Use After Free Affecting kernel-doc package, versions *
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Test your applications- Snyk ID SNYK-RHEL8-KERNELDOC-6338286
- published 29 Feb 2024
- disclosed 28 Feb 2024
Introduced: 28 Feb 2024
CVE-2021-46999 Open this link in a new tabHow to fix?
There is no fixed version for RHEL:8 kernel-doc.
NVD Description
Note: Versions mentioned in the description apply only to the upstream kernel-doc package and not the kernel-doc package as distributed by RHEL.
See How to fix? for RHEL:8 relevant fixed versions and status.
In the Linux kernel, the following vulnerability has been resolved:
sctp: do asoc update earlier in sctp_sf_do_dupcook_a
There's a panic that occurs in a few of envs, the call trace is as below:
[] general protection fault, ... 0x29acd70f1000a: 0000 [#1] SMP PTI [] RIP: 0010:sctp_ulpevent_notify_peer_addr_change+0x4b/0x1fa [sctp] [] sctp_assoc_control_transport+0x1b9/0x210 [sctp] [] sctp_do_8_2_transport_strike.isra.16+0x15c/0x220 [sctp] [] sctp_cmd_interpreter.isra.21+0x1231/0x1a10 [sctp] [] sctp_do_sm+0xc3/0x2a0 [sctp] [] sctp_generate_timeout_event+0x81/0xf0 [sctp]
This is caused by a transport use-after-free issue. When processing a duplicate COOKIE-ECHO chunk in sctp_sf_do_dupcook_a(), both COOKIE-ACK and SHUTDOWN chunks are allocated with the transort from the new asoc. However, later in the sideeffect machine, the old asoc is used to send them out and old asoc's shutdown_last_sent_to is set to the transport that SHUTDOWN chunk attached to in sctp_cmd_setup_t2(), which actually belongs to the new asoc. After the new_asoc is freed and the old asoc T2 timeout, the old asoc's shutdown_last_sent_to that is already freed would be accessed in sctp_sf_t2_timer_expire().
Thanks Alexander and Jere for helping dig into this issue.
To fix it, this patch is to do the asoc update first, then allocate the COOKIE-ACK and SHUTDOWN chunks with the 'updated' old asoc. This would make more sense, as a chunk from an asoc shouldn't be sent out with another asoc. We had fixed quite a few issues caused by this.
References
- https://access.redhat.com/security/cve/CVE-2021-46999
- https://git.kernel.org/stable/c/0bfd913c2121b3d553bfd52810fe6061d542d625
- https://git.kernel.org/stable/c/35b4f24415c854cd718ccdf38dbea6297f010aae
- https://git.kernel.org/stable/c/61b877bad9bb0d82b7d8841be50872557090a704
- https://git.kernel.org/stable/c/b1b31948c0af44628e43353828453461bb74098f
- https://git.kernel.org/stable/c/d624f2991b977821375fbd56c91b0c91d456a697
- https://git.kernel.org/stable/c/f01988ecf3654f805282dce2d3bb9afe68d2691e