// For flags

CVE-2021-47637

ubifs: Fix deadlock in concurrent rename whiteout and inode writeback

Time Line
Published
2024-03-19
Updated
2024-03-19
Firt exploit
2024-03-19
Overview
Descriptions (1)
MITRE
CWE (0)
CAPEC (-)
Risk
CVSS Score
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SSVC
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KEV
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EPSS
Affected Products (-)
Vendors (1)
linux
Products (1)
linux_kernel
Versions (7)
>= 4.9 < 4.19.238, >= 4.9 < 5.4.189, >= 4.9 < 5.10.110, >= 4.9 < 5.15.33, >= 4.9 < 5.16.19, >= 4.9 < 5.17.2, >= 4.9 < 5.18
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References (8)
General (1)
kernel
Exploits & POcs (-)
Patches (7)
kernel
Advisories (-)
Summary
Descriptions

In the Linux kernel, the following vulnerability has been resolved: ubifs: Fix deadlock in concurrent rename whiteout and inode writeback Following hung tasks:
[ 77.028764] task:kworker/u8:4 state:D stack: 0 pid: 132
[ 77.028820] Call Trace:
[ 77.029027] schedule+0x8c/0x1b0
[ 77.029067] mutex_lock+0x50/0x60
[ 77.029074] ubifs_write_inode+0x68/0x1f0 [ubifs]
[ 77.029117] __writeback_single_inode+0x43c/0x570
[ 77.029128] writeback_sb_inodes+0x259/0x740
[ 77.029148] wb_writeback+0x107/0x4d0
[ 77.029163] wb_workfn+0x162/0x7b0 [ 92.390442] task:aa state:D stack: 0 pid: 1506
[ 92.390448] Call Trace:
[ 92.390458] schedule+0x8c/0x1b0
[ 92.390461] wb_wait_for_completion+0x82/0xd0
[ 92.390469] __writeback_inodes_sb_nr+0xb2/0x110
[ 92.390472] writeback_inodes_sb_nr+0x14/0x20
[ 92.390476] ubifs_budget_space+0x705/0xdd0 [ubifs]
[ 92.390503] do_rename.cold+0x7f/0x187 [ubifs]
[ 92.390549] ubifs_rename+0x8b/0x180 [ubifs]
[ 92.390571] vfs_rename+0xdb2/0x1170
[ 92.390580] do_renameat2+0x554/0x770 , are caused by concurrent rename whiteout and inode writeback processes: rename_whiteout(Thread 1) wb_workfn(Thread2)
ubifs_rename do_rename lock_4_inodes (Hold ui_mutex) ubifs_budget_space make_free_space shrink_liability __writeback_inodes_sb_nr bdi_split_work_to_wbs (Queue new wb work) wb_do_writeback(wb work) __writeback_single_inode ubifs_write_inode LOCK(ui_mutex) ↑ wb_wait_for_completion (Wait wb work) <-- deadlock! Reproducer (Detail program in [Link]): 1. SYS_renameat2("/mp/dir/file", "/mp/dir/whiteout", RENAME_WHITEOUT) 2. Consume out of space before kernel(mdelay) doing budget for whiteout Fix it by doing whiteout space budget before locking ubifs inodes.
BTW, it also fixes wrong goto tag 'out_release' in whiteout budget
error handling path(It should at least recover dir i_size and unlock
4 ubifs inodes).

*Credits: N/A
CVSS Scores
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* Common Vulnerability Scoring System
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* Organization's Worst-case Scenario
Timeline
  • 2025-02-26 CVE Reserved
  • 2025-02-26 CVE Published
  • 2025-02-26 CVE Updated
  • ---------- EPSS Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
  • ---------- First Exploit
CWE
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Threat Intelligence Resources (0)
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Affected Vendors, Products, and Versions
Vendor Product Version Other Status
Vendor Product Version Other Status <-- --> Vendor Product Version Other Status
Linux
Search vendor "Linux"
 Linux Kernel
Search vendor "Linux" for product "Linux Kernel"
 >= 4.9 < 4.19.238
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en
Affected
Linux
Search vendor "Linux"
 Linux Kernel
Search vendor "Linux" for product "Linux Kernel"
 >= 4.9 < 5.4.189
Search vendor "Linux" for product "Linux Kernel" and version " >= 4.9 < 5.4.189"
en
Affected
Linux
Search vendor "Linux"
 Linux Kernel
Search vendor "Linux" for product "Linux Kernel"
 >= 4.9 < 5.10.110
Search vendor "Linux" for product "Linux Kernel" and version " >= 4.9 < 5.10.110"
en
Affected
Linux
Search vendor "Linux"
 Linux Kernel
Search vendor "Linux" for product "Linux Kernel"
 >= 4.9 < 5.15.33
Search vendor "Linux" for product "Linux Kernel" and version " >= 4.9 < 5.15.33"
en
Affected
Linux
Search vendor "Linux"
 Linux Kernel
Search vendor "Linux" for product "Linux Kernel"
 >= 4.9 < 5.16.19
Search vendor "Linux" for product "Linux Kernel" and version " >= 4.9 < 5.16.19"
en
Affected
Linux
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 Linux Kernel
Search vendor "Linux" for product "Linux Kernel"
 >= 4.9 < 5.17.2
Search vendor "Linux" for product "Linux Kernel" and version " >= 4.9 < 5.17.2"
en
Affected
Linux
Search vendor "Linux"
 Linux Kernel
Search vendor "Linux" for product "Linux Kernel"
 >= 4.9 < 5.18
Search vendor "Linux" for product "Linux Kernel" and version " >= 4.9 < 5.18"
en
Affected