Driver-Core: extend devnode callbacks to provide permissions

This allows subsytems to provide devtmpfs with non-default permissions
for the device node. Instead of the default mode of 0600, null, zero,
random, urandom, full, tty, ptmx now have a mode of 0666, which allows
non-privileged processes to access standard device nodes in case no
other userspace process applies the expected permissions.

This also fixes a wrong assignment in pktcdvd and a checkpatch.pl complain.

Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 16 insertions, 8 deletions

diff --git a/drivers/base/devtmpfs.c b/drivers/base/devtmpfs.c
index fd488ad4263a..a1cb5afe6801 100644
--- a/drivers/base/devtmpfs.c
+++ b/drivers/base/devtmpfs.c
@@ -6,9 +6,10 @@
  * During bootup, before any driver core device is registered,
  * devtmpfs, a tmpfs-based filesystem is created. Every driver-core
  * device which requests a device node, will add a node in this
- * filesystem. The node is named after the the name of the device,
- * or the susbsytem can provide a custom name. All devices are
- * owned by root and have a mode of 0600.
+ * filesystem.
+ * By default, all devices are named after the the name of the
+ * device, owned by root and have a default mode of 0600. Subsystems
+ * can overwrite the default setting if needed.
  */
 
 #include <linux/kernel.h>
@@ -20,6 +21,7 @@
 #include <linux/fs.h>
 #include <linux/shmem_fs.h>
 #include <linux/cred.h>
+#include <linux/sched.h>
 #include <linux/init_task.h>
 
 static struct vfsmount *dev_mnt;
@@ -134,7 +136,7 @@ int devtmpfs_create_node(struct device *dev)
         const char *tmp = NULL;
         const char *nodename;
         const struct cred *curr_cred;
-        mode_t mode;
+        mode_t mode = 0;
         struct nameidata nd;
         struct dentry *dentry;
         int err;
@@ -142,14 +144,16 @@ int devtmpfs_create_node(struct device *dev)
         if (!dev_mnt)
                 return 0;
 
-        nodename = device_get_nodename(dev, &tmp);
+        nodename = device_get_devnode(dev, &mode, &tmp);
         if (!nodename)
                 return -ENOMEM;
 
+        if (mode == 0)
+                mode = 0600;
         if (is_blockdev(dev))
-                mode = S_IFBLK|0600;
+                mode |= S_IFBLK;
         else
-                mode = S_IFCHR|0600;
+                mode |= S_IFCHR;
 
         curr_cred = override_creds(&init_cred);
         err = vfs_path_lookup(dev_mnt->mnt_root, dev_mnt,
@@ -165,8 +169,12 @@ int devtmpfs_create_node(struct device *dev)
 
         dentry = lookup_create(&nd, 0);
         if (!IS_ERR(dentry)) {
+                int umask;
+
+                umask = sys_umask(0000);
                 err = vfs_mknod(nd.path.dentry->d_inode,
                                 dentry, mode, dev->devt);
+                sys_umask(umask);
                 /* mark as kernel created inode */
                 if (!err)
                         dentry->d_inode->i_private = &dev_mnt;
@@ -271,7 +279,7 @@ int devtmpfs_delete_node(struct device *dev)
         if (!dev_mnt)
                 return 0;
 
-        nodename = device_get_nodename(dev, &tmp);
+        nodename = device_get_devnode(dev, NULL, &tmp);
         if (!nodename)
                 return -ENOMEM;