From e454cea20bdcff10ee698d11b8882662a0153a47 Mon Sep 17 00:00:00 2001 From: Kay Sievers Date: Fri, 18 Sep 2009 23:01:12 +0200 Subject: 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 Signed-off-by: Greg Kroah-Hartman --- drivers/base/core.c | 19 ++++++++++++------- drivers/base/devtmpfs.c | 24 ++++++++++++++++-------- 2 files changed, 28 insertions(+), 15 deletions(-) (limited to 'drivers/base') diff --git a/drivers/base/core.c b/drivers/base/core.c index 390e664ec1c..6bee6af8d8e 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 fd488ad4263..a1cb5afe680 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 @@ -20,6 +21,7 @@ #include #include #include +#include #include 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; -- cgit v1.2.3