linux.git/net/tipc, branch master

tipc: fix integer overflow in tipc_recvmsg() and tipc_recvstream()

2026-07-23T17:11:48Z

In tipc_recvmsg(), the copy length is computed as: copy = min_t(int, dlen - offset, buflen); buflen is size_t but min_t(int, ...) casts it to int. When buflen exceeds INT_MAX (e.g. 0xFFFFFFFF via io_uring provided buffers), it wraps negative, wins the comparison, and the negative copy length propagates to simple_copy_to_iter() where int-to-size_t promotion makes it SIZE_MAX, triggering a WARN_ON. tipc_recvstream() has the same pattern. Kernel panic - not syncing: kernel: panic_on_warn set ... RIP: 0010:simple_copy_to_iter+0x9e/0xd0 (net/core/datagram.c:521) Call Trace: __skb_datagram_iter+0x123/0x8b0 (net/core/datagram.c:402) skb_copy_datagram_iter+0x77/0x1a0 (net/core/datagram.c:534) tipc_recvmsg+0x3d7/0xe80 (net/tipc/socket.c:1934) io_recvmsg+0x47e/0xda0 Fix by changing min_t(int, ...) to min_t(size_t, ...) in both functions. The result is always <= (dlen - offset), which is bounded by TIPC maximum message size (0x1ffff bytes), so the implicit narrowing on assignment to int copy is always safe. Fixes: e9f8b10101c6 ("tipc: refactor function tipc_sk_recvmsg()") Fixes: ec8a09fbbeff ("tipc: refactor function tipc_sk_recv_stream()") Reported-by: AutonomousCodeSecurity@microsoft.com Signed-off-by: Cen Zhang (Microsoft) Reviewed-by: Tung Nguyen Link: https://patch.msgid.link/20260720214103.47732-1-blbllhy@gmail.com Signed-off-by: Jakub Kicinski

tipc: clear sock->sk on the failed-insert path in tipc_sk_create()

2026-07-23T10:58:06Z

When tipc_sk_create() fails to insert the new socket (tipc_sk_insert() returns non-zero), its error path frees the sk with sk_free() but leaves sock->sk pointing at the freed object: if (tipc_sk_insert(tsk)) { sk_free(sk); pr_warn("Socket create failed; port number exhausted\n"); return -EINVAL; } This is harmless for plain socket(): the syscall layer clears sock->ops before releasing, so tipc_release() is never called. It is not harmless on the accept() path. tipc_accept() creates the pre-allocated child socket with tipc_sk_create(net, new_sock, 0, kern); on failure it leaves new_sock->sk dangling and new_sock->ops non-NULL, and do_accept() then fput()s the new file, so __sock_release() -> tipc_release() runs lock_sock(new_sock->sk) on the freed sk -- a use-after-free write of the sk_lock spinlock. tipc_release() already guards this exact "failed accept() releases a pre-allocated child" case with "if (sk == NULL) return 0;", but the guard is bypassed because tipc_sk_create() left sock->sk non-NULL (dangling) rather than NULL. Clear sock->sk on the failed-insert path so the existing tipc_release() NULL check fires and the use-after-free is avoided. The tipc_sk_insert() failure is reached when the per-netns socket rhashtable hits its max_size (tsk_rht_params.max_size = 1048576, ~2M elements) -- i.e. once a netns holds ~2M TIPC sockets every insert returns -E2BIG. BUG: KASAN: slab-use-after-free in lock_sock_nested (net/core/sock.c:3839) Write of size 8 at addr ffff8880047cdc38 by task init/1 lock_sock_nested (net/core/sock.c:3839) tipc_release (net/tipc/socket.c:638) __sock_release (net/socket.c:710) sock_close (net/socket.c:1501) __fput (fs/file_table.c:512) Allocated by task 1: sk_alloc (net/core/sock.c:2308) tipc_sk_create (net/tipc/socket.c:487) tipc_accept (net/tipc/socket.c:2744) do_accept (net/socket.c:2034) Freed by task 1: __sk_destruct (net/core/sock.c:2391) tipc_sk_create (net/tipc/socket.c:504) tipc_accept (net/tipc/socket.c:2744) do_accept (net/socket.c:2034) Fixes: 00aff3590fc0 ("net: tipc: fix possible refcount leak in tipc_sk_create()") Cc: stable@vger.kernel.org Reviewed-by: Tung Nguyen Reviewed-by: Breno Leitao Signed-off-by: Daehyeon Ko <4ncienth@gmail.com> Reviewed-by: Simon Horman Link: https://patch.msgid.link/20260714131939.1255974-1-4ncienth@gmail.com Signed-off-by: Paolo Abeni

tipc: fix u16 MTU truncation in media and bearer MTU validation

2026-07-23T09:41:03Z

Both TIPC_NL_MEDIA_SET and TIPC_NL_BEARER_SET accept user-supplied MTU values but only enforce a minimum bound, not a maximum. When a user sets the MTU to a value exceeding U16_MAX (65535), it passes validation but is silently truncated when assigned to u16 fields l->mtu and l->advertised_mtu in tipc_link_create(). Values like 65536 (0x10000) truncate to 0, causing a division by zero in tipc_link_set_queue_limits() which computes TIPC_MAX_PUBL / (l->mtu / ITEM_SIZE). Other overflowing values (e.g. 65537-131071) produce small incorrect MTU values, resulting in link malfunction behaviors. Crash stack (triggered as unprivileged user via user namespace): tipc_link_set_queue_limits net/tipc/link.c:2531 tipc_link_create net/tipc/link.c:520 tipc_node_check_dest net/tipc/node.c:1279 tipc_disc_rcv net/tipc/discover.c:252 tipc_rcv net/tipc/node.c:2129 tipc_udp_recv net/tipc/udp_media.c:392 Two independent paths lack the upper bound check: 1. tipc_udp_mtu_bad() -- called from __tipc_nl_media_set() (MEDIA_SET) 2. inline check in __tipc_nl_bearer_set() at bearer.c:1160 (BEARER_SET) Fix both by rejecting MTU values above U16_MAX. Fixes: 901271e0403a ("tipc: implement configuration of UDP media MTU") Reported-by: AutonomousCodeSecurity@microsoft.com Closes: https://lore.kernel.org/all/CAB8m9WgETt0AjmFwE=F-CKjGXsK6_WDv0=kbYRcC8-noo+amnA@mail.gmail.com Reviewed-by: Vadim Fedorenko Signed-off-by: Cen Zhang (Microsoft) Reviewed-by: Simon Horman Link: https://patch.msgid.link/20260714041541.307702-1-blbllhy@gmail.com Signed-off-by: Paolo Abeni

tipc: fix infinite loop in __tipc_nl_compat_dumpit

2026-07-21T22:12:23Z

cmd->dumpit callback can return a negative errno, causing an infinite loop due to the while(len) condition. As the loop never terminates, genl_mutex is never released, and other tasks waiting on it starve in D state. Check dumpit's return value, propagate it and jump to err_out on error. Reported-by: syzbot+85d0bec020d805014a3a@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=85d0bec020d805014a3a Fixes: d0796d1ef63d ("tipc: convert legacy nl bearer dump to nl compat") Signed-off-by: Helen Koike Reviewed-by: Tung Nguyen Link: https://patch.msgid.link/20260713204940.647668-1-koike@igalia.com Signed-off-by: Jakub Kicinski

tipc: serialize udp bearer replicast list updates

2026-07-21T18:57:21Z

tipc_udp_rcast_add() and cleanup_bearer() both update ub->rcast.list with list_add_rcu() / list_del_rcu(), but nothing serializes them. The add runs from the encap receive softirq (via tipc_udp_rcast_disc()) without rtnl_lock(), so it can race the cleanup delete and corrupt the list: list_del corruption. prev->next should be ffff8880298d7ab8, but was ffff88802449ad38. (prev=ffff888027e3ec98) kernel BUG at lib/list_debug.c:62! RIP: __list_del_entry_valid_or_report+0x17a/0x200 Workqueue: events cleanup_bearer Call Trace: cleanup_bearer (net/tipc/udp_media.c:811) process_one_work (kernel/workqueue.c:3302) worker_thread (kernel/workqueue.c:3466) The bearer can be enabled from an unprivileged user namespace, as the TIPCv2 generic-netlink ops carry no GENL_ADMIN_PERM. Add a spinlock to struct udp_bearer and take it around the list_add_rcu() in tipc_udp_rcast_add() and the list_del_rcu() loop in cleanup_bearer() so the two writers can no longer corrupt the list. Reject a duplicate peer under the same lock before allocating, and remove tipc_udp_is_known_peer(). The old lockless pre-check in tipc_udp_rcast_disc() was racy: two softirqs discovering the same peer could both find it absent and add it twice. cleanup_bearer() runs from a workqueue after tipc_udp_disable() clears the bearer's up bit, so an encap softirq can still reach tipc_udp_rcast_add() and add a peer after cleanup_bearer() has already emptied the list, leaking that entry when the bearer is freed. Mark the bearer disabled under rcast_lock once the list is emptied and refuse further additions. Fixes: ef20cd4dd163 ("tipc: introduce UDP replicast") Reported-by: Xiang Mei Suggested-by: Tung Nguyen Signed-off-by: Weiming Shi Reviewed-by: Tung Nguyen Link: https://patch.msgid.link/20260716025203.9332-2-bestswngs@gmail.com Signed-off-by: Jakub Kicinski

tipc: fix out-of-bounds read in broadcast Gap ACK blocks

2026-06-30T00:30:20Z

A broadcast PROTOCOL/STATE_MSG can carry a Gap ACK blocks record in its data area. tipc_get_gap_ack_blks() only verifies that the record's len field is self-consistent with its ugack_cnt/bgack_cnt counts (sz == struct_size(p, gacks, ugack_cnt + bgack_cnt)); it does not check that the record actually fits in the message data area, msg_data_sz(). The unicast caller tipc_link_proto_rcv() bounds it ("if (glen > dlen) break;"), but the broadcast caller tipc_bcast_sync_rcv() discards the returned size, so tipc_link_advance_transmq() copies the record off the receive skb with an attacker-controlled count: this_ga = kmemdup(ga, struct_size(ga, gacks, ga->bgack_cnt), GFP_ATOMIC); A TIPC neighbour that negotiated TIPC_GAP_ACK_BLOCK triggers it with one ordinary broadcast STATE_MSG (msg_bc_ack_invalid() clear), sized so its data area is short, carrying a Gap ACK record with len = 0x400, bgack_cnt = 0xff and ugack_cnt = 0. len then equals struct_size(p, gacks, 255), so the consistency check passes and ga is non-NULL; kmemdup() reads struct_size(ga, gacks, 255) = 1024 bytes out of the much smaller skb: BUG: KASAN: slab-out-of-bounds in kmemdup_noprof+0x48/0x60 Read of size 1024 at addr ffff0000c7030d38 by task poc864/69 Call trace: kmemdup_noprof+0x48/0x60 tipc_link_advance_transmq+0x86c/0xb80 tipc_link_bc_ack_rcv+0x19c/0x1e0 tipc_bcast_sync_rcv+0x1c4/0x2c4 tipc_rcv+0x85c/0x1340 tipc_l2_rcv_msg+0xac/0x104 The buggy address belongs to the object at ffff0000c7030d00 which belongs to the cache skbuff_small_head of size 704 The buggy address is located 56 bytes inside of allocated 704-byte region [ffff0000c7030d00, ffff0000c7030fc0) The copied-out bytes are subsequently consumed as gap/ack values, but the read is already out of bounds at the kmemdup() regardless of how they are used. The unicast STATE path drops such a message: "if (glen > dlen) break;" skips the rest of STATE_MSG handling and the skb is freed. Make the broadcast path drop it too. tipc_bcast_sync_rcv() now bounds the record against msg_data_sz() and, when it does not fit, reports it back through tipc_node_bc_sync_rcv() to tipc_rcv() so the skb is discarded rather than processed. ga is not cleared on this path: ga == NULL already means "legacy peer without Selective ACK", a distinct legitimate state. Fixes: d7626b5acff9 ("tipc: introduce Gap ACK blocks for broadcast link") Cc: stable@vger.kernel.org Signed-off-by: Samuel Page Reviewed-by: Tung Nguyen Link: https://patch.msgid.link/20260625143815.1525412-1-sam@bynar.io Signed-off-by: Jakub Kicinski

tipc: avoid busy looping in tipc_exit_net()

2026-06-25T15:53:00Z

Blamed commit introduced a busy-wait loop in tipc_exit_net() to wait for pending UDP bearer cleanup works to complete: while (atomic_read(&tn->wq_count)) cond_resched(); This loop can busy-wait for a long time if cond_resched() is a NOP. This typically happens if the netns exit is executed by a high priority task, or under kernels configured without preemption (CONFIG_PREEMPT_NONE). In such cases, it wastes CPU cycles and can lead to soft lockups. Fix this by replacing the busy loop with wait_var_event(), allowing the thread to sleep properly until the work queue count reaches zero. Accordingly, update cleanup_bearer() to use atomic_dec_and_test() and wake_up_var() to wake up the waiter when the count drops to zero. This uses the global wait queue hash table, avoiding the need to bloat struct tipc_net with a wait_queue_head_t. The atomic_dec_and_test() provides the necessary memory barrier to ensure the wakeup is not missed. Fixes: 04c26faa51d1 ("tipc: wait and exit until all work queues are done") Signed-off-by: Eric Dumazet Cc: Jon Maloy Cc: tipc-discussion@lists.sourceforge.net Reviewed-by: Xin Long Link: https://patch.msgid.link/20260623173030.2925059-3-edumazet@google.com Signed-off-by: Jakub Kicinski

tipc: fix UAF in cleanup_bearer() due to premature dst_cache_destroy()

2026-06-25T15:53:00Z

TIPC UDP media bearer teardown calls dst_cache_destroy() on its replicast caches before calling synchronize_net() to wait for concurrent RCU readers (transmitters) to finish: static void cleanup_bearer(struct work_struct *work) { ... list_for_each_entry_safe(rcast, tmp, &ub->rcast.list, list) { dst_cache_destroy(&rcast->dst_cache); list_del_rcu(&rcast->list); kfree_rcu(rcast, rcu); } ... dst_cache_destroy(&ub->rcast.dst_cache); udp_tunnel_sock_release(ub->sk); synchronize_net(); ... } This is highly buggy because dst_cache_destroy() immediately frees the per-CPU cache memory (free_percpu()) and releases the cached dst entries without any synchronization. If a concurrent transmitter (e.g., tipc_udp_xmit()) is running on another CPU under RCU protection, it can call dst_cache_get() concurrently, leading to: 1. Use-After-Free on the per-CPU cache pointer itself (crash). 2. "rcuref - imbalanced put()" warning if it attempts to release a dst that was concurrently released by dst_cache_destroy(). Furthermore, calling kfree(ub) immediately after synchronize_net() without closing the socket first (or waiting after closing it) leaves a window where a concurrent receiver (tipc_udp_recv()) could start after synchronize_net(), access ub, and suffer a UAF when kfree(ub) runs. To fix this, we must defer dst_cache_destroy() and kfree(ub) until after we have ensured that no more readers can see the bearer/socket and all existing readers have finished: 1. Defer rcast entry destruction (both dst_cache_destroy() and kfree()) to an RCU callback using call_rcu_hurry(). Using call_rcu_hurry() ensures the dst entries are released quickly. 2. Release the bearer socket using udp_tunnel_sock_release() (stops new receive readers). 3. Call synchronize_net() to wait for all outstanding RCU readers (both transmit and receive) to finish. 4. Now that it is safe, call dst_cache_destroy() on the main bearer cache, and free ub. Note: 3) and 4) can be changed later in net-next to also use call_rcu_hurry() and get rid of the synchronize_net() latency. Fixes: e9c1a793210f ("tipc: add dst_cache support for udp media") Reported-by: syzbot+e14bc5d4942756023b77@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/6a396a66.52ae72c2.136ac7.0003.GAE@google.com/T/#u Signed-off-by: Eric Dumazet Cc: Jon Maloy Cc: tipc-discussion@lists.sourceforge.net Reviewed-by: Xin Long Link: https://patch.msgid.link/20260623173030.2925059-2-edumazet@google.com Signed-off-by: Jakub Kicinski

tipc: fix use-after-free of the discoverer in tipc_disc_rcv()

2026-06-21T21:28:22Z

bearer_disable() frees b->disc with tipc_disc_delete()'s plain kfree(), but tipc_disc_rcv() still dereferences b->disc in RX softirq under rcu_read_lock() (tipc_udp_recv -> tipc_rcv -> tipc_disc_rcv). L2 bearers are safe thanks to the synchronize_net() in tipc_disable_l2_media(), but the UDP bearer defers that call to the cleanup_bearer() workqueue, so the discoverer is freed with no grace period: BUG: KASAN: slab-use-after-free in tipc_disc_rcv (net/tipc/discover.c:149) Read of size 8 at addr ffff88802348b728 by task poc_tipc/184 tipc_disc_rcv (net/tipc/discover.c:149) tipc_rcv (net/tipc/node.c:2126) tipc_udp_recv (net/tipc/udp_media.c:391) udp_rcv (net/ipv4/udp.c:2643) ip_local_deliver_finish (net/ipv4/ip_input.c:241) Freed by task 181: kfree (mm/slub.c:6565) bearer_disable (net/tipc/bearer.c:418) tipc_nl_bearer_disable (net/tipc/bearer.c:1001) The bearer is freed with kfree_rcu(); free the discoverer the same way. Add an rcu_head to struct tipc_discoverer and free it and its skb from an RCU callback. Because the RCU callback (tipc_disc_free_rcu) lives in module text, a call_rcu() that is still pending when the tipc module is unloaded would invoke a freed function. Add an rcu_barrier() to tipc_exit() after the bearer subsystem has been torn down, so all pending discoverer callbacks have run before the module text goes away. Reachable from an unprivileged user namespace: the TIPCv2 genl family is netnsok and its bearer commands have no GENL_ADMIN_PERM. Needs CONFIG_TIPC and CONFIG_TIPC_MEDIA_UDP. Fixes: 25b0b9c4e835 ("tipc: handle collisions of 32-bit node address hash values") Reported-by: Xiang Mei Signed-off-by: Weiming Shi Reviewed-by: Tung Nguyen Link: https://patch.msgid.link/20260617135744.3383175-3-bestswngs@gmail.com Signed-off-by: Jakub Kicinski

tipc: fix slab-use-after-free Read in tipc_aead_decrypt_done

2026-06-19T01:35:35Z

tipc_aead_decrypt() goes straight from tipc_bearer_hold(b) to crypto_aead_decrypt(req) without taking a reference on the netns, unlike the encrypt path. When crypto_aead_decrypt() is offloaded asynchronously (e.g. the SIMD aead wrapper queuing to cryptd), the cryptd worker runs tipc_aead_decrypt_done() later. If the bearer's netns is torn down in the meantime, cleanup_net() -> tipc_exit_net() -> tipc_crypto_stop() frees the per-netns tipc_crypto, and the completion then reads it: tipc_aead_decrypt_done() dereferences aead->crypto->stats and aead->crypto->net, and tipc_crypto_rcv_complete() dereferences aead->crypto->aead[] and the node table -- reading freed memory. Decoded KASAN splat (v7.1-rc7, CONFIG_KASAN_INLINE + TIPC + TIPC_CRYPTO): BUG: KASAN: slab-use-after-free in tipc_aead_decrypt_done (net/tipc/crypto.c:999) Read of size 8 at addr ffff8881056258a8 by task kworker/u16:2/51 Workqueue: events_unbound Call Trace: tipc_aead_decrypt_done (net/tipc/crypto.c:999) process_one_work (kernel/workqueue.c:3314) worker_thread (kernel/workqueue.c:3397 kernel/workqueue.c:3478) kthread (kernel/kthread.c:436) ret_from_fork (arch/x86/kernel/process.c:158) ret_from_fork_asm (arch/x86/entry/entry_64.S:245) Allocated by task 169: __kasan_kmalloc (mm/kasan/common.c:398 mm/kasan/common.c:415) tipc_crypto_start (net/tipc/crypto.c:1502) tipc_init_net (net/tipc/core.c:72) ops_init (net/core/net_namespace.c:137) setup_net (net/core/net_namespace.c:446) copy_net_ns (net/core/net_namespace.c:579) create_new_namespaces (kernel/nsproxy.c:132) __x64_sys_unshare (kernel/fork.c:3316) do_syscall_64 (arch/x86/entry/syscall_64.c:63) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121) Freed by task 8: kfree (mm/slub.c:6566) tipc_exit_net (net/tipc/core.c:119) cleanup_net (net/core/net_namespace.c:704) process_one_work (kernel/workqueue.c:3314) kthread (kernel/kthread.c:436) This is the same class of bug that commit e279024617134 ("net/tipc: fix slab-use-after-free Read in tipc_aead_encrypt_done") fixed for the encrypt side. The encrypt path takes maybe_get_net(aead->crypto->net) before crypto_aead_encrypt() and drops it with put_net() on the synchronous return paths and in tipc_aead_encrypt_done(); the -EINPROGRESS/-EBUSY return keeps the reference for the async callback to release. The decrypt path was left without the equivalent guard. Mirror the encrypt-side fix on the decrypt path: take a net reference before crypto_aead_decrypt() (failing with -ENODEV and the matching bearer put if it cannot be acquired), keep it across the -EINPROGRESS/-EBUSY async return, and drop it with put_net() on the synchronous success/error return and at the end of tipc_aead_decrypt_done(). Reproduced under KASAN on v7.1-rc7: a UDP bearer with a cluster key is flooded with crafted encrypted frames from an unknown peer (driving the cluster-key decrypt path) while the bearer's netns is repeatedly torn down. The completion must run asynchronously to outlive tipc_crypto_stop(); on x86 the stock aesni gcm(aes) now decrypts synchronously, so the async path was exercised via cryptd offload. The unguarded aead->crypto dereference in tipc_aead_decrypt_done() is the unpatched upstream path; tipc_aead_decrypt() still lacks maybe_get_net(aead->crypto->net), so the completion can outlive the free on any config where crypto_aead_decrypt() goes async. Found by 0sec automated security-research tooling (https://0sec.ai). Fixes: fc1b6d6de220 ("tipc: introduce TIPC encryption & authentication") Cc: stable@vger.kernel.org Signed-off-by: Doruk Tan Ozturk Reviewed-by: Alexander Lobakin Reviewed-by: Tung Nguyen Reviewed-by: Simon Horman Link: https://patch.msgid.link/20260617075818.37431-1-doruk@0sec.ai Signed-off-by: Jakub Kicinski