Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
f2fs: fix KMSAN uninit-value in extent_info usage
KMSAN reported a use of uninitialized value in __is_extent_mergeable()
and __is_back_mergeable() via the read extent tree path.
The root cause is that get_read_extent_info() only initializes three
fields (fofs, blk, len) of struct extent_info, leaving the
remaining fields uninitialized. This leads to undefined behavior
when those fields are accessed later, especially during
extent merging.
Fix it by zero-initializing the extent_info struct before population.
Details
- Affected product:
- Ubuntu 20.04 ELS
- Affected packages:
- linux @ 5.4.0
In the Linux kernel, the following vulnerability has been resolved:
f2fs: fix KMSAN uninit-value in extent_info usage
KMSAN reported a use of uninitialized value in __is_extent_mergeable()
and __is_back_mergeable() via the read extent tree path.
The root cause is that get_read_extent_info() only initializes three
fields (fofs, blk, len) of struct extent_info, leaving the
remaining fields uninitialized. This leads to undefined behavior
when those fields are accessed later, especially during
extent merging.
Fix it by zero-initializing the extent_info struct before population.