diff options
| author | Ryusuke Konishi <konishi.ryusuke@gmail.com> | 2023-05-10 00:29:56 +0900 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2023-05-17 15:24:34 -0700 |
| commit | 9b5a04ac3ad9898c4745cba46ea26de74ba56a8e (patch) | |
| tree | c1510a8587a8813f492a2b9f15455a8ce3978c90 /fs/nilfs2 | |
| parent | 04fc7816089c5a32c29a04ec94b998e219dfb946 (diff) | |
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>
Diffstat (limited to 'fs/nilfs2')
| -rw-r--r-- | fs/nilfs2/inode.c | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/fs/nilfs2/inode.c b/fs/nilfs2/inode.c index 1310d2d5feb3..a8ce522ac747 100644 --- a/fs/nilfs2/inode.c +++ b/fs/nilfs2/inode.c @@ -917,6 +917,7 @@ void nilfs_evict_inode(struct inode *inode) struct nilfs_transaction_info ti; struct super_block *sb = inode->i_sb; struct nilfs_inode_info *ii = NILFS_I(inode); + struct the_nilfs *nilfs; int ret; if (inode->i_nlink || !ii->i_root || unlikely(is_bad_inode(inode))) { @@ -929,6 +930,23 @@ void nilfs_evict_inode(struct inode *inode) truncate_inode_pages_final(&inode->i_data); + nilfs = sb->s_fs_info; + if (unlikely(sb_rdonly(sb) || !nilfs->ns_writer)) { + /* + * If this inode is about to be disposed after the file system + * has been degraded to read-only due to file system corruption + * or after the writer has been detached, do not make any + * changes that cause writes, just clear it. + * Do this check after read-locking ns_segctor_sem by + * nilfs_transaction_begin() in order to avoid a race with + * the writer detach operation. + */ + clear_inode(inode); + nilfs_clear_inode(inode); + nilfs_transaction_abort(sb); + return; + } + /* TODO: some of the following operations may fail. */ nilfs_truncate_bmap(ii, 0); nilfs_mark_inode_dirty(inode); |