Linux Kernel up to 5.18.2 fb_deferred_io_mkwrite initialization

Summaryinfo

A vulnerability, which was classified as problematic, has been found in Linux Kernel up to 5.18.2. The impacted element is the function fb_deferred_io_mkwrite. The manipulation leads to initialization. This vulnerability is referenced as CVE-2022-49511. No exploit is available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 5.18.2 and classified as problematic. This issue affects the function fb_deferred_io_mkwrite. The manipulation with an unknown input leads to a initialization vulnerability. Using CWE to declare the problem leads to CWE-665. The product does not initialize or incorrectly initializes a resource, which might leave the resource in an unexpected state when it is accessed or used. The impact remains unknown. The summary by CVE is:

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: 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)

It is possible to read the advisory at git.kernel.org. The identification of this vulnerability is CVE-2022-49511 since 02/26/2025. The exploitation is known to be difficult. Technical details of the vulnerability are known, but there is no available exploit.

Upgrading to version 5.18.3 eliminates this vulnerability. Applying the patch e79b2b2aadeffe1db54a6b569b9b621575c3eb07/6a9ae2fe887042f76fd3d334349e64e8ab3c55a2/856082f021a28221db2c32bd0531614a8382be67 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 5.18.0
• 5.18.1
• 5.18.2

License

• open-source

Website

• Vendor: https://www.kernel.org/

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CPE 2.2info

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