[PATCH] fuse: validate rootmode mount option

If rootmode isn't valid, we hit the BUG() in fuse_init_inode.  Now
EINVAL is returned.

Signed-off-by: Timo Savola <tsavola@movial.fi>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 10 insertions, 2 deletions

diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index 406bf61ed510..8890eba1db52 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -195,7 +195,7 @@ static struct dentry_operations fuse_dentry_operations = {
         .d_revalidate   = fuse_dentry_revalidate,
 };
 
-static int valid_mode(int m)
+int fuse_valid_type(int m)
 {
         return S_ISREG(m) || S_ISDIR(m) || S_ISLNK(m) || S_ISCHR(m) ||
                 S_ISBLK(m) || S_ISFIFO(m) || S_ISSOCK(m);
@@ -248,7 +248,8 @@ static struct dentry *fuse_lookup(struct inode *dir, struct dentry *entry,
         fuse_put_request(fc, req);
         /* Zero nodeid is same as -ENOENT, but with valid timeout */
         if (!err && outarg.nodeid &&
-            (invalid_nodeid(outarg.nodeid) || !valid_mode(outarg.attr.mode)))
+            (invalid_nodeid(outarg.nodeid) ||
+             !fuse_valid_type(outarg.attr.mode)))
                 err = -EIO;
         if (!err && outarg.nodeid) {
                 inode = fuse_iget(dir->i_sb, outarg.nodeid, outarg.generation,
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index b98b20de7405..68ae87cbafab 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -552,3 +552,8 @@ int fuse_ctl_add_conn(struct fuse_conn *fc);
  * Remove connection from control filesystem
  */
 void fuse_ctl_remove_conn(struct fuse_conn *fc);
+
+/**
+ * Is file type valid?
+ */
+int fuse_valid_type(int m);
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 5ab8e50e7808..608db81219a0 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -330,6 +330,8 @@ static int parse_fuse_opt(char *opt, struct fuse_mount_data *d, int is_bdev)
                 case OPT_ROOTMODE:
                         if (match_octal(&args[0], &value))
                                 return 0;
+                        if (!fuse_valid_type(value))
+                                return 0;
                         d->rootmode = value;
                         d->rootmode_present = 1;
                         break;