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Driver-Core: extend devnode callbacks to provide permissions

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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>
This commit is contained in:
Kay Sievers
2009-09-18 23:01:12 +02:00
committed by Live-CD User
parent 78f28b7c55
commit e454cea20b
30 changed files with 116 additions and 79 deletions
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24
drivers/base/devtmpfs.c
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@@ -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;