CVE-2026-23125

Description

In the Linux kernel, the following vulnerability has been resolved:sctp: move SCTP_CMD_ASSOC_SHKEY right after SCTP_CMD_PEER_INITA null-ptr-deref was reported in the SCTP transmit path when SCTP-AUTH keyinitialization fails: ================================================================== KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f] CPU: 0 PID: 16 Comm: ksoftirqd/0 Tainted: G W 6.6.0 #2 RIP: 0010:sctp_packet_bundle_auth net/sctp/output.c:264 [inline] RIP: 0010:sctp_packet_append_chunk+0xb36/0x1260 net/sctp/output.c:401 Call Trace: sctp_packet_transmit_chunk+0x31/0x250 net/sctp/output.c:189 sctp_outq_flush_data+0xa29/0x26d0 net/sctp/outqueue.c:1111 sctp_outq_flush+0xc80/0x1240 net/sctp/outqueue.c:1217 sctp_cmd_interpreter.isra.0+0x19a5/0x62c0 net/sctp/sm_sideeffect.c:1787 sctp_side_effects net/sctp/sm_sideeffect.c:1198 [inline] sctp_do_sm+0x1a3/0x670 net/sctp/sm_sideeffect.c:1169 sctp_assoc_bh_rcv+0x33e/0x640 net/sctp/associola.c:1052 sctp_inq_push+0x1dd/0x280 net/sctp/inqueue.c:88 sctp_rcv+0x11ae/0x3100 net/sctp/input.c:243 sctp6_rcv+0x3d/0x60 net/sctp/ipv6.c:1127The issue is triggered when sctp_auth_asoc_init_active_key() fails insctp_sf_do_5_1C_ack() while processing an INIT_ACK. In this case, thecommand sequence is currently:- SCTP_CMD_PEER_INIT- SCTP_CMD_TIMER_STOP (T1_INIT)- SCTP_CMD_TIMER_START (T1_COOKIE)- SCTP_CMD_NEW_STATE (COOKIE_ECHOED)- SCTP_CMD_ASSOC_SHKEY- SCTP_CMD_GEN_COOKIE_ECHOIf SCTP_CMD_ASSOC_SHKEY fails, asoc->shkey remains null, whileasoc->peer.auth_capable and asoc->peer.peer_chunks have already been set bySCTP_CMD_PEER_INIT. This allows a DATA chunk with auth = 1 and shkey = nullto be queued by sctp_datamsg_from_user().Since command interpretation stops on failure, no COOKIE_ECHO should beensent via SCTP_CMD_GEN_COOKIE_ECHO. However, the T1_COOKIE timer has alreadybeen started, and it may enqueue a COOKIE_ECHO into the outqueue later. Asa result, the DATA chunk can be transmitted together with the COOKIE_ECHOin sctp_outq_flush_data(), leading to the observed issue.Similar to the other places where it calls sctp_auth_asoc_init_active_key()right after sctp_process_init(), this patch moves the SCTP_CMD_ASSOC_SHKEYimmediately after SCTP_CMD_PEER_INIT, before stopping T1_INIT and startingT1_COOKIE. This ensures that if shared key generation fails, authenticatedDATA cannot be sent. It also allows the T1_INIT timer to retransmit INIT,giving the client another chance to process INIT_ACK and retry key setup.

Risk Information

Associated Vulnerability

Patch Details

References

https://nvd.nist.gov/vuln/detail/CVE-2023-1234
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-1234