CVE-2022-49880 in Linux
Zusammenfassung
von VulDB • 05.06.2026
Im Linux-Kernel wurde folgende Schwachstelle behoben:
ext4: Warnung in 'ext4_da_release_space' beheben
Der Syzkaller-Bericht weist das folgende Problem aus: EXT4-fs (loop0): Details zu freien/schmutzigen Blöcken EXT4-fs (loop0): free_blocks=0 EXT4-fs (loop0): dirty_blocks=0 EXT4-fs (loop0): Details zur Blockzuweisung EXT4-fs (loop0): ext4_es_remove_extent: block 0, len 1, flags 0x1 EXT4-fs (loop0): ext4_es_remove_extent: block 0, len 1, flags 0x1 WARNING: CPU: 0 PID: 10000 at fs/ext4/extents_status.c:1461 ext4_es_remove_extent+0x1ab/0x260 fs/ext4/extents_status.c:1461 RIP: 0010:ext4_es_remove_extent+0x1ab/0x260 fs/ext4/extents_status.c:1461 Call Trace: mpage_release_unused_pages+0x24d/0xef0 fs/ext4/inode.c:1589 ext4_writepages+0x12eb/0x3be0 fs/ext4/inode.c:2852 do_writepages+0x3c3/0x680 mm/page-writeback.c:2469 __writeback_single_inode+0xd1/0x670 fs/fs-writeback.c:1587 writeback_sb_inodes+0xb3b/0x18f0 fs/fs-writeback.c:1870 wb_writeback+0x41f/0x7b0 fs/fs-writeback.c:2044 wb_do_writeback fs/fs-writeback.c:2187 [inline]
wb_workfn+0x3cb/0xef0 fs/fs-writeback.c:2227 process_one_work+0x877/0xdb0 kernel/workqueue.c:2289 worker_thread+0xb14/0x1330 kernel/workqueue.c:2436 kthread+0x266/0x300 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
Dieses Problem kann wie folgt auftreten: ext4_da_write_begin ext4_create_inline_data ext4_clear_inode_flag(inode, EXT4_INODE_EXTENTS); ext4_set_inode_flag(inode, EXT4_INODE_INLINE_DATA); __ext4_ioctl ext4_ext_migrate -> führt dazu, dass eh->eh_entries nicht null ist, und setzt das Extent-Flag ext4_da_write_begin ext4_da_convert_inline_data_to_extent ext4_da_write_inline_data_begin ext4_da_map_blocks ext4_insert_delayed_block if (!ext4_es_scan_clu(inode, &ext4_es_is_delonly, lblk)) if (!ext4_es_scan_clu(inode, &ext4_es_is_mapped, lblk)) ext4_clu_mapped(inode, EXT4_B2C(sbi, lblk)); -> gibt 1 zurück allocated = true; ext4_es_insert_delayed_block(inode, lblk, allocated); ext4_writepages mpage_map_and_submit_extent(handle, &mpd, &give_up_on_write); -> gibt -ENOSPC zurück mpage_release_unused_pages(&mpd, give_up_on_write); -> give_up_on_write == 1 ext4_es_remove_extent ext4_da_release_space(inode, reserved); if (unlikely(to_free > ei->i_reserved_data_blocks)) -> to_free == 1, aber ei->i_reserved_data_blocks == 0 -> löst dann die obige Warnung aus
Um dieses Problem zu lösen, wird das Migrieren von Inodes mit Inline-Daten verboten.
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