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| author | Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> | 2018-07-04 11:23:50 +0200 |
|---|---|---|
| committer | Michal Hocko <mhocko@suse.com> | 2018-07-04 11:23:50 +0200 |
| commit | 55a71e8e08dfce6d73687f1e2019c21907c36b3e (patch) | |
| tree | a73453c6259b1dd7205502544fa267a4936f1ce5 | |
| parent | fc36def997cfd6cbff3eda4f82853a5c311c5466 (diff) | |
| download | mm-55a71e8e08dfce6d73687f1e2019c21907c36b3e.tar.gz | |
hfsplus: don't return 0 when fill_super() failed
syzbot is reporting NULL pointer dereference at mount_fs() [1]. This is
because hfsplus_fill_super() is by error returning 0 when
hfsplus_fill_super() detected invalid filesystem image, and mount_bdev()
is returning NULL because dget(s->s_root) == NULL if s->s_root == NULL,
and mount_fs() is accessing root->d_sb because IS_ERR(root) == false if
root == NULL. Fix this by returning -EINVAL when hfsplus_fill_super()
detected invalid filesystem image.
[1] https://syzkaller.appspot.com/bug?id=21acb6850cecbc960c927229e597158cf35f33d0
Link: http://lkml.kernel.org/r/d83ce31a-874c-dd5b-f790-41405983a5be@I-love.SAKURA.ne.jp
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reported-by: syzbot <syzbot+01ffaf5d9568dd1609f7@syzkaller.appspotmail.com>
Reviewed-by: Ernesto A. Fernández <ernesto.mnd.fernandez@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| -rw-r--r-- | fs/hfsplus/super.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/fs/hfsplus/super.c b/fs/hfsplus/super.c index a6c0f54c48c30f..80abba550bfa64 100644 --- a/fs/hfsplus/super.c +++ b/fs/hfsplus/super.c @@ -524,8 +524,10 @@ static int hfsplus_fill_super(struct super_block *sb, void *data, int silent) goto out_put_root; if (!hfs_brec_read(&fd, &entry, sizeof(entry))) { hfs_find_exit(&fd); - if (entry.type != cpu_to_be16(HFSPLUS_FOLDER)) + if (entry.type != cpu_to_be16(HFSPLUS_FOLDER)) { + err = -EINVAL; goto out_put_root; + } inode = hfsplus_iget(sb, be32_to_cpu(entry.folder.id)); if (IS_ERR(inode)) { err = PTR_ERR(inode); |