[PATCH net-next v3 1/9] sysfs: add sysfs_file_change_owner{_by_name}()
From: Christian Brauner <hidden>
Date: 2020-02-18 16:30:09
Also in:
linux-pm, lkml
Subsystem:
driver core, kobjects, debugfs and sysfs, filesystems (vfs and infrastructure), the rest · Maintainers:
Greg Kroah-Hartman, "Rafael J. Wysocki", Danilo Krummrich, Alexander Viro, Christian Brauner, Linus Torvalds
Add helpers to change the owner of a sysfs files.
This function will be used to correctly account for kobject ownership
changes, e.g. when moving network devices between network namespaces.
Signed-off-by: Christian Brauner <redacted>
---
/* v2 */
- Greg Kroah-Hartman [off-list ref]:
- Better naming for sysfs_file_change_owner() to reflect the fact that it
can be used to change the owner of the kobject itself by passing NULL as
argument.
- Christian Brauner [off-list ref]:
- Split sysfs_file_change_owner() into two helpers sysfs_change_owner() and
sysfs_change_owner_by_name(). The former changes the owner of the kobject
itself, the latter the owner of the kobject looked up via the name
argument.
/* v3 */
- Greg Kroah-Hartman [off-list ref]:
- Add explicit uid/gid parameters.
---
fs/sysfs/file.c | 67 +++++++++++++++++++++++++++++++++++++++++++
include/linux/sysfs.h | 17 +++++++++++
2 files changed, 84 insertions(+)
diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index 130fc6fbcc03..32bb04b4d9d9 100644
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c@@ -558,3 +558,70 @@ void sysfs_remove_bin_file(struct kobject *kobj, kernfs_remove_by_name(kobj->sd, attr->attr.name); } EXPORT_SYMBOL_GPL(sysfs_remove_bin_file); + +static int internal_change_owner(struct kernfs_node *kn, struct kobject *kobj, + kuid_t kuid, kgid_t kgid) +{ + struct iattr newattrs = { + .ia_valid = ATTR_UID | ATTR_GID, + .ia_uid = kuid, + .ia_gid = kgid, + }; + return kernfs_setattr(kn, &newattrs); +} + +/** + * sysfs_file_change_owner_by_name - change owner of a file. + * @kobj: object. + * @name: name of the file to change. + * @kuid: new owner's kuid + * @kgid: new owner's kgid + */ +int sysfs_file_change_owner_by_name(struct kobject *kobj, const char *name, + kuid_t kuid, kgid_t kgid) +{ + struct kernfs_node *kn; + int error; + + if (!name) + return -EINVAL; + + if (!kobj->state_in_sysfs) + return -EINVAL; + + kn = kernfs_find_and_get(kobj->sd, name); + if (!kn) + return -ENOENT; + + error = internal_change_owner(kn, kobj, kuid, kgid); + + kernfs_put(kn); + + return error; +} +EXPORT_SYMBOL_GPL(sysfs_file_change_owner_by_name); + +/** + * sysfs_file_change_owner - change owner of a file. + * @kobj: object. + * @kuid: new owner's kuid + * @kgid: new owner's kgid + */ +int sysfs_file_change_owner(struct kobject *kobj, kuid_t kuid, kgid_t kgid) +{ + struct kernfs_node *kn; + int error; + + if (!kobj->state_in_sysfs) + return -EINVAL; + + kernfs_get(kobj->sd); + + kn = kobj->sd; + error = internal_change_owner(kn, kobj, kuid, kgid); + + kernfs_put(kn); + + return error; +} +EXPORT_SYMBOL_GPL(sysfs_file_change_owner);
diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h
index fa7ee503fb76..c11d11c78713 100644
--- a/include/linux/sysfs.h
+++ b/include/linux/sysfs.h@@ -310,6 +310,10 @@ static inline void sysfs_enable_ns(struct kernfs_node *kn) return kernfs_enable_ns(kn); } +int sysfs_file_change_owner(struct kobject *kobj, kuid_t kuid, kgid_t kgid); +int sysfs_file_change_owner_by_name(struct kobject *kobj, const char *name, + kuid_t kuid, kgid_t kgid); + #else /* CONFIG_SYSFS */ static inline int sysfs_create_dir_ns(struct kobject *kobj, const void *ns)
@@ -522,6 +526,19 @@ static inline void sysfs_enable_ns(struct kernfs_node *kn) { } +static inline int int sysfs_file_change_owner(struct kobject *kobj, kuid_t kuid, + kgid_t kgid) +{ + return 0; +} + +static inline int sysfs_file_change_owner_by_name(struct kobject *kobj, + const char *name, kuid_t kuid, + kgid_t kgid) +{ + return 0; +} + #endif /* CONFIG_SYSFS */ static inline int __must_check sysfs_create_file(struct kobject *kobj,
--
2.25.0