nilfs2: fix use-after-free bug of nilfs_root in nilfs_evict_inode()
authorRyusuke Konishi <konishi.ryusuke@gmail.com>
Tue, 9 May 2023 15:29:56 +0000 (00:29 +0900)
committerAndrew Morton <akpm@linux-foundation.org>
Wed, 17 May 2023 22:24:34 +0000 (15:24 -0700)
commit9b5a04ac3ad9898c4745cba46ea26de74ba56a8e
treec1510a8587a8813f492a2b9f15455a8ce3978c90
parent04fc7816089c5a32c29a04ec94b998e219dfb946
nilfs2: fix use-after-free bug of nilfs_root in nilfs_evict_inode()

During unmount process of nilfs2, nothing holds nilfs_root structure after
nilfs2 detaches its writer in nilfs_detach_log_writer().  However, since
nilfs_evict_inode() uses nilfs_root for some cleanup operations, it may
cause use-after-free read if inodes are left in "garbage_list" and
released by nilfs_dispose_list() at the end of nilfs_detach_log_writer().

Fix this issue by modifying nilfs_evict_inode() to only clear inode
without additional metadata changes that use nilfs_root if the file system
is degraded to read-only or the writer is detached.

Link: https://lkml.kernel.org/r/20230509152956.8313-1-konishi.ryusuke@gmail.com
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Reported-by: syzbot+78d4495558999f55d1da@syzkaller.appspotmail.com
Closes: https://lkml.kernel.org/r/00000000000099e5ac05fb1c3b85@google.com
Tested-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
fs/nilfs2/inode.c