f2fs: fix to avoid dirent corruption

Vulnerability 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