fuse: don't keep dead fuse_conn at fuse_fill_super().

commit 543b8f8662fe6d21f19958b666ab0051af9db21a upstream.

syzbot is reporting use-after-free at fuse_kill_sb_blk() [1].
Since sb->s_fs_info field is not cleared after fc was released by
fuse_conn_put() when initialization failed, fuse_kill_sb_blk() finds
already released fc and tries to hold the lock. Fix this by clearing
sb->s_fs_info field after calling fuse_conn_put().

[1] https://syzkaller.appspot.com/bug?id=a07a680ed0a9290585ca424546860464dd9658db

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reported-by: syzbot <syzbot+ec3986119086fe4eec97@syzkaller.appspotmail.com>
Fixes: 3b463ae0c6 ("fuse: invalidation reverse calls")
Cc: John Muir <john@jmuir.com>
Cc: Csaba Henk <csaba@gluster.com>
Cc: Anand Avati <avati@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

This commit is contained in:

Tetsuo Handa

2018-05-01 13:12:14 +09:00

committed by

syphyr

parent 643ac210e7

commit 09d1205fa1

1 changed files with 1 additions and 0 deletions

									
										1

fs/fuse/inode.c

										View File
									
				@ -1133,6 +1133,7 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent)

				 err_put_conn:

					fuse_bdi_destroy(fc);

					fuse_conn_put(fc);

					sb->s_fs_info = NULL;

				 err_fput:

					fput(file);

				 err:

fuse: don't keep dead fuse_conn at fuse_fill_super().

1 fs/fuse/inode.c Unescape Escape View File

1

fs/fuse/inode.c

View File