kernel/linux.git/include/net/sctp, branch v6.12.80

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

sctp: delete the obsolete code for the host name address param

2023-04-17T07:28:20+00:00

In the latest RFC9260, the Host Name Address param has been deprecated. For INIT chunk: Note 3: An INIT chunk MUST NOT contain the Host Name Address parameter. The receiver of an INIT chunk containing a Host Name Address parameter MUST send an ABORT chunk and MAY include an "Unresolvable Address" error cause. For Supported Address Types: The value indicating the Host Name Address parameter MUST NOT be used when sending this parameter and MUST be ignored when receiving this parameter. Currently Linux SCTP doesn't really support Host Name Address param, but only saves some flag and print debug info, which actually won't even be triggered due to the verification in sctp_verify_param(). This patch is to delete those dead code. Signed-off-by: Xin Long Signed-off-by: David S. Miller