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authorDmitry Torokhov <dmitry.torokhov@gmail.com>2018-07-21 00:56:47 +0300
committerDavid S. Miller <davem@davemloft.net>2018-07-21 09:44:35 +0300
commit488dee96bb62f0b3d9e678cf42574034d5b033a5 (patch)
tree2969d47ffb0ffeaf15d20ffb0eda78a2bb694a40 /fs/kernfs
parent7c4ec749a3bd89237d7195ccd621bf5d4124d6b5 (diff)
downloadlinux-488dee96bb62f0b3d9e678cf42574034d5b033a5.tar.xz
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: Tyler Hicks <tyhicks@canonical.com> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> Signed-off-by: Tyler Hicks <tyhicks@canonical.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'fs/kernfs')
-rw-r--r--fs/kernfs/dir.c29
-rw-r--r--fs/kernfs/file.c8
-rw-r--r--fs/kernfs/inode.c2
-rw-r--r--fs/kernfs/kernfs-internal.h2
-rw-r--r--fs/kernfs/symlink.c11
5 files changed, 45 insertions, 7 deletions
diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
index d66cc0777303..4ca0b5c18192 100644
--- a/fs/kernfs/dir.c
+++ b/fs/kernfs/dir.c
@@ -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);
diff --git a/fs/kernfs/file.c b/fs/kernfs/file.c
index 2015d8c45e4a..dbf5bc250bfd 100644
--- a/fs/kernfs/file.c
+++ b/fs/kernfs/file.c
@@ -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);
diff --git a/fs/kernfs/inode.c b/fs/kernfs/inode.c
index 3d73fe9d56e2..80cebcd94c90 100644
--- a/fs/kernfs/inode.c
+++ b/fs/kernfs/inode.c
@@ -63,7 +63,7 @@ out_unlock:
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;
diff --git a/fs/kernfs/kernfs-internal.h b/fs/kernfs/kernfs-internal.h
index 0f260dcca177..3d83b114bb08 100644
--- a/fs/kernfs/kernfs-internal.h
+++ b/fs/kernfs/kernfs-internal.h
@@ -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);
diff --git a/fs/kernfs/symlink.c b/fs/kernfs/symlink.c
index 08ccabd7047f..5ffed48f3d0e 100644
--- a/fs/kernfs/symlink.c
+++ b/fs/kernfs/symlink.c
@@ -21,6 +21,7 @@
* @target: target node for the symlink to point to
*
* Returns the created node on success, ERR_PTR() value on error.
+ * Ownership of the link matches ownership of the target.
*/
struct kernfs_node *kernfs_create_link(struct kernfs_node *parent,
const char *name,
@@ -28,8 +29,16 @@ struct kernfs_node *kernfs_create_link(struct kernfs_node *parent,
{
struct kernfs_node *kn;
int error;
+ kuid_t uid = GLOBAL_ROOT_UID;
+ kgid_t gid = GLOBAL_ROOT_GID;
- kn = kernfs_new_node(parent, name, S_IFLNK|S_IRWXUGO, KERNFS_LINK);
+ if (target->iattr) {
+ uid = target->iattr->ia_iattr.ia_uid;
+ gid = target->iattr->ia_iattr.ia_gid;
+ }
+
+ kn = kernfs_new_node(parent, name, S_IFLNK|S_IRWXUGO, uid, gid,
+ KERNFS_LINK);
if (!kn)
return ERR_PTR(-ENOMEM);