From bippy-d175d3acf727 Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman To: Reply-to: , Subject: CVE-2024-35880: io_uring/kbuf: hold io_buffer_list reference over mmap Description =========== In the Linux kernel, the following vulnerability has been resolved: io_uring/kbuf: hold io_buffer_list reference over mmap If we look up the kbuf, ensure that it doesn't get unregistered until after we're done with it. Since we're inside mmap, we cannot safely use the io_uring lock. Rely on the fact that we can lookup the buffer list under RCU now and grab a reference to it, preventing it from being unregistered until we're done with it. The lookup returns the io_buffer_list directly with it referenced. The Linux kernel CVE team has assigned CVE-2024-35880 to this issue. Affected and fixed versions =========================== Issue introduced in 6.6.5 with commit 09f7520048ea and fixed in 6.6.26 with commit 65938e81df21 Issue introduced in 6.7 with commit 5cf4f52e6d8a and fixed in 6.8.5 with commit 5fd8e2359498 Issue introduced in 6.7 with commit 5cf4f52e6d8a and fixed in 6.9 with commit 561e4f9451d6 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-2024-35880 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: io_uring/io_uring.c io_uring/kbuf.c io_uring/kbuf.h 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/65938e81df2197203bda4b9a0c477e7987218d66 https://git.kernel.org/stable/c/5fd8e2359498043e0b5329a05f02d10a9eb91eb9 https://git.kernel.org/stable/c/561e4f9451d65fc2f7eef564e0064373e3019793