Skip to content
CVE PROGRAM SOURCE RECORDUnscored

CVE-2025-38059

btrfs: avoid NULL pointer dereference if no valid csum tree

Read JSON ↗CVE.org ↗
Status
Published
Published
Updated
Assigning organization
Linux

Description

In the Linux kernel, the following vulnerability has been resolved: btrfs: avoid NULL pointer dereference if no valid csum tree [BUG] When trying read-only scrub on a btrfs with rescue=idatacsums mount option, it will crash with the following call trace: BUG: kernel NULL pointer dereference, address: 0000000000000208 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page CPU: 1 UID: 0 PID: 835 Comm: btrfs Tainted: G O 6.15.0-rc3-custom+ #236 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS unknown 02/02/2022 RIP: 0010:btrfs_lookup_csums_bitmap+0x49/0x480 [btrfs] Call Trace: <TASK> scrub_find_fill_first_stripe+0x35b/0x3d0 [btrfs] scrub_simple_mirror+0x175/0x290 [btrfs] scrub_stripe+0x5f7/0x6f0 [btrfs] scrub_chunk+0x9a/0x150 [btrfs] scrub_enumerate_chunks+0x333/0x660 [btrfs] btrfs_scrub_dev+0x23e/0x600 [btrfs] btrfs_ioctl+0x1dcf/0x2f80 [btrfs] __x64_sys_ioctl+0x97/0xc0 do_syscall_64+0x4f/0x120 entry_SYSCALL_64_after_hwframe+0x76/0x7e [CAUSE] Mount option "rescue=idatacsums" will completely skip loading the csum tree, so that any data read will not find any data csum thus we will ignore data checksum verification. Normally call sites utilizing csum tree will check the fs state flag NO_DATA_CSUMS bit, but unfortunately scrub does not check that bit at all. This results in scrub to call btrfs_search_slot() on a NULL pointer and triggered above crash. [FIX] Check both extent and csum tree root before doing any tree search.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • 74ef00185eb864252156022ff129b01549504175 to < 2db25048a61c0909459b074af04e06ab8a8b939eaffected
  • 74ef00185eb864252156022ff129b01549504175 to < 50d0de59f66cbe6d597481e099bf1c70fd07e0a9affected
  • 74ef00185eb864252156022ff129b01549504175 to < 6e9770de024964b1017f99ee94f71967bd6edaebaffected
  • 74ef00185eb864252156022ff129b01549504175 to < d35bed14b0bc95c6845863a3744ecd10b888c830affected
  • 74ef00185eb864252156022ff129b01549504175 to < f95d186255b319c48a365d47b69bd997fecb674eaffected

Linux Linux

Default version status: affected

  • 5.9affected
  • 0 to < 5.9unaffected
  • 6.1.191 to ≤ 6.1.*unaffected
  • 6.6.93 to ≤ 6.6.*unaffected
  • 6.12.31 to ≤ 6.12.*unaffected
  • 6.14.9 to ≤ 6.14.*unaffected
  • 6.15 to ≤ *unaffected

References