CVE-2024-43828

In the Linux kernel, the following vulnerability has been resolved:

ext4: fix infinite loop when replaying fast_commit

When doing fastcommit replay an infinite loop may occur due to an uninitialized extentstatus struct. ext4extdetermineinserthole() does not detect the replay and calls ext4esfindextentrange(), which will return immediately without initializing the 'es' variable.

Because 'es' contains garbage, an integer overflow may happen causing an infinite loop in this function, easily reproducible using fstest generic/039.

This commit fixes this issue by unconditionally initializing the structure in function ext4esfindextentrange().

Thanks to Zhang Yi, for figuring out the real problem!