In the Linux kernel, the following vulnerability has been resolved:
Squashfs: sanity check symbolic link size
Syzkiller reports a "KMSAN: uninit-value in pick_link" bug.
This is caused by an uninitialised page, which is ultimately caused
by a corrupted symbolic link size read from disk.
The reason why the corrupted symlink size causes an uninitialised
page is due to the following sequence of events:
1. squashfs_read_inode() is called to read the symbolic
link from disk. This assigns the corrupted value
3875536935 to inode->i_size.
2. Later squashfs_symlink_read_folio() is called, which assigns
this corrupted value to the length variable, which being a
signed int, overflows producing a negative number.
3. The following loop that fills in the page contents checks that
the copied bytes is less than length, which being negative means
the loop is skipped, producing an uninitialised page.
This patch adds a sanity check which checks that the symbolic
link size is not larger than expected.
--
V2: fix spelling mistake.
Metrics
Affected Vendors & Products
References
History
Wed, 18 Sep 2024 14:15:00 +0000
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Wed, 18 Sep 2024 07:30:00 +0000
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Description | In the Linux kernel, the following vulnerability has been resolved: Squashfs: sanity check symbolic link size Syzkiller reports a "KMSAN: uninit-value in pick_link" bug. This is caused by an uninitialised page, which is ultimately caused by a corrupted symbolic link size read from disk. The reason why the corrupted symlink size causes an uninitialised page is due to the following sequence of events: 1. squashfs_read_inode() is called to read the symbolic link from disk. This assigns the corrupted value 3875536935 to inode->i_size. 2. Later squashfs_symlink_read_folio() is called, which assigns this corrupted value to the length variable, which being a signed int, overflows producing a negative number. 3. The following loop that fills in the page contents checks that the copied bytes is less than length, which being negative means the loop is skipped, producing an uninitialised page. This patch adds a sanity check which checks that the symbolic link size is not larger than expected. -- V2: fix spelling mistake. | |
Title | Squashfs: sanity check symbolic link size | |
References |
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MITRE
Status: PUBLISHED
Assigner: Linux
Published: 2024-09-18T07:12:04.975Z
Updated: 2024-09-18T07:12:04.975Z
Reserved: 2024-09-11T15:12:18.266Z
Link: CVE-2024-46744
Vulnrichment
No data.
NVD
Status : Awaiting Analysis
Published: 2024-09-18T08:15:03.603
Modified: 2024-09-20T12:30:51.220
Link: CVE-2024-46744
Redhat