In the Linux kernel, the following vulnerability has been resolved:
ovl: support encoding fid from inode with no alias
Dmitry Safonov reported that a WARN_ON() assertion can be trigered by
userspace when calling inotify_show_fdinfo() for an overlayfs watched
inode, whose dentry aliases were discarded with drop_caches.
The WARN_ON() assertion in inotify_show_fdinfo() was removed, because
it is possible for encoding file handle to fail for other reason, but
the impact of failing to encode an overlayfs file handle goes beyond
this assertion.
As shown in the LTP test case mentioned in the link below, failure to
encode an overlayfs file handle from a non-aliased inode also leads to
failure to report an fid with FAN_DELETE_SELF fanotify events.
As Dmitry notes in his analyzis of the problem, ovl_encode_fh() fails
if it cannot find an alias for the inode, but this failure can be fixed.
ovl_encode_fh() seldom uses the alias and in the case of non-decodable
file handles, as is often the case with fanotify fid info,
ovl_encode_fh() never needs to use the alias to encode a file handle.
Defer finding an alias until it is actually needed so ovl_encode_fh()
will not fail in the common case of FAN_DELETE_SELF fanotify events.
ovl: support encoding fid from inode with no alias
Dmitry Safonov reported that a WARN_ON() assertion can be trigered by
userspace when calling inotify_show_fdinfo() for an overlayfs watched
inode, whose dentry aliases were discarded with drop_caches.
The WARN_ON() assertion in inotify_show_fdinfo() was removed, because
it is possible for encoding file handle to fail for other reason, but
the impact of failing to encode an overlayfs file handle goes beyond
this assertion.
As shown in the LTP test case mentioned in the link below, failure to
encode an overlayfs file handle from a non-aliased inode also leads to
failure to report an fid with FAN_DELETE_SELF fanotify events.
As Dmitry notes in his analyzis of the problem, ovl_encode_fh() fails
if it cannot find an alias for the inode, but this failure can be fixed.
ovl_encode_fh() seldom uses the alias and in the case of non-decodable
file handles, as is often the case with fanotify fid info,
ovl_encode_fh() never needs to use the alias to encode a file handle.
Defer finding an alias until it is actually needed so ovl_encode_fh()
will not fail in the common case of FAN_DELETE_SELF fanotify events.
Metrics
Affected Vendors & Products
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Fri, 26 Sep 2025 20:00:00 +0000
Type | Values Removed | Values Added |
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First Time appeared |
Linux
Linux linux Kernel |
|
Weaknesses | CWE-617 | |
CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.13:rc1:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.13:rc2:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.13:rc3:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.13:rc4:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.13:rc5:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.13:rc6:*:*:*:*:*:* |
|
Vendors & Products |
Linux
Linux linux Kernel |
Thu, 13 Feb 2025 01:00:00 +0000
Type | Values Removed | Values Added |
---|---|---|
Weaknesses | CWE-20 | |
Metrics |
threat_severity
|
threat_severity
|
Fri, 24 Jan 2025 16:45:00 +0000
Type | Values Removed | Values Added |
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References |
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Thu, 23 Jan 2025 17:15:00 +0000
Type | Values Removed | Values Added |
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References |
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Tue, 21 Jan 2025 10:30:00 +0000
Type | Values Removed | Values Added |
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References |
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Tue, 21 Jan 2025 03:15:00 +0000
Type | Values Removed | Values Added |
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References |
| |
Metrics |
threat_severity
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cvssV3_1
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Sun, 19 Jan 2025 10:30:00 +0000
Type | Values Removed | Values Added |
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Description | In the Linux kernel, the following vulnerability has been resolved: ovl: support encoding fid from inode with no alias Dmitry Safonov reported that a WARN_ON() assertion can be trigered by userspace when calling inotify_show_fdinfo() for an overlayfs watched inode, whose dentry aliases were discarded with drop_caches. The WARN_ON() assertion in inotify_show_fdinfo() was removed, because it is possible for encoding file handle to fail for other reason, but the impact of failing to encode an overlayfs file handle goes beyond this assertion. As shown in the LTP test case mentioned in the link below, failure to encode an overlayfs file handle from a non-aliased inode also leads to failure to report an fid with FAN_DELETE_SELF fanotify events. As Dmitry notes in his analyzis of the problem, ovl_encode_fh() fails if it cannot find an alias for the inode, but this failure can be fixed. ovl_encode_fh() seldom uses the alias and in the case of non-decodable file handles, as is often the case with fanotify fid info, ovl_encode_fh() never needs to use the alias to encode a file handle. Defer finding an alias until it is actually needed so ovl_encode_fh() will not fail in the common case of FAN_DELETE_SELF fanotify events. | |
Title | ovl: support encoding fid from inode with no alias | |
References |
|

Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2025-05-04T07:18:19.475Z
Reserved: 2024-12-29T08:45:45.729Z
Link: CVE-2025-21654

No data.

Status : Analyzed
Published: 2025-01-19T11:15:11.040
Modified: 2025-09-26T19:48:53.530
Link: CVE-2025-21654


No data.