Description
In the Linux kernel, the following vulnerability has been resolved: sctp: stop processing a packet once its association is deleted 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.
Affected products
Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.
Linux Linux
Default version status: unaffected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < 7d970353eeb98f46a3b9dc602850e4f6336a9889affected1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < 09c3b193a3e8fe53e1f416e2f8e3283d2a785405affected1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < ed85fe91a61bc0e0da6b585c07102b20f4cc65a0affected1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < 5c0b2dbbdafc9eeeb11fffe1e46551fc3b55d8eeaffected1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < ee3f04cf566f6041aa9a0360494fd8db5ade383aaffected1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < fa306a40e716c5abcd967475459ce1ebd56e5115affected1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < a713e1b3a265f180ad25a08e17be15d67a2f7149affected1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < 47e15a8d12e366d0d261bcbc394394f44418938daffected
Linux Linux
Default version status: affected
2.6.12affected0 to < 2.6.12unaffected5.10.270 to ≤ 5.10.*unaffected5.15.221 to ≤ 5.15.*unaffected6.1.188 to ≤ 6.1.*unaffected6.6.157 to ≤ 6.6.*unaffected6.12.109 to ≤ 6.12.*unaffected6.18.50 to ≤ 6.18.*unaffected7.2.4 to ≤ 7.2.*unaffected7.3 to ≤ *unaffected
References
- https://git.kernel.org/stable/c/7d970353eeb98f46a3b9dc602850e4f6336a9889 ↗
- https://git.kernel.org/stable/c/09c3b193a3e8fe53e1f416e2f8e3283d2a785405 ↗
- https://git.kernel.org/stable/c/ed85fe91a61bc0e0da6b585c07102b20f4cc65a0 ↗
- https://git.kernel.org/stable/c/5c0b2dbbdafc9eeeb11fffe1e46551fc3b55d8ee ↗
- https://git.kernel.org/stable/c/ee3f04cf566f6041aa9a0360494fd8db5ade383a ↗
- https://git.kernel.org/stable/c/fa306a40e716c5abcd967475459ce1ebd56e5115 ↗
- https://git.kernel.org/stable/c/a713e1b3a265f180ad25a08e17be15d67a2f7149 ↗
- https://git.kernel.org/stable/c/47e15a8d12e366d0d261bcbc394394f44418938d ↗