fuse: fix allowing operations

The following operation didn't check if sending the request was allowed:

  setattr
  listxattr
  statfs

Some other operations don't explicitly do the check, but VFS calls
->permission() which checks this.

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, 17 insertions, 1 deletions

diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index d1acab931330..b18e06daeffb 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -721,7 +721,7 @@ static int fuse_refresh_attributes(struct inode *inode)
  * for which the owner of the mount has ptrace privilege.  This
  * excludes processes started by other users, suid or sgid processes.
  */
-static int fuse_allow_task(struct fuse_conn *fc, struct task_struct *task)
+int fuse_allow_task(struct fuse_conn *fc, struct task_struct *task)
 {
         if (fc->flags & FUSE_ALLOW_OTHER)
                 return 1;
@@ -1005,6 +1005,9 @@ static int fuse_setattr(struct dentry *entry, struct iattr *attr)
         struct fuse_attr_out outarg;
         int err;
 
+        if (!fuse_allow_task(fc, current))
+                return -EACCES;
+
         if (fc->flags & FUSE_DEFAULT_PERMISSIONS) {
                 err = inode_change_ok(inode, attr);
                 if (err)
@@ -1172,6 +1175,9 @@ static ssize_t fuse_listxattr(struct dentry *entry, char *list, size_t size)
         struct fuse_getxattr_out outarg;
         ssize_t ret;
 
+        if (!fuse_allow_task(fc, current))
+                return -EACCES;
+
         if (fc->no_listxattr)
                 return -EOPNOTSUPP;
 
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index 1764506fdd11..e7464b8ebbfb 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -565,3 +565,8 @@ void fuse_ctl_remove_conn(struct fuse_conn *fc);
  * Is file type valid?
  */
 int fuse_valid_type(int m);
+
+/**
+ * Is task allowed to perform filesystem operation?
+ */
+int fuse_allow_task(struct fuse_conn *fc, struct task_struct *task);
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index fd0735715c14..00bb5a255ded 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -287,6 +287,11 @@ static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf)
         struct fuse_statfs_out outarg;
         int err;
 
+        if (!fuse_allow_task(fc, current)) {
+                buf->f_type = FUSE_SUPER_MAGIC;
+                return 0;
+        }
+
         req = fuse_get_req(fc);
         if (IS_ERR(req))
                 return PTR_ERR(req);