lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Tue, 25 Feb 2020 13:49:40 +0100 From: Christian Brauner <christian.brauner@...ntu.com> To: "David S. Miller" <davem@...emloft.net>, Greg Kroah-Hartman <gregkh@...uxfoundation.org>, linux-kernel@...r.kernel.org, netdev@...r.kernel.org Cc: "Rafael J. Wysocki" <rafael@...nel.org>, Pavel Machek <pavel@....cz>, Jakub Kicinski <kuba@...nel.org>, Eric Dumazet <edumazet@...gle.com>, Stephen Hemminger <stephen@...workplumber.org>, linux-pm@...r.kernel.org, Christian Brauner <christian.brauner@...ntu.com> Subject: [PATCH v5 1/9] sysfs: add sysfs_file_change_owner_by_name() 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 <christian.brauner@...ntu.com> --- /* v2 */ - Greg Kroah-Hartman <gregkh@...uxfoundation.org>: - 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 <christian.brauner@...ntu.com>: - 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 <gregkh@...uxfoundation.org>: - Add explicit uid/gid parameters. /* v4 */ - Greg Kroah-Hartman <gregkh@...uxfoundation.org>: - Remove the second helper which changes the ownership of the kobject itself and do it in-place instead later on in the series. A separate helper is not needed for that. - Christian Brauner <christian.brauner@...ntu.com>: - Add more documentation. /* v5 */ unchanged --- fs/sysfs/file.c | 47 +++++++++++++++++++++++++++++++++++++++++++ include/linux/sysfs.h | 10 +++++++++ 2 files changed, 57 insertions(+) diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c index 130fc6fbcc03..4ca936ca3ba4 100644 --- a/fs/sysfs/file.c +++ b/fs/sysfs/file.c @@ -558,3 +558,50 @@ 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, 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 - change owner of a sysfs file. + * @kobj: object. + * @name: name of the file to change. + * @kuid: new owner's kuid + * @kgid: new owner's kgid + * + * This function looks up the sysfs entry @name under @kobj and changes the + * ownership to @kuid/@...d. + * + * Returns 0 on success or error code on failure. + */ +int sysfs_file_change_owner(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, 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..a7884024a911 100644 --- a/include/linux/sysfs.h +++ b/include/linux/sysfs.h @@ -310,6 +310,9 @@ static inline void sysfs_enable_ns(struct kernfs_node *kn) return kernfs_enable_ns(kn); } +int sysfs_file_change_owner(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 +525,13 @@ static inline void sysfs_enable_ns(struct kernfs_node *kn) { } +static inline int sysfs_file_change_owner(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, -- 2.25.1
Powered by blists - more mailing lists