Bug 1220234 (CVE-2023-52444)

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

f2fs: fix to avoid dirent corruption

As Al reported in link[1]:

f2fs_rename()
...
	if (old_dir != new_dir && !whiteout)
		f2fs_set_link(old_inode, old_dir_entry,
					old_dir_page, new_dir);
	else
		f2fs_put_page(old_dir_page, 0);

You want correct inumber in the ".." link.  And cross-directory
rename does move the source to new parent, even if you'd been asked
to leave a whiteout in the old place.

[1] https://lore.kernel.org/all/20231017055040.GN800259@ZenIV/

With below testcase, it may cause dirent corruption, due to it missed
to call f2fs_set_link() to update ".." link to new directory.
- mkdir -p dir/foo
- renameat2 -w dir/foo bar

[ASSERT] (__chk_dots_dentries:1421)  --> Bad inode number[0x4] for '..', parent parent ino is [0x3]
[FSCK] other corrupted bugs                           [Fail]

References:
http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2023-52444
https://www.cve.org/CVERecord?id=CVE-2023-52444
https://git.kernel.org/stable/c/02160112e6d45c2610b049df6eb693d7a2e57b46
https://git.kernel.org/stable/c/2fb4867f4405aea8c0519d7d188207f232a57862
https://git.kernel.org/stable/c/53edb549565f55ccd0bdf43be3d66ce4c2d48b28
https://git.kernel.org/stable/c/5624a3c1b1ebc8991318e1cce2aa719542991024
https://git.kernel.org/stable/c/6f866885e147d33efc497f1095f35b2ee5ec7310
https://git.kernel.org/stable/c/d3c0b49aaa12a61d560528f5d605029ab57f0728
https://git.kernel.org/stable/c/f0145860c20be6bae6785c7a2249577674702ac7
https://git.kernel.org/stable/c/f100ba617d8be6c98a68f3744ef7617082975b77