CVE-2024-26601

En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: ext4: regenerar amigo después de que falló la liberación del bloque si se encuentra en reproducción fc. Esto revierte principalmente el commit 6bd97bf273bd ("ext4: eliminar mb_regenerate_buddy() redundante") y reintroduce mb_regenerate_buddy(). Según el código en mb_free_blocks(), la repetición de commit rápido puede terminar marcando como bloques libres que ya están marcados como tales. Esto causa corrupción en el mapa de bits del amigo, por lo que debemos regenerarlo en ese caso.

A flaw was found in the Linux kernel's ext4 filesystem related to the fast commit replay process. During this process, blocks that are already marked as free can be incorrectly marked as free again, leading to the corruption of the buddy bitmap, which is used to track free and allocated blocks. This corruption can result in filesystem inconsistencies and potential data loss. The issue is resolved by reintroducing the mb_regenerate_buddy() function, which regenerates the buddy bitmap to ensure its integrity.

In the Linux kernel, the following vulnerability has been resolved: ext4: regenerate buddy after block freeing failed if under fc replay This mostly reverts commit 6bd97bf273bd ("ext4: remove redundant mb_regenerate_buddy()") and reintroduces mb_regenerate_buddy(). Based on code in mb_free_blocks(), fast commit replay can end up marking as free blocks that are already marked as such. This causes corruption of the buddy bitmap so we need to regenerate it in that case.