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authorTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>2018-08-21 21:59:12 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-08-22 10:52:50 -0700
commit7464726cb5998846306ed0a7d6714afb2e37b25d (patch)
tree51d590633d18949e920b8132ac785f2deb6f09ed /fs
parentc8ed98cd88a2b39f504e1ce6af42423c71ebe5b7 (diff)
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> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs')
-rw-r--r--fs/hfsplus/super.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/fs/hfsplus/super.c b/fs/hfsplus/super.c
index a6c0f54c48c3..80abba550bfa 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);