kernel/linux.git/net/sctp, branch v6.6.148

sctp: don't free the ASCONF's own transport in DEL-IP processing

2026-08-03T09:15:29+00:00

commit 9b2854f86f0b56e9027d68e7a3fc909d1a9b566f upstream. sctp_process_asconf() caches the transport the ASCONF chunk is processed against in asconf->transport (== chunk->transport, set once in sctp_rcv()). For an ASCONF located through its Address Parameter by __sctp_rcv_asconf_lookup(), that cached transport corresponds to the Address Parameter, which need not be the packet's source address. sctp_process_asconf_param() rejects a DEL-IP for the packet source address (ADDIP D8, SCTP_ERROR_DEL_SRC_IP), but nothing protects asconf->transport. A single ASCONF can therefore carry, in order: [Address Parameter L] [DEL-IP L] [DEL-IP 0.0.0.0] where L differs from the source. The DEL-IP for L passes the D8 check and calls sctp_assoc_rm_peer() on the transport that asconf->transport still points at, freeing it (RCU-deferred). The following wildcard DEL-IP then reuses the now-dangling asconf->transport in sctp_assoc_set_primary() and sctp_assoc_del_nonprimary_peers(): set_primary() dereferences the freed transport (->ipaddr, ->state) and plants the dangling pointer into asoc->peer.primary_path / active_path, and del_nonprimary_peers(), keeping only the pointer that is no longer on the list, removes every real transport, leaving the association with a transport_count of 0 and primary_path/active_path pointing at freed memory. Reject a DEL-IP that targets the transport the ASCONF is being processed against, mirroring the existing source-address guard, so the wildcard branch can never reuse a freed transport. Fixes: 42e30bf3463c ("[SCTP]: Handle the wildcard ADD-IP Address parameter") Cc: stable@kernel.org Signed-off-by: Jun Yang Acked-by: Xin Long Link: https://patch.msgid.link/tencent_73762ED1DF08CC9D5F5F61954B01350CFE0A@qq.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman

sctp: auth: verify auth requirement when auth_chunk is NULL

2026-08-03T09:15:21+00:00

[ Upstream commit 8e04823c120b376ef7dab14b60ebf6823aa16c14 ] sctp_auth_chunk_verify() returns true unconditionally when chunk->auth_chunk is NULL, silently skipping authentication. This is incorrect when: 1. skb_clone() failed in the BH receive path, leaving auth_chunk NULL. In sctp_endpoint_bh_rcv() asoc is NULL for new connections, so the early sctp_auth_recv_cid() check cannot catch this. 2. No AUTH chunk precedes COOKIE-ECHO, so skb_clone() is never called and auth_chunk remains NULL. Fix by checking sctp_auth_recv_cid() when auth_chunk is NULL: if authentication is required, return false to drop the chunk; otherwise continue normally. Fixes: bbd0d59809f9 ("[SCTP]: Implement the receive and verification of AUTH chunk") Signed-off-by: Qing Luo Acked-by: Xin Long Link: https://patch.msgid.link/20260721015532.120157-2-l1138897701@163.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

sctp: validate stream count in sctp_process_strreset_inreq()

2026-08-03T09:15:20+00:00

[ Upstream commit 18ae07691d43183d270de8be9dc8e027906015d9 ] When processing a RESET_IN_REQUEST from a peer, sctp_process_strreset_inreq() derives the stream count from the parameter length but does not check whether the resulting RESET_OUT_REQUEST would exceed SCTP_MAX_CHUNK_LEN. The OUT request header (sctp_strreset_outreq, 16 bytes) is 8 bytes larger than the IN request header (sctp_strreset_inreq, 8 bytes). Generally, the IP payload is bounded to 65535 bytes, so the stream list cannot be large enough to trigger the overflow. However, on interfaces with MTU > 65535 (e.g., loopback with IPv6 jumbograms), a stream list that fits within the incoming IN parameter can cause a __u16 overflow in sctp_make_strreset_req() when computing the OUT request size, leading to an undersized skb allocation and a kernel BUG: net/core/skbuff.c:207 skb_panic net/core/skbuff.c:2625 skb_put net/sctp/sm_make_chunk.c:1535 sctp_addto_chunk net/sctp/sm_make_chunk.c:3695 sctp_make_strreset_req net/sctp/stream.c:655 sctp_process_strreset_inreq The local setsockopt path validates the generated reset request size. However, for an incoming-only reset, it accounts for the smaller IN request even though the peer must generate an OUT request with the same stream list. Such a request cannot be completed successfully by the peer. Reject peer IN requests whose corresponding OUT request would exceed SCTP_MAX_CHUNK_LEN. Also tighten the local check so it does not send an IN request that would require an oversized OUT request from the peer. Fixes: 7f9d68ac944e ("sctp: implement sender-side procedures for SSN Reset Request Parameter") Reported-by: AutonomousCodeSecurity@microsoft.com Closes: https://lore.kernel.org/all/20260707203215.2752-1-blbllhy@gmail.com/ Suggested-by: Xin Long Signed-off-by: Cen Zhang (Microsoft) Acked-by: Xin Long Link: https://patch.msgid.link/20260710010718.20318-1-blbllhy@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

sctp: fix auth_chunk_list capacity check in sctp_auth_ep_add_chunkid

2026-08-03T09:15:20+00:00

[ Upstream commit ff04b26794a16a8a879eb4fd2c02c2d6b03850e9 ] sctp_auth_ep_add_chunkid() uses SCTP_NUM_CHUNK_TYPES (20) as the capacity limit for ep->auth_chunk_list, allowing it to hold up to 20 chunk entries (param_hdr.length up to 24). However, the copy destination asoc->c.auth_chunks in struct sctp_cookie is only SCTP_AUTH_MAX_CHUNKS (16) entries (20 bytes). When more than 16 chunks are added, sctp_association_init() memcpy overflows the destination by up to 4 bytes. Fix by using SCTP_AUTH_MAX_CHUNKS as the capacity limit, matching the destination capacity. Fixes: 1f485649f529 ("[SCTP]: Implement SCTP-AUTH internals") Signed-off-by: HanQuan Acked-by: Xin Long Link: https://patch.msgid.link/20260713032021.3491702-1-zhoujian.zja@antgroup.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

sctp: validate STALE_COOKIE cause length before reading staleness

2026-07-24T14:03:39+00:00

commit 1cd23ca80784223fa2204e16203f754da4e821f8 upstream. When an ERROR chunk with a STALE_COOKIE cause is received in the COOKIE_ECHOED state, sctp_sf_do_5_2_6_stale() reads the 4-byte Measure of Staleness that follows the cause header: err = (struct sctp_errhdr *)(chunk->skb->data); stale = ntohl(*(__be32 *)((u8 *)err + sizeof(*err))); err is the first cause in the chunk, not the STALE_COOKIE cause that caused the dispatch, and nothing guarantees the staleness field is present. sctp_walk_errors() only requires a cause to be as long as the 4-byte header, so for a STALE_COOKIE cause of length 4 the read runs past the cause, and for a minimal ERROR chunk past skb->tail. The value is echoed to the peer in the Cookie Preservative of the reply INIT, leaking uninitialized memory. sctp_sf_cookie_echoed_err() already walks to the STALE_COOKIE cause, so check its length there and pass it to sctp_sf_do_5_2_6_stale(), which reads that cause instead of the first one. A STALE_COOKIE cause too short to hold the staleness field is discarded. The read is reachable by any peer that can drive an association into COOKIE_ECHOED, including an unprivileged process using a raw SCTP socket in a user and network namespace. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: Xiang Mei Assisted-by: Claude:claude-opus-4-8 Cc: stable@vger.kernel.org Signed-off-by: Weiming Shi Acked-by: Xin Long Link: https://patch.msgid.link/20260704033545.2438373-2-bestswngs@gmail.com Signed-off-by: Paolo Abeni Signed-off-by: Greg Kroah-Hartman

sctp: fix SCTP_RESET_STREAMS stream list length limit

2026-07-24T14:03:24+00:00

[ Upstream commit 2b9f5ef534184bd81b8a4772780626c40eed1fd5 ] SCTP_RESET_STREAMS carries a flexible array of u16 stream IDs, but the optlen clamps treat USHRT_MAX as a byte count and then multiply sizeof(__u16) by the fixed header size. That caps the copied and validated option buffer at about 64 KiB, which rejects valid requests containing more than about half of the u16 stream ID range. Use struct_size_t() for the maximum struct sctp_reset_streams layout instead, so the bound matches the flexible array described by srs_number_streams. Fixes: 5960cefab9df ("sctp: add a ceiling to optlen in some sockopts") Acked-by: Xin Long Signed-off-by: Yousef Alhouseen Link: https://patch.msgid.link/20260625142354.2600-1-alhouseenyousef@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

sctp: hold socket lock when dumping endpoints in sctp_diag

2026-07-24T14:03:19+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: validate embedded address parameter length

2026-07-24T14:03:11+00:00

[ Upstream commit e9361d0ca55c4af12aac09e2572852fa91046229 ] sctp_verify_asconf() and sctp_verify_param() only validate ADD_IP, DEL_IP, and SET_PRIMARY parameters against a fixed minimum size of sizeof(struct sctp_addip_param) + sizeof(struct sctp_paramhdr). This ensures the outer parameter is large enough to contain an embedded address parameter header, but does not verify that the embedded address parameter's declared length fits within the bounds of the outer parameter. Later, sctp_process_param() and sctp_process_asconf_param() extract the embedded address parameter and pass it to af->from_addr_param(), which uses the address parameter length to parse the variable-length address payload. A malformed peer can therefore advertise an embedded address parameter length that exceeds the remaining bytes in the enclosing parameter. Validate that addr_param->p.length does not exceed the space available after the sctp_addip_param header before processing the embedded address parameter. Reject malformed parameters when the embedded address length extends beyond the enclosing parameter bounds. This prevents out-of-bounds reads when parsing malformed parameters carried in INIT or ASCONF processing paths. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: sashiko Signed-off-by: Xin Long Link: https://patch.msgid.link/7838b86b69f52add28808fb59034c8f992e97b2d.1781043268.git.lucien.xin@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

sctp: stream: fully roll back denied add-stream state

2026-06-19T11:39:36+00:00

commit a5f8a90ac9f77c678a9781c0a464b635e0d63e49 upstream. When ADD_OUT_STREAMS is denied, SCTP only shrinks the queued chunks and then lowers outcnt. That leaves removed stream metadata behind, so a later re-add can reuse a stale ext and hit a null-pointer dereference in the scheduler get path. Fix the rollback by tearing down the removed stream state the same way other stream resizes do. Unschedule the current scheduler state, drop the removed stream ext state with sctp_stream_outq_migrate(), and then reschedule the remaining streams. This keeps scheduler-private RR/FC/PRIO lists consistent while fully rolling back denied outgoing stream additions. Fixes: 637784ade221 ("sctp: introduce priority based stream scheduler") Cc: stable@kernel.org Reported-by: Yuan Tan Reported-by: Yifan Wu Reported-by: Juefei Pu Reported-by: Zhengchuan Liang Reported-by: Xin Liu Signed-off-by: Wyatt Feng Signed-off-by: Ren Wei Acked-by: Xin Long Link: https://patch.msgid.link/d78954ecd94954653ee299400e98d74a03a6f7d3.1780603399.git.bronzed_45_vested@icloud.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman

sctp: diag: reject stale associations in dump_one path

2026-06-19T11:39:36+00:00

commit 5eba3e48d78edd7551b992cb7ba687019b3a78da upstream. The SCTP exact sock_diag lookup can hold a transport reference, block on lock_sock(sk), and then resume after sctp_association_free() has marked the association dead and freed its bind address list. When that happens, inet_assoc_attr_size() and inet_diag_msg_sctpasoc_fill() can still dereference association state that is no longer valid for reporting. In particular, inet_diag_msg_sctpasoc_fill() may read an empty bind-address list as a real sctp_sockaddr_entry and trigger an out-of-bounds read from unrelated association memory. Reject the association after taking the socket lock if it has been reaped or detached from the endpoint, and report the lookup as stale. This keeps the exact dump-one path from formatting torn association state. Fixes: 8f840e47f190 ("sctp: add the sctp_diag.c file") Cc: stable@kernel.org Reported-by: Yuan Tan Reported-by: Yifan Wu Reported-by: Juefei Pu Reported-by: Zhengchuan Liang Reported-by: Xin Liu Signed-off-by: Zhao Zhang Signed-off-by: Ren Wei Acked-by: Xin Long Link: https://patch.msgid.link/fac6043fa20a2ff68e12958c431836f692c51268.1780113823.git.zzhan461@ucr.edu Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman