CVE-2022-49171
Linux Kernel ext4 Unprivileged Denial of Service Vulnerability
Description
In the Linux kernel, the following vulnerability has been resolved: ext4: don't BUG if someone dirty pages without asking ext4 first [un]pin_user_pages_remote is dirtying pages without properly warning the file system in advance. A related race was noted by Jan Kara in 2018[1]; however, more recently instead of it being a very hard-to-hit race, it could be reliably triggered by process_vm_writev(2) which was discovered by Syzbot[2]. This is technically a bug in mm/gup.c, but arguably ext4 is fragile in that if some other kernel subsystem dirty pages without properly notifying the file system using page_mkwrite(), ext4 will BUG, while other file systems will not BUG (although data will still be lost). So instead of crashing with a BUG, issue a warning (since there may be potential data loss) and just mark the page as clean to avoid unprivileged denial of service attacks until the problem can be properly fixed. More discussion and background can be found in the thread starting at [2]. [1] https://lore.kernel.org/linux-mm/[email protected] [2] https://lore.kernel.org/r/[email protected]
INFO
Published Date :
Feb. 26, 2025, 7 a.m.
Last Modified :
Feb. 26, 2025, 7 a.m.
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Remotely Exploitable :
No
Impact Score :
Exploitability Score :
References to Advisories, Solutions, and Tools
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CVE-2022-49171.
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Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Feb. 26, 2025
Action Type Old Value New Value Added Description In the Linux kernel, the following vulnerability has been resolved: ext4: don't BUG if someone dirty pages without asking ext4 first [un]pin_user_pages_remote is dirtying pages without properly warning the file system in advance. A related race was noted by Jan Kara in 2018[1]; however, more recently instead of it being a very hard-to-hit race, it could be reliably triggered by process_vm_writev(2) which was discovered by Syzbot[2]. This is technically a bug in mm/gup.c, but arguably ext4 is fragile in that if some other kernel subsystem dirty pages without properly notifying the file system using page_mkwrite(), ext4 will BUG, while other file systems will not BUG (although data will still be lost). So instead of crashing with a BUG, issue a warning (since there may be potential data loss) and just mark the page as clean to avoid unprivileged denial of service attacks until the problem can be properly fixed. More discussion and background can be found in the thread starting at [2]. [1] https://lore.kernel.org/linux-mm/[email protected] [2] https://lore.kernel.org/r/[email protected] Added Reference https://git.kernel.org/stable/c/0d3a6926f7e8be3c897fa46216ce13b119a9f56a Added Reference https://git.kernel.org/stable/c/330d0e44fc5a47c27df958ecdd4693a3cb1d8b81 Added Reference https://git.kernel.org/stable/c/343117559ef41e992e326f7a92da1a8f254dfa8c Added Reference https://git.kernel.org/stable/c/5a016c053f426a73752c3b41b60b497b58694d48 Added Reference https://git.kernel.org/stable/c/5db60e76edf5680ff1f3a7221036fc44b308f146 Added Reference https://git.kernel.org/stable/c/677c9d30e8487bee6c8e3b034070319d98f6e203 Added Reference https://git.kernel.org/stable/c/a0856764dc1276ad2dc7891288c2e9246bf11a37 Added Reference https://git.kernel.org/stable/c/cc5095747edfb054ca2068d01af20be3fcc3634f Added Reference https://git.kernel.org/stable/c/d666dfaa571465a19f014534a214c255ea33f301
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2022-49171 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2022-49171
weaknesses.