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>
diff --git a/drivers/base/core.c b/drivers/base/core.c
index 390e664..6bee6af 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -166,13 +166,16 @@
if (MAJOR(dev->devt)) {
const char *tmp;
const char *name;
+ mode_t mode = 0;
add_uevent_var(env, "MAJOR=%u", MAJOR(dev->devt));
add_uevent_var(env, "MINOR=%u", MINOR(dev->devt));
- name = device_get_nodename(dev, &tmp);
+ name = device_get_devnode(dev, &mode, &tmp);
if (name) {
add_uevent_var(env, "DEVNAME=%s", name);
kfree(tmp);
+ if (mode)
+ add_uevent_var(env, "DEVMODE=%#o", mode & 0777);
}
}
@@ -1148,8 +1151,9 @@
}
/**
- * device_get_nodename - path of device node file
+ * device_get_devnode - path of device node file
* @dev: device
+ * @mode: returned file access mode
* @tmp: possibly allocated string
*
* Return the relative path of a possible device node.
@@ -1157,21 +1161,22 @@
* a name. This memory is returned in tmp and needs to be
* freed by the caller.
*/
-const char *device_get_nodename(struct device *dev, const char **tmp)
+const char *device_get_devnode(struct device *dev,
+ mode_t *mode, const char **tmp)
{
char *s;
*tmp = NULL;
/* the device type may provide a specific name */
- if (dev->type && dev->type->nodename)
- *tmp = dev->type->nodename(dev);
+ if (dev->type && dev->type->devnode)
+ *tmp = dev->type->devnode(dev, mode);
if (*tmp)
return *tmp;
/* the class may provide a specific name */
- if (dev->class && dev->class->nodename)
- *tmp = dev->class->nodename(dev);
+ if (dev->class && dev->class->devnode)
+ *tmp = dev->class->devnode(dev, mode);
if (*tmp)
return *tmp;
diff --git a/drivers/base/devtmpfs.c b/drivers/base/devtmpfs.c
index fd488ad..a1cb5af 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 @@
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 @@
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 @@
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 @@
if (!dev_mnt)
return 0;
- nodename = device_get_nodename(dev, &tmp);
+ nodename = device_get_devnode(dev, NULL, &tmp);
if (!nodename)
return -ENOMEM;