Vulnerabilidad en kernel de Linux (CVE-2024-26658)

En el kernel de Linux, se resolvió la siguiente vulnerabilidad: bcachefs: toma s_umount solo si se toma una instantánea Cuando estaba probando mongodb sobre bcachefs con compresión, hay una advertencia de lockdep al tomar una instantánea del volumen de datos de mongodb. $ cat test.sh prog=bcachefs $prog subvolumen crear /mnt/data $prog subvolumen crear /mnt/data/snapshots mientras es verdadero;do $prog subvolumen snapshot /mnt/data /mnt/data/snapshots/$(fecha +% s) dormir 1 hecho $ cat /etc/mongodb.conf systemLog: destino: archivo logAppend: verdadera ruta: /mnt/data/mongod.log almacenamiento: dbPath: /mnt/data/ lockdep informes: [3437.452330] ==== ==================================================== [ 3437.452750] ADVERTENCIA: posible dependencia de bloqueo circular detectada [ 3437.453168] 6.7.0-rc7-custom+ #85 Contaminado: GE [ 3437.453562] ---------------------- -------------------------------- [ 3437.453981] bcachefs/35533 está intentando adquirir el bloqueo: [ 3437.454325] ffffa0a02b2b1418 (sb_writers #10){.+.+}-{0:0}, en: filename_create+0x62/0x190 [ 3437.454875] pero la tarea ya mantiene el bloqueo: [ 3437.455268] ffffa0a02b2b10e0 (&type->s_umount_key#48){.+.+ }-{3:3}, en: bch2_fs_file_ioctl+0x232/0xc90 [bcachefs] [ 3437.456009] cuyo bloqueo ya depende del nuevo bloqueo. [ 3437.456553] la cadena de dependencia existente (en orden inverso) es: [ 3437.457054] -> #3 (&type->s_umount_key#48){.+.+}-{3:3}: [ 3437.457507] down_read+0x3e/0x170 [ 3437.457772] bch2_fs_file_ioctl+0x232/0xc90 [bcachefs] [ 3437.458206] __x64_sys_ioctl+0x93/0xd0 [ 3437.458498] do_syscall_64+0x42/0xf0 [ 3437.458 779] Entry_SYSCALL_64_after_hwframe+0x6e/0x76 [3437.459155] -> #2 (&c->snapshot_create_lock){+ +++}-{3:3}: [ 3437.459615] down_read+0x3e/0x170 [ 3437.459878] bch2_truncate+0x82/0x110 [bcachefs] [ 3437.460276] bchfs_truncate+0x254/0x3c0 [bcachefs] [ 3437.4 60686] notificar_cambio+0x1f1/0x4a0 [ 3437.461283] do_truncate+0x7f/0xd0 [ 3437.461555] path_openat+0xa57/0xce0 [ 3437.461836] do_filp_open+0xb4/0x160 [ 3437.462116] do_sys_openat2+0x91/0xc0 [ 34 37.462402] __x64_sys_openat+0x53/0xa0 [ 3437.462701] do_syscall_64+0x42/0xf0 [ 3437.462982] Entry_SYSCALL_64_after_hwframe+0x6e/0x76 [ 3437.463359] -> #1 (&sb->s_type->i_mutex_key#15){+.+.}-{3:3}: [ 3437.463843] down_write+0x3b/0xc0 [ 3437.464223] bch2_write_it e+0x5b /0xcc0 [bcachefs] [ 3437.464493] vfs_write+0x21b/0x4c0 [ 3437.464653] ksys_write+0x69/0xf0 [ 3437.464839] do_syscall_64+0x42/0xf0 [ 3437.465009] entrada_SYSCALL _64_after_hwframe+0x6e/0x76 [ 3437.465231] -> #0 (sb_writers#10){ .+.+}-{0:0}: [ 3437.465471] __lock_acquire+0x1455/0x21b0 [ 3437.465656] lock_acquire+0xc6/0x2b0 [ 3437.465822] mnt_want_write+0x46/0x1a0 [ 3437.465996] nombre de archivo _create+0x62/0x190 [ 3437.466175] ruta_usuario_create+0x2d /0x50 [ 3437.466352] bch2_fs_file_ioctl+0x2ec/0xc90 [bcachefs] [ 3437.466617] __x64_sys_ioctl+0x93/0xd0 [ 3437.466791] do_syscall_64+0x42/0xf0 [ 3437 .466957] Entry_SYSCALL_64_after_hwframe+0x6e/0x76 [ 3437.467180] otra información que podría ayudarnos a depurar esto: [ 3437.469670] 2 bloqueos mantenidos por bcachefs/35533: otra información que podría ayudarnos a depurar esto: [3437.467507] Existe cadena de: sb_writers#10 --> &c->snapshot_create_lock --> &type->s_umount_key#48 [3437.467979] Posiblemente inseguro escenario de bloqueo: [3437.468223] CPU0 CPU1 [3437.468405] ---- ---- [3437.468585] rlock(&type->s_umount_key#48); [ 3437.468758] bloqueo(&c->snapshot_create_lock); [ 3437.469030] bloqueo(&type->s_umount_key#48); [3437.469291] rlock(sb_writers#10); [ 3437.469434] *** INTERBLOQUEO *** [ 3437.469 ---truncado---