From bippy-d175d3acf727 Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman To: Reply-to: , Subject: CVE-2021-47339: media: v4l2-core: explicitly clear ioctl input data Description =========== In the Linux kernel, the following vulnerability has been resolved: media: v4l2-core: explicitly clear ioctl input data As seen from a recent syzbot bug report, mistakes in the compat ioctl implementation can lead to uninitialized kernel stack data getting used as input for driver ioctl handlers. The reported bug is now fixed, but it's possible that other related bugs are still present or get added in the future. As the drivers need to check user input already, the possible impact is fairly low, but it might still cause an information leak. To be on the safe side, always clear the entire ioctl buffer before calling the conversion handler functions that are meant to initialize them. The Linux kernel CVE team has assigned CVE-2021-47339 to this issue. Affected and fixed versions =========================== Fixed in 5.12.18 with commit dc02c0b2bd60 Fixed in 5.13.3 with commit bfb48b54db25 Fixed in 5.14 with commit 7b53cca764f9 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-2021-47339 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: drivers/media/v4l2-core/v4l2-ioctl.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/dc02c0b2bd6096f2f3ce63e1fc317aeda05f74d8 https://git.kernel.org/stable/c/bfb48b54db25c3b4ef4bef5e0691464ebc4aa335 https://git.kernel.org/stable/c/7b53cca764f9b291b7907fcd39d9e66ad728ee0b