kernel/linux.git/net/core/sock_map.c, branch v5.10.257

bpf, sockmap: Don't let sock_map_{close,destroy,unhash} call itself

2026-01-19T12:12:09+00:00

commit 5b4a79ba65a1ab479903fff2e604865d229b70a9 upstream. sock_map proto callbacks should never call themselves by design. Protect against bugs like [1] and break out of the recursive loop to avoid a stack overflow in favor of a resource leak. [1] https://lore.kernel.org/all/00000000000073b14905ef2e7401@google.com/ Suggested-by: Eric Dumazet Signed-off-by: Jakub Sitnicki Acked-by: John Fastabend Link: https://lore.kernel.org/r/20230113-sockmap-fix-v2-1-1e0ee7ac2f90@cloudflare.com Signed-off-by: Alexei Starovoitov [Harinadh: Modified to apply on v5.10.y ] Signed-off-by: Harinadh Dommaraju Signed-off-by: Greg Kroah-Hartman

bpf: Clean up sockmap related Kconfigs

2025-06-27T10:04:09+00:00

[ Upstream commit 887596095ec2a9ea39ffcf98f27bf2e77c5eb512 ] As suggested by John, clean up sockmap related Kconfigs: Reduce the scope of CONFIG_BPF_STREAM_PARSER down to TCP stream parser, to reflect its name. Make the rest sockmap code simply depend on CONFIG_BPF_SYSCALL and CONFIG_INET, the latter is still needed at this point because of TCP/UDP proto update. And leave CONFIG_NET_SOCK_MSG untouched, as it is used by non-sockmap cases. Signed-off-by: Cong Wang Signed-off-by: Alexei Starovoitov Reviewed-by: Lorenz Bauer Acked-by: John Fastabend Acked-by: Jakub Sitnicki Link: https://lore.kernel.org/bpf/20210223184934.6054-2-xiyou.wangcong@gmail.com Stable-dep-of: 2660a544fdc0 ("net: Fix TOCTOU issue in sk_is_readable()") Signed-off-by: Sasha Levin

bpf, sockmap: Fix race between element replace and close()

2025-04-10T12:30:53+00:00

commit ed1fc5d76b81a4d681211333c026202cad4d5649 upstream. Element replace (with a socket different from the one stored) may race with socket's close() link popping & unlinking. __sock_map_delete() unconditionally unrefs the (wrong) element: // set map[0] = s0 map_update_elem(map, 0, s0) // drop fd of s0 close(s0) sock_map_close() lock_sock(sk) (s0!) sock_map_remove_links(sk) link = sk_psock_link_pop() sock_map_unlink(sk, link) sock_map_delete_from_link // replace map[0] with s1 map_update_elem(map, 0, s1) sock_map_update_elem (s1!) lock_sock(sk) sock_map_update_common psock = sk_psock(sk) spin_lock(&stab->lock) osk = stab->sks[idx] sock_map_add_link(..., &stab->sks[idx]) sock_map_unref(osk, &stab->sks[idx]) psock = sk_psock(osk) sk_psock_put(sk, psock) if (refcount_dec_and_test(&psock)) sk_psock_drop(sk, psock) spin_unlock(&stab->lock) unlock_sock(sk) __sock_map_delete spin_lock(&stab->lock) sk = *psk // s1 replaced s0; sk == s1 if (!sk_test || sk_test == sk) // sk_test (s0) != sk (s1); no branch sk = xchg(psk, NULL) if (sk) sock_map_unref(sk, psk) // unref s1; sks[idx] will dangle psock = sk_psock(sk) sk_psock_put(sk, psock) if (refcount_dec_and_test()) sk_psock_drop(sk, psock) spin_unlock(&stab->lock) release_sock(sk) Then close(map) enqueues bpf_map_free_deferred, which finally calls sock_map_free(). This results in some refcount_t warnings along with a KASAN splat [1]. Fix __sock_map_delete(), do not allow sock_map_unref() on elements that may have been replaced. [1]: BUG: KASAN: slab-use-after-free in sock_map_free+0x10e/0x330 Write of size 4 at addr ffff88811f5b9100 by task kworker/u64:12/1063 CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Not tainted 6.12.0+ #125 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014 Workqueue: events_unbound bpf_map_free_deferred Call Trace: dump_stack_lvl+0x68/0x90 print_report+0x174/0x4f6 kasan_report+0xb9/0x190 kasan_check_range+0x10f/0x1e0 sock_map_free+0x10e/0x330 bpf_map_free_deferred+0x173/0x320 process_one_work+0x846/0x1420 worker_thread+0x5b3/0xf80 kthread+0x29e/0x360 ret_from_fork+0x2d/0x70 ret_from_fork_asm+0x1a/0x30 Allocated by task 1202: kasan_save_stack+0x1e/0x40 kasan_save_track+0x10/0x30 __kasan_slab_alloc+0x85/0x90 kmem_cache_alloc_noprof+0x131/0x450 sk_prot_alloc+0x5b/0x220 sk_alloc+0x2c/0x870 unix_create1+0x88/0x8a0 unix_create+0xc5/0x180 __sock_create+0x241/0x650 __sys_socketpair+0x1ce/0x420 __x64_sys_socketpair+0x92/0x100 do_syscall_64+0x93/0x180 entry_SYSCALL_64_after_hwframe+0x76/0x7e Freed by task 46: kasan_save_stack+0x1e/0x40 kasan_save_track+0x10/0x30 kasan_save_free_info+0x37/0x60 __kasan_slab_free+0x4b/0x70 kmem_cache_free+0x1a1/0x590 __sk_destruct+0x388/0x5a0 sk_psock_destroy+0x73e/0xa50 process_one_work+0x846/0x1420 worker_thread+0x5b3/0xf80 kthread+0x29e/0x360 ret_from_fork+0x2d/0x70 ret_from_fork_asm+0x1a/0x30 The buggy address belongs to the object at ffff88811f5b9080 which belongs to the cache UNIX-STREAM of size 1984 The buggy address is located 128 bytes inside of freed 1984-byte region [ffff88811f5b9080, ffff88811f5b9840) The buggy address belongs to the physical page: page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11f5b8 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 memcg:ffff888127d49401 flags: 0x17ffffc0000040(head|node=0|zone=2|lastcpupid=0x1fffff) page_type: f5(slab) raw: 0017ffffc0000040 ffff8881042e4500 dead000000000122 0000000000000000 raw: 0000000000000000 00000000800f000f 00000001f5000000 ffff888127d49401 head: 0017ffffc0000040 ffff8881042e4500 dead000000000122 0000000000000000 head: 0000000000000000 00000000800f000f 00000001f5000000 ffff888127d49401 head: 0017ffffc0000003 ffffea00047d6e01 ffffffffffffffff 0000000000000000 head: 0000000000000008 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88811f5b9000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88811f5b9080: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88811f5b9180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88811f5b9200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb Disabling lock debugging due to kernel taint refcount_t: addition on 0; use-after-free. WARNING: CPU: 14 PID: 1063 at lib/refcount.c:25 refcount_warn_saturate+0xce/0x150 CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Tainted: G B 6.12.0+ #125 Tainted: [B]=BAD_PAGE Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014 Workqueue: events_unbound bpf_map_free_deferred RIP: 0010:refcount_warn_saturate+0xce/0x150 Code: 34 73 eb 03 01 e8 82 53 ad fe 0f 0b eb b1 80 3d 27 73 eb 03 00 75 a8 48 c7 c7 80 bd 95 84 c6 05 17 73 eb 03 01 e8 62 53 ad fe <0f> 0b eb 91 80 3d 06 73 eb 03 00 75 88 48 c7 c7 e0 bd 95 84 c6 05 RSP: 0018:ffff88815c49fc70 EFLAGS: 00010282 RAX: 0000000000000000 RBX: ffff88811f5b9100 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000001 RBP: 0000000000000002 R08: 0000000000000001 R09: ffffed10bcde6349 R10: ffff8885e6f31a4b R11: 0000000000000000 R12: ffff88813be0b000 R13: ffff88811f5b9100 R14: ffff88811f5b9080 R15: ffff88813be0b024 FS: 0000000000000000(0000) GS:ffff8885e6f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055dda99b0250 CR3: 000000015dbac000 CR4: 0000000000752ef0 PKRU: 55555554 Call Trace: ? __warn.cold+0x5f/0x1ff ? refcount_warn_saturate+0xce/0x150 ? report_bug+0x1ec/0x390 ? handle_bug+0x58/0x90 ? exc_invalid_op+0x13/0x40 ? asm_exc_invalid_op+0x16/0x20 ? refcount_warn_saturate+0xce/0x150 sock_map_free+0x2e5/0x330 bpf_map_free_deferred+0x173/0x320 process_one_work+0x846/0x1420 worker_thread+0x5b3/0xf80 kthread+0x29e/0x360 ret_from_fork+0x2d/0x70 ret_from_fork_asm+0x1a/0x30 irq event stamp: 10741 hardirqs last enabled at (10741): [] asm_sysvec_apic_timer_interrupt+0x16/0x20 hardirqs last disabled at (10740): [] handle_softirqs+0x60d/0x770 softirqs last enabled at (10506): [] __irq_exit_rcu+0x109/0x210 softirqs last disabled at (10301): [] __irq_exit_rcu+0x109/0x210 refcount_t: underflow; use-after-free. WARNING: CPU: 14 PID: 1063 at lib/refcount.c:28 refcount_warn_saturate+0xee/0x150 CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Tainted: G B W 6.12.0+ #125 Tainted: [B]=BAD_PAGE, [W]=WARN Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014 Workqueue: events_unbound bpf_map_free_deferred RIP: 0010:refcount_warn_saturate+0xee/0x150 Code: 17 73 eb 03 01 e8 62 53 ad fe 0f 0b eb 91 80 3d 06 73 eb 03 00 75 88 48 c7 c7 e0 bd 95 84 c6 05 f6 72 eb 03 01 e8 42 53 ad fe <0f> 0b e9 6e ff ff ff 80 3d e6 72 eb 03 00 0f 85 61 ff ff ff 48 c7 RSP: 0018:ffff88815c49fc70 EFLAGS: 00010282 RAX: 0000000000000000 RBX: ffff88811f5b9100 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000001 RBP: 0000000000000003 R08: 0000000000000001 R09: ffffed10bcde6349 R10: ffff8885e6f31a4b R11: 0000000000000000 R12: ffff88813be0b000 R13: ffff88811f5b9100 R14: ffff88811f5b9080 R15: ffff88813be0b024 FS: 0000000000000000(0000) GS:ffff8885e6f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055dda99b0250 CR3: 000000015dbac000 CR4: 0000000000752ef0 PKRU: 55555554 Call Trace: ? __warn.cold+0x5f/0x1ff ? refcount_warn_saturate+0xee/0x150 ? report_bug+0x1ec/0x390 ? handle_bug+0x58/0x90 ? exc_invalid_op+0x13/0x40 ? asm_exc_invalid_op+0x16/0x20 ? refcount_warn_saturate+0xee/0x150 sock_map_free+0x2d3/0x330 bpf_map_free_deferred+0x173/0x320 process_one_work+0x846/0x1420 worker_thread+0x5b3/0xf80 kthread+0x29e/0x360 ret_from_fork+0x2d/0x70 ret_from_fork_asm+0x1a/0x30 irq event stamp: 10741 hardirqs last enabled at (10741): [] asm_sysvec_apic_timer_interrupt+0x16/0x20 hardirqs last disabled at (10740): [] handle_softirqs+0x60d/0x770 softirqs last enabled at (10506): [] __irq_exit_rcu+0x109/0x210 softirqs last disabled at (10301): [] __irq_exit_rcu+0x109/0x210 Fixes: 604326b41a6f ("bpf, sockmap: convert to generic sk_msg interface") Signed-off-by: Michal Luczaj Signed-off-by: Daniel Borkmann Reviewed-by: John Fastabend Link: https://lore.kernel.org/bpf/20241202-sockmap-replace-v1-3-1e88579e7bd5@rbox.co Signed-off-by: Bin Lan Signed-off-by: He Zhe Signed-off-by: Greg Kroah-Hartman

bpf, sockmap: Fix update element with same

2024-12-19T17:06:09+00:00

commit 75e072a390da9a22e7ae4a4e8434dfca5da499fb upstream. Consider a sockmap entry being updated with the same socket: osk = stab->sks[idx]; sock_map_add_link(psock, link, map, &stab->sks[idx]); stab->sks[idx] = sk; if (osk) sock_map_unref(osk, &stab->sks[idx]); Due to sock_map_unref(), which invokes sock_map_del_link(), all the psock's links for stab->sks[idx] are torn: list_for_each_entry_safe(link, tmp, &psock->link, list) { if (link->link_raw == link_raw) { ... list_del(&link->list); sk_psock_free_link(link); } } And that includes the new link sock_map_add_link() added just before the unref. This results in a sockmap holding a socket, but without the respective link. This in turn means that close(sock) won't trigger the cleanup, i.e. a closed socket will not be automatically removed from the sockmap. Stop tearing the links when a matching link_raw is found. Fixes: 604326b41a6f ("bpf, sockmap: convert to generic sk_msg interface") Signed-off-by: Michal Luczaj Signed-off-by: Daniel Borkmann Reviewed-by: John Fastabend Link: https://lore.kernel.org/bpf/20241202-sockmap-replace-v1-1-1e88579e7bd5@rbox.co Signed-off-by: Greg Kroah-Hartman

sock_map: Add a cond_resched() in sock_hash_free()

2024-10-17T13:07:40+00:00

[ Upstream commit b1339be951ad31947ae19bc25cb08769bf255100 ] Several syzbot soft lockup reports all have in common sock_hash_free() If a map with a large number of buckets is destroyed, we need to yield the cpu when needed. Fixes: 75e68e5bf2c7 ("bpf, sockhash: Synchronize delete from bucket list on map free") Reported-by: syzbot Signed-off-by: Eric Dumazet Signed-off-by: Daniel Borkmann Acked-by: Martin KaFai Lau Acked-by: John Fastabend Link: https://lore.kernel.org/bpf/20240906154449.3742932-1-edumazet@google.com Signed-off-by: Sasha Levin

bpf, sockmap: Fix sk->sk_forward_alloc warn_on in sk_stream_kill_queues

2024-07-18T11:05:43+00:00

commit d8616ee2affcff37c5d315310da557a694a3303d upstream. During TCP sockmap redirect pressure test, the following warning is triggered: WARNING: CPU: 3 PID: 2145 at net/core/stream.c:205 sk_stream_kill_queues+0xbc/0xd0 CPU: 3 PID: 2145 Comm: iperf Kdump: loaded Tainted: G W 5.10.0+ #9 Call Trace: inet_csk_destroy_sock+0x55/0x110 inet_csk_listen_stop+0xbb/0x380 tcp_close+0x41b/0x480 inet_release+0x42/0x80 __sock_release+0x3d/0xa0 sock_close+0x11/0x20 __fput+0x9d/0x240 task_work_run+0x62/0x90 exit_to_user_mode_prepare+0x110/0x120 syscall_exit_to_user_mode+0x27/0x190 entry_SYSCALL_64_after_hwframe+0x44/0xa9 The reason we observed is that: When the listener is closing, a connection may have completed the three-way handshake but not accepted, and the client has sent some packets. The child sks in accept queue release by inet_child_forget()->inet_csk_destroy_sock(), but psocks of child sks have not released. To fix, add sock_map_destroy to release psocks. Signed-off-by: Wang Yufen Signed-off-by: Daniel Borkmann Signed-off-by: Andrii Nakryiko Acked-by: Jakub Sitnicki Acked-by: John Fastabend Link: https://lore.kernel.org/bpf/20220524075311.649153-1-wangyufen@huawei.com [ Conflict in include/linux/bpf.h due to function declaration position and remove non-existed sk_psock_stop helper from sock_map_destroy. ] Signed-off-by: Wen Gu Signed-off-by: Greg Kroah-Hartman

bpf, sockmap: Prevent lock inversion deadlock in map delete elem

2024-04-13T10:59:25+00:00

commit ff91059932401894e6c86341915615c5eb0eca48 upstream. syzkaller started using corpuses where a BPF tracing program deletes elements from a sockmap/sockhash map. Because BPF tracing programs can be invoked from any interrupt context, locks taken during a map_delete_elem operation must be hardirq-safe. Otherwise a deadlock due to lock inversion is possible, as reported by lockdep: CPU0 CPU1 ---- ---- lock(&htab->buckets[i].lock); local_irq_disable(); lock(&host->lock); lock(&htab->buckets[i].lock); lock(&host->lock); Locks in sockmap are hardirq-unsafe by design. We expects elements to be deleted from sockmap/sockhash only in task (normal) context with interrupts enabled, or in softirq context. Detect when map_delete_elem operation is invoked from a context which is _not_ hardirq-unsafe, that is interrupts are disabled, and bail out with an error. Note that map updates are not affected by this issue. BPF verifier does not allow updating sockmap/sockhash from a BPF tracing program today. Fixes: 604326b41a6f ("bpf, sockmap: convert to generic sk_msg interface") Reported-by: xingwei lee Reported-by: yue sun Reported-by: syzbot+bc922f476bd65abbd466@syzkaller.appspotmail.com Reported-by: syzbot+d4066896495db380182e@syzkaller.appspotmail.com Signed-off-by: Jakub Sitnicki Signed-off-by: Daniel Borkmann Tested-by: syzbot+d4066896495db380182e@syzkaller.appspotmail.com Acked-by: John Fastabend Closes: https://syzkaller.appspot.com/bug?extid=d4066896495db380182e Closes: https://syzkaller.appspot.com/bug?extid=bc922f476bd65abbd466 Link: https://lore.kernel.org/bpf/20240402104621.1050319-1-jakub@cloudflare.com Signed-off-by: Greg Kroah-Hartman

bpf: sockmap: Remove preempt_disable in sock_map_sk_acquire

2023-08-11T09:57:49+00:00

[ Upstream commit 13d2618b48f15966d1adfe1ff6a1985f5eef40ba ] Disabling preemption in sock_map_sk_acquire conflicts with GFP_ATOMIC allocation later in sk_psock_init_link on PREEMPT_RT kernels, since GFP_ATOMIC might sleep on RT (see bpf: Make BPF and PREEMPT_RT co-exist patchset notes for details). This causes calling bpf_map_update_elem on BPF_MAP_TYPE_SOCKMAP maps to BUG (sleeping function called from invalid context) on RT kernels. preempt_disable was introduced together with lock_sk and rcu_read_lock in commit 99ba2b5aba24e ("bpf: sockhash, disallow bpf_tcp_close and update in parallel"), probably to match disabled migration of BPF programs, and is no longer necessary. Remove preempt_disable to fix BUG in sock_map_update_common on RT. Signed-off-by: Tomas Glozar Reviewed-by: Jakub Sitnicki Link: https://lore.kernel.org/all/20200224140131.461979697@linutronix.de/ Fixes: 99ba2b5aba24 ("bpf: sockhash, disallow bpf_tcp_close and update in parallel") Reviewed-by: John Fastabend Link: https://lore.kernel.org/r/20230728064411.305576-1-tglozar@redhat.com Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin

bpf, sockmap: Revert buggy deadlock fix in the sockhash and sockmap

2023-05-17T09:47:52+00:00

[ Upstream commit 8c5c2a4898e3d6bad86e29d471e023c8a19ba799 ] syzbot reported a splat and bisected it to recent commit ed17aa92dc56 ("bpf, sockmap: fix deadlocks in the sockhash and sockmap"): [...] WARNING: CPU: 1 PID: 9280 at kernel/softirq.c:376 __local_bh_enable_ip+0xbe/0x130 kernel/softirq.c:376 Modules linked in: CPU: 1 PID: 9280 Comm: syz-executor.1 Not tainted 6.2.0-syzkaller-13249-gd319f344561d #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/30/2023 RIP: 0010:__local_bh_enable_ip+0xbe/0x130 kernel/softirq.c:376 [...] Call Trace: spin_unlock_bh include/linux/spinlock.h:395 [inline] sock_map_del_link+0x2ea/0x510 net/core/sock_map.c:165 sock_map_unref+0xb0/0x1d0 net/core/sock_map.c:184 sock_hash_delete_elem+0x1ec/0x2a0 net/core/sock_map.c:945 map_delete_elem kernel/bpf/syscall.c:1536 [inline] __sys_bpf+0x2edc/0x53e0 kernel/bpf/syscall.c:5053 __do_sys_bpf kernel/bpf/syscall.c:5166 [inline] __se_sys_bpf kernel/bpf/syscall.c:5164 [inline] __x64_sys_bpf+0x79/0xc0 kernel/bpf/syscall.c:5164 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7fe8f7c8c169 [...] Revert for now until we have a proper solution. Fixes: ed17aa92dc56 ("bpf, sockmap: fix deadlocks in the sockhash and sockmap") Reported-by: syzbot+49f6cef45247ff249498@syzkaller.appspotmail.com Cc: Hsin-Wei Hung Cc: Xin Liu Cc: John Fastabend Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/000000000000f1db9605f939720e@google.com/ Signed-off-by: Sasha Levin

bpf, sockmap: fix deadlocks in the sockhash and sockmap

2023-05-17T09:47:51+00:00

[ Upstream commit ed17aa92dc56b6d8883e4b7a8f1c6fbf5ed6cd29 ] When huang uses sched_switch tracepoint, the tracepoint does only one thing in the mounted ebpf program, which deletes the fixed elements in sockhash ([0]) It seems that elements in sockhash are rarely actively deleted by users or ebpf program. Therefore, we do not pay much attention to their deletion. Compared with hash maps, sockhash only provides spin_lock_bh protection. This causes it to appear to have self-locking behavior in the interrupt context. [0]:https://lore.kernel.org/all/CABcoxUayum5oOqFMMqAeWuS8+EzojquSOSyDA3J_2omY=2EeAg@mail.gmail.com/ Reported-by: Hsin-Wei Hung Fixes: 604326b41a6f ("bpf, sockmap: convert to generic sk_msg interface") Signed-off-by: Xin Liu Acked-by: John Fastabend Link: https://lore.kernel.org/r/20230406122622.109978-1-liuxin350@huawei.com Signed-off-by: Alexei Starovoitov Signed-off-by: Sasha Levin