The Linux kernel plays a crucial role in the operating system's function and stability. Recently, a vulnerability (CVE-2021-46999) was discovered and resolved in the Linux kernel's Stream Control Transmission Protocol (SCTP) module, specifically in sctp_sf_do_dupcook_a. This vulnerability was causing panic in some environments, potentially leading to a use-after-free issue and crashing the system.
[] general protection fault, ... x29acd70f100a: 000 [#1] SMP PTI
[] RIP: 001:sctp_ulpevent_notify_peer_addr_change+x4b/x1fa [sctp]
[] sctp_assoc_control_transport+x1b9/x210 [sctp]
[] sctp_do_8_2_transport_strike.isra.16+x15c/x220 [sctp]
[] sctp_cmd_interpreter.isra.21+x1231/x1a10 [sctp]
[] sctp_do_sm+xc3/x2a [sctp]
[] sctp_generate_timeout_event+x81/xf [sctp]
The underlying issue seemed to be related to the processing of a duplicate COOKIE-ECHO chunk in the function sctp_sf_do_dupcook_a(). When this happened, the COOKIE-ACK and SHUTDOWN chunks were allocated with the transport from the new asoc. However, later in the sideeffect machine, the old asoc was used to send these chunks, causing the use-after-free problem.
The solution proposed to resolve this vulnerability is to update the asoc first, and then allocate the COOKIE-ACK and SHUTDOWN chunks with the 'updated' old asoc. This would allow a chunk from an asoc to be sent out with the correct association and reduce the chance of causing issues in the future.
This issue was tackled with the help of Alexander and Jere, who collaborated in identifying the cause of the issue and proposing the appropriate patch to fix it.
The updated code snippet for this patch is not available in this post. However, for more information about the vulnerability and related updates, you can refer to the Linux kernel's GitHub repository, mailing list, or related blog posts.
In conclusion, the Linux kernel vulnerability CVE-2021-46999 has been resolved. It is essential to keep your systems up to date by applying kernel updates and patches as they become available. Doing so will ensure the stability and security of your Linux-based systems.
Timeline
Published on: 02/28/2024 09:15:38 UTC
Last modified on: 02/28/2024 14:06:45 UTC