introduce new LSM hooks where vfsmount is available.

Add new LSM hooks for path-based checks.  Call them on directory-modifying
operations at the points where we still know the vfsmount involved.

Signed-off-by: Kentaro Takeda <takedakn@nttdata.co.jp>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Toshiharu Harada <haradats@nttdata.co.jp>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 137 insertions, 0 deletions

diff --git a/include/linux/security.h b/include/linux/security.h
index 3416cb85e77b..b92b5e453f64 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -335,17 +335,37 @@ static inline void security_free_mnt_opts(struct security_mnt_opts *opts)
  *      @dir contains the inode structure of the parent directory of the new link.
  *      @new_dentry contains the dentry structure for the new link.
  *      Return 0 if permission is granted.
+ * @path_link:
+ *      Check permission before creating a new hard link to a file.
+ *      @old_dentry contains the dentry structure for an existing link
+ *      to the file.
+ *      @new_dir contains the path structure of the parent directory of
+ *      the new link.
+ *      @new_dentry contains the dentry structure for the new link.
+ *      Return 0 if permission is granted.
  * @inode_unlink:
  *      Check the permission to remove a hard link to a file.
  *      @dir contains the inode structure of parent directory of the file.
  *      @dentry contains the dentry structure for file to be unlinked.
  *      Return 0 if permission is granted.
+ * @path_unlink:
+ *      Check the permission to remove a hard link to a file.
+ *      @dir contains the path structure of parent directory of the file.
+ *      @dentry contains the dentry structure for file to be unlinked.
+ *      Return 0 if permission is granted.
  * @inode_symlink:
  *      Check the permission to create a symbolic link to a file.
  *      @dir contains the inode structure of parent directory of the symbolic link.
  *      @dentry contains the dentry structure of the symbolic link.
  *      @old_name contains the pathname of file.
  *      Return 0 if permission is granted.
+ * @path_symlink:
+ *      Check the permission to create a symbolic link to a file.
+ *      @dir contains the path structure of parent directory of
+ *      the symbolic link.
+ *      @dentry contains the dentry structure of the symbolic link.
+ *      @old_name contains the pathname of file.
+ *      Return 0 if permission is granted.
  * @inode_mkdir:
  *      Check permissions to create a new directory in the existing directory
  *      associated with inode strcture @dir.
@@ -353,11 +373,25 @@ static inline void security_free_mnt_opts(struct security_mnt_opts *opts)
  *      @dentry contains the dentry structure of new directory.
  *      @mode contains the mode of new directory.
  *      Return 0 if permission is granted.
+ * @path_mkdir:
+ *      Check permissions to create a new directory in the existing directory
+ *      associated with path strcture @path.
+ *      @dir containst the path structure of parent of the directory
+ *      to be created.
+ *      @dentry contains the dentry structure of new directory.
+ *      @mode contains the mode of new directory.
+ *      Return 0 if permission is granted.
  * @inode_rmdir:
  *      Check the permission to remove a directory.
  *      @dir contains the inode structure of parent of the directory to be removed.
  *      @dentry contains the dentry structure of directory to be removed.
  *      Return 0 if permission is granted.
+ * @path_rmdir:
+ *      Check the permission to remove a directory.
+ *      @dir contains the path structure of parent of the directory to be
+ *      removed.
+ *      @dentry contains the dentry structure of directory to be removed.
+ *      Return 0 if permission is granted.
  * @inode_mknod:
  *      Check permissions when creating a special file (or a socket or a fifo
  *      file created via the mknod system call).  Note that if mknod operation
@@ -368,6 +402,15 @@ static inline void security_free_mnt_opts(struct security_mnt_opts *opts)
  *      @mode contains the mode of the new file.
  *      @dev contains the device number.
  *      Return 0 if permission is granted.
+ * @path_mknod:
+ *      Check permissions when creating a file. Note that this hook is called
+ *      even if mknod operation is being done for a regular file.
+ *      @dir contains the path structure of parent of the new file.
+ *      @dentry contains the dentry structure of the new file.
+ *      @mode contains the mode of the new file.
+ *      @dev contains the undecoded device number. Use new_decode_dev() to get
+ *      the decoded device number.
+ *      Return 0 if permission is granted.
  * @inode_rename:
  *      Check for permission to rename a file or directory.
  *      @old_dir contains the inode structure for parent of the old link.
@@ -375,6 +418,13 @@ static inline void security_free_mnt_opts(struct security_mnt_opts *opts)
  *      @new_dir contains the inode structure for parent of the new link.
  *      @new_dentry contains the dentry structure of the new link.
  *      Return 0 if permission is granted.
+ * @path_rename:
+ *      Check for permission to rename a file or directory.
+ *      @old_dir contains the path structure for parent of the old link.
+ *      @old_dentry contains the dentry structure of the old link.
+ *      @new_dir contains the path structure for parent of the new link.
+ *      @new_dentry contains the dentry structure of the new link.
+ *      Return 0 if permission is granted.
  * @inode_readlink:
  *      Check the permission to read the symbolic link.
  *      @dentry contains the dentry structure for the file link.
@@ -403,6 +453,12 @@ static inline void security_free_mnt_opts(struct security_mnt_opts *opts)
  *      @dentry contains the dentry structure for the file.
  *      @attr is the iattr structure containing the new file attributes.
  *      Return 0 if permission is granted.
+ * @path_truncate:
+ *      Check permission before truncating a file.
+ *      @path contains the path structure for the file.
+ *      @length is the new length of the file.
+ *      @time_attrs is the flags passed to do_truncate().
+ *      Return 0 if permission is granted.
  * @inode_getattr:
  *      Check permission before obtaining file attributes.
  *      @mnt is the vfsmount where the dentry was looked up
@@ -1331,6 +1387,22 @@ struct security_operations {
                                    struct super_block *newsb);
         int (*sb_parse_opts_str) (char *options, struct security_mnt_opts *opts);
 
+#ifdef CONFIG_SECURITY_PATH
+        int (*path_unlink) (struct path *dir, struct dentry *dentry);
+        int (*path_mkdir) (struct path *dir, struct dentry *dentry, int mode);
+        int (*path_rmdir) (struct path *dir, struct dentry *dentry);
+        int (*path_mknod) (struct path *dir, struct dentry *dentry, int mode,
+                           unsigned int dev);
+        int (*path_truncate) (struct path *path, loff_t length,
+                              unsigned int time_attrs);
+        int (*path_symlink) (struct path *dir, struct dentry *dentry,
+                             const char *old_name);
+        int (*path_link) (struct dentry *old_dentry, struct path *new_dir,
+                          struct dentry *new_dentry);
+        int (*path_rename) (struct path *old_dir, struct dentry *old_dentry,
+                            struct path *new_dir, struct dentry *new_dentry);
+#endif
+
         int (*inode_alloc_security) (struct inode *inode);
         void (*inode_free_security) (struct inode *inode);
         int (*inode_init_security) (struct inode *inode, struct inode *dir,
@@ -2705,6 +2777,71 @@ static inline void security_skb_classify_flow(struct sk_buff *skb, struct flowi
 
 #endif  /* CONFIG_SECURITY_NETWORK_XFRM */
 
+#ifdef CONFIG_SECURITY_PATH
+int security_path_unlink(struct path *dir, struct dentry *dentry);
+int security_path_mkdir(struct path *dir, struct dentry *dentry, int mode);
+int security_path_rmdir(struct path *dir, struct dentry *dentry);
+int security_path_mknod(struct path *dir, struct dentry *dentry, int mode,
+                        unsigned int dev);
+int security_path_truncate(struct path *path, loff_t length,
+                           unsigned int time_attrs);
+int security_path_symlink(struct path *dir, struct dentry *dentry,
+                          const char *old_name);
+int security_path_link(struct dentry *old_dentry, struct path *new_dir,
+                       struct dentry *new_dentry);
+int security_path_rename(struct path *old_dir, struct dentry *old_dentry,
+                         struct path *new_dir, struct dentry *new_dentry);
+#else   /* CONFIG_SECURITY_PATH */
+static inline int security_path_unlink(struct path *dir, struct dentry *dentry)
+{
+        return 0;
+}
+
+static inline int security_path_mkdir(struct path *dir, struct dentry *dentry,
+                                      int mode)
+{
+        return 0;
+}
+
+static inline int security_path_rmdir(struct path *dir, struct dentry *dentry)
+{
+        return 0;
+}
+
+static inline int security_path_mknod(struct path *dir, struct dentry *dentry,
+                                      int mode, unsigned int dev)
+{
+        return 0;
+}
+
+static inline int security_path_truncate(struct path *path, loff_t length,
+                                         unsigned int time_attrs)
+{
+        return 0;
+}
+
+static inline int security_path_symlink(struct path *dir, struct dentry *dentry,
+                                        const char *old_name)
+{
+        return 0;
+}
+
+static inline int security_path_link(struct dentry *old_dentry,
+                                     struct path *new_dir,
+                                     struct dentry *new_dentry)
+{
+        return 0;
+}
+
+static inline int security_path_rename(struct path *old_dir,
+                                       struct dentry *old_dentry,
+                                       struct path *new_dir,
+                                       struct dentry *new_dentry)
+{
+        return 0;
+}
+#endif  /* CONFIG_SECURITY_PATH */
+
 #ifdef CONFIG_KEYS
 #ifdef CONFIG_SECURITY