CVE-2021-46989

hfsplus: prevent corruption in shrinking truncate

7.1 HighFix available

In the Linux kernel, the following vulnerability has been resolved:

hfsplus: prevent corruption in shrinking truncate

I believe there are some issues introduced by commit 31651c607151 ("hfsplus: avoid deadlock on file truncation")

HFS+ has extent records which always contains 8 extents. In case the first extent record in catalog file gets full, new ones are allocated from extents overflow file.

In case shrinking truncate happens to middle of an extent record which locates in extents overflow file, the logic in hfsplus_file_truncate() was changed so that call to hfs_brec_remove() is not guarded any more.

Right action would be just freeing the extents that exceed the new size inside extent record by calling hfsplus_free_extents(), and then check if the whole extent record should be removed. However since the guard (blk_cnt > start) is now after the call to hfs_brec_remove(), this has unfortunate effect that the last matching extent record is removed unconditionally.

To reproduce this issue, create a file which has at least 10 extents, and then perform shrinking truncate into middle of the last extent record, so that the number of remaining extents is not under or divisible by 8. This causes the last extent record (8 extents) to be removed totally instead of truncating into middle of it. Thus this causes corruption, and lost data.

Fix for this is simply checking if the new truncated end is below the start of this extent record, making it safe to remove the full extent record. However call to hfs_brec_remove() can't be moved to it's previous place since we're dropping ->tree_lock and it can cause a race condition and the cached info being invalidated possibly corrupting the node data.

Another issue is related to this one. When entering into the block (blk_cnt > start) we are not holding the ->tree_lock. We break out from the loop not holding the lock, but hfs_find_exit() does unlock it. Not sure if it's possible for someone else to take the lock under our feet, but it can cause hard to debug errors and premature unlocking. Even if there's no real risk of it, the locking should still always be kept in balance. Thus taking the lock now just before the check.

Attack profile

How easy it is to exploit

Attack vector: Local
Complexity: Low
Privileges needed: Low
User interaction: None

What an attacker can affect

Confidentiality: None
Integrity: High
Availability: High

Exploit likelihood

0.24%Up 0.2 points since Feb 29, 2024

What each source reports

CVE List Score used 7.1

hfsplus: prevent corruption in shrinking truncate

In the Linux kernel, the following vulnerability has been resolved:

hfsplus: prevent corruption in shrinking truncate

I believe there are some issues introduced by commit 31651c607151 ("hfsplus: avoid deadlock on file truncation")

HFS+ has extent records which always contains 8 extents. In case the first extent record in catalog file gets full, new ones are allocated from extents overflow file.

Record: CVE-2021-46989
CVSS 3.1: 7.1 HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
CVSS 3.1: 5.5 MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Updated: 2026-11-02

EUVDEUVD-2021-33637 7.1

In the Linux kernel, the following vulnerability has been resolved:

hfsplus: prevent corruption in shrinking truncate

I believe there are some issues introduced by commit 31651c607151 ("hfsplus: avoid deadlock on file truncation")

HFS+ has extent records which always contains 8 extents. In case the first extent record in catalog file gets full, new ones are allocated from extents overflow file.

Record: EUVD-2021-33637
CVSS 3.1: 7.1 HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
Updated: 2026-11-02

GitHub AdvisoriesGHSA-758g-j8h5-xvgg 5.5

In the Linux kernel, the following vulnerability has been resolved: hfsplus: prevent corruption...

In the Linux kernel, the following vulnerability has been resolved:

hfsplus: prevent corruption in shrinking truncate

I believe there are some issues introduced by commit 31651c607151 ("hfsplus: avoid deadlock on file truncation")

HFS+ has extent records which always contains 8 extents. In case the first extent record in catalog file gets full, new ones are allocated from extents overflow file.

Record: GHSA-758g-j8h5-xvgg
CVSS 3.1: 5.5 MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Updated: 2026-11-02

NVD 7.1

In the Linux kernel, the following vulnerability has been resolved:

hfsplus: prevent corruption in shrinking truncate

I believe there are some issues introduced by commit 31651c607151 ("hfsplus: avoid deadlock on file truncation")

HFS+ has extent records which always contains 8 extents. In case the first extent record in catalog file gets full, new ones are allocated from extents overflow file.

Record: CVE-2021-46989
CVSS 3.1: 7.1 HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
CVSS 3.1: 5.5 MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Updated: 2026-11-02

OSV 5.5

In the Linux kernel, the following vulnerability has been resolved:

hfsplus: prevent corruption in shrinking truncate

I believe there are some issues introduced by commit 31651c607151 ("hfsplus: avoid deadlock on file truncation")

HFS+ has extent records which always contains 8 extents. In case the first extent record in catalog file gets full, new ones are allocated from extents overflow file.

Record: CVE-2021-46989
CVSS 3.1: 5.5 MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Updated: 2026-11-02

OSVDEBIAN-CVE-2021-46989 7.1

In the Linux kernel, the following vulnerability has been resolved: hfsplus: prevent corruption in shrinking truncate I believe there are some issues introduced by commit 31651c607151 ("hfsplus: avoid deadlock on file truncation") HFS+ has extent records which always contains 8 extents. In case the first extent record in catalog file gets full, new ones are allocated from extents overflow file. In case shrinking truncate happens to middle of an extent record which locates in extents overflow file, the logic in hfsplus_file_truncate() was changed so that call to hfs_brec_remove() is not guarded any more. Right action would be just freeing the extents that exceed the new size inside extent record by calling hfsplus_free_extents(), and then check if the whole extent record should be removed. However since the guard (blk_cnt > start) is now after the call to hfs_brec_remove(), this has unfortunate effect that the last matching extent record is removed unconditionally. To reproduce this issue, create a file which has at least 10 extents, and then perform shrinking truncate into middle of the last extent record, so that the number of remaining extents is not under or divisible by 8. This causes the last extent record (8 extents) to be removed totally instead of truncating into middle of it. Thus this causes corruption, and lost data. Fix for this is simply checking if the new truncated end is below the start of this extent record, making it safe to remove the full extent record. However call to hfs_brec_remove() can't be moved to it's previous place since we're dropping ->tree_lock and it can cause a race condition and the cached info being invalidated possibly corrupting the node data. Another issue is related to this one. When entering into the block (blk_cnt > start) we are not holding the ->tree_lock. We break out from the loop not holding the lock, but hfs_find_exit() does unlock it. Not sure if it's possible for someone else to take the lock under our feet, but it can cause hard to debug errors and premature unlocking. Even if there's no real risk of it, the locking should still always be kept in balance. Thus taking the lock now just before the check.

Record: DEBIAN-CVE-2021-46989
CVSS 3.1: 7.1 HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
Updated: 2026-11-02

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OSVOESA-2024-1392 7.8

kernel security update

The Linux Kernel, the operating system core itself.

Security Fix(es):

In the Linux kernel, the following vulnerability has been resolved:

media: dvbdev: Fix memory leak in dvb_media_device_free()

dvb_media_device_free() is leaking memory. Free dvbdev->adapter->conn before setting it to NULL, as documented in include/media/media-device.h: "The media_entity instance itself must be freed explicitly by the driver if required."(CVE-2020-36777)

In the Linux kernel, the following vulnerability has been resolved:

i2c: sprd: fix reference leak when pm_runtime_get_sync fails

The PM reference count is not expected to be incremented on return in sprd_i2c_master_xfer() and sprd_i2c_remove().

However, pm_runtime_get_sync will increment the PM reference count even failed. Forgetting to putting operation will result in a reference leak here.

Replace it with pm_runtime_resume_and_get to keep usage counter balanced.(CVE-2020-36780)

In the Linux kernel, the following vulnerability has been resolved:

i2c: cadence: fix reference leak when pm_runtime_get_sync fails

The PM reference count is not expected to be incremented on return in functions cdns_i2c_master_xfer and cdns_reg_slave.

However, pm_runtime_get_sync will increment pm usage counter even failed. Forgetting to putting operation will result in a reference leak here.

Replace it with pm_runtime_resume_and_get to keep usage counter balanced.(CVE-2020-36784)

In the Linux kernel, the following vulnerability has been resolved:

net: hso: fix null-ptr-deref during tty device unregistration

Multiple ttys try to claim the same the minor number causing a double unregistration of the same device. The first unregistration succeeds but the next one results in a null-ptr-deref.

The get_free_serial_index() function returns an available minor number but doesn't assign it immediately. The assignment is done by the caller later. But before this assignment, calls to get_free_serial_index() would return the same minor number.

Fix this by modifying get_free_serial_index to assign the minor number immediately after one is found to be and rename it to obtain_minor() to better reflect what it does. Similary, rename set_serial_by_index() to release_minor() and modify it to free up the minor number of the given hso_serial. Every obtain_minor() should have corresponding release_minor() call.(CVE-2021-46904)

In the Linux kernel, the following vulnerability has been resolved:

NFC: st21nfca: Fix memory leak in device probe and remove

'phy->pending_skb' is alloced when device probe, but forgot to free in the error handling path and remove path, this cause memory leak as follows:

unreferenced object 0xffff88800bc06800 (size 512): comm "8", pid 11775, jiffies 4295159829 (age 9.032s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<00000000d66c09ce>] __kmalloc_node_track_caller+0x1ed/0x450 [<00000000c93382b3>] kmalloc_reserve+0x37/0xd0 [<000000005fea522c>] __alloc_skb+0x124/0x380 [<0000000019f29f9a>] st21nfca_hci_i2c_probe+0x170/0x8f2

Fix it by freeing 'pending_skb' in error and remove.(CVE-2021-46924)

In the Linux kernel, the following vulnerability has been resolved:

ALSA: hda: intel-sdw-acpi: harden detection of controller

The existing code currently sets a pointer to an ACPI handle before checking that it's actually a SoundWire controller. This can lead to issues where the graph walk continues and eventually fails, but the pointer was set already.

This patch changes the logic so that the information provided to the caller is set when a controller is found.(CVE-2021-46926)

In the Linux kernel, the following vulnerability has been resolved:

parisc: Clear stale IIR value on instruction access rights…

Record: OESA-2024-1392
CVSS 3.1: 7.8 HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Updated: 2026-11-02

OSVOESA-2024-1393 7.8