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>

20 files changed, 94 insertions, 59 deletions

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 390e664ec1c7..6bee6af8d8e1 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -166,13 +166,16 @@ static int dev_uevent(struct kset *kset, struct kobject *kobj,
         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 @@ static struct device *next_device(struct klist_iter *i)
 }
 
 /**
- * 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 @@ static struct device *next_device(struct klist_iter *i)
  * 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 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;
 
diff --git a/drivers/block/aoe/aoechr.c b/drivers/block/aoe/aoechr.c
index 19888354188f..62141ec09a22 100644
--- a/drivers/block/aoe/aoechr.c
+++ b/drivers/block/aoe/aoechr.c
@@ -266,7 +266,7 @@ static const struct file_operations aoe_fops = {
         .owner = THIS_MODULE,
 };
 
-static char *aoe_nodename(struct device *dev)
+static char *aoe_devnode(struct device *dev, mode_t *mode)
 {
         return kasprintf(GFP_KERNEL, "etherd/%s", dev_name(dev));
 }
@@ -288,7 +288,7 @@ aoechr_init(void)
                 unregister_chrdev(AOE_MAJOR, "aoechr");
                 return PTR_ERR(aoe_class);
         }
-        aoe_class->nodename = aoe_nodename;
+        aoe_class->devnode = aoe_devnode;
 
         for (i = 0; i < ARRAY_SIZE(chardevs); ++i)
                 device_create(aoe_class, NULL,
diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c
index 95f11cdef203..fd5bb8ad59a9 100644
--- a/drivers/block/pktcdvd.c
+++ b/drivers/block/pktcdvd.c
@@ -2857,7 +2857,7 @@ static struct block_device_operations pktcdvd_ops = {
         .media_changed =        pkt_media_changed,
 };
 
-static char *pktcdvd_nodename(struct gendisk *gd)
+static char *pktcdvd_devnode(struct gendisk *gd, mode_t *mode)
 {
         return kasprintf(GFP_KERNEL, "pktcdvd/%s", gd->disk_name);
 }
@@ -2914,7 +2914,7 @@ static int pkt_setup_dev(dev_t dev, dev_t* pkt_dev)
         disk->fops = &pktcdvd_ops;
         disk->flags = GENHD_FL_REMOVABLE;
         strcpy(disk->disk_name, pd->name);
-        disk->nodename = pktcdvd_nodename;
+        disk->devnode = pktcdvd_devnode;
         disk->private_data = pd;
         disk->queue = blk_alloc_queue(GFP_KERNEL);
         if (!disk->queue)
@@ -3070,7 +3070,7 @@ static const struct file_operations pkt_ctl_fops = {
 static struct miscdevice pkt_misc = {
         .minor          = MISC_DYNAMIC_MINOR,
         .name           = DRIVER_NAME,
-        .name           = "pktcdvd/control",
+        .nodename       = "pktcdvd/control",
         .fops           = &pkt_ctl_fops
 };
 
diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c
index fc93e2fc7c71..1573aebd54b5 100644
--- a/drivers/char/hw_random/core.c
+++ b/drivers/char/hw_random/core.c
@@ -153,7 +153,7 @@ static const struct file_operations rng_chrdev_ops = {
 static struct miscdevice rng_miscdev = {
         .minor          = RNG_MISCDEV_MINOR,
         .name           = RNG_MODULE_NAME,
-        .devnode        = "hwrng",
+        .nodename       = "hwrng",
         .fops           = &rng_chrdev_ops,
 };
 
diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index 0491cdf63f2a..0aede1d6a9ea 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -866,24 +866,25 @@ static const struct file_operations kmsg_fops = {
 
 static const struct memdev {
         const char *name;
+        mode_t mode;
         const struct file_operations *fops;
         struct backing_dev_info *dev_info;
 } devlist[] = {
-        [ 1] = { "mem", &mem_fops, &directly_mappable_cdev_bdi },
+         [1] = { "mem", 0, &mem_fops, &directly_mappable_cdev_bdi },
 #ifdef CONFIG_DEVKMEM
-        [ 2] = { "kmem", &kmem_fops, &directly_mappable_cdev_bdi },
+         [2] = { "kmem", 0, &kmem_fops, &directly_mappable_cdev_bdi },
 #endif
-        [ 3] = {"null", &null_fops, NULL },
+         [3] = { "null", 0666, &null_fops, NULL },
 #ifdef CONFIG_DEVPORT
-        [ 4] = { "port", &port_fops, NULL },
+         [4] = { "port", 0, &port_fops, NULL },
 #endif
-        [ 5] = { "zero", &zero_fops, &zero_bdi },
-        [ 7] = { "full", &full_fops, NULL },
-        [ 8] = { "random", &random_fops, NULL },
-        [ 9] = { "urandom", &urandom_fops, NULL },
-        [11] = { "kmsg", &kmsg_fops, NULL },
+         [5] = { "zero", 0666, &zero_fops, &zero_bdi },
+         [7] = { "full", 0666, &full_fops, NULL },
+         [8] = { "random", 0666, &random_fops, NULL },
+         [9] = { "urandom", 0666, &urandom_fops, NULL },
+        [11] = { "kmsg", 0, &kmsg_fops, NULL },
 #ifdef CONFIG_CRASH_DUMP
-        [12] = { "oldmem", &oldmem_fops, NULL },
+        [12] = { "oldmem", 0, &oldmem_fops, NULL },
 #endif
 };
 
@@ -920,6 +921,13 @@ static const struct file_operations memory_fops = {
         .open           = memory_open,
 };
 
+static char *mem_devnode(struct device *dev, mode_t *mode)
+{
+        if (mode && devlist[MINOR(dev->devt)].mode)
+                *mode = devlist[MINOR(dev->devt)].mode;
+        return NULL;
+}
+
 static struct class *mem_class;
 
 static int __init chr_dev_init(void)
@@ -935,6 +943,7 @@ static int __init chr_dev_init(void)
                 printk("unable to get major %d for memory devs\n", MEM_MAJOR);
 
         mem_class = class_create(THIS_MODULE, "mem");
+        mem_class->devnode = mem_devnode;
         for (minor = 1; minor < ARRAY_SIZE(devlist); minor++) {
                 if (!devlist[minor].name)
                         continue;
diff --git a/drivers/char/misc.c b/drivers/char/misc.c
index 62c99fa59e2b..1ee27cc23426 100644
--- a/drivers/char/misc.c
+++ b/drivers/char/misc.c
@@ -263,12 +263,14 @@ int misc_deregister(struct miscdevice *misc)
 EXPORT_SYMBOL(misc_register);
 EXPORT_SYMBOL(misc_deregister);
 
-static char *misc_nodename(struct device *dev)
+static char *misc_devnode(struct device *dev, mode_t *mode)
 {
         struct miscdevice *c = dev_get_drvdata(dev);
 
-        if (c->devnode)
-                return kstrdup(c->devnode, GFP_KERNEL);
+        if (mode && c->mode)
+                *mode = c->mode;
+        if (c->nodename)
+                return kstrdup(c->nodename, GFP_KERNEL);
         return NULL;
 }
 
@@ -287,7 +289,7 @@ static int __init misc_init(void)
         err = -EIO;
         if (register_chrdev(MISC_MAJOR,"misc",&misc_fops))
                 goto fail_printk;
-        misc_class->nodename = misc_nodename;
+        misc_class->devnode = misc_devnode;
         return 0;
 
 fail_printk:
diff --git a/drivers/char/raw.c b/drivers/char/raw.c
index 40268db02e22..64acd05f71c8 100644
--- a/drivers/char/raw.c
+++ b/drivers/char/raw.c
@@ -261,7 +261,7 @@ static const struct file_operations raw_ctl_fops = {
 
 static struct cdev raw_cdev;
 
-static char *raw_nodename(struct device *dev)
+static char *raw_devnode(struct device *dev, mode_t *mode)
 {
         return kasprintf(GFP_KERNEL, "raw/%s", dev_name(dev));
 }
@@ -289,7 +289,7 @@ static int __init raw_init(void)
                 ret = PTR_ERR(raw_class);
                 goto error_region;
         }
-        raw_class->nodename = raw_nodename;
+        raw_class->devnode = raw_devnode;
         device_create(raw_class, NULL, MKDEV(RAW_MAJOR, 0), NULL, "rawctl");
 
         return 0;
diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
index a3afa0c387cd..c70d9dabefae 100644
--- a/drivers/char/tty_io.c
+++ b/drivers/char/tty_io.c
@@ -3056,11 +3056,22 @@ void __init console_init(void)
         }
 }
 
+static char *tty_devnode(struct device *dev, mode_t *mode)
+{
+        if (!mode)
+                return NULL;
+        if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
+            dev->devt == MKDEV(TTYAUX_MAJOR, 2))
+                *mode = 0666;
+        return NULL;
+}
+
 static int __init tty_class_init(void)
 {
         tty_class = class_create(THIS_MODULE, "tty");
         if (IS_ERR(tty_class))
                 return PTR_ERR(tty_class);
+        tty_class->devnode = tty_devnode;
         return 0;
 }
 
diff --git a/drivers/gpu/drm/drm_sysfs.c b/drivers/gpu/drm/drm_sysfs.c
index f7a615b80c70..5301f226cb1c 100644
--- a/drivers/gpu/drm/drm_sysfs.c
+++ b/drivers/gpu/drm/drm_sysfs.c
@@ -76,7 +76,7 @@ static ssize_t version_show(struct class *dev, char *buf)
                        CORE_MINOR, CORE_PATCHLEVEL, CORE_DATE);
 }
 
-static char *drm_nodename(struct device *dev)
+static char *drm_devnode(struct device *dev, mode_t *mode)
 {
         return kasprintf(GFP_KERNEL, "dri/%s", dev_name(dev));
 }
@@ -112,7 +112,7 @@ struct class *drm_sysfs_create(struct module *owner, char *name)
         if (err)
                 goto err_out_class;
 
-        class->nodename = drm_nodename;
+        class->devnode = drm_devnode;
 
         return class;
 
diff --git a/drivers/hid/usbhid/hiddev.c b/drivers/hid/usbhid/hiddev.c
index 4d1dc0cf1401..8b6ee247bfe4 100644
--- a/drivers/hid/usbhid/hiddev.c
+++ b/drivers/hid/usbhid/hiddev.c
@@ -852,14 +852,14 @@ static const struct file_operations hiddev_fops = {
 #endif
 };
 
-static char *hiddev_nodename(struct device *dev)
+static char *hiddev_devnode(struct device *dev, mode_t *mode)
 {
         return kasprintf(GFP_KERNEL, "usb/%s", dev_name(dev));
 }
 
 static struct usb_class_driver hiddev_class = {
         .name =         "hiddev%d",
-        .nodename =     hiddev_nodename,
+        .devnode =      hiddev_devnode,
         .fops =         &hiddev_fops,
         .minor_base =   HIDDEV_MINOR_BASE,
 };
diff --git a/drivers/input/input.c b/drivers/input/input.c
index 851791d955f3..556539d617a4 100644
--- a/drivers/input/input.c
+++ b/drivers/input/input.c
@@ -1265,14 +1265,14 @@ static struct device_type input_dev_type = {
         .uevent         = input_dev_uevent,
 };
 
-static char *input_nodename(struct device *dev)
+static char *input_devnode(struct device *dev, mode_t *mode)
 {
         return kasprintf(GFP_KERNEL, "input/%s", dev_name(dev));
 }
 
 struct class input_class = {
         .name           = "input",
-        .nodename       = input_nodename,
+        .devnode        = input_devnode,
 };
 EXPORT_SYMBOL_GPL(input_class);
 
diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c
index 7f77f18fcafa..a67942931582 100644
--- a/drivers/md/dm-ioctl.c
+++ b/drivers/md/dm-ioctl.c
@@ -1532,7 +1532,7 @@ static const struct file_operations _ctl_fops = {
 static struct miscdevice _dm_misc = {
         .minor          = MISC_DYNAMIC_MINOR,
         .name           = DM_NAME,
-        .devnode        = "mapper/control",
+        .nodename       = "mapper/control",
         .fops           = &_ctl_fops
 };
 
diff --git a/drivers/media/dvb/dvb-core/dvbdev.c b/drivers/media/dvb/dvb-core/dvbdev.c
index 479dd05762a5..94159b90f733 100644
--- a/drivers/media/dvb/dvb-core/dvbdev.c
+++ b/drivers/media/dvb/dvb-core/dvbdev.c
@@ -447,7 +447,7 @@ static int dvb_uevent(struct device *dev, struct kobj_uevent_env *env)
         return 0;
 }
 
-static char *dvb_nodename(struct device *dev)
+static char *dvb_devnode(struct device *dev, mode_t *mode)
 {
         struct dvb_device *dvbdev = dev_get_drvdata(dev);
 
@@ -478,7 +478,7 @@ static int __init init_dvbdev(void)
                 goto error;
         }
         dvb_class->dev_uevent = dvb_uevent;
-        dvb_class->nodename = dvb_nodename;
+        dvb_class->devnode = dvb_devnode;
         return 0;
 
 error:
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 3f5d28851aa2..d3ee1994b02f 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -1370,7 +1370,7 @@ static const struct file_operations tun_fops = {
 static struct miscdevice tun_miscdev = {
         .minor = TUN_MINOR,
         .name = "tun",
-        .devnode = "net/tun",
+        .nodename = "net/tun",
         .fops = &tun_fops,
 };
 
diff --git a/drivers/usb/class/usblp.c b/drivers/usb/class/usblp.c
index 26c09f0257db..9bc112ee7803 100644
--- a/drivers/usb/class/usblp.c
+++ b/drivers/usb/class/usblp.c
@@ -1057,14 +1057,14 @@ static const struct file_operations usblp_fops = {
         .release =      usblp_release,
 };
 
-static char *usblp_nodename(struct device *dev)
+static char *usblp_devnode(struct device *dev, mode_t *mode)
 {
         return kasprintf(GFP_KERNEL, "usb/%s", dev_name(dev));
 }
 
 static struct usb_class_driver usblp_class = {
         .name =         "lp%d",
-        .nodename =     usblp_nodename,
+        .devnode =      usblp_devnode,
         .fops =         &usblp_fops,
         .minor_base =   USBLP_MINOR_BASE,
 };
diff --git a/drivers/usb/core/file.c b/drivers/usb/core/file.c
index 5cef88929b3e..222ee07ea680 100644
--- a/drivers/usb/core/file.c
+++ b/drivers/usb/core/file.c
@@ -67,14 +67,14 @@ static struct usb_class {
         struct class *class;
 } *usb_class;
 
-static char *usb_nodename(struct device *dev)
+static char *usb_devnode(struct device *dev, mode_t *mode)
 {
         struct usb_class_driver *drv;
 
         drv = dev_get_drvdata(dev);
-        if (!drv || !drv->nodename)
+        if (!drv || !drv->devnode)
                 return NULL;
-        return drv->nodename(dev);
+        return drv->devnode(dev, mode);
 }
 
 static int init_usb_class(void)
@@ -100,7 +100,7 @@ static int init_usb_class(void)
                 kfree(usb_class);
                 usb_class = NULL;
         }
-        usb_class->class->nodename = usb_nodename;
+        usb_class->class->devnode = usb_devnode;
 
 exit:
         return result;
diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c
index a26f73880c32..43ee943d757a 100644
--- a/drivers/usb/core/usb.c
+++ b/drivers/usb/core/usb.c
@@ -311,7 +311,7 @@ static struct dev_pm_ops usb_device_pm_ops = {
 #endif  /* CONFIG_PM */
 
 
-static char *usb_nodename(struct device *dev)
+static char *usb_devnode(struct device *dev, mode_t *mode)
 {
         struct usb_device *usb_dev;
 
@@ -324,7 +324,7 @@ struct device_type usb_device_type = {
         .name =         "usb_device",
         .release =      usb_release_dev,
         .uevent =       usb_dev_uevent,
-        .nodename =     usb_nodename,
+        .devnode =      usb_devnode,
         .pm =           &usb_device_pm_ops,
 };
 
diff --git a/drivers/usb/misc/iowarrior.c b/drivers/usb/misc/iowarrior.c
index 90e1a8dedfa9..e75bb87ee92b 100644
--- a/drivers/usb/misc/iowarrior.c
+++ b/drivers/usb/misc/iowarrior.c
@@ -727,7 +727,7 @@ static const struct file_operations iowarrior_fops = {
         .poll = iowarrior_poll,
 };
 
-static char *iowarrior_nodename(struct device *dev)
+static char *iowarrior_devnode(struct device *dev, mode_t *mode)
 {
         return kasprintf(GFP_KERNEL, "usb/%s", dev_name(dev));
 }
@@ -738,7 +738,7 @@ static char *iowarrior_nodename(struct device *dev)
  */
 static struct usb_class_driver iowarrior_class = {
         .name = "iowarrior%d",
-        .nodename = iowarrior_nodename,
+        .devnode = iowarrior_devnode,
         .fops = &iowarrior_fops,
         .minor_base = IOWARRIOR_MINOR_BASE,
 };
diff --git a/drivers/usb/misc/legousbtower.c b/drivers/usb/misc/legousbtower.c
index c1e2433f640d..97efeaec4d52 100644
--- a/drivers/usb/misc/legousbtower.c
+++ b/drivers/usb/misc/legousbtower.c
@@ -266,7 +266,7 @@ static const struct file_operations tower_fops = {
         .llseek =       tower_llseek,
 };
 
-static char *legousbtower_nodename(struct device *dev)
+static char *legousbtower_devnode(struct device *dev, mode_t *mode)
 {
         return kasprintf(GFP_KERNEL, "usb/%s", dev_name(dev));
 }
@@ -277,7 +277,7 @@ static char *legousbtower_nodename(struct device *dev)
  */
 static struct usb_class_driver tower_class = {
         .name =         "legousbtower%d",
-        .nodename =     legousbtower_nodename,
+        .devnode =      legousbtower_devnode,
         .fops =         &tower_fops,
         .minor_base =   LEGO_USB_TOWER_MINOR_BASE,
 };