Vulnerability CVE-2023-52444
Published: 2024-02-22

Description:
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:
https://git.kernel.org/stable/c/02160112e6d45c2610b049df6eb693d7a2e57b46
https://git.kernel.org/stable/c/5624a3c1b1ebc8991318e1cce2aa719542991024
https://git.kernel.org/stable/c/6f866885e147d33efc497f1095f35b2ee5ec7310
https://git.kernel.org/stable/c/f100ba617d8be6c98a68f3744ef7617082975b77
https://git.kernel.org/stable/c/f0145860c20be6bae6785c7a2249577674702ac7
https://git.kernel.org/stable/c/d3c0b49aaa12a61d560528f5d605029ab57f0728
https://git.kernel.org/stable/c/2fb4867f4405aea8c0519d7d188207f232a57862
https://git.kernel.org/stable/c/53edb549565f55ccd0bdf43be3d66ce4c2d48b28
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