Bugzilla – Bug 1223010
VUL-0: CVE-2024-26826: kernel: mptcp: fix data re-injection from stale subflow
Last modified: 2024-07-12 16:34:35 UTC
In the Linux kernel, the following vulnerability has been resolved: mptcp: fix data re-injection from stale subflow When the MPTCP PM detects that a subflow is stale, all the packet scheduler must re-inject all the mptcp-level unacked data. To avoid acquiring unneeded locks, it first try to check if any unacked data is present at all in the RTX queue, but such check is currently broken, as it uses TCP-specific helper on an MPTCP socket. Funnily enough fuzzers and static checkers are happy, as the accessed memory still belongs to the mptcp_sock struct, and even from a functional perspective the recovery completed successfully, as the short-cut test always failed. A recent unrelated TCP change - commit d5fed5addb2b ("tcp: reorganize tcp_sock fast path variables") - exposed the issue, as the tcp field reorganization makes the mptcp code always skip the re-inection. Fix the issue dropping the bogus call: we are on a slow path, the early optimization proved once again to be evil. References: http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2024-26826 https://www.cve.org/CVERecord?id=CVE-2024-26826 https://git.kernel.org/stable/c/624902eab7abcb8731b333ec73f206d38d839cd8 https://git.kernel.org/stable/c/6673d9f1c2cd984390550dbdf7d5ae07b20abbf8 https://git.kernel.org/stable/c/6f95120f898b40d13fd441225ef511307853c9c2 https://git.kernel.org/stable/c/b609c783c535493aa3fca22c7e40a120370b1ca5 https://git.kernel.org/stable/c/b6c620dc43ccb4e802894e54b651cf81495e9598 https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2024/CVE-2024-26826.mbox https://bugzilla.redhat.com/show_bug.cgi?id=2275604