| 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-2022-49419: video: fbdev: vesafb: Fix a use-after-free due early fb_info cleanup |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| video: fbdev: vesafb: Fix a use-after-free due early fb_info cleanup |
| |
| Commit b3c9a924aab6 ("fbdev: vesafb: Cleanup fb_info in .fb_destroy rather |
| than .remove") fixed a use-after-free error due the vesafb driver freeing |
| the fb_info in the .remove handler instead of doing it in .fb_destroy. |
| |
| This can happen if the .fb_destroy callback is executed after the .remove |
| callback, since the former tries to access a pointer freed by the latter. |
| |
| But that change didn't take into account that another possible scenario is |
| that .fb_destroy is called before the .remove callback. For example, if no |
| process has the fbdev chardev opened by the time the driver is removed. |
| |
| If that's the case, fb_info will be freed when unregister_framebuffer() is |
| called, making the fb_info pointer accessed in vesafb_remove() after that |
| to no longer be valid. |
| |
| To prevent that, move the expression containing the info->par to happen |
| before the unregister_framebuffer() function call. |
| |
| The Linux kernel CVE team has assigned CVE-2022-49419 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.15.41 with commit f94aa46efaa087ec075c83e4508f943fb5e43977 and fixed in 5.15.46 with commit 0fac5f8fb1bc2fc4f8714bf5e743c9cc3f547c63 |
| Issue introduced in 5.17.9 with commit a1aac13288de2935dc1a9330a93b1ac92f1e2b72 and fixed in 5.17.14 with commit f605f5558ecc175ec70016a3c15f007cb6386531 |
| Issue introduced in 5.18 with commit b3c9a924aab61adbc29df110006aa03afe1a78ba and fixed in 5.18.3 with commit d260cad015945d1f4bb9b028a096f648506106a2 |
| Issue introduced in 5.18 with commit b3c9a924aab61adbc29df110006aa03afe1a78ba and fixed in 5.19 with commit acde4003efc16480375543638484d8f13f2e99a3 |
| |
| 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-2022-49419 |
| 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/video/fbdev/vesafb.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/0fac5f8fb1bc2fc4f8714bf5e743c9cc3f547c63 |
| https://git.kernel.org/stable/c/f605f5558ecc175ec70016a3c15f007cb6386531 |
| https://git.kernel.org/stable/c/d260cad015945d1f4bb9b028a096f648506106a2 |
| https://git.kernel.org/stable/c/acde4003efc16480375543638484d8f13f2e99a3 |
