In the Linux kernel, the following vulnerability has been resolved: ntfs: fix use-after-free in ntfs_attr_find() Patch series "ntfs: fix bugs about Attribute", v2. This patchset fixes three bugs relative to Attribute in record: Patch 1 adds a sanity check to ensure that, attrs_offset field in first mft record loading from disk is within bounds. Patch 2 moves the ATTR_RECORD's bounds checking earlier, to avoid dereferencing ATTR_RECORD before checking this ATTR_RECORD is within bounds. Patch 3 adds an overflow checking to avoid possible forever loop in ntfs_attr_find(). Without patch 1 and patch 2, the kernel triggersa KASAN use-after-free detection as reported by Syzkaller. Although one of patch 1 or patch 2 can fix this, we still need both of them. Because patch 1 fixes the root cause, and patch 2 not only fixes the direct cause, but also fixes the potential out-of-bounds bug. This patch (of 3): Syzkaller reported use-after-free read as follows: ================================================================== BUG: KASAN: use-after-free in ntfs_attr_find+0xc02/0xce0 fs/ntfs/attrib.c:597 Read of size 2 at addr ffff88807e352009 by task syz-executor153/3607 [...] Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:317 [inline] print_report.cold+0x2ba/0x719 mm/kasan/report.c:433 kasan_report+0xb1/0x1e0 mm/kasan/report.c:495 ntfs_attr_find+0xc02/0xce0 fs/ntfs/attrib.c:597 ntfs_attr_lookup+0x1056/0x2070 fs/ntfs/attrib.c:1193 ntfs_read_inode_mount+0x89a/0x2580 fs/ntfs/inode.c:1845 ntfs_fill_super+0x1799/0x9320 fs/ntfs/super.c:2854 mount_bdev+0x34d/0x410 fs/super.c:1400 legacy_get_tree+0x105/0x220 fs/fs_context.c:610 vfs_get_tree+0x89/0x2f0 fs/super.c:1530 do_new_mount fs/namespace.c:3040 [inline] path_mount+0x1326/0x1e20 fs/namespace.c:3370 do_mount fs/namespace.c:3383 [inline] __do_sys_mount fs/namespace.c:3591 [inline] __se_sys_mount fs/namespace.c:3568 [inline] __x64_sys_mount+0x27f/0x300 fs/namespace.c:3568 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd [...] </TASK> The buggy address belongs to the physical page: page:ffffea0001f8d400 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7e350 head:ffffea0001f8d400 order:3 compound_mapcount:0 compound_pincount:0 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 0000000000000000 dead000000000122 ffff888011842140 raw: 0000000000000000 0000000000040004 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88807e351f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88807e351f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88807e352000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88807e352080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88807e352100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== Kernel will loads $MFT/$DATA's first mft record in ntfs_read_inode_mount(). Yet the problem is that after loading, kernel doesn't check whether attrs_offset field is a valid value. To be more specific, if attrs_offset field is larger than bytes_allocated field, then it may trigger the out-of-bounds read bug(reported as use-after-free bug) in ntfs_attr_find(), when kernel tries to access the corresponding mft record's attribute. This patch solves it by adding the sanity check between attrs_offset field and bytes_allocated field, after loading the first mft record.
History

Tue, 17 Jun 2025 16:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-416
Metrics cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

cvssV3_1

{'score': 7.8, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'}


Fri, 02 May 2025 13:45:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate


Thu, 01 May 2025 14:30:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: ntfs: fix use-after-free in ntfs_attr_find() Patch series "ntfs: fix bugs about Attribute", v2. This patchset fixes three bugs relative to Attribute in record: Patch 1 adds a sanity check to ensure that, attrs_offset field in first mft record loading from disk is within bounds. Patch 2 moves the ATTR_RECORD's bounds checking earlier, to avoid dereferencing ATTR_RECORD before checking this ATTR_RECORD is within bounds. Patch 3 adds an overflow checking to avoid possible forever loop in ntfs_attr_find(). Without patch 1 and patch 2, the kernel triggersa KASAN use-after-free detection as reported by Syzkaller. Although one of patch 1 or patch 2 can fix this, we still need both of them. Because patch 1 fixes the root cause, and patch 2 not only fixes the direct cause, but also fixes the potential out-of-bounds bug. This patch (of 3): Syzkaller reported use-after-free read as follows: ================================================================== BUG: KASAN: use-after-free in ntfs_attr_find+0xc02/0xce0 fs/ntfs/attrib.c:597 Read of size 2 at addr ffff88807e352009 by task syz-executor153/3607 [...] Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:317 [inline] print_report.cold+0x2ba/0x719 mm/kasan/report.c:433 kasan_report+0xb1/0x1e0 mm/kasan/report.c:495 ntfs_attr_find+0xc02/0xce0 fs/ntfs/attrib.c:597 ntfs_attr_lookup+0x1056/0x2070 fs/ntfs/attrib.c:1193 ntfs_read_inode_mount+0x89a/0x2580 fs/ntfs/inode.c:1845 ntfs_fill_super+0x1799/0x9320 fs/ntfs/super.c:2854 mount_bdev+0x34d/0x410 fs/super.c:1400 legacy_get_tree+0x105/0x220 fs/fs_context.c:610 vfs_get_tree+0x89/0x2f0 fs/super.c:1530 do_new_mount fs/namespace.c:3040 [inline] path_mount+0x1326/0x1e20 fs/namespace.c:3370 do_mount fs/namespace.c:3383 [inline] __do_sys_mount fs/namespace.c:3591 [inline] __se_sys_mount fs/namespace.c:3568 [inline] __x64_sys_mount+0x27f/0x300 fs/namespace.c:3568 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd [...] </TASK> The buggy address belongs to the physical page: page:ffffea0001f8d400 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7e350 head:ffffea0001f8d400 order:3 compound_mapcount:0 compound_pincount:0 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 0000000000000000 dead000000000122 ffff888011842140 raw: 0000000000000000 0000000000040004 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88807e351f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88807e351f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88807e352000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88807e352080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88807e352100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== Kernel will loads $MFT/$DATA's first mft record in ntfs_read_inode_mount(). Yet the problem is that after loading, kernel doesn't check whether attrs_offset field is a valid value. To be more specific, if attrs_offset field is larger than bytes_allocated field, then it may trigger the out-of-bounds read bug(reported as use-after-free bug) in ntfs_attr_find(), when kernel tries to access the corresponding mft record's attribute. This patch solves it by adding the sanity check between attrs_offset field and bytes_allocated field, after loading the first mft record.
Title ntfs: fix use-after-free in ntfs_attr_find()
References

cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published: 2025-05-01T14:09:03.607Z

Updated: 2025-05-04T08:44:51.803Z

Reserved: 2025-04-16T07:17:33.804Z

Link: CVE-2022-49763

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2025-05-01T15:15:59.047

Modified: 2025-05-02T13:53:20.943

Link: CVE-2022-49763

cve-icon Redhat

Severity : Moderate

Publid Date: 2025-05-01T00:00:00Z

Links: CVE-2022-49763 - Bugzilla