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Date: Mon, 24 Feb 2020 18:21:04 +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 v4 3/9] sysfs: add sysfs_group{s}_change_owner()
Add helpers to change the owner of sysfs groups.
This function will be used to correctly account for kobject ownership
changes, e.g. when moving network devices between network namespaces.
Reviewed-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Signed-off-by: Christian Brauner <christian.brauner@...ntu.com>
---
/* v2 */
- Greg Kroah-Hartman <gregkh@...uxfoundation.org>:
- Add comment how ownership of sysfs object is changed.
/* v3 */
- Greg Kroah-Hartman <gregkh@...uxfoundation.org>:
- Add explicit uid/gid parameters.
- Christian Brauner <christian.brauner@...ntu.com>:
- Collapse groups ownership helper patches into a single patch.
/* v4 */
unchanged
---
fs/sysfs/group.c | 117 ++++++++++++++++++++++++++++++++++++++++++
include/linux/sysfs.h | 20 ++++++++
2 files changed, 137 insertions(+)
diff --git a/fs/sysfs/group.c b/fs/sysfs/group.c
index c4ab045926b7..7436f729dd07 100644
--- a/fs/sysfs/group.c
+++ b/fs/sysfs/group.c
@@ -13,6 +13,7 @@
#include <linux/dcache.h>
#include <linux/namei.h>
#include <linux/err.h>
+#include <linux/fs.h>
#include "sysfs.h"
@@ -457,3 +458,119 @@ int __compat_only_sysfs_link_entry_to_kobj(struct kobject *kobj,
return PTR_ERR_OR_ZERO(link);
}
EXPORT_SYMBOL_GPL(__compat_only_sysfs_link_entry_to_kobj);
+
+static int sysfs_group_attrs_change_owner(struct kernfs_node *grp_kn,
+ const struct attribute_group *grp,
+ struct iattr *newattrs)
+{
+ struct kernfs_node *kn;
+ int error;
+
+ if (grp->attrs) {
+ struct attribute *const *attr;
+
+ for (attr = grp->attrs; *attr; attr++) {
+ kn = kernfs_find_and_get(grp_kn, (*attr)->name);
+ if (!kn)
+ return -ENOENT;
+
+ error = kernfs_setattr(kn, newattrs);
+ kernfs_put(kn);
+ if (error)
+ return error;
+ }
+ }
+
+ if (grp->bin_attrs) {
+ struct bin_attribute *const *bin_attr;
+
+ for (bin_attr = grp->bin_attrs; *bin_attr; bin_attr++) {
+ kn = kernfs_find_and_get(grp_kn, (*bin_attr)->attr.name);
+ if (!kn)
+ return -ENOENT;
+
+ error = kernfs_setattr(kn, newattrs);
+ kernfs_put(kn);
+ if (error)
+ return error;
+ }
+ }
+
+ return 0;
+}
+
+/**
+ * sysfs_group_change_owner - change owner of an attribute group.
+ * @kobj: The kobject containing the group.
+ * @grp: The attribute group.
+ * @kuid: new owner's kuid
+ * @kgid: new owner's kgid
+ *
+ * Returns 0 on success or error code on failure.
+ */
+int sysfs_group_change_owner(struct kobject *kobj,
+ const struct attribute_group *grp, kuid_t kuid,
+ kgid_t kgid)
+{
+ struct kernfs_node *grp_kn;
+ kuid_t uid;
+ kgid_t gid;
+ int error;
+ struct iattr newattrs = {
+ .ia_valid = ATTR_UID | ATTR_GID,
+ .ia_uid = kuid,
+ .ia_gid = kgid,
+ };
+
+ if (!kobj->state_in_sysfs)
+ return -EINVAL;
+
+ if (grp->name) {
+ grp_kn = kernfs_find_and_get(kobj->sd, grp->name);
+ } else {
+ kernfs_get(kobj->sd);
+ grp_kn = kobj->sd;
+ }
+ if (!grp_kn)
+ return -ENOENT;
+
+ error = kernfs_setattr(grp_kn, &newattrs);
+ if (!error)
+ error = sysfs_group_attrs_change_owner(grp_kn, grp, &newattrs);
+
+ kernfs_put(grp_kn);
+
+ return error;
+}
+EXPORT_SYMBOL_GPL(sysfs_group_change_owner);
+
+/**
+ * sysfs_groups_change_owner - change owner of a set of attribute groups.
+ * @kobj: The kobject containing the groups.
+ * @groups: The attribute groups.
+ * @kuid: new owner's kuid
+ * @kgid: new owner's kgid
+ *
+ * Returns 0 on success or error code on failure.
+ */
+int sysfs_groups_change_owner(struct kobject *kobj,
+ const struct attribute_group **groups,
+ kuid_t kuid, kgid_t kgid)
+{
+ int error = 0, i;
+
+ if (!kobj->state_in_sysfs)
+ return -EINVAL;
+
+ if (!groups)
+ return 0;
+
+ for (i = 0; groups[i]; i++) {
+ error = sysfs_group_change_owner(kobj, groups[i], kuid, kgid);
+ if (error)
+ break;
+ }
+
+ return error;
+}
+EXPORT_SYMBOL_GPL(sysfs_groups_change_owner);
diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h
index 7e15ebfd750e..3fcaabdb05ef 100644
--- a/include/linux/sysfs.h
+++ b/include/linux/sysfs.h
@@ -314,6 +314,12 @@ int sysfs_file_change_owner(struct kobject *kobj, const char *name, kuid_t kuid,
kgid_t kgid);
int sysfs_link_change_owner(struct kobject *kobj, struct kobject *targ,
const char *name, kuid_t kuid, kgid_t kgid);
+int sysfs_groups_change_owner(struct kobject *kobj,
+ const struct attribute_group **groups,
+ kuid_t kuid, kgid_t kgid);
+int sysfs_group_change_owner(struct kobject *kobj,
+ const struct attribute_group *groups, kuid_t kuid,
+ kgid_t kgid);
#else /* CONFIG_SYSFS */
@@ -542,6 +548,20 @@ static inline int sysfs_link_change_owner(struct kobject *kobj,
return 0;
}
+static inline int sysfs_groups_change_owner(struct kobject *kobj,
+ const struct attribute_group **groups,
+ kuid_t kuid, kgid_t kgid)
+{
+ return 0;
+}
+
+static inline int sysfs_group_change_owner(struct kobject *kobj,
+ const struct attribute_group **groups,
+ 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
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