[patch 01/12] fuse: fix allowing operations

[Miklos Szeredi]

From: Miklos Szeredi <mszeredi@xxxxxxx>

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@xxxxxxx>
---

Index: linux/fs/fuse/dir.c
===================================================================
--- linux.orig/fs/fuse/dir.c	2007-09-25 21:19:00.000000000 +0200
+++ linux/fs/fuse/dir.c	2007-09-25 21:19:13.000000000 +0200
@@ -721,7 +721,7 @@ static int fuse_refresh_attributes(struc
  * 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 *e
 	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 den
 	struct fuse_getxattr_out outarg;
 	ssize_t ret;
 
+	if (!fuse_allow_task(fc, current))
+		return -EACCES;
+
 	if (fc->no_listxattr)
 		return -EOPNOTSUPP;
 
Index: linux/fs/fuse/fuse_i.h
===================================================================
--- linux.orig/fs/fuse/fuse_i.h	2007-09-25 21:19:00.000000000 +0200
+++ linux/fs/fuse/fuse_i.h	2007-09-25 21:19:13.000000000 +0200
@@ -565,3 +565,8 @@ void fuse_ctl_remove_conn(struct fuse_co
  * 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);
Index: linux/fs/fuse/inode.c
===================================================================
--- linux.orig/fs/fuse/inode.c	2007-09-25 21:19:00.000000000 +0200
+++ linux/fs/fuse/inode.c	2007-09-25 21:19:13.000000000 +0200
@@ -287,6 +287,11 @@ static int fuse_statfs(struct dentry *de
 	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);

--
-
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