From bippy-1e70cc10feda Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman To: Reply-to: , Subject: CVE-2021-47123: io_uring: fix ltout double free on completion race Description =========== In the Linux kernel, the following vulnerability has been resolved: io_uring: fix ltout double free on completion race Always remove linked timeout on io_link_timeout_fn() from the master request link list, otherwise we may get use-after-free when first io_link_timeout_fn() puts linked timeout in the fail path, and then will be found and put on master's free. The Linux kernel CVE team has assigned CVE-2021-47123 to this issue. Affected and fixed versions =========================== Issue introduced in 5.11 with commit 90cd7e424969 and fixed in 5.12.10 with commit 1f64f5e903b9 Issue introduced in 5.11 with commit 90cd7e424969 and fixed in 5.13 with commit 447c19f3b507 Please see https://www.kernel.org for a full list of currently supported kernel versions by the kernel community. Unaffected versions might change over time as fixes are backported to older supported kernel versions. The official CVE entry at https://cve.org/CVERecord/?id=CVE-2021-47123 will be updated if fixes are backported, please check that for the most up to date information about this issue. Affected files ============== The file(s) affected by this issue are: fs/io_uring.c Mitigation ========== The Linux kernel CVE team recommends that you update to the latest stable kernel version for this, and many other bugfixes. Individual changes are never tested alone, but rather are part of a larger kernel release. Cherry-picking individual commits is not recommended or supported by the Linux kernel community at all. If however, updating to the latest release is impossible, the individual changes to resolve this issue can be found at these commits: https://git.kernel.org/stable/c/1f64f5e903b9d1d157875721e02adadc9d6f0a5d https://git.kernel.org/stable/c/447c19f3b5074409c794b350b10306e1da1ef4ba