00:00:00 2001 From: Jonas Köppeler Date: Mon, 23 Mar 2026 18:49:20 +0100 Subject: net_sched: codel: fix stale state for empty flows in fq_codel MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When codel_dequeue() finds an empty queue, it resets vars->dropping but does not reset vars->first_above_time. The reference CoDel algorithm (Nichols & Jacobson, ACM Queue 2012) resets both: dodeque_result codel_queue_t::dodeque(time_t now) { ... if (r.p == NULL) { first_above_time = 0; // <-- Linux omits this } ... } Note that codel_should_drop() does reset first_above_time when called with a NULL skb, but codel_dequeue() returns early before ever calling codel_should_drop() in the empty-queue case. The post-drop code paths do reach codel_should_drop(NULL) and correctly reset the timer, so a dropped packet breaks the cycle -- but the next delivered packet re-arms first_above_time and the cycle repeats. For sparse flows such as ICMP ping (one packet every 200ms-1s), the first packet arms first_above_time, the flow goes empty, and the second packet arrives after the interval has elapsed and gets dropped. The pattern repeats, producing sustained loss on flows that are not actually congested. Test: veth pair, fq_codel, BQL disabled, 30000 iptables rules in the consumer namespace (NAPI-64 cycle ~14ms, well above fq_codel's 5ms target), ping at 5 pps under UDP flood: Before fix: 26% ping packet loss After fix: 0% ping packet loss Fix by resetting first_above_time to zero in the empty-queue path of codel_dequeue(), matching the reference algorithm. Fixes: 76e3cc126bb2 ("codel: Controlled Delay AQM") Fixes: d068ca2ae2e6 ("codel: split into multiple files") Co-developed-by: Jesper Dangaard Brouer Signed-off-by: Jesper Dangaard Brouer Signed-off-by: Jonas Köppeler Reported-by: Chris Arges Tested-by: Jonas Köppeler Reviewed-by: Toke Høiland-Jørgensen Link: https://lore.kernel.org/all/20260318134826.1281205-7-hawk@kernel.org/ Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20260323174920.253526-1-hawk@kernel.org Signed-off-by: Jakub Kicinski --- include/net/codel_impl.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/net') diff --git a/include/net/codel_impl.h b/include/net/codel_impl.h index 78a27ac73070..b2c359c6dd1b 100644 --- a/include/net/codel_impl.h +++ b/include/net/codel_impl.h @@ -158,6 +158,7 @@ static struct sk_buff *codel_dequeue(void *ctx, bool drop; if (!skb) { + vars->first_above_time = 0; vars->dropping = false; return skb; } -- cgit v1.2.3 From 9c42bc9db90a154bc61ae337a070465f3393485a Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Wed, 25 Mar 2026 14:11:02 +0100 Subject: netfilter: nf_conntrack_expect: honor expectation helper field The expectation helper field is mostly unused. As a result, the netfilter codebase relies on accessing the helper through exp->master. Always set on the expectation helper field so it can be used to reach the helper. nf_ct_expect_init() is called from packet path where the skb owns the ct object, therefore accessing exp->master for the newly created expectation is safe. This saves a lot of updates in all callsites to pass the ct object as parameter to nf_ct_expect_init(). This is a preparation patches for follow up fixes. Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- include/net/netfilter/nf_conntrack_expect.h | 2 +- net/netfilter/nf_conntrack_broadcast.c | 2 +- net/netfilter/nf_conntrack_expect.c | 14 +++++++++++++- net/netfilter/nf_conntrack_h323_main.c | 12 ++++++------ net/netfilter/nf_conntrack_helper.c | 7 ++++++- net/netfilter/nf_conntrack_netlink.c | 2 +- net/netfilter/nf_conntrack_sip.c | 2 +- 7 files changed, 29 insertions(+), 12 deletions(-) (limited to 'include/net') diff --git a/include/net/netfilter/nf_conntrack_expect.h b/include/net/netfilter/nf_conntrack_expect.h index 165e7a03b8e9..1b01400b10bd 100644 --- a/include/net/netfilter/nf_conntrack_expect.h +++ b/include/net/netfilter/nf_conntrack_expect.h @@ -40,7 +40,7 @@ struct nf_conntrack_expect { struct nf_conntrack_expect *this); /* Helper to assign to new connection */ - struct nf_conntrack_helper *helper; + struct nf_conntrack_helper __rcu *helper; /* The conntrack of the master connection */ struct nf_conn *master; diff --git a/net/netfilter/nf_conntrack_broadcast.c b/net/netfilter/nf_conntrack_broadcast.c index a7552a46d6ac..1964c596c646 100644 --- a/net/netfilter/nf_conntrack_broadcast.c +++ b/net/netfilter/nf_conntrack_broadcast.c @@ -70,7 +70,7 @@ int nf_conntrack_broadcast_help(struct sk_buff *skb, exp->expectfn = NULL; exp->flags = NF_CT_EXPECT_PERMANENT; exp->class = NF_CT_EXPECT_CLASS_DEFAULT; - exp->helper = NULL; + rcu_assign_pointer(exp->helper, helper); nf_ct_expect_related(exp, 0); nf_ct_expect_put(exp); diff --git a/net/netfilter/nf_conntrack_expect.c b/net/netfilter/nf_conntrack_expect.c index cfc2daa3fc7f..841e316240da 100644 --- a/net/netfilter/nf_conntrack_expect.c +++ b/net/netfilter/nf_conntrack_expect.c @@ -309,12 +309,19 @@ struct nf_conntrack_expect *nf_ct_expect_alloc(struct nf_conn *me) } EXPORT_SYMBOL_GPL(nf_ct_expect_alloc); +/* This function can only be used from packet path, where accessing + * master's helper is safe, because the packet holds a reference on + * the conntrack object. Never use it from control plane. + */ void nf_ct_expect_init(struct nf_conntrack_expect *exp, unsigned int class, u_int8_t family, const union nf_inet_addr *saddr, const union nf_inet_addr *daddr, u_int8_t proto, const __be16 *src, const __be16 *dst) { + struct nf_conntrack_helper *helper = NULL; + struct nf_conn *ct = exp->master; + struct nf_conn_help *help; int len; if (family == AF_INET) @@ -325,7 +332,12 @@ void nf_ct_expect_init(struct nf_conntrack_expect *exp, unsigned int class, exp->flags = 0; exp->class = class; exp->expectfn = NULL; - exp->helper = NULL; + + help = nfct_help(ct); + if (help) + helper = rcu_dereference(help->helper); + + rcu_assign_pointer(exp->helper, helper); exp->tuple.src.l3num = family; exp->tuple.dst.protonum = proto; diff --git a/net/netfilter/nf_conntrack_h323_main.c b/net/netfilter/nf_conntrack_h323_main.c index a2a0e22ccee1..3f5c50455b71 100644 --- a/net/netfilter/nf_conntrack_h323_main.c +++ b/net/netfilter/nf_conntrack_h323_main.c @@ -643,7 +643,7 @@ static int expect_h245(struct sk_buff *skb, struct nf_conn *ct, &ct->tuplehash[!dir].tuple.src.u3, &ct->tuplehash[!dir].tuple.dst.u3, IPPROTO_TCP, NULL, &port); - exp->helper = &nf_conntrack_helper_h245; + rcu_assign_pointer(exp->helper, &nf_conntrack_helper_h245); nathook = rcu_dereference(nfct_h323_nat_hook); if (memcmp(&ct->tuplehash[dir].tuple.src.u3, @@ -767,7 +767,7 @@ static int expect_callforwarding(struct sk_buff *skb, nf_ct_expect_init(exp, NF_CT_EXPECT_CLASS_DEFAULT, nf_ct_l3num(ct), &ct->tuplehash[!dir].tuple.src.u3, &addr, IPPROTO_TCP, NULL, &port); - exp->helper = nf_conntrack_helper_q931; + rcu_assign_pointer(exp->helper, nf_conntrack_helper_q931); nathook = rcu_dereference(nfct_h323_nat_hook); if (memcmp(&ct->tuplehash[dir].tuple.src.u3, @@ -1234,7 +1234,7 @@ static int expect_q931(struct sk_buff *skb, struct nf_conn *ct, &ct->tuplehash[!dir].tuple.src.u3 : NULL, &ct->tuplehash[!dir].tuple.dst.u3, IPPROTO_TCP, NULL, &port); - exp->helper = nf_conntrack_helper_q931; + rcu_assign_pointer(exp->helper, nf_conntrack_helper_q931); exp->flags = NF_CT_EXPECT_PERMANENT; /* Accept multiple calls */ nathook = rcu_dereference(nfct_h323_nat_hook); @@ -1306,7 +1306,7 @@ static int process_gcf(struct sk_buff *skb, struct nf_conn *ct, nf_ct_expect_init(exp, NF_CT_EXPECT_CLASS_DEFAULT, nf_ct_l3num(ct), &ct->tuplehash[!dir].tuple.src.u3, &addr, IPPROTO_UDP, NULL, &port); - exp->helper = nf_conntrack_helper_ras; + rcu_assign_pointer(exp->helper, nf_conntrack_helper_ras); if (nf_ct_expect_related(exp, 0) == 0) { pr_debug("nf_ct_ras: expect RAS "); @@ -1523,7 +1523,7 @@ static int process_acf(struct sk_buff *skb, struct nf_conn *ct, &ct->tuplehash[!dir].tuple.src.u3, &addr, IPPROTO_TCP, NULL, &port); exp->flags = NF_CT_EXPECT_PERMANENT; - exp->helper = nf_conntrack_helper_q931; + rcu_assign_pointer(exp->helper, nf_conntrack_helper_q931); if (nf_ct_expect_related(exp, 0) == 0) { pr_debug("nf_ct_ras: expect Q.931 "); @@ -1577,7 +1577,7 @@ static int process_lcf(struct sk_buff *skb, struct nf_conn *ct, &ct->tuplehash[!dir].tuple.src.u3, &addr, IPPROTO_TCP, NULL, &port); exp->flags = NF_CT_EXPECT_PERMANENT; - exp->helper = nf_conntrack_helper_q931; + rcu_assign_pointer(exp->helper, nf_conntrack_helper_q931); if (nf_ct_expect_related(exp, 0) == 0) { pr_debug("nf_ct_ras: expect Q.931 "); diff --git a/net/netfilter/nf_conntrack_helper.c b/net/netfilter/nf_conntrack_helper.c index ceb48c3ca0a4..294a6ffcbccd 100644 --- a/net/netfilter/nf_conntrack_helper.c +++ b/net/netfilter/nf_conntrack_helper.c @@ -399,7 +399,7 @@ static bool expect_iter_me(struct nf_conntrack_expect *exp, void *data) const struct nf_conntrack_helper *me = data; const struct nf_conntrack_helper *this; - if (exp->helper == me) + if (rcu_access_pointer(exp->helper) == me) return true; this = rcu_dereference_protected(help->helper, @@ -421,6 +421,11 @@ void nf_conntrack_helper_unregister(struct nf_conntrack_helper *me) nf_ct_expect_iterate_destroy(expect_iter_me, NULL); nf_ct_iterate_destroy(unhelp, me); + + /* nf_ct_iterate_destroy() does an unconditional synchronize_rcu() as + * last step, this ensures rcu readers of exp->helper are done. + * No need for another synchronize_rcu() here. + */ } EXPORT_SYMBOL_GPL(nf_conntrack_helper_unregister); diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c index c156574e1273..a42d14290786 100644 --- a/net/netfilter/nf_conntrack_netlink.c +++ b/net/netfilter/nf_conntrack_netlink.c @@ -3573,7 +3573,7 @@ ctnetlink_alloc_expect(const struct nlattr * const cda[], struct nf_conn *ct, exp->class = class; exp->master = ct; - exp->helper = helper; + rcu_assign_pointer(exp->helper, helper); exp->tuple = *tuple; exp->mask.src.u3 = mask->src.u3; exp->mask.src.u.all = mask->src.u.all; diff --git a/net/netfilter/nf_conntrack_sip.c b/net/netfilter/nf_conntrack_sip.c index 4ab5ef71d96d..106b2f419e19 100644 --- a/net/netfilter/nf_conntrack_sip.c +++ b/net/netfilter/nf_conntrack_sip.c @@ -1297,7 +1297,7 @@ static int process_register_request(struct sk_buff *skb, unsigned int protoff, nf_ct_expect_init(exp, SIP_EXPECT_SIGNALLING, nf_ct_l3num(ct), saddr, &daddr, proto, NULL, &port); exp->timeout.expires = sip_timeout * HZ; - exp->helper = helper; + rcu_assign_pointer(exp->helper, helper); exp->flags = NF_CT_EXPECT_PERMANENT | NF_CT_EXPECT_INACTIVE; hooks = rcu_dereference(nf_nat_sip_hooks); -- cgit v1.2.3 From bffcaad9afdfe45d7fc777397d3b83c1e3ebffe5 Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Wed, 25 Mar 2026 14:11:04 +0100 Subject: netfilter: ctnetlink: ensure safe access to master conntrack Holding reference on the expectation is not sufficient, the master conntrack object can just go away, making exp->master invalid. To access exp->master safely: - Grab the nf_conntrack_expect_lock, this gets serialized with clean_from_lists() which also holds this lock when the master conntrack goes away. - Hold reference on master conntrack via nf_conntrack_find_get(). Not so easy since the master tuple to look up for the master conntrack is not available in the existing problematic paths. This patch goes for extending the nf_conntrack_expect_lock section to address this issue for simplicity, in the cases that are described below this is just slightly extending the lock section. The add expectation command already holds a reference to the master conntrack from ctnetlink_create_expect(). However, the delete expectation command needs to grab the spinlock before looking up for the expectation. Expand the existing spinlock section to address this to cover the expectation lookup. Note that, the nf_ct_expect_iterate_net() calls already grabs the spinlock while iterating over the expectation table, which is correct. The get expectation command needs to grab the spinlock to ensure master conntrack does not go away. This also expands the existing spinlock section to cover the expectation lookup too. I needed to move the netlink skb allocation out of the spinlock to keep it GFP_KERNEL. For the expectation events, the IPEXP_DESTROY event is already delivered under the spinlock, just move the delivery of IPEXP_NEW under the spinlock too because the master conntrack event cache is reached through exp->master. While at it, add lockdep notations to help identify what codepaths need to grab the spinlock. Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- include/net/netfilter/nf_conntrack_core.h | 5 +++++ net/netfilter/nf_conntrack_ecache.c | 2 ++ net/netfilter/nf_conntrack_expect.c | 10 +++++++++- net/netfilter/nf_conntrack_netlink.c | 28 +++++++++++++++++++--------- 4 files changed, 35 insertions(+), 10 deletions(-) (limited to 'include/net') diff --git a/include/net/netfilter/nf_conntrack_core.h b/include/net/netfilter/nf_conntrack_core.h index 3384859a8921..8883575adcc1 100644 --- a/include/net/netfilter/nf_conntrack_core.h +++ b/include/net/netfilter/nf_conntrack_core.h @@ -83,6 +83,11 @@ void nf_conntrack_lock(spinlock_t *lock); extern spinlock_t nf_conntrack_expect_lock; +static inline void lockdep_nfct_expect_lock_held(void) +{ + lockdep_assert_held(&nf_conntrack_expect_lock); +} + /* ctnetlink code shared by both ctnetlink and nf_conntrack_bpf */ static inline void __nf_ct_set_timeout(struct nf_conn *ct, u64 timeout) diff --git a/net/netfilter/nf_conntrack_ecache.c b/net/netfilter/nf_conntrack_ecache.c index 81baf2082604..9df159448b89 100644 --- a/net/netfilter/nf_conntrack_ecache.c +++ b/net/netfilter/nf_conntrack_ecache.c @@ -247,6 +247,8 @@ void nf_ct_expect_event_report(enum ip_conntrack_expect_events event, struct nf_ct_event_notifier *notify; struct nf_conntrack_ecache *e; + lockdep_nfct_expect_lock_held(); + rcu_read_lock(); notify = rcu_dereference(net->ct.nf_conntrack_event_cb); if (!notify) diff --git a/net/netfilter/nf_conntrack_expect.c b/net/netfilter/nf_conntrack_expect.c index 64977db12b1d..1cbe5f1108c2 100644 --- a/net/netfilter/nf_conntrack_expect.c +++ b/net/netfilter/nf_conntrack_expect.c @@ -51,6 +51,7 @@ void nf_ct_unlink_expect_report(struct nf_conntrack_expect *exp, struct net *net = nf_ct_exp_net(exp); struct nf_conntrack_net *cnet; + lockdep_nfct_expect_lock_held(); WARN_ON(!master_help); WARN_ON(timer_pending(&exp->timeout)); @@ -118,6 +119,8 @@ nf_ct_exp_equal(const struct nf_conntrack_tuple *tuple, bool nf_ct_remove_expect(struct nf_conntrack_expect *exp) { + lockdep_nfct_expect_lock_held(); + if (timer_delete(&exp->timeout)) { nf_ct_unlink_expect(exp); nf_ct_expect_put(exp); @@ -177,6 +180,8 @@ nf_ct_find_expectation(struct net *net, struct nf_conntrack_expect *i, *exp = NULL; unsigned int h; + lockdep_nfct_expect_lock_held(); + if (!cnet->expect_count) return NULL; @@ -454,6 +459,8 @@ static inline int __nf_ct_expect_check(struct nf_conntrack_expect *expect, unsigned int h; int ret = 0; + lockdep_nfct_expect_lock_held(); + if (!master_help) { ret = -ESHUTDOWN; goto out; @@ -510,8 +517,9 @@ int nf_ct_expect_related_report(struct nf_conntrack_expect *expect, nf_ct_expect_insert(expect); - spin_unlock_bh(&nf_conntrack_expect_lock); nf_ct_expect_event_report(IPEXP_NEW, expect, portid, report); + spin_unlock_bh(&nf_conntrack_expect_lock); + return 0; out: spin_unlock_bh(&nf_conntrack_expect_lock); diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c index 8477c3736432..89540112d165 100644 --- a/net/netfilter/nf_conntrack_netlink.c +++ b/net/netfilter/nf_conntrack_netlink.c @@ -3355,31 +3355,37 @@ static int ctnetlink_get_expect(struct sk_buff *skb, if (err < 0) return err; + skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); + if (!skb2) + return -ENOMEM; + + spin_lock_bh(&nf_conntrack_expect_lock); exp = nf_ct_expect_find_get(info->net, &zone, &tuple); - if (!exp) + if (!exp) { + spin_unlock_bh(&nf_conntrack_expect_lock); + kfree_skb(skb2); return -ENOENT; + } if (cda[CTA_EXPECT_ID]) { __be32 id = nla_get_be32(cda[CTA_EXPECT_ID]); if (id != nf_expect_get_id(exp)) { nf_ct_expect_put(exp); + spin_unlock_bh(&nf_conntrack_expect_lock); + kfree_skb(skb2); return -ENOENT; } } - skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); - if (!skb2) { - nf_ct_expect_put(exp); - return -ENOMEM; - } - rcu_read_lock(); err = ctnetlink_exp_fill_info(skb2, NETLINK_CB(skb).portid, info->nlh->nlmsg_seq, IPCTNL_MSG_EXP_NEW, exp); rcu_read_unlock(); nf_ct_expect_put(exp); + spin_unlock_bh(&nf_conntrack_expect_lock); + if (err <= 0) { kfree_skb(skb2); return -ENOMEM; @@ -3426,22 +3432,26 @@ static int ctnetlink_del_expect(struct sk_buff *skb, if (err < 0) return err; + spin_lock_bh(&nf_conntrack_expect_lock); + /* bump usage count to 2 */ exp = nf_ct_expect_find_get(info->net, &zone, &tuple); - if (!exp) + if (!exp) { + spin_unlock_bh(&nf_conntrack_expect_lock); return -ENOENT; + } if (cda[CTA_EXPECT_ID]) { __be32 id = nla_get_be32(cda[CTA_EXPECT_ID]); if (id != nf_expect_get_id(exp)) { nf_ct_expect_put(exp); + spin_unlock_bh(&nf_conntrack_expect_lock); return -ENOENT; } } /* after list removal, usage count == 1 */ - spin_lock_bh(&nf_conntrack_expect_lock); if (timer_delete(&exp->timeout)) { nf_ct_unlink_expect_report(exp, NETLINK_CB(skb).portid, nlmsg_report(info->nlh)); -- cgit v1.2.3 From 02a3231b6d82efe750da6554ebf280e4a6f78756 Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Wed, 25 Mar 2026 22:39:55 +0100 Subject: netfilter: nf_conntrack_expect: store netns and zone in expectation __nf_ct_expect_find() and nf_ct_expect_find_get() are called under rcu_read_lock() but they dereference the master conntrack via exp->master. Since the expectation does not hold a reference on the master conntrack, this could be dying conntrack or different recycled conntrack than the real master due to SLAB_TYPESAFE_RCU. Store the netns, the master_tuple and the zone in struct nf_conntrack_expect as a safety measure. This patch is required by the follow up fix not to dump expectations that do not belong to this netns. Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- include/net/netfilter/nf_conntrack_expect.h | 18 +++++++++++++++++- net/netfilter/nf_conntrack_broadcast.c | 6 +++++- net/netfilter/nf_conntrack_expect.c | 9 +++++++-- net/netfilter/nf_conntrack_netlink.c | 5 +++++ 4 files changed, 34 insertions(+), 4 deletions(-) (limited to 'include/net') diff --git a/include/net/netfilter/nf_conntrack_expect.h b/include/net/netfilter/nf_conntrack_expect.h index 1b01400b10bd..e9a8350e7ccf 100644 --- a/include/net/netfilter/nf_conntrack_expect.h +++ b/include/net/netfilter/nf_conntrack_expect.h @@ -22,10 +22,16 @@ struct nf_conntrack_expect { /* Hash member */ struct hlist_node hnode; + /* Network namespace */ + possible_net_t net; + /* We expect this tuple, with the following mask */ struct nf_conntrack_tuple tuple; struct nf_conntrack_tuple_mask mask; +#ifdef CONFIG_NF_CONNTRACK_ZONES + struct nf_conntrack_zone zone; +#endif /* Usage count. */ refcount_t use; @@ -62,7 +68,17 @@ struct nf_conntrack_expect { static inline struct net *nf_ct_exp_net(struct nf_conntrack_expect *exp) { - return nf_ct_net(exp->master); + return read_pnet(&exp->net); +} + +static inline bool nf_ct_exp_zone_equal_any(const struct nf_conntrack_expect *a, + const struct nf_conntrack_zone *b) +{ +#ifdef CONFIG_NF_CONNTRACK_ZONES + return a->zone.id == b->id; +#else + return true; +#endif } #define NF_CT_EXP_POLICY_NAME_LEN 16 diff --git a/net/netfilter/nf_conntrack_broadcast.c b/net/netfilter/nf_conntrack_broadcast.c index 1964c596c646..4f39bf7c843f 100644 --- a/net/netfilter/nf_conntrack_broadcast.c +++ b/net/netfilter/nf_conntrack_broadcast.c @@ -21,6 +21,7 @@ int nf_conntrack_broadcast_help(struct sk_buff *skb, unsigned int timeout) { const struct nf_conntrack_helper *helper; + struct net *net = read_pnet(&ct->ct_net); struct nf_conntrack_expect *exp; struct iphdr *iph = ip_hdr(skb); struct rtable *rt = skb_rtable(skb); @@ -71,7 +72,10 @@ int nf_conntrack_broadcast_help(struct sk_buff *skb, exp->flags = NF_CT_EXPECT_PERMANENT; exp->class = NF_CT_EXPECT_CLASS_DEFAULT; rcu_assign_pointer(exp->helper, helper); - + write_pnet(&exp->net, net); +#ifdef CONFIG_NF_CONNTRACK_ZONES + exp->zone = ct->zone; +#endif nf_ct_expect_related(exp, 0); nf_ct_expect_put(exp); diff --git a/net/netfilter/nf_conntrack_expect.c b/net/netfilter/nf_conntrack_expect.c index 1cbe5f1108c2..db28801b1688 100644 --- a/net/netfilter/nf_conntrack_expect.c +++ b/net/netfilter/nf_conntrack_expect.c @@ -113,8 +113,8 @@ nf_ct_exp_equal(const struct nf_conntrack_tuple *tuple, const struct net *net) { return nf_ct_tuple_mask_cmp(tuple, &i->tuple, &i->mask) && - net_eq(net, nf_ct_net(i->master)) && - nf_ct_zone_equal_any(i->master, zone); + net_eq(net, read_pnet(&i->net)) && + nf_ct_exp_zone_equal_any(i, zone); } bool nf_ct_remove_expect(struct nf_conntrack_expect *exp) @@ -326,6 +326,7 @@ void nf_ct_expect_init(struct nf_conntrack_expect *exp, unsigned int class, { struct nf_conntrack_helper *helper = NULL; struct nf_conn *ct = exp->master; + struct net *net = read_pnet(&ct->ct_net); struct nf_conn_help *help; int len; @@ -343,6 +344,10 @@ void nf_ct_expect_init(struct nf_conntrack_expect *exp, unsigned int class, helper = rcu_dereference(help->helper); rcu_assign_pointer(exp->helper, helper); + write_pnet(&exp->net, net); +#ifdef CONFIG_NF_CONNTRACK_ZONES + exp->zone = ct->zone; +#endif exp->tuple.src.l3num = family; exp->tuple.dst.protonum = proto; diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c index 89540112d165..6e6aeb0ab0a1 100644 --- a/net/netfilter/nf_conntrack_netlink.c +++ b/net/netfilter/nf_conntrack_netlink.c @@ -3538,6 +3538,7 @@ ctnetlink_alloc_expect(const struct nlattr * const cda[], struct nf_conn *ct, struct nf_conntrack_tuple *tuple, struct nf_conntrack_tuple *mask) { + struct net *net = read_pnet(&ct->ct_net); struct nf_conntrack_expect *exp; struct nf_conn_help *help; u32 class = 0; @@ -3577,6 +3578,10 @@ ctnetlink_alloc_expect(const struct nlattr * const cda[], struct nf_conn *ct, exp->class = class; exp->master = ct; + write_pnet(&exp->net, net); +#ifdef CONFIG_NF_CONNTRACK_ZONES + exp->zone = ct->zone; +#endif if (!helper) helper = rcu_dereference(help->helper); rcu_assign_pointer(exp->helper, helper); -- cgit v1.2.3 From 629ec78ef8608d955ce217880cdc3e1873af3a15 Mon Sep 17 00:00:00 2001 From: Sabrina Dubroca Date: Tue, 24 Mar 2026 00:25:57 +0100 Subject: mpls: add seqcount to protect the platform_label{,s} pair The RCU-protected codepaths (mpls_forward, mpls_dump_routes) can have an inconsistent view of platform_labels vs platform_label in case of a concurrent resize (resize_platform_label_table, under platform_mutex). This can lead to OOB accesses. This patch adds a seqcount, so that we get a consistent snapshot. Note that mpls_label_ok is also susceptible to this, so the check against RTA_DST in rtm_to_route_config, done outside platform_mutex, is not sufficient. This value gets passed to mpls_label_ok once more in both mpls_route_add and mpls_route_del, so there is no issue, but that additional check must not be removed. Reported-by: Yuan Tan Reported-by: Yifan Wu Reported-by: Juefei Pu Reported-by: Xin Liu Fixes: 7720c01f3f590 ("mpls: Add a sysctl to control the size of the mpls label table") Fixes: dde1b38e873c ("mpls: Convert mpls_dump_routes() to RCU.") Signed-off-by: Sabrina Dubroca Link: https://patch.msgid.link/cd8fca15e3eb7e212b094064cd83652e20fd9d31.1774284088.git.sd@queasysnail.net Signed-off-by: Jakub Kicinski --- include/net/netns/mpls.h | 1 + net/mpls/af_mpls.c | 29 +++++++++++++++++++++++++---- 2 files changed, 26 insertions(+), 4 deletions(-) (limited to 'include/net') diff --git a/include/net/netns/mpls.h b/include/net/netns/mpls.h index 6682e51513ef..2073cbac2afb 100644 --- a/include/net/netns/mpls.h +++ b/include/net/netns/mpls.h @@ -17,6 +17,7 @@ struct netns_mpls { size_t platform_labels; struct mpls_route __rcu * __rcu *platform_label; struct mutex platform_mutex; + seqcount_mutex_t platform_label_seq; struct ctl_table_header *ctl; }; diff --git a/net/mpls/af_mpls.c b/net/mpls/af_mpls.c index d5417688f69e..18d3da8ab384 100644 --- a/net/mpls/af_mpls.c +++ b/net/mpls/af_mpls.c @@ -83,14 +83,30 @@ static struct mpls_route *mpls_route_input(struct net *net, unsigned int index) return mpls_dereference(net, platform_label[index]); } +static struct mpls_route __rcu **mpls_platform_label_rcu(struct net *net, size_t *platform_labels) +{ + struct mpls_route __rcu **platform_label; + unsigned int sequence; + + do { + sequence = read_seqcount_begin(&net->mpls.platform_label_seq); + platform_label = rcu_dereference(net->mpls.platform_label); + *platform_labels = net->mpls.platform_labels; + } while (read_seqcount_retry(&net->mpls.platform_label_seq, sequence)); + + return platform_label; +} + static struct mpls_route *mpls_route_input_rcu(struct net *net, unsigned int index) { struct mpls_route __rcu **platform_label; + size_t platform_labels; + + platform_label = mpls_platform_label_rcu(net, &platform_labels); - if (index >= net->mpls.platform_labels) + if (index >= platform_labels) return NULL; - platform_label = rcu_dereference(net->mpls.platform_label); return rcu_dereference(platform_label[index]); } @@ -2240,8 +2256,7 @@ static int mpls_dump_routes(struct sk_buff *skb, struct netlink_callback *cb) if (index < MPLS_LABEL_FIRST_UNRESERVED) index = MPLS_LABEL_FIRST_UNRESERVED; - platform_label = rcu_dereference(net->mpls.platform_label); - platform_labels = net->mpls.platform_labels; + platform_label = mpls_platform_label_rcu(net, &platform_labels); if (filter.filter_set) flags |= NLM_F_DUMP_FILTERED; @@ -2645,8 +2660,12 @@ static int resize_platform_label_table(struct net *net, size_t limit) } /* Update the global pointers */ + local_bh_disable(); + write_seqcount_begin(&net->mpls.platform_label_seq); net->mpls.platform_labels = limit; rcu_assign_pointer(net->mpls.platform_label, labels); + write_seqcount_end(&net->mpls.platform_label_seq); + local_bh_enable(); mutex_unlock(&net->mpls.platform_mutex); @@ -2728,6 +2747,8 @@ static __net_init int mpls_net_init(struct net *net) int i; mutex_init(&net->mpls.platform_mutex); + seqcount_mutex_init(&net->mpls.platform_label_seq, &net->mpls.platform_mutex); + net->mpls.platform_labels = 0; net->mpls.platform_label = NULL; net->mpls.ip_ttl_propagate = 1; -- cgit v1.2.3