CVE-2025-21752

What the bug is

Don't use btrfs_set_item_key_safe() to modify the keys in the RAID stripe-tree, as this can lead to corruption of the tree, which is caught by the checks in btrfs_set_item_key_safe(): BTRFS info (device nvme1n1): leaf 49168384 gen 15 total ptrs 194 free space 8329 owner 12 BTRFS info (device nvme1n1): refs 2 lock_owner 1030 current 1030 [ snip ] item 105 key (354549760 230 20480) itemoff 14587 itemsize 16 stride 0 devid 5 physical 67502080 item 106 key (354631680 230 4096) itemoff 14571 itemsize 16 stride 0 devid 1 physical 88559616 item 107 key (354631680 230 32768) itemoff 14555 itemsize 16 stride 0 devid 1 physical 88555520 item 108 key (354717696 230 28672) itemoff 14539 itemsize 16 stride 0 devid 2 physical 67604480 [ snip ] BTRFS critical (device nvme1n1): slot 106 key (354631680 230 32768) new key (354635776 230 4096) ------------[ cut here ]------------ kernel BUG at fs/btrfs/ctree.c:2602! Oops: invalid opcode: 0000 [#1] PREEMPT SMP PTI CPU: 1 UID: 0 PID: 1055 Comm: fsstress Not tainted 6.13.0-rc1+ #1464 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.2-3-gd478f380-rebuilt.opensuse.org 04/01/2014 RIP: 0010:btrfs_set_item_key_safe+0xf7/0x270 Code: <snip> RSP: 0018:ffffc90001337ab0 EFLAGS: 00010287 RAX: 0000000000000000 RBX: ffff8881115fd000 RCX: 0000000000000000 RDX: 0000000000000001 RSI: 0000000000000001 RDI: 00000000ffffffff RBP: ffff888110ed6f50 R08: 00000000ffffefff R09: ffffffff8244c500 R10: 00000000ffffefff R11: 00000000ffffffff R12: ffff888100586000 R13: 00000000000000c9 R14: ffffc90001337b1f R15: ffff888110f23b58 FS: 00007f7d75c72740(0000) GS:ffff88813bd00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fa811652c60 CR3: 0000000111398001 CR4: 0000000000370eb0 Call Trace: <TASK> ? __die_body.cold+0x14/0x1a ? die+0x2e/0x50 ? do_trap+0xca/0x110 ? do_error_trap+0x65/0x80 ? btrfs_set_item_key_safe+0xf7/0x270 ? exc_invalid_op+0x50/0x70 ? btrfs_set_item_key_safe+0xf7/0x270 ? asm_exc_invalid_op+0x1a/0x20 ? btrfs_set_item_key_safe+0xf7/0x270 btrfs_partially_delete_raid_extent+0xc4/0xe0 btrfs_delete_raid_extent+0x227/0x240 __btrfs_free_extent.isra.0+0x57f/0x9c0 ? exc_coproc_segment_overrun+0x40/0x40 __btrfs_run_delayed_refs+0x2fa/0xe80 btrfs_run_delayed_refs+0x81/0xe0 btrfs_commit_transaction+0x2dd/0xbe0 ? preempt_count_add+0x52/0xb0 btrfs_sync_file+0x375/0x4c0 do_fsync+0x39/0x70 __x64_sys_fsync+0x13/0x20 do_syscall_64+0x54/0x110 entry_SYSCALL_64_after_hwframe+0x76/0x7e RIP: 0033:0x7f7d7550ef90 Code: <snip> RSP: 002b:00007ffd70237248 EFLAGS: 00000202 ORIG_RAX: 000000000000004a RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007f7d7550ef90 RDX: 000000000000013a RSI: 000000000040eb28 RDI: 0000000000000004 RBP: 000000000000001b R08: 0000000000000078 R09: 00007ffd7023725c R10: 00007f7d75400390 R11: 0000000000000202 R12: 028f5c28f5c28f5c R13: 8f5c28f5c28f5c29 R14: 000000000040b520 R15: 00007f7d75c726c8 </TASK> While the root cause of the tree order corruption isn't clear, using btrfs_duplicate_item() to copy the item and then adjusting both the key and the per-device physical addresses is a safe way to counter this problem.

Where it lives

The fix touches these files. If the subsystem is one you do not use, the practical exposure is lower, though the package is still the vulnerable one.

fs/btrfs/raid-stripe-tree.c

What this is

BTRFS FILE SYSTEMMAINTAINERS section matched on fs/btrfs/ · linux-btrfs@vger.kernel.org · Maintained

Kernel module

btrfs

Check it on the machine

grep -w CONFIG_BTRFS_FS /boot/config-$(uname -r)

Reads the booted kernel's own configuration, on the machine and nowhere else. =y is built in, =m is a module, and an is not set line means the code is not there.

lsmod | grep -w btrfs

Prints a line if that module is loaded right now, and nothing if it is not. One that is not loaded can still be loaded later by anything that needs it.

Show whether Debian builds this, per release

Debian builds this as a loadable module. Every release with an answer below compiles it as a module on every flavour, so whether the code is in the running kernel depends on whether that module is loaded. The build rule could not be established for 1 release, so nothing is claimed about those.

• bookworm?
• trixie, forky, sidm

?

not established - no Makefile entry for the affected file

m

a loadable module on every flavour - check lsmod, can be blacklisted

Where a release above reads "not established", no build rule for the affected file was found in that release's kernel tree. That is a gap in this lookup, not a finding that the code is absent.

Build switch

CONFIG_BTRFS_FS

From the configuration Debian publishes for every kernel flavour it builds. It covers only the architectures Debian ships a linux-config package for, and nothing about a kernel you built yourself. Debian's own status above stays authoritative about the source package.MAINTAINERS kbuild Makefiles Debian linux-config packages

Signals

Published

2025-02-27 (20 months ago)source

CVSS

no vector published, unrated

Attack vector

not published

EPSS

0.17%, higher than 6.4% of all CVEssource

CISA KEV

not listedthe KEV catalogue

Debian urgency

unimportantsource

Subsystem

fs/btrfs

Upstream fixes

The versions the CNA records as introducing and fixing this, and the commit for each. source

Introduced	Fixed in	Commit
6.7	6.13.3	1c25eff52ee5
6.7	6.14	dc14ba10781b
6.6.130	0	0