| From bippy-5f407fcff5a0 Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| To: <linux-cve-announce@vger.kernel.org> |
| Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org> |
| Subject: CVE-2024-36895: usb: gadget: uvc: use correct buffer size when parsing configfs lists |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| usb: gadget: uvc: use correct buffer size when parsing configfs lists |
| |
| This commit fixes uvc gadget support on 32-bit platforms. |
| |
| Commit 0df28607c5cb ("usb: gadget: uvc: Generalise helper functions for |
| reuse") introduced a helper function __uvcg_iter_item_entries() to aid |
| with parsing lists of items on configfs attributes stores. This function |
| is a generalization of another very similar function, which used a |
| stack-allocated temporary buffer of fixed size for each item in the list |
| and used the sizeof() operator to check for potential buffer overruns. |
| The new function was changed to allocate the now variably sized temp |
| buffer on heap, but wasn't properly updated to also check for max buffer |
| size using the computed size instead of sizeof() operator. |
| |
| As a result, the maximum item size was 7 (plus null terminator) on |
| 64-bit platforms, and 3 on 32-bit ones. While 7 is accidentally just |
| barely enough, 3 is definitely too small for some of UVC configfs |
| attributes. For example, dwFrameInteval, specified in 100ns units, |
| usually has 6-digit item values, e.g. 166666 for 60fps. |
| |
| The Linux kernel CVE team has assigned CVE-2024-36895 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 6.3 with commit 0df28607c5cb4fe60bba591e9858a8f7ba39aa4a and fixed in 6.6.31 with commit 7a54e5052bde582fd0e7677334fe7a5be92e242c |
| Issue introduced in 6.3 with commit 0df28607c5cb4fe60bba591e9858a8f7ba39aa4a and fixed in 6.8.10 with commit a422089ce42ced73713e5032aad29a9a7cbe9528 |
| Issue introduced in 6.3 with commit 0df28607c5cb4fe60bba591e9858a8f7ba39aa4a and fixed in 6.9 with commit 650ae71c80749fc7cb8858c8049f532eaec64410 |
| |
| 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-2024-36895 |
| 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/usb/gadget/function/uvc_configfs.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/7a54e5052bde582fd0e7677334fe7a5be92e242c |
| https://git.kernel.org/stable/c/a422089ce42ced73713e5032aad29a9a7cbe9528 |
| https://git.kernel.org/stable/c/650ae71c80749fc7cb8858c8049f532eaec64410 |
