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9 dayssctp: reject forged cookie peer_addr with unknown address familyXingyuan Mo
When cookie authentication is disabled, COOKIE-ECHO peer_addr is attacker-controlled. An invalid sa_family made sctp_get_af_specific() return NULL and crash in sctp_transport_init() on af_specific->sockaddr_len. Validate it with af->addr_valid() in sctp_unpack_cookie(), which also rejects a mismatched family, e.g. an AF_INET6 peer_addr on an IPv4 socket that would later crash in sctp_v6_get_dst() on inet6_sk(sk)->opt. Validate a copy of peer_addr, since addr_valid() rewrites a v4-mapped v6 address in place and the cookie still lives in the received skb, which is not guaranteed to be unshared. Store the validated copy in the new association and pass it to sctp_process_init() instead of the raw cookie, so a v4-mapped v6 address is normalised to AF_INET before the association and its primary transport are built from it. For that, sctp_v6_addr_valid() has to return 0 for a non-v4-mapped address when it is called with a socket that is not PF_INET6, so that IPv6 addresses are never used on IPv4 sockets. The check is done after the v4-mapped handling, so v4-mapped addresses passed to an IPv4 socket through the socket API keep being accepted. As addr_valid() now also checks sk_family and ipv6_only_sock, simplify the address handling in sctp_process_param() with it, as it additionally filters out non-unicast addresses. As a side effect, a v4-mapped address in an IPv6 address parameter is now normalised to AF_INET before the transport is created, matching what the socket API paths already do. Also add the missing !af check in sctp_process_init(), as sctp_get_af_specific(AF_INET6) returns NULL on CONFIG_IPV6=n builds. BUG: KASAN: null-ptr-deref in sctp_transport_new+0xa7/0x350 Read of size 4 at addr 00000000000000b4 by task poc/682 Call Trace: <IRQ> sctp_transport_new+0xa7/0x350 sctp_assoc_add_peer+0x153/0x850 sctp_process_init+0xf9/0x1180 sctp_sf_do_5_1D_ce+0x464/0xbc0 sctp_do_sm+0x114/0x2990 sctp_endpoint_bh_rcv+0x280/0x430 sctp_inq_push+0xdd/0x100 sctp_rcv+0x17f5/0x1ae0 sctp4_rcv+0x2b/0x40 ip_protocol_deliver_rcu+0x25b/0x270 ip_local_deliver+0xd1/0xe0 </IRQ> Kernel panic - not syncing: Fatal exception in interrupt Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Xingyuan Mo <hdthky0@gmail.com> Acked-by: Xin Long <lucien.xin@gmail.com> Link: https://patch.msgid.link/20261019073747.178626-1-hdthky0@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
10 daysMerge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netPaolo Abeni
Merge in late fixes in preparation for the net-next PR. Conflicts: net/netfilter/nf_conntrack_netlink.c cd37ab22a74e0 ("netfilter: nf_conntrack_netlink: fix inverted IPv6 tuple filter") 1ae2d094b0200 ("netfilter: ctnetlink: fix inverted IPv6 address match in dump filter") Adjacent changes: drivers/net/ethernet/marvell/octeontx2/af/rvu_nix.c 8830e65ed46de ("net: use assign_bit() where applicable") 07bd391eb957 ("octeontx2-af: Fix CQ enable state tracking after AQ writes") net/core/sock.c 31c5ea8a3296 ("ipv6: Remove IPV6_ADDRFORM.") 31b564f70d88 ("net: use the full socket in sk_mc_loop()") net/mptcp/protocol.h 0cb6910130a3 ("mptcp: remove thmac from subflow ctx") 7538fa33bb2f ("mptcp: fix subflow bitfield misuse") Signed-off-by: Paolo Abeni <pabeni@redhat.com>
12 daysnet: rename skb_unshare() to skb_unclone_full()Nicolai Buchwitz
skb_unshare() only copies cloned skbs. A shared skb that is not a clone comes back unchanged, which the name doesn't suggest. The loopback selftest hooks got caught by this and hit BUG_ON(skb_shared()). Rename it to skb_unclone_full(). Like skb_unclone() it only acts on clones, but it copies the whole skb, not just the head. Suggested-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Nicolai Buchwitz <nb@tipi-net.de> Reviewed-by: Ioana Ciornei <ioana.ciornei@nxp.com> # dpaa2 Link: https://patch.msgid.link/20261015-nb-skb-unclone-full-v1-1-0dfbf01f60f2@tipi-net.de Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-10-15sctp: hold transport reference across connect waitSeung Min Shin
sctp_sendmsg_to_asoc() selects a transport before waiting for a new interleaved association to become established. sctp_wait_for_connect() drops the socket lock while sleeping. While the lock is dropped, backlog processing can handle a COOKIE ACK and an ASCONF DEL-IP that removes the selected transport. sctp_assoc_rm_peer() then marks the transport dead and drops its association-owned reference. The transport can be freed through RCU before the send path resumes. After the wait, the stale pointer is assigned to newly created DATA or I-DATA chunks and later dereferenced by sctp_outq_select_transport(). Hold a reference to the selected transport across sctp_wait_for_connect(). After the socket lock is reacquired, abort the send if the transport was marked dead. Callers without a selected transport pass NULL and retain their existing behavior. Cc: stable@vger.kernel.org Fixes: 668c9beb9020 ("sctp: implement assign_number for sctp_stream_interleave") Acked-by: Xin Long <lucien.xin@gmail.com> Signed-off-by: Seung Min Shin <guncraft2000@naver.com> Link: https://patch.msgid.link/20261011162750.1529631-1-guncraft2000@naver.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-10-15sctp: re-point retained control chunks on association migrationJun Yang
sctp_sock_migrate() transfers DATA chunk ownership but leaves retained control chunks pointing at the old socket. A later retransmission can therefore access the socket after it has been freed. Extend the migration walk to cover retained control chunks and use sctp_control_set_owner_w() to assign their new owner. Reuse the DATA ownership check so each chunk is processed once per pass, even when it is reachable through multiple lists or retained pointers. Preserve a control chunk's existing authentication key across migration so its final release can still generate SCTP_AUTH_FREE_KEY when needed. Fixes: d04adf1b3551 ("sctp: reset owner sk for data chunks on out queues when migrating a sock") Cc: stable@kernel.org Reported-by: TencentOS Corvus AI <corvus@tencent.com> Signed-off-by: Jun Yang <junvyyang@tencent.com> Acked-by: Xin Long <lucien.xin@gmail.com> Link: https://patch.msgid.link/20261009074244.3718-3-juny24602@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-10-15sctp: hold shkey across socket migrationDavid Lee
sctp_sock_migrate() transfers queued DATA skbs from the old socket to the new one. skb_orphan() invokes sctp_wfree() during that transfer and drops the skb-owned shared-key reference. If userspace has removed that key from the association, this can be the final reference. The following sctp_set_owner_w() then dereferences the freed chunk->shkey while trying to take the new owner reference. Take a temporary shared-key reference before orphaning the skb and release it after the new owner has taken its reference. This preserves the selected authentication key throughout the ownership transfer. Bug found and triaged by OpenAI Security Research and validated by Trail of Bits. Fixes: 1b1e0bc99474 ("sctp: add refcnt support for sh_key") Signed-off-by: Kyle Zeng <kylebot@openai.com> Signed-off-by: David Lee <david.lee@trailofbits.com> Acked-by: Xin Long <lucien.xin@gmail.com> Link: https://patch.msgid.link/20261009074244.3718-2-juny24602@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-10-15Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
Cross-merge networking fixes after downstream PR (net-7.3-rc8). No conflicts. Adjacent changes: drivers/net/ethernet/microchip/lan865x/lan865x.c 2a3f6d2a9ac3 ("microchip: lan865x: move setting of netops to fix crash") 15358c2c3dca ("net: ethernet: oa_tc6: return ERR_PTR from oa_tc6_init()") Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-10-13sctp: revalidate output stream after association connect waitDaehyeon Ko
When message interleaving is enabled, the first send waits for association establishment before building its data chunks. The wait drops the socket lock, and handshake processing can reduce the output stream count to the peer-advertised inbound stream count. sctp_stream_init() then frees the extension of every removed stream. The sender resumes with the stream that it checked before the wait. If the peer removed that stream, sctp_outq_tail() later dereferences its NULL extension. Fatal-oops policies then panic the host. KASAN: null-ptr-deref in range [0x38-0x3f] RIP: sctp_outq_tail+0x49e/0xaa0 Call Trace: sctp_primitive_SEND sctp_sendmsg_to_asoc sctp_sendmsg A range check alone is insufficient. Stream reconfiguration can grow the output count again while the lock is released without recreating extensions freed by the earlier shrink. The stream can then be in range while its extension remains NULL. The send-buffer wait has the same issue. Factor the range and extension checks into a helper and repeat both after each send-path wait that drops the socket lock. Once the lock is reacquired, the validation remains stable through data creation and queueing. If validation fails after the connect wait, the auto-created association is already established. Return ESRCH so the existing caller path keeps it under state-machine ownership instead of freeing it directly, which would leave protocol, counter and socket state inconsistent. Fixes: 668c9beb9020 ("sctp: implement assign_number for sctp_stream_interleave") Cc: stable@vger.kernel.org Assisted-by: LLM Signed-off-by: Daehyeon Ko <4ncienth@gmail.com> Acked-by: Xin Long <lucien.xin@gmail.com> Link: https://patch.msgid.link/20261007035739.3472432-1-4ncienth@gmail.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2026-10-08Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
Cross-merge networking fixes after downstream PR (net-7.3-rc7). Conflicts: include/net/strparser.h 0984ebc631792 ("strparser: make sure __strp_recv isn't running before tearing down the parser") 02fd0a2111374 ("net: strparser: removed the aborted bit and aborts counter") https://lore.kernel.org/asYfmLsfy-SCxXjr@sirena.co.uk Adjacent changes: Documentation/networking/strparser.rst 5f193cdabf25 ("docs: networking: strparser: remove general mode") 0984ebc63179 ("strparser: make sure __strp_recv isn't running before tearing down the parser") Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-10-06sctp: copy zeroed stats to user in sctp_getsockopt_pr_streamstatus() when ↵Hui Peng
!streamoute When an SCTP stream output extension structure (streamoute) has not yet been allocated, sctp_getsockopt_pr_streamstatus() sets the local stack variables params.sprstat_abandoned_unsent = 0 and params.sprstat_abandoned_sent = 0, but then immediately jumps to 'out:', bypassing copy_to_user(). As a result, when an uninitialized user buffer is passed to getsockopt(SCTP_PR_STREAM_STATUS), the kernel returns success (0) without copying the zeroed stats back to user space, leaving uninitialized data in the user buffer. Refactor the !streamoute check into an if-else chain so that when streamoute is NULL, params is zeroed and falls through to copy_to_user(), copying the zeroed stats to user space and setting retval = 0 once before returning. Tested in QEMU against Linux 7.3.0-rc3 using an uninitialized sctp_prstatus user struct passed to getsockopt(SCTP_PR_STREAM_STATUS) on a freshly created stream: on the unfixed kernel the user struct contains uninitialized stack garbage; whereas with this fix applied, getsockopt() copies zeroed stats into user space and returns 0. Cc: stable@vger.kernel.org Reviewed-by: Xin Long <lucien.xin@gmail.com> Signed-off-by: Hui Peng <benquike@gmail.com> Fixes: f952be79cebd ("sctp: introduce struct sctp_stream_out_ext") Link: https://patch.msgid.link/20260930044611.204739-1-benquike@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-10-01Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
Cross-merge networking fixes after downstream PR (net-7.3-rc6). Conflicts: net/mac80211/tx.c net/mac80211/ieee80211_i.h 8effab902fa34 ("wifi: mac80211: prevent AP VLAN tx from other interfaces") 78b843974fb83 ("wifi: mac80211: report multicast transmission from lookup_ra_sta()") https://lore.kernel.org/arJmcuhpJ69wAvYK@sirena.co.uk drivers/net/ethernet/realtek/r8169_main.c 3cdeaef1754ab ("r8169: disable EEE on RTL8168h/8111h") 8a3c76523e449 ("r8169: add support for phylink") https://lore.kernel.org/ar5vAxEqS8tO8aVT@sirena.org.uk Adjacent changes: rust/kernel/net/netlink.rs 5e5916923759 ("rust: net: netlink: Migrate to zerocopy's IntoBytes") 0923198be4ae ("rust: net: netlink: validate attribute length before casting to `c_int`") Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-09-30sctp: check RCV_SHUTDOWN after the sendmsg connect waitJun Yang
sctp_wait_for_connect() drops the socket lock while it sleeps. An out-of-the-blue ABORT can then be processed from the socket backlog and unlink the association. If a concurrent shutdown(fd, SHUT_RD) sets RCV_SHUTDOWN, the waiter breaks with err == 0 before checking asoc->base.dead. Its final sctp_association_put() can then free the association, leaving sctp_sendmsg_to_asoc() to continue with a dangling pointer. Check RCV_SHUTDOWN along with the wait error in sctp_sendmsg_to_asoc() before using the association again. The check only accesses the socket, so it needs no additional association reference. Return the existing -ESRCH so that sctp_sendmsg() skips freeing a new association that may already have been destroyed. Keep sctp_wait_for_connect() unchanged to preserve its behavior for the connect() caller. Fixes: 668c9beb9020 ("sctp: implement assign_number for sctp_stream_interleave") Cc: stable@vger.kernel.org Reported-by: TencentOS Corvus AI <corvus@tencent.com> Signed-off-by: Jun Yang <junvyyang@tencent.com> Acked-by: Xin Long <lucien.xin@gmail.com> Link: https://patch.msgid.link/20260926095606.68601-1-juny24602@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-09-24Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
Cross-merge networking fixes after downstream PR (net-7.3-rc5). Conflicts: drivers/net/mdio/mdio-realtek-rtl9300.c 89a8a1eef2d44 ("net: mdio: realtek-rtl9300: fix RTL931x C22 extended page selection") cc3cb8db1eef9 ("net: mdio: realtek-rtl9300: Add page tracking") https://lore.kernel.org/arUZOqy73bE2pp0w@sirena.org.uk net/8021q/vlan_dev.c cd5dd68267c4 ("vlan: ensure sufficient headroom in vlan_dev_hard_header()") ca6ff8dd70eb ("vlan: annotate data-races in vlan_dev_priv fields") Adjacent changes: net/ipv6/ip6_gre.c dd47bcf279f1 ("ip6_gre: Call ip6erspan_tunnel_unlink_md() in ip6erspan_changelink().") cce829e2aa1d ("ip6_gre: Protect ip6gre_net.tunnels[][] with mutex.") drivers/net/ethernet/meta/fbnic/fbnic_txrx.c b5d9e9d4d0c1 ("eth: fbnic: use the Rx queue napi pointer to find the napi vector") c0aca269ec07 ("eth: fbnic: Make Rx completion coalescing configurable") drivers/net/ethernet/stmicro/stmmac/stmmac_selftests.c d68acbf93531 ("net: stmmac: selftests: Support running selftests on DSA conduits") 85ca3292d7a3 ("net: stmmac: Remove ARP offload code") drivers/net/ethernet/wangxun/libwx/wx_hw.c 3173cba11701 ("net: libwx: fix races in Tx timestamp handling") 7042c8c193e5 ("net: libwx: rename wx_pf_flags to wx_flags") Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-09-22sctp: hold asoc or transport before mod_timer() in timer handlersXin Long
Take the association or transport reference before rearming a timer in the timer handlers. The existing code calls mod_timer() before taking the reference needed by the rearmed timer without holding the sock lock. This creates a race with timer cleanup: if the timer is deleted after mod_timer() returns but before the reference is taken, the cleanup path can drop the timer's reference and destroy the transport or association. The timer handler then takes a reference on the already freed object and eventually drops it, causing a refcount underflow. Hold the object before mod_timer() and drop the reference if mod_timer() reports that the timer was already pending in timer handlers. Apply the same ordering to the proto-unreachable path, which can rearm a transport timer outside the timer handlers without holding the sock lock. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: Tangxin Xie <xietangxin@h-partners.com> Signed-off-by: Xin Long <lucien.xin@gmail.com> Link: https://patch.msgid.link/c31b5e3ee2b7274e804f5eba2f21e2412e7eef7a.1790013825.git.lucien.xin@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-09-22sctp: discard the rest of the packet on a stale-cookie errorAohan Mei
When an association is in COOKIE-ECHOED state and the peer sends a bundled [ERROR(Stale Cookie)][DATA] packet from one of its non-primary addresses, processing the ERROR chunk takes the non-fatal stale-cookie retry path sctp_sf_do_5_2_6_stale(), which queues SCTP_CMD_DEL_NON_PRIMARY while keeping the association alive. sctp_cmd_del_non_primary() removes every non-primary transport - including the very transport this packet arrived on, which is still referenced by the receive lookup and shared by all chunks of the packet via chunk->transport. sctp_assoc_rm_peer() does redirect asoc->peer.last_data_from away from the removed transport, but right afterwards the bundled DATA chunk makes sctp_assoc_bh_rcv() re-register asoc->peer.last_data_from = chunk->transport unconditionally, undoing the redirection with the just-removed transport. Once the packet is done, the receive reference is dropped and the transport is RCU-freed, while the surviving association keeps the dangling last_data_from. A later FWD-TSN (or the delayed SACK timer) makes sctp_gen_sack() dereference it (->param_flags and friends), and sctp_make_sack()/sctp_outq_select_transport() may write to the freed object and link it into the live transport list. This is a use-after-free triggerable by any malicious SCTP peer (or a local unprivileged user acting as one) with no capabilities required: BUG: KASAN: slab-use-after-free in sctp_do_sm+0x498a/0x5660 Read of size 4 at addr ffff88800e1e356c by task poc/115 Call Trace: sctp_do_sm <- sctp_assoc_bh_rcv <- sctp_inq_push <- sctp_rcv <- ip_protocol_deliver_rcu <- ip_rcv Allocated: sctp_transport_new <- sctp_assoc_add_peer <- sctp_process_init (INIT-ACK processing) Freed: kfree <- sctp_transport_destroy_rcu <- rcu_core (call_rcu queued by sctp_transport_put at end of sctp_rcv) The buggy address is located 364 bytes inside of freed 1024-byte region [ffff88800e1e3400, ffff88800e1e3800), cache kmalloc-1k Note that commit 03a9d10ecf71 ("sctp: drop a chunk if its transport was removed") only covers the window between the receive lookup and the chunk processing (e.g. an ASCONF DEL-IP racing the socket backlog); here the transport is removed *while* the packet is being processed, by an earlier chunk of the same packet, so the drop in sctp_inq_push() does not reach this path. Verified with the bundled [ERROR(Stale Cookie)][DATA] + FWD-TSN reproducer: the KASAN report above still fires with that commit applied, and is gone with this patch on top. Fix it by discarding the rest of the packet on this path, as suggested by Xin. After the stale-cookie ERROR has sent the association back to COOKIE-WAIT and removed the non-primary transports, the remaining chunks of the packet can only run against the restarted handshake while referencing the removed arrival transport through chunk->transport: besides the last_data_from registration above, sctp_cmd_setup_t2() and the sctp_make_*() reply builders would also copy that pointer into association-lifetime state that sctp_assoc_rm_peer() has already sanitized. Let the peer retransmit them, in line with what sctp_inq_push() does for chunks whose transport was removed before processing. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Suggested-by: Xin Long <lucien.xin@gmail.com> Reported-by: TencentOS Corvus AI <corvus@tencent.com> Cc: stable@vger.kernel.org Signed-off-by: Aohan Mei <henrymei@tencent.com> Acked-by: Xin Long <lucien.xin@gmail.com> Link: https://patch.msgid.link/20260921093707.1432184-1-ljp1205831794@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-09-18sctp: avoid livelock while updating retransmit pathYiqi Sun
sctp_assoc_update_retran_path() can loop forever when every remaining transport, including retran_path, is SCTP_UNCONFIRMED: the state check runs before the wraparound test, so the loop cannot observe that it has completed a full pass. Fix this by considering a transport only when it is not UNCONFIRMED, then checking whether the walk has returned to retran_path. This makes the full-pass termination independent of the transport state while preserving the existing fallback selection semantics. Also restore the NULL guard around the retran_path assignment. In the all-UNCONFIRMED case there is no eligible replacement transport, and installing NULL would leave later retransmit-path users and the debug print with a NULL path. Fixes: 4c47af4d5eb2 ("net: sctp: rework multihoming retransmission path selection to rfc4960") Signed-off-by: Yiqi Sun <sunyiqixm@gmail.com> Acked-by: Xin Long <lucien.xin@gmail.com> Link: https://patch.msgid.link/20260915095017.942213-1-sunyiqixm@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-09-03Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
Cross-merge networking fixes after downstream PR (net-7.3-rc2). No conflicts, or adjacent changes. Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-09-02net: Replace %pK output with 0Sebastian Andrzej Siewior
Commit 71338aa7d050c ("net: convert %p usage to %pK") which is from 2011 and changed the %p annotation for pointer to %pK. Back then the default behaviour for %p was to print the pointer. The %pK modifier was introduced to able to control the behaviour of specific pointer values without changing the behaviour of %p for everyone. It was dedicated to avoid leaking pointers via /proc. There was also the idea to remove the check from formatting the string and move to the open callback with some helpers but this did not happen. Things changed over time. The default behaviour for %p is now to print a hash pointer which does not leak the address but allows to correlate if two pointers are equal. The policy on %p is to not introduce new ones. This is somehow in between since it already exists. The pointer are usually socket pointers and I don't see any value in exposing them. Therefore I am following the recommendation of removing them. Since their usage in /proc/ can be considered ABI I replace the pointer with a 0. Replace the %pK annotation with 0 value. Correct the spacing for the cases where pointer is at the beginning. Reviewed-by: Kees Cook <kees@kernel.org> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Link: https://patch.msgid.link/20260901160345.eeknHmY2@linutronix.de Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-08-30sctp: validate chunk length in the inqueue parserCharles Vosburgh
SCTP chunks always include a four-byte generic header, but sctp_inq_pop() currently accepts shorter declared lengths. A zero-length chunk leaves chunk_end at the current header. When ASCONF is covered by the association's SCTP-AUTH policy, sctp_assoc_bh_rcv() can continue before the state machine performs its normal chunk-length check. sctp_inq_pop() then returns the same malformed chunk repeatedly and the receive softirq can lock up. A remote SCTP peer can trigger this after establishing an association on a kernel built with CONFIG_IP_SCTP and configured with net.sctp.addip_enable=1 and net.sctp.auth_enable=1. The reproducer did not require application credentials, a shared SCTP AUTH key, or net.sctp.addip_noauth_enable=1. On commit f967455fb2a5 ("seg6: reset IP6CB after IPv6 decapsulation"), one zero-length ASCONF caused repeated watchdog soft-lockup reports in a two-vCPU KVM guest. All 3 pre-trigger health probes succeeded, while 36 of 37 post-trigger probes failed. With this change, all 37 post-trigger probes succeeded and no equivalent soft-lockup signature appeared. Reject chunks shorter than the generic SCTP header at the shared inqueue parser boundary. Mark the packet for discard before either caller can continue processing it, while preserving the four-byte generic minimum. Declared-length 1 through 4 controls and kernel-generated ASCONF traffic remained healthy. The patched sctp_hello selftest passed for IPv4 and IPv6. The complete private reproducer and validation evidence are available directly to maintainers on request. Fixes: bbd0d59809f9 ("[SCTP]: Implement the receive and verification of AUTH chunk") Cc: stable@vger.kernel.org Signed-off-by: Charles Vosburgh <theminershive@gmail.com> Acked-by: Xin Long <lucien.xin@gmail.com> Link: https://patch.msgid.link/20260827-sctp-zero-chunk-inqueue-v2-1-2e7669c6a6cb@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-08-30sctp: fix soft lockup from unpadded ASCONF-ACK parameter iterationHenry Martin
sctp_verify_asconf() walks ASCONF-ACK parameters with sctp_walk_params(), which advances by SCTP_PAD4(length), while the consumer sctp_get_asconf_response() iterates the same parameters advancing by the raw length, without padding. A single odd-length parameter desynchronises the two walks and makes the consumer interpret attacker-controlled bytes at a misaligned offset. When those bytes yield a length of zero, the while loop over asconf_ack_len makes no progress, spinning forever in softirq context, and the watchdog reports a soft lockup. All reads stay within the received skb, so the lockup is a pure remote denial of service. A remote peer can trigger it with a crafted ASCONF-ACK on an ADD-IP enabled association with an outstanding ASCONF (RFC 5061 section 4.1.2 requires the chunk to be authenticated, but the predefined empty key id 0 allows the peer to compute the same association HMAC from publicly exchanged parameters, so the gate does not help). The SCTP_PARAM_ERR_CAUSE case of sctp_verify_asconf() also performs no length check, letting a parameter without a complete error header reach the consumer, which reads errhdr.cause past the end of the parameter, an out-of-bounds read. Reject SCTP_PARAM_ERR_CAUSE parameters shorter than sizeof(struct sctp_addip_param) + sizeof(struct sctp_errhdr) at the verifier, and advance the consumer iterator with the same padding rule as the verifier to keep the two walks in lockstep. The verifier change guarantees a complete error header in every ERR_CAUSE parameter the consumer can see, so the consumer's asconf_ack_len check is dropped and it returns err_param->cause directly. The consumer padding fix is still required because odd lengths remain valid for SCTP_PARAM_ERR_CAUSE per RFC 5061. The issue was found by ZeroHive, a vulnerability hunting agent at Tencent Yunding Lab. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Henry Martin <bsdhenrymartin@gmail.com> Acked-by: Xin Long <lucien.xin@gmail.com> Link: https://patch.msgid.link/20260828042431.3873725-1-bsdhenrymartin@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-08-28sctp: fix a TOCTOU race in SCTP_CMD_TIMER_STARTXin Long
The SCTP_CMD_TIMER_START handler checks timer_pending() before calling timer_reduce(). The timer can expire and detach between these operations, causing timer_reduce() to rearm the timer without taking the association reference required for the newly armed timer. The timer callback later unconditionally drops its association reference, which can leave the association reference count unbalanced and result in use-after-free during association teardown. Use the return value of timer_reduce() to determine whether the timer was actually armed. Take the association reference only when timer_reduce() successfully starts a new timer, closing the race between checking the timer state and rearming it. This issue was reported by Nico Yip (@_cyeaa_) working with TrendAI Zero Day Initiative. Fixes: 20a785aa52c8 ("sctp: Don't add the shutdown timer if its already been added") Reported-by: Zero Day Initiative <zdi-disclosures@trendmicro.com> Signed-off-by: Xin Long <lucien.xin@gmail.com> Link: https://patch.msgid.link/9d8f1b5c50329d5ea7c642128d35681abaa9ed20.1787773744.git.lucien.xin@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-08-25sctp: fix stream->outcnt underflow on duplicate RECONF responsesJun Yang
A cached RECONF chunk may contain more than one request parameter. A duplicate response can therefore find and process the same ADD_OUT request again while another parameter is still outstanding, rolling back outcnt twice and possibly underflowing it. Track outstanding request types as bits and clear each bit after its first response. Later responses for the same request are then ignored. Fixes: 11ae76e67a17 ("sctp: implement receiver-side procedures for the Reconf Response Parameter") Cc: stable@kernel.org Reported-by: TencentOS Corvus AI <corvus@tencent.com> Link: https://lore.kernel.org/netdev/20260730110225.37371-1-juny24602@gmail.com/ Suggested-by: Xin Long <lucien.xin@gmail.com> Assisted-by: tencentos-corvus-ai:kimi-k3 Signed-off-by: Jun Yang <junvyyang@tencent.com> Link: https://patch.msgid.link/20260824081832.98717-3-juny24602@gmail.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2026-08-25sctp: distinguish sequence zero from wildcard in reconf lookupJun Yang
Zero is a valid response sequence after strreset_outseq wraps, but sctp_chunk_lookup_strreset_param() currently treats it as a wildcard. Add match_seq so response lookups match zero exactly while the one type-only lookup can still ignore the sequence. Fixes: 50a41591f110 ("sctp: implement receiver-side procedures for the Add Outgoing Streams Request Parameter") Cc: stable@kernel.org Suggested-by: Simon Horman <horms@kernel.org> Acked-by: Xin Long <lucien.xin@gmail.com> Signed-off-by: Jun Yang <junvyyang@tencent.com> Link: https://patch.msgid.link/20260824081832.98717-2-juny24602@gmail.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2026-08-25sctp: fix NULL deref on untransmitted RECONF completionWeiming Shi
sctp_process_strreset_outreq(), sctp_process_strreset_addstrm_out() and sctp_process_strreset_resp() complete a pending stream reconfiguration request by stopping the reconf timer on the transport it was sent on: t = asoc->strreset_chunk->transport; if (timer_delete(&t->reconf_timer)) sctp_transport_put(t); chunk->transport is assigned by __sctp_packet_append_chunk() when the chunk is appended to an outbound packet, and sctp_outq_flush_ctrl() arms the reconf timer at that same point. A request already published in asoc->strreset_chunk but not yet transmitted has neither, so completing it dereferences NULL. Two ways to get there. sctp_send_asconf_del_ip() sets asoc->src_out_of_asoc_ok without sending anything when the address being removed is the association's last one, and sctp_outq_flush_ctrl() then leaves every non-ASCONF control chunk queued; as only sctp_process_asconf_ack() clears that flag, it persists. An unprivileged process that removes such an address and then asks for a stream reset panics the kernel from softirq. A peer needs neither ASCONF nor local help: sctp_cmd_interpreter() uncorks the outqueue only once the whole packet has been processed, so a reply built while walking a RECONF chunk stays untransmitted for the rest of that walk, and one RECONF chunk carrying [Incoming SSN Reset Request, Outgoing SSN Reset Request, Response] -- or two RECONF chunks in one packet -- reaches the same dereference. KASAN: null-ptr-deref in range [0x00000000000001e8-0x00000000000001ef] RIP: 0010:timer_delete+0x67/0x110 Call Trace: <IRQ> sctp_process_strreset_addstrm_out (net/sctp/stream.c:832) sctp_sf_do_reconf (net/sctp/sm_statefuns.c:4212) sctp_do_sm (net/sctp/sm_sideeffect.c:1172) sctp_assoc_bh_rcv (net/sctp/associola.c:1044) sctp_rcv (net/sctp/input.c:243) ip_local_deliver (net/ipv4/ip_input.c:262) process_backlog (net/core/dev.c:6680) </IRQ> A response can only acknowledge a request that was actually sent, so do not match asoc->strreset_chunk while chunk->transport is NULL. Guarding the lookup covers all three completion sites. Fixes: 810544764536 ("sctp: implement receiver-side procedures for the Outgoing SSN Reset Request Parameter") Cc: stable@vger.kernel.org Reported-by: Xiang Mei <xmei5@asu.edu> Suggested-by: Xin Long <lucien.xin@gmail.com> Assisted-by: Claude:claude-opus-5 Signed-off-by: Weiming Shi <bestswngs@gmail.com> Acked-by: Xin Long <lucien.xin@gmail.com> Link: https://patch.msgid.link/20260823172857.896146-2-bestswngs@gmail.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2026-08-20sctp: drop a chunk if its transport was removedHyunwoo Kim
sctp_rcv() resolves the transport once per packet and leaves it in chunk->transport. The lookup reference, or the one sctp_add_backlog() takes if the socket is owned by userspace, keeps it around until the chunk has been processed. An authenticated ASCONF DEL-IP can remove it in the meantime. sctp_assoc_rm_peer() takes the transport out of the association and calls sctp_transport_free(), which tags it dead and drops the reference the association held. There is a window on both paths: the packet can sit on the socket backlog, and on the direct path the lookup completes before bh_lock_sock(). The DATA chunk in that packet puts the removed transport back into asoc->peer.last_data_from. Once the packet is done that reference goes away and the transport is freed by RCU, so the next delayed SACK carries the pointer into the SACK chunk and sctp_outq_select_transport() reads the freed transport's state. Drop the chunk in sctp_inq_push(), next to the existing rcvr->dead check. Both paths reach it with the association's socket lock held. The peer retransmits it. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Signed-off-by: Hyunwoo Kim <imv4bel@gmail.com> Acked-by: Xin Long <lucien.xin@gmail.com> Link: https://patch.msgid.link/aoUJHQmxL0LFIMCw@v4bel Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-08-18Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
Merge in late fixes in preparation for the net-next PR. Conflicts: drivers/dpll/dpll_core.c drivers/dpll/dpll_netlink.c 33f016b23a219 ("dpll: fix NULL deref in dpll_device_ops() during teardown race") b1d0c412088e3 ("dpll: add STATE_CONNECTED_OVERRIDE pin capability") https://lore.kernel.org/aoR9YYY2P5--3x0N@sirena.org.uk https://lore.kernel.org/aoR9VmKllVGwmQn_@sirena.org.uk No adjacent changes. Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-08-18sctp: stop processing a packet once its association is deletedHyunwoo Kim
sctp_endpoint_bh_rcv() looks the association up only when chunk->asoc is NULL, and caches the result in chunk->asoc and chunk->transport without taking a reference. A packet that matches no association is handed to the endpoint, so a peer can bundle COOKIE ECHO, SHUTDOWN and SHUTDOWN ACK in one packet. The COOKIE ECHO creates the association, the SHUTDOWN chunk caches it, and with the outqueue empty the SHUTDOWN ACK reaches sctp_sf_do_9_2_final(), so the association and its transports are freed. The endpoint loop has no counterpart to the asoc->base.dead check in sctp_assoc_bh_rcv(). The next chunk writes to last_time_heard in the freed transport and is then passed to sctp_do_sm() with the freed association. The transport is freed through RCU, so this needs the packet to come off the socket backlog, where the loop runs in task context. The endpoint loop cannot do the same check: it holds no reference on the association, so reading asoc->base.dead would itself be a use-after-free. Mark the packet for discard in the command interpreter, just before it deletes the association. That is also before sctp_inq_free() releases the chunk on the association receive path. sctp_sf_do_5_2_4_dupcook() issues SCTP_CMD_DELETE_TCB for the temporary association, while the one the packet belongs to stays alive. A restarting peer can bundle DATA behind its COOKIE ECHO, so compare against chunk->asoc and leave that case alone. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Signed-off-by: Hyunwoo Kim <imv4bel@gmail.com> Acked-by: Xin Long <lucien.xin@gmail.com> Link: https://patch.msgid.link/an-YYtoqw1QpTXUL@v4bel Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-08-13Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
Cross-merge networking fixes after downstream PR (net-7.2-rc8). No conflicts. Adjacent changes: drivers/net/ethernet/wangxun/ngbe/ngbe_main.c 5f3a13e0bb5e ("net: ngbe: fix NULL pointer dereference in non-MSI-X interrupt enabling") d661abdc30c2 ("net: ngbe: correct misleading interrupt comment") drivers/net/ipvlan/ipvlan_main.c e16e960d55a4 ("ipvlan: inherit needed_headroom and needed_tailroom from phy_dev") 00a40d809207 ("ipvlan: Support per-netns netdev unregistration.") Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-08-13net: Const qualify ctl_tables that kmemdup unconditionallyJoel Granados
Const qualify clt_table arrays in the net directory that always pass a memory duplicate to sysctl register. The template would then be in .rodata and the kmemdup'ed array would be outside. Signed-off-by: Joel Granados <joel.granados@kernel.org> Link: https://patch.msgid.link/20260810-jag-net_const_qualify-v4-2-77e888237c69@kernel.org Reviewed-by: Simon Horman <horms@kernel.org> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2026-08-12sctp: fix use-after-free of cached ASCONF chunkYuxiang Yang
addip_last_asconf caches the outstanding outbound ASCONF chunk. The normal ASCONF-ACK completion path releases the chunk and clears the pointer. However, sctp_asconf_queue_teardown() releases the cached chunk without clearing addip_last_asconf. During peer restart handling, sctp_sf_do_dupcook_a() queues SCTP_CMD_PURGE_ASCONF_QUEUE, which invokes sctp_asconf_queue_teardown() while the association remains alive and leaves the pointer dangling. A delayed authenticated ASCONF-ACK can then reach sctp_sf_do_asconf_ack(), which accesses the stale chunk and passes it to sctp_process_asconf_ack(), causing a use-after-free and a second release. Clearing the pointer exposes a race with T4 expiry. Peer restart handling queues the timer stop before the purge, but SCTP_CMD_TIMER_STOP uses timer_delete(), which does not wait for a callback already running on another CPU. Such a callback can reach sctp_sf_t4_timer_expire() after the purge and dereference NULL. Clear addip_last_asconf after releasing the cached chunk, and make sctp_sf_t4_timer_expire() consume a stale T4 expiry if no outstanding ASCONF remains. Fixes: a000c01e60e4 ("sctp: stop pending timers and purge queues when peer restart asoc") Cc: stable@vger.kernel.org Suggested-by: Xin Long <lucien.xin@gmail.com> Signed-off-by: Yuxiang Yang <yangyx22@mails.tsinghua.edu.cn> Acked-by: Xin Long <lucien.xin@gmail.com> Link: https://patch.msgid.link/20260809043806.2768302-1-yangyx22@mails.tsinghua.edu.cn Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-08-12sctp: clear new_transport when removing a peerQing Ming
sctp_process_asconf_param() stores a newly added peer transport in asoc->new_transport. After all parameters in the ASCONF chunk have been processed, sctp_sf_do_asconf() uses this pointer to send a HEARTBEAT to the new transport. An authenticated ASCONF from a remote SCTP peer can add a transport and remove it again with a wildcard DEL-IP parameter in the same chunk. The wildcard deletion preserves the transport on which the ASCONF arrived, but removes the newly added transport through sctp_assoc_del_nonprimary_peers(). The removal does not clear asoc->new_transport, leaving it pointing to the removed transport. sctp_sf_do_asconf() then creates a HEARTBEAT whose chunk->transport points to the removed transport without holding a transport reference. During local address replacement, src_out_of_asoc_ok keeps this HEARTBEAT on control_chunk_list. After the transport is freed by RCU, a successful ASCONF_ACK for the replacement address releases the queued HEARTBEAT and sctp_outq_select_transport() reads the freed transport's state. The issue was found during a static audit of SCTP objects. With an authenticated peer, the reproducer triggered the same KASAN report in 2 of 2 unpatched runs on a KASAN-enabled netdev/main kernel: BUG: KASAN: slab-use-after-free in sctp_outq_select_transport Read of size 4 at addr ffff88800b9bd95c by task python3/197 Call Trace: sctp_outq_select_transport+0x549/0x8b0 [sctp] sctp_outq_flush+0x306/0x2c60 [sctp] sctp_transport_immediate_rtx+0xaf/0x260 [sctp] sctp_process_asconf_ack+0xa48/0xf70 [sctp] Allocated by task 197: sctp_transport_new+0x68/0x650 [sctp] sctp_assoc_add_peer+0x258/0x12a0 [sctp] sctp_process_asconf+0x5e9/0x1090 [sctp] Last potentially related work creation: __call_rcu_common.constprop.0+0x77/0xb70 sctp_assoc_del_nonprimary_peers+0x7c/0xd0 [sctp] sctp_process_asconf+0xd9c/0x1090 [sctp] The first invalid access was a four-byte read of transport->state at net/sctp/outqueue.c:833. The same reproducer completed the full authenticated ASCONF and local-address replacement sequence with this change without a KASAN report or oops. Clear new_transport when its peer is removed, before it can be used to create the HEARTBEAT. Fixes: 6af29ccc223b ("sctp: Bundle HEAERTBEAT into ASCONF_ACK") Cc: stable@vger.kernel.org Signed-off-by: Qing Ming <a0yami@mailbox.org> Acked-by: Xin Long <lucien.xin@gmail.com> Link: https://patch.msgid.link/20260811152803.5629-1-a0yami@mailbox.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-08-11sctp: auth: propagate HMAC calculation errors to callersQing Luo
sctp_auth_calculate_hmac() can fail when building the association secret under memory pressure, but its void return silently leaves the HMAC digest zeroed. On the receive path, sctp_sf_authenticate() compares this zeroed digest against the peer-supplied one using crypto_memneq(), potentially accepting an all-zero HMAC from the peer if the allocation failed. On the send path, sctp_packet_pack() transmits a packet with a zeroed HMAC that the peer would reject. Improve error handling by making sctp_auth_calculate_hmac() return int: - sctp_sf_authenticate() returns SCTP_IERROR_NOMEM instead of accepting a zero HMAC. - sctp_packet_pack() drops the packet on failure instead of transmitting a zeroed HMAC. Update the declaration in auth.h accordingly. Assisted-by: LLM Signed-off-by: Qing Luo <luoqing@kylinos.cn> Acked-by: Xin Long <lucien.xin@gmail.com> Link: https://patch.msgid.link/20260807064314.500742-1-l1138897701@163.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2026-08-07sctp: validate cookie AUTH state before useJérémy Jean
When cookie authentication is disabled, COOKIE_ECHO restores fixed-size AUTH fields directly from peer-controlled cookie bytes. A forged RANDOM length, HMAC list, or CHUNKS list can then reach association consumers with lengths or identifiers that were never validated against the local backing arrays. A forged RANDOM length can cause out-of-bounds reads during key-vector construction. A forged HMAC identifier also caused a 32-byte write past a zero-length AUTH chunk, providing a primitive for a local privilege escalation chain. Validate the cookie's RANDOM, HMACS, and CHUNKS parameters at the cookie trust boundary before copying them into the association. Reject invalid types, malformed lengths, unsupported HMAC identifiers, HMAC lists without SHA1, and forbidden chunk ids. Fixes: bbd0d59809f9 ("[SCTP]: Implement the receive and verification of AUTH chunk") Fixes: 1f485649f529 ("[SCTP]: Implement SCTP-AUTH internals") Signed-off-by: Jérémy Jean <Jeremy.Jean@oss.cyber.gouv.fr> Acked-by: Xin Long <lucien.xin@gmail.com> Link: https://patch.msgid.link/20260804200042.2412009-1-Jeremy.Jean@oss.cyber.gouv.fr Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-08-06Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
Cross-merge networking fixes after downstream PR (net-7.2-rc7). No conflicts, or adjacent changes. Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-08-06sctp: clear control chunk transport if it is being removedXin Long
sctp_make_heartbeat_ack() caches the destination transport in chunk->transport without taking a reference. When src_out_of_asoc_ok is enabled, the HEARTBEAT ACK may remain queued on control_chunk_list instead of being transmitted immediately. If the peer transport is removed while the chunk is still queued, sctp_assoc_rm_peer() drops the transport and schedules it for RCU freeing, but only clears cached transport pointers in out_chunk_list. The queued control chunk therefore retains a dangling transport pointer. Once an ASCONF_ACK clears the suppression and the queued control chunk is transmitted, SCTP dereferences the stale transport pointer, leading to a use-after-free. Fix this by also clearing chunk->transport for queued control chunks in control_chunk_list when removing the transport. Fixes: 8a07eb0a50ae ("sctp: Add ASCONF operation on the single-homed host") Reported-by: Daniele Linguaglossa <danielelinguaglossa@gmail.com> Signed-off-by: Xin Long <lucien.xin@gmail.com> Link: https://patch.msgid.link/7e1168cb722132152a29d47e5eafaeac4a3bf6f3.1785943120.git.lucien.xin@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-08-04sctp: fix addip_serial increment on ASCONF_ACK allocation failureQing Luo
In sctp_process_asconf(), when sctp_make_asconf_ack() fails to allocate the ASCONF_ACK chunk due to memory pressure, the code jumps to the done label where asoc->peer.addip_serial is unconditionally incremented. This leaves the peer's ASCONF (serial N) unacknowledged while the local endpoint now expects serial N+1. When the peer retransmits serial N, it falls into the serial < addip_serial + 1 branch , which attempts to look up a cached ACK for serial N. No cached ACK exists since the allocation failed, so the retransmission is silently discarded. The peer eventually times out and ABORTs the association. Move the addip_serial increment inside the if (asconf_ack) block so that the serial number is only advanced when the ASCONF_ACK is successfully created and cached. This way, on allocation failure, the serial number is unchanged and the peer's retransmitted ASCONF will be correctly re-processed. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Qing Luo <luoqing@kylinos.cn> Acked-by: Xin Long <lucien.xin@gmail.com> Link: https://patch.msgid.link/20260804025514.241767-1-l1138897701@163.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-08-03sctp: keep chunk->transport in step with the list it is queued onBaul Lee
__sctp_outq_flush_rtx() moves a gap-acked chunk onto another transport's transmitted list without updating chunk->transport: if (chunk->tsn_gap_acked) { list_move_tail(&chunk->transmitted_list, &transport->transmitted); continue; } The chunk then sits on a live transport's list while chunk->transport still names a different one. If that transport is removed - sctp_assoc_rm_peer() from an ASCONF Delete-IP - sctp_transport_free() RCU-frees it and the chunk is left with a dangling pointer. sctp_assoc_rm_peer() scrubs peer->transmitted and asoc->outqueue.out_chunk_list, but the chunk is on neither. The pointer is not followed while tsn_gap_acked is set. A SACK that reneges on the TSN clears the flag, and the next SACK reaches tchunk->transport->flight_size -= sctp_data_size(tchunk); inside the freed transport. KASAN reports a slab-use-after-free read in sctp_check_transmitted(), freed from sctp_assoc_rm_peer(). Both the removal and the SACKs come from the association peer. Set chunk->transport at the move. The ordinary resend path needs nothing: it reaches its list_move_tail() only after sctp_packet_append_chunk() returned SCTP_XMIT_OK, and __sctp_packet_append_chunk() has rebound the chunk by then. Discovered by XBOW, triaged by Baul Lee <baul.lee@xbow.com> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Signed-off-by: Baul Lee <baul.lee@xbow.com> Acked-by: Xin Long <lucien.xin@gmail.com> Link: https://patch.msgid.link/20260729160028.54546-1-baul.lee@xbow.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-07-30Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
Cross-merge networking fixes after downstream PR (net-7.2-rc6). No conflicts. Adjacent changes: net/ipv4/route.c dbc3791e3b24 ("net: do not send ICMP/NDISC Redirects when peer allocation fails") 7804eaa057fe ("ipv4: snapshot dst.dev in ip_rt_send_redirect() and ip_rt_get_source()") drivers/net/tun.c 23dad2d088df ("tun: no longer rely on RTNL in tun_fill_info()") c3da92af07ea ("Revert "tun/tap: add ptr_ring consume helper with netdev queue wakeup"") drivers/net/ethernet/marvell/octeontx2/af/rvu_npc.c 3bd438a58e91 ("octeontx2-af: Block VFs from clobbering special CGX PKIND state") 5ba5611ef946 ("octeontx2-af: reserve 4 PKINDs for skip-size custom use") drivers/net/wireless/ath/ath12k/core.h drivers/net/wireless/ath/ath12k/mac.c drivers/net/wireless/ath/ath12k/peer.c 469d7e6077c1 ("wifi: ath12k: resolve PENDING ML peer ID from MLO_PEER_MAP HTT event") 378e659029d5 ("wifi: ath12k: introduce host_alloc_ml_id hardware parameter") c42b27336eef ("wifi: ath12k: fix survey indexing across bands") Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-07-29sctp: validate Adaptation Indication parameter lengthCharles Vosburgh
The Adaptation Layer Indication parameter contains a fixed 32-bit Adaptation Code Point after its parameter header. However, sctp_verify_param() accepts a header-only parameter because the generic parameter walker only requires the header to be present. sctp_process_param() then reads adaptation_ind beyond the declared parameter. When the malformed parameter is last in an INIT, the read starts at the receive skb tail, and the value is copied into the state cookie returned in the INIT ACK. This may disclose four receive-buffer tail bytes. Require the declared parameter length to match the fixed structure size and abort the association through the existing invalid parameter length path otherwise. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Signed-off-by: Charles Vosburgh <trilobyte777@gmail.com> Acked-by: Xin Long <lucien.xin@gmail.com> Link: https://patch.msgid.link/20260727-sctp-adaptation-length-v1-1-0ab58b2810a5@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-07-29sctp: auth: discard auth_chunk when skb_clone failsQing Luo
When processing AUTH + COOKIE-ECHO packets, if skb_clone() fails due to memory pressure, chunk->auth_chunk is NULL. The original code still sets chunk->auth = 1 and continues, leaving the COOKIE-ECHO to be processed without a valid auth_chunk for deferred verification. Discard the AUTH chunk early via pdiscard when skb_clone() fails, so that the receive loop can continue processing remaining chunks in the inqueue instead of stalling the entire packet. Signed-off-by: Qing Luo <luoqing@kylinos.cn> Acked-by: Xin Long <lucien.xin@gmail.com> Link: https://patch.msgid.link/20260723061107.384106-1-l1138897701@163.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-07-27sctp: prevent peer transport count overflowAsim Viladi Oglu Manizada
sctp_assoc_add_peer() increments the association's 16-bit transport_count for every new unique peer. Adding the 65,536th transport wraps the count to zero. SCTP sock_diag uses transport_count to reserve the INET_DIAG_PEERS payload, then copies one sockaddr_storage for every entry in transport_addr_list. After the wrap, a diagnostic dump reserves an empty payload and writes 8 MiB of peer addresses past the skb tail. Reject a new unique peer when transport_count has reached U16_MAX. Perform the check after the existing-peer lookup so a duplicate address continues to return its existing transport at the limit. Fixes: 8f840e47f190 ("sctp: add the sctp_diag.c file") Cc: stable@vger.kernel.org Signed-off-by: Asim Viladi Oglu Manizada <manizada@pm.me> Acked-by: Xin Long <lucien.xin@gmail.com> Link: https://patch.msgid.link/20260725032053.521705-1-manizada@pm.me Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-07-27sctp: reject stale cookies with mismatched verification tagsYuxiang Yang
sctp_unpack_cookie() skips cookie expiration checks whenever an association already exists. This is broader than the exception in RFC 9260 Section 5.2.4. For an existing association, Section 5.2.4 permits an expired State Cookie only when both Verification Tags in the cookie match the current association. Otherwise, the packet SHOULD be discarded and a Stale Cookie ERROR MUST be sent. The broad check lets an expired Action A restart cookie reach sctp_sf_do_dupcook_a(). In a runtime test with the default 60 second cookie lifetime, replaying such a cookie after 65 seconds returned a COOKIE-ACK and restarted the association. Check cookie expiration unless both Verification Tags match. This preserves the Action D exception for a lost COOKIE ACK while rejecting expired cookies in all other cases. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Signed-off-by: Yuxiang Yang <yangyx22@mails.tsinghua.edu.cn> Acked-by: Xin Long <lucien.xin@gmail.com> Link: https://patch.msgid.link/20260723225623.2658868-1-yangyx22@mails.tsinghua.edu.cn Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-07-23sctp: don't free the ASCONF's own transport in DEL-IP processingJun Yang
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 <junvyyang@tencent.com> Acked-by: Xin Long <lucien.xin@gmail.com> Link: https://patch.msgid.link/tencent_73762ED1DF08CC9D5F5F61954B01350CFE0A@qq.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-07-22sctp: auth: verify auth requirement when auth_chunk is NULLQing Luo
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 <luoqing@kylinos.cn> Acked-by: Xin Long <lucien.xin@gmail.com> Link: https://patch.msgid.link/20260721015532.120157-2-l1138897701@163.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-07-21sctp: close UDP tunnel sockets during netns teardownZhiling Zou
proc_sctp_do_udp_port() starts per-net SCTP UDP tunneling sockets when net.sctp.udp_port is set, and stops/restarts them when the sysctl value changes. The netns exit path does not stop these sockets, so a namespace can be torn down while its SCTP UDP tunnel sockets are still installed. Close the UDP tunnel sockets from sctp_ctrlsock_exit() after unregistering the per-net sysctl table. This prevents new sysctl writes from racing in while the sockets are being released, and closes the sockets before the control socket is destroyed. Fixes: 046c052b475e ("sctp: enable udp tunneling socks") Cc: stable@vger.kernel.org Reported-by: Sashiko <sashiko-bot@kernel.org> Closes: https://sashiko.dev/#/patchset/b9f1f02b0780ad6a719e2413f5f0bb8eb7702d94.1782585631.git.roxy520tt%40gmail.com Signed-off-by: Zhiling Zou <roxy520tt@gmail.com> Signed-off-by: Ren Wei <n05ec@lzu.edu.cn> Acked-by: Xin Long <lucien.xin@gmail.com> Link: https://patch.msgid.link/6dab75f22855cb219e2e30a5497cab03b970ab91.1784033357.git.roxy520tt@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-07-21sctp: avoid auth_enable sysctl UAF during netns teardownZhiling Zou
proc_sctp_do_auth() updates the SCTP control socket after changing net.sctp.auth_enable. The handler gets the per-net SCTP state from ctl->data, so an already opened sysctl file can still target a network namespace while that namespace is being torn down. SCTP previously registered its per-net sysctls from sctp_defaults_init(), while the control socket is created later from sctp_ctrlsock_init(). This exposed a window during initialization where auth_enable was writable before net->sctp.ctl_sock existed, and a teardown window where auth_enable stayed writable after inet_ctl_sock_destroy() had released the control socket. Move the per-net SCTP sysctl registration into sctp_ctrlsock_init() after sctp_ctl_sock_init() succeeds, and unregister the sysctl table before destroying the control socket in sctp_ctrlsock_exit(). If sysctl registration fails after the control socket was created, destroy the control socket in the same init path. Make sctp_sysctl_net_unregister() tolerate a missing header and clear the saved pointer so init-error and exit paths can safely share the unregister helper. Fixes: 15649fd5415e ("sctp: sysctl: auth_enable: avoid using current->nsproxy") Cc: stable@vger.kernel.org Reported-by: Yuan Tan <yuantan098@gmail.com> Reported-by: Yifan Wu <yifanwucs@gmail.com> Reported-by: Juefei Pu <tomapufckgml@gmail.com> Reported-by: Xin Liu <bird@lzu.edu.cn> Co-developed-by: Qi Tang <tpluszz77@gmail.com> Signed-off-by: Qi Tang <tpluszz77@gmail.com> Signed-off-by: Zhiling Zou <roxy520tt@gmail.com> Signed-off-by: Ren Wei <n05ec@lzu.edu.cn> Acked-by: Xin Long <lucien.xin@gmail.com> Link: https://patch.msgid.link/390cd5e91ed60eea27b0b64d0468301a9e73b808.1784033357.git.roxy520tt@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-07-21sctp: validate stream count in sctp_process_strreset_inreq()Cen Zhang (Microsoft)
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 <lucien.xin@gmail.com> Signed-off-by: Cen Zhang (Microsoft) <blbllhy@gmail.com> Acked-by: Xin Long <lucien.xin@gmail.com> Link: https://patch.msgid.link/20260710010718.20318-1-blbllhy@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-07-21sctp: fix auth_chunk_list capacity check in sctp_auth_ep_add_chunkidHanQuan
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 <eilaimemedsnaimel@gmail.com> Acked-by: Xin Long <lucien.xin@gmail.com> Link: https://patch.msgid.link/20260713032021.3491702-1-zhoujian.zja@antgroup.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-07-10sctp: validate STALE_COOKIE cause length before reading stalenessWeiming Shi
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 <xmei5@asu.edu> Assisted-by: Claude:claude-opus-4-8 Cc: stable@vger.kernel.org Signed-off-by: Weiming Shi <bestswngs@gmail.com> Acked-by: Xin Long <lucien.xin@gmail.com> Link: https://patch.msgid.link/20260704033545.2438373-2-bestswngs@gmail.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2026-06-30sctp: fix addr_wq_timer race in sctp_free_addr_wq()Xin Long
sctp_free_addr_wq() previously removed addr_wq_timer using timer_delete() while holding addr_wq_lock. However, timer_delete() does not guarantee that a currently running timer handler has completed. This allows a race with sctp_addr_wq_timeout_handler(), where the handler may still run after addr_waitq has been freed, acquire addr_wq_lock, and access freed memory, leading to a use-after-free. Fix this by calling timer_shutdown_sync() before taking addr_wq_lock. This guarantees that any in-flight timer handler has finished and prevents the timer from being re-armed during teardown, making subsequent cleanup safe. Fixes: 4db67e808640 ("sctp: Make the address lists per network namespace") Reported-by: Sashiko <sashiko-bot@kernel.org> Signed-off-by: Xin Long <lucien.xin@gmail.com> Link: https://patch.msgid.link/5dc95f295bdb5c3f60e880dd9aa5112dc5c071cc.1782757874.git.lucien.xin@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>