From bippy-d175d3acf727 Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman To: Reply-to: , Subject: CVE-2021-47232: can: j1939: fix Use-after-Free, hold skb ref while in use Description =========== In the Linux kernel, the following vulnerability has been resolved: can: j1939: fix Use-after-Free, hold skb ref while in use This patch fixes a Use-after-Free found by the syzbot. The problem is that a skb is taken from the per-session skb queue, without incrementing the ref count. This leads to a Use-after-Free if the skb is taken concurrently from the session queue due to a CTS. The Linux kernel CVE team has assigned CVE-2021-47232 to this issue. Affected and fixed versions =========================== Issue introduced in 5.4 with commit 9d71dd0c7009 and fixed in 5.4.128 with commit 22cba878abf6 Issue introduced in 5.4 with commit 9d71dd0c7009 and fixed in 5.10.46 with commit 509ab6bfdd0c Issue introduced in 5.4 with commit 9d71dd0c7009 and fixed in 5.12.13 with commit 1071065eeb33 Issue introduced in 5.4 with commit 9d71dd0c7009 and fixed in 5.13 with commit 2030043e616c 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-2021-47232 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: net/can/j1939/transport.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/22cba878abf646cd3a02ee7c8c2cef7afe66a256 https://git.kernel.org/stable/c/509ab6bfdd0c76daebbad0f0af07da712116de22 https://git.kernel.org/stable/c/1071065eeb33d32b7d98c2ce7591881ae7381705 https://git.kernel.org/stable/c/2030043e616cab40f510299f09b636285e0a3678