In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
ntfs: avoid stale runlist element dereference in MFT writeback<\/p>\n
ntfs_write_mft_block() maps each $MFT record through the $MFT data
\nrunlist. For sub-folio clusters it looks up a struct runlist_element under
\nni->runlist.lock, drops the lock, and later uses rl->length and rl->vcn
\nwhen choosing folio_sz.<\/p>\n
That pointer is only borrowed from ni->runlist.rl. Concurrent $MFT
\nallocation extension can merge a replacement runlist under the same lock,
\nand ntfs_rl_realloc() can free the old backing array. If that happens
\nbetween the lookup and the later folio_sz decision, writeback can
\ndereference freed runlist storage.<\/p>\n
The buggy scenario involves two paths, with each column showing the order
\nwithin that path:<\/p>\n
MFT writeback path: $MFT allocation extension:
\n1. Look up rl under 1. Extend the $MFT data allocation.
\n ni->runlist.lock. 2. Publish a replacement runlist.
\n2. Drop ni->runlist.lock. 3. Free the old runlist array.
\n3. Read rl->length and rl->vcn
\n to choose folio_sz.<\/p>\n
Compute the remaining run length while ni->runlist.lock is still held, and
\nuse that scalar after unlock. This preserves the existing folio sizing
\ndecision without carrying a borrowed runlist_element across the lock
\nboundary.<\/p>\n
Validation reproduced this kernel report:
\nBUG: KASAN: slab-use-after-free in ntfs_mft_writepages+0x1c8d\/0x1fb0<\/p>\n
Call Trace:<\/p>\n
dump_stack_lvl+0x66\/0xa0
\n print_report+0xce\/0x630
\n ? ntfs_mft_writepages+0x1c8d\/0x1fb0
\n ? srso_alias_return_thunk+0x5\/0xfbef5
\n ? __virt_addr_valid+0x20d\/0x410
\n ? ntfs_mft_writepages+0x1c8d\/0x1fb0
\n kasan_report+0xe0\/0x110
\n ? ntfs_mft_writepages+0x1c8d\/0x1fb0
\n ntfs_mft_writepages+0x1c8d\/0x1fb0
\n ? __pfx_ntfs_mft_writepages+0x10\/0x10
\n ? __pfx___mutex_unlock_slowpath+0x10\/0x10
\n ? srso_alias_return_thunk+0x5\/0xfbef5
\n ? iput+0x92\/0xa80
\n do_writepages+0x219\/0x530
\n ? __pfx_do_writepages+0x10\/0x10
\n __writeback_single_inode+0x117\/0xf50
\n ? do_raw_spin_lock+0x130\/0x270
\n ? __pfx_do_raw_spin_lock+0x10\/0x10
\n ? __pfx___writeback_single_inode+0x10\/0x10
\n ? srso_alias_return_thunk+0x5\/0xfbef5
\n writeback_sb_inodes+0x65b\/0x1810
\n ? srso_alias_return_thunk+0x5\/0xfbef5
\n ? lock_acquire+0x2b8\/0x2f0
\n ? __pfx_writeback_sb_inodes+0x10\/0x10
\n ? lock_release+0x1e0\/0x280
\n ? _raw_spin_unlock+0x23\/0x40
\n ? move_expired_inodes+0x2b8\/0x850
\n __writeback_inodes_wb+0xf4\/0x270
\n ? __pfx___writeback_inodes_wb+0x10\/0x10
\n ? srso_alias_return_thunk+0x5\/0xfbef5
\n ? queue_io+0x2e4\/0x410
\n wb_writeback+0x666\/0x880
\n ? srso_alias_return_thunk+0x5\/0xfbef5
\n ? __pfx_wb_writeback+0x10\/0x10
\n ? srso_alias_return_thunk+0x5\/0xfbef5
\n ? srso_alias_return_thunk+0x5\/0xfbef5
\n ? get_nr_dirty_inodes+0x1c\/0x170
\n wb_workfn+0x75e\/0xbb0
\n ? srso_alias_return_thunk+0x5\/0xfbef5
\n ? _raw_spin_unlock_irqrestore+0x27\/0x60
\n ? __pfx_wb_workfn+0x10\/0x10
\n ? __pfx_debug_object_deactivate+0x10\/0x10
\n ? lock_acquire+0x2b8\/0x2f0
\n ? srso_alias_return_thunk+0x5\/0xfbef5
\n ? lock_release+0x1e0\/0x280
\n process_one_work+0x8d0\/0x1870
\n ? __pfx_process_one_work+0x10\/0x10
\n ? srso_alias_return_thunk+0x5\/0xfbef5
\n worker_thread+0x575\/0xf80
\n ? __pfx_worker_thread+0x10\/0x10
\n kthread+0x2e7\/0x3c0
\n ? __pfx_kthread+0x10\/0x10
\n ret_from_fork+0x576\/0x810
\n ? __pfx_ret_from_fork+0x10\/0x10
\n ? srso_alias_return_thunk+0x5\/0xfbef5
\n ? __switch_to+0x57e\/0xe10
\n ? __switch_to_asm+0x33\/0x70
\n ? __pfx_kthread+0x10\/0x10
\n ret_from_fork_asm+0x1a\/0x30<\/p>\n
Allocated by task 970:
\n kasan_save_stack+0x33\/0x60
\n kasan_save_track+0x14\/0x30
\n __kasan_kmalloc+0xaa\/0xb0
\n __kvmalloc_node_noprof+0x353\/0x920
\n ntfs_rl_realloc+0x3c\/0x80
\n ntfs_runlists_merge+0x1212\/0x3010
\n ntfs_mft_data_extend_allocation_nolock+0x3e0\/0x1f40
\n ntfs_mft_record_alloc+0x1ab4\/0x4f10
\n __ntfs_create+0x680\/0x2e50
\n ntfs_create+0x1e6\/0x3a0
\n path_openat+0x2b55\/0x3c10
\n do_file_open+0x1f4\/0x460
\n do_sys_openat2+0xde\/0x170
\n __x64_sys_openat+0x122\/0x1e0
\n do_syscall_64+0x115\/0x6a0
\n entry_SYSCALL_64_after_hwframe+0x77\/0x7f<\/p>\n
Freed by task 1294:
\n kasan_save_
\n—truncated—<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
ntfs: avoid stale runlist element dereference in MFT writeback<\/p>\n
ntfs_write_mft_block() maps each $MFT record through the $MFT data<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-6989","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/6989","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln"}],"about":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/types\/vuln"}],"wp:attachment":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=6989"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=6989"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=6989"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}