| 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-2022-49511: fbdev: defio: fix the pagelist corruption |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| fbdev: defio: fix the pagelist corruption |
| |
| Easily hit the below list corruption: |
| == |
| list_add corruption. prev->next should be next (ffffffffc0ceb090), but |
| was ffffec604507edc8. (prev=ffffec604507edc8). |
| WARNING: CPU: 65 PID: 3959 at lib/list_debug.c:26 |
| __list_add_valid+0x53/0x80 |
| CPU: 65 PID: 3959 Comm: fbdev Tainted: G U |
| RIP: 0010:__list_add_valid+0x53/0x80 |
| Call Trace: |
| <TASK> |
| fb_deferred_io_mkwrite+0xea/0x150 |
| do_page_mkwrite+0x57/0xc0 |
| do_wp_page+0x278/0x2f0 |
| __handle_mm_fault+0xdc2/0x1590 |
| handle_mm_fault+0xdd/0x2c0 |
| do_user_addr_fault+0x1d3/0x650 |
| exc_page_fault+0x77/0x180 |
| ? asm_exc_page_fault+0x8/0x30 |
| asm_exc_page_fault+0x1e/0x30 |
| RIP: 0033:0x7fd98fc8fad1 |
| == |
| |
| Figure out the race happens when one process is adding &page->lru into |
| the pagelist tail in fb_deferred_io_mkwrite(), another process is |
| re-initializing the same &page->lru in fb_deferred_io_fault(), which is |
| not protected by the lock. |
| |
| This fix is to init all the page lists one time during initialization, |
| it not only fixes the list corruption, but also avoids INIT_LIST_HEAD() |
| redundantly. |
| |
| V2: change "int i" to "unsigned int i" (Geert Uytterhoeven) |
| |
| The Linux kernel CVE team has assigned CVE-2022-49511 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.18 with commit 105a940416fc622406653b6fe54732897642dfbc and fixed in 5.18.3 with commit 6a9ae2fe887042f76fd3d334349e64e8ab3c55a2 |
| Issue introduced in 5.18 with commit 105a940416fc622406653b6fe54732897642dfbc and fixed in 5.19 with commit 856082f021a28221db2c32bd0531614a8382be67 |
| |
| 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-2022-49511 |
| 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/core/fb_defio.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/e79b2b2aadeffe1db54a6b569b9b621575c3eb07 |
| https://git.kernel.org/stable/c/6a9ae2fe887042f76fd3d334349e64e8ab3c55a2 |
| https://git.kernel.org/stable/c/856082f021a28221db2c32bd0531614a8382be67 |
