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Commit 488dee96 authored by Dmitry Torokhov's avatar Dmitry Torokhov Committed by David S. Miller
Browse files

kernfs: allow creating kernfs objects with arbitrary uid/gid 



This change allows creating kernfs files and directories with arbitrary
uid/gid instead of always using GLOBAL_ROOT_UID/GID by extending
kernfs_create_dir_ns() and kernfs_create_file_ns() with uid/gid arguments.
The "simple" kernfs_create_file() and kernfs_create_dir() are left alone
and always create objects belonging to the global root.

When creating symlinks ownership (uid/gid) is taken from the target kernfs
object.

Co-Developed-by: default avatarTyler Hicks <tyhicks@canonical.com>
Signed-off-by: default avatarDmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: default avatarTyler Hicks <tyhicks@canonical.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 7c4ec749

arch/x86/kernel/cpu/intel_rdt_rdtgroup.c

+3 −1
Original line number Diff line number Diff line
@@ -146,6 +146,7 @@ static int rdtgroup_add_file(struct kernfs_node *parent_kn, struct rftype *rft) 
	int ret;



	kn = __kernfs_create_file(parent_kn, rft->name, rft->mode,

				  GLOBAL_ROOT_UID, GLOBAL_ROOT_GID,

				  0, rft->kf_ops, rft, NULL, NULL);

	if (IS_ERR(kn))

		return PTR_ERR(kn);
@@ -1503,7 +1504,8 @@ static int mon_addfile(struct kernfs_node *parent_kn, const char *name, 
	struct kernfs_node *kn;

	int ret = 0;



	kn = __kernfs_create_file(parent_kn, name, 0444, 0,

	kn = __kernfs_create_file(parent_kn, name, 0444,

				  GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, 0,

				  &kf_mondata_ops, priv, NULL, NULL);

	if (IS_ERR(kn))

		return PTR_ERR(kn);

fs/kernfs/dir.c

+26 −3
Original line number Diff line number Diff line
@@ -619,6 +619,7 @@ struct kernfs_node *kernfs_node_from_dentry(struct dentry *dentry) 


static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root,

					     const char *name, umode_t mode,

					     kuid_t uid, kgid_t gid,

					     unsigned flags)

{

	struct kernfs_node *kn;
@@ -661,8 +662,22 @@ static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root, 
	kn->mode = mode;

	kn->flags = flags;



	if (!uid_eq(uid, GLOBAL_ROOT_UID) || !gid_eq(gid, GLOBAL_ROOT_GID)) {

		struct iattr iattr = {

			.ia_valid = ATTR_UID | ATTR_GID,

			.ia_uid = uid,

			.ia_gid = gid,

		};



		ret = __kernfs_setattr(kn, &iattr);

		if (ret < 0)

			goto err_out3;

	}



	return kn;



 err_out3:

	idr_remove(&root->ino_idr, kn->id.ino);

 err_out2:

	kmem_cache_free(kernfs_node_cache, kn);

 err_out1:
@@ -672,11 +687,13 @@ static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root, 


struct kernfs_node *kernfs_new_node(struct kernfs_node *parent,

				    const char *name, umode_t mode,

				    kuid_t uid, kgid_t gid,

				    unsigned flags)

{

	struct kernfs_node *kn;



	kn = __kernfs_new_node(kernfs_root(parent), name, mode, flags);

	kn = __kernfs_new_node(kernfs_root(parent),

			       name, mode, uid, gid, flags);

	if (kn) {

		kernfs_get(parent);

		kn->parent = parent;
@@ -946,6 +963,7 @@ struct kernfs_root *kernfs_create_root(struct kernfs_syscall_ops *scops, 
	root->next_generation = 1;



	kn = __kernfs_new_node(root, "", S_IFDIR | S_IRUGO | S_IXUGO,

			       GLOBAL_ROOT_UID, GLOBAL_ROOT_GID,

			       KERNFS_DIR);

	if (!kn) {

		idr_destroy(&root->ino_idr);
@@ -984,6 +1002,8 @@ void kernfs_destroy_root(struct kernfs_root *root) 
 * @parent: parent in which to create a new directory

 * @name: name of the new directory

 * @mode: mode of the new directory

 * @uid: uid of the new directory

 * @gid: gid of the new directory

 * @priv: opaque data associated with the new directory

 * @ns: optional namespace tag of the directory

 *
@@ -991,13 +1011,15 @@ void kernfs_destroy_root(struct kernfs_root *root) 
 */

struct kernfs_node *kernfs_create_dir_ns(struct kernfs_node *parent,

					 const char *name, umode_t mode,

					 kuid_t uid, kgid_t gid,

					 void *priv, const void *ns)

{

	struct kernfs_node *kn;

	int rc;



	/* allocate */

	kn = kernfs_new_node(parent, name, mode | S_IFDIR, KERNFS_DIR);

	kn = kernfs_new_node(parent, name, mode | S_IFDIR,

			     uid, gid, KERNFS_DIR);

	if (!kn)

		return ERR_PTR(-ENOMEM);
@@ -1028,7 +1050,8 @@ struct kernfs_node *kernfs_create_empty_dir(struct kernfs_node *parent, 
	int rc;



	/* allocate */

	kn = kernfs_new_node(parent, name, S_IRUGO|S_IXUGO|S_IFDIR, KERNFS_DIR);

	kn = kernfs_new_node(parent, name, S_IRUGO|S_IXUGO|S_IFDIR,

			     GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, KERNFS_DIR);

	if (!kn)

		return ERR_PTR(-ENOMEM);

fs/kernfs/file.c

+6 −2
Original line number Diff line number Diff line
@@ -965,6 +965,8 @@ const struct file_operations kernfs_file_fops = { 
 * @parent: directory to create the file in

 * @name: name of the file

 * @mode: mode of the file

 * @uid: uid of the file

 * @gid: gid of the file

 * @size: size of the file

 * @ops: kernfs operations for the file

 * @priv: private data for the file
@@ -975,7 +977,8 @@ const struct file_operations kernfs_file_fops = { 
 */

struct kernfs_node *__kernfs_create_file(struct kernfs_node *parent,

					 const char *name,

					 umode_t mode, loff_t size,

					 umode_t mode, kuid_t uid, kgid_t gid,

					 loff_t size,

					 const struct kernfs_ops *ops,

					 void *priv, const void *ns,

					 struct lock_class_key *key)
@@ -986,7 +989,8 @@ struct kernfs_node *__kernfs_create_file(struct kernfs_node *parent, 


	flags = KERNFS_FILE;



	kn = kernfs_new_node(parent, name, (mode & S_IALLUGO) | S_IFREG, flags);

	kn = kernfs_new_node(parent, name, (mode & S_IALLUGO) | S_IFREG,

			     uid, gid, flags);

	if (!kn)

		return ERR_PTR(-ENOMEM);

fs/kernfs/inode.c

+1 −1
Original line number Diff line number Diff line
@@ -63,7 +63,7 @@ static struct kernfs_iattrs *kernfs_iattrs(struct kernfs_node *kn) 
	return ret;

}



static int __kernfs_setattr(struct kernfs_node *kn, const struct iattr *iattr)

int __kernfs_setattr(struct kernfs_node *kn, const struct iattr *iattr)

{

	struct kernfs_iattrs *attrs;

	struct iattr *iattrs;

fs/kernfs/kernfs-internal.h

+2 −0
Original line number Diff line number Diff line
@@ -90,6 +90,7 @@ int kernfs_iop_setattr(struct dentry *dentry, struct iattr *iattr); 
int kernfs_iop_getattr(const struct path *path, struct kstat *stat,

		       u32 request_mask, unsigned int query_flags);

ssize_t kernfs_iop_listxattr(struct dentry *dentry, char *buf, size_t size);

int __kernfs_setattr(struct kernfs_node *kn, const struct iattr *iattr);



/*

 * dir.c
@@ -104,6 +105,7 @@ void kernfs_put_active(struct kernfs_node *kn); 
int kernfs_add_one(struct kernfs_node *kn);

struct kernfs_node *kernfs_new_node(struct kernfs_node *parent,

				    const char *name, umode_t mode,

				    kuid_t uid, kgid_t gid,

				    unsigned flags);

struct kernfs_node *kernfs_find_and_get_node_by_ino(struct kernfs_root *root,

						    unsigned int ino);