kernel/linux.git/include/net/sctp, branch v6.12.98

sctp: hold socket lock when dumping endpoints in sctp_diag

2026-07-24T14:11:11+00:00

[ Upstream commit 7d8297e26b4e20b5d1c3c3fe51fe81a1c7fbc823 ] SCTP_DIAG endpoint dumping was traversing endpoint address lists without holding lock_sock(), while those lists could change concurrently via socket operations (e.g., bindx changes). This creates a race where nla_reserve() counts addresses under RCU protection, but the subsequent copy may see fewer entries, potentially leaking uninitialized memory to userspace. Fix this by: - Taking a reference on each endpoint during hash traversal - Moving socket operations (lock_sock()) outside read_lock_bh() - Serializing address list access during dump - Reworking sctp_for_each_endpoint() to support restart-based traversal with (net, pos) tracking Also: - Add WARN_ON_ONCE() for inconsistent address counts - Fix idiag_states filtering for LISTEN vs association cases - Skip dumping endpoints being freed (ep->base.dead) - Move dump position tracking into iterator, removing cb->args[4] and its comment for sctp_ep_dump()., - Update the comment for cb->args[4] and remove the comment for unused cb->args[5] for sctp_sock_dump(). Note: traversal is restart-based and may re-scan buckets multiple times, but this is acceptable due to small bucket sizes and required to support sleeping-safe callbacks. This issue was reported by Nico Yip (@_cyeaa_) working with TrendAI Zero Day Initiative. Reported-by: Zero Day Initiative Fixes: 8f840e47f190 ("sctp: add the sctp_diag.c file") Signed-off-by: Xin Long Link: https://patch.msgid.link/4c1b49ab87e0f7d552ebd8172b364b1994e913c9.1781552190.git.lucien.xin@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

sctp: detect and prevent references to a freed transport in sendmsg

2025-04-20T08:15:50+00:00

commit f1a69a940de58b16e8249dff26f74c8cc59b32be upstream. sctp_sendmsg() re-uses associations and transports when possible by doing a lookup based on the socket endpoint and the message destination address, and then sctp_sendmsg_to_asoc() sets the selected transport in all the message chunks to be sent. There's a possible race condition if another thread triggers the removal of that selected transport, for instance, by explicitly unbinding an address with setsockopt(SCTP_SOCKOPT_BINDX_REM), after the chunks have been set up and before the message is sent. This can happen if the send buffer is full, during the period when the sender thread temporarily releases the socket lock in sctp_wait_for_sndbuf(). This causes the access to the transport data in sctp_outq_select_transport(), when the association outqueue is flushed, to result in a use-after-free read. This change avoids this scenario by having sctp_transport_free() signal the freeing of the transport, tagging it as "dead". In order to do this, the patch restores the "dead" bit in struct sctp_transport, which was removed in commit 47faa1e4c50e ("sctp: remove the dead field of sctp_transport"). Then, in the scenario where the sender thread has released the socket lock in sctp_wait_for_sndbuf(), the bit is checked again after re-acquiring the socket lock to detect the deletion. This is done while holding a reference to the transport to prevent it from being freed in the process. If the transport was deleted while the socket lock was relinquished, sctp_sendmsg_to_asoc() will return -EAGAIN to let userspace retry the send. The bug was found by a private syzbot instance (see the error report [1] and the C reproducer that triggers it [2]). Link: https://people.igalia.com/rcn/kernel_logs/20250402__KASAN_slab-use-after-free_Read_in_sctp_outq_select_transport.txt [1] Link: https://people.igalia.com/rcn/kernel_logs/20250402__KASAN_slab-use-after-free_Read_in_sctp_outq_select_transport__repro.c [2] Cc: stable@vger.kernel.org Fixes: df132eff4638 ("sctp: clear the transport of some out_chunk_list chunks in sctp_assoc_rm_peer") Suggested-by: Xin Long Signed-off-by: Ricardo Cañuelo Navarro Acked-by: Xin Long Link: https://patch.msgid.link/20250404-kasan_slab-use-after-free_read_in_sctp_outq_select_transport__20250404-v1-1-5ce4a0b78ef2@igalia.com Signed-off-by: Paolo Abeni Signed-off-by: Greg Kroah-Hartman

sctp: Correct spelling in headers

2024-08-26T16:37:23+00:00

Correct spelling in sctp.h and structs.h. As reported by codespell. Cc: Marcelo Ricardo Leitner Signed-off-by: Simon Horman Acked-by: Xin Long Link: https://patch.msgid.link/20240822-net-spell-v1-10-3a98971ce2d2@kernel.org Signed-off-by: Jakub Kicinski

sctp: Fix typos and improve comments

2024-07-09T09:31:32+00:00

Fix typos s/steam/stream/ and spell out Schedule/Unschedule in the comments. Compile-tested only. Signed-off-by: Thorsten Blum Reviewed-by: Simon Horman Link: https://patch.msgid.link/20240704202558.62704-2-thorsten.blum@toblux.com Signed-off-by: Paolo Abeni

sctp: preserve const qualifier in sctp_sk()

2024-02-05T11:08:06+00:00

We can change sctp_sk() to propagate its argument const qualifier, thanks to container_of_const(). Signed-off-by: Eric Dumazet Cc: Marcelo Ricardo Leitner Cc: Xin Long Acked-by: Xin Long Signed-off-by: David S. Miller

sctp: Remove unused declaration sctp_backlog_migrate()

2023-08-11T02:31:52+00:00

Commit 61c9fed41638 ("[SCTP]: A better solution to fix the race between sctp_peeloff() and sctp_rcv().") removed the implementation but left declaration in place. Remove it. Signed-off-by: Yue Haibing Acked-by: Xin Long Link: https://lore.kernel.org/r/20230809142323.9428-1-yuehaibing@huawei.com Signed-off-by: Jakub Kicinski

sctp: Remove unused function declarations

2023-08-03T01:42:03+00:00

These declarations are never implemented since beginning of git history. Signed-off-by: Yue Haibing Reviewed-by: Simon Horman Acked-by: Xin Long Link: https://lore.kernel.org/r/20230731141030.32772-1-yuehaibing@huawei.com Signed-off-by: Jakub Kicinski

sctp: delete the nested flexible array peer_init

2023-04-21T07:19:30+00:00

This patch deletes the flexible-array peer_init[] from the structure sctp_cookie to avoid some sparse warnings: # make C=2 CF="-Wflexible-array-nested" M=./net/sctp/ net/sctp/sm_make_chunk.c: note: in included file (through include/net/sctp/sctp.h): ./include/net/sctp/structs.h:1588:28: warning: nested flexible array ./include/net/sctp/structs.h:343:28: warning: nested flexible array Signed-off-by: Xin Long Signed-off-by: David S. Miller

sctp: delete the nested flexible array skip

2023-04-21T07:19:29+00:00

This patch deletes the flexible-array skip[] from the structure sctp_ifwdtsn/fwdtsn_hdr to avoid some sparse warnings: # make C=2 CF="-Wflexible-array-nested" M=./net/sctp/ net/sctp/stream_interleave.c: note: in included file (through include/net/sctp/structs.h, include/net/sctp/sctp.h): ./include/linux/sctp.h:611:32: warning: nested flexible array ./include/linux/sctp.h:628:33: warning: nested flexible array Signed-off-by: Xin Long Signed-off-by: David S. Miller

sctp: delete the nested flexible array params

2023-04-21T07:19:29+00:00

This patch deletes the flexible-array params[] from the structure sctp_inithdr, sctp_addiphdr and sctp_reconf_chunk to avoid some sparse warnings: # make C=2 CF="-Wflexible-array-nested" M=./net/sctp/ net/sctp/input.c: note: in included file (through include/net/sctp/structs.h, include/net/sctp/sctp.h): ./include/linux/sctp.h:278:29: warning: nested flexible array ./include/linux/sctp.h:675:30: warning: nested flexible array This warning is reported if a structure having a flexible array member is included by other structures. Signed-off-by: Xin Long Signed-off-by: David S. Miller