--- /dev/null
+
+=========
+ID Mapper
+=========
+Id mapper is used by NFS to translate user and group ids into names, and to
+translate user and group names into ids. Part of this translation involves
+performing an upcall to userspace to request the information. Id mapper will
+user request-key to perform this upcall and cache the result. The program
+/usr/sbin/nfs.upcall should be called by request-key, and will perform the
+translation and initialize a key with the resulting information.
+
+ NFS_USE_NEW_IDMAPPER must be selected when configuring the kernel to use this
+ feature.
+
+===========
+Configuring
+===========
+The file /etc/request-key.conf will need to be modified so /sbin/request-key can
+direct the upcall. The following line should be added:
+
+#OP TYPE DESCRIPTION CALLOUT INFO PROGRAM ARG1 ARG2 ARG3 ...
+#====== ======= =============== =============== ===============================
+create id_resolver * * /usr/sbin/nfs.upcall %k %d 600
+
+This will direct all id_resolver requests to the program /usr/sbin/nfs.upcall.
+The last parameter, 600, defines how many seconds into the future the key will
+expire. This parameter is optional for /usr/sbin/nfs.upcall. When the timeout
+is not specified, nfs.upcall will default to 600 seconds.
+
+id mapper uses for key descriptions:
+ uid: Find the UID for the given user
+ gid: Find the GID for the given group
+ user: Find the user name for the given UID
+ group: Find the group name for the given GID
+
+You can handle any of these individually, rather than using the generic upcall
+program. If you would like to use your own program for a uid lookup then you
+would edit your request-key.conf so it look similar to this:
+
+#OP TYPE DESCRIPTION CALLOUT INFO PROGRAM ARG1 ARG2 ARG3 ...
+#====== ======= =============== =============== ===============================
+create id_resolver uid:* * /some/other/program %k %d 600
+create id_resolver * * /usr/sbin/nfs.upcall %k %d 600
+
+Notice that the new line was added above the line for the generic program.
+request-key will find the first matching line and corresponding program. In
+this case, /some/other/program will handle all uid lookups and
+/usr/sbin/nfs.upcall will handle gid, user, and group lookups.
+
+See <file:Documentation/keys-request-keys.txt> for more information about the
+request-key function.
+
+
+==========
+nfs.upcall
+==========
+nfs.upcall is designed to be called by request-key, and should not be run "by
+hand". This program takes two arguments, a serialized key and a key
+description. The serialized key is first converted into a key_serial_t, and
+then passed as an argument to keyctl_instantiate (both are part of keyutils.h).
+
+The actual lookups are performed by functions found in nfsidmap.h. nfs.upcall
+determines the correct function to call by looking at the first part of the
+description string. For example, a uid lookup description will appear as
+"uid:user@domain".
+
+nfs.upcall will return 0 if the key was instantiated, and non-zero otherwise.
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
+#ifdef CONFIG_NFS_USE_NEW_IDMAPPER
+
+#include <linux/slab.h>
+#include <linux/cred.h>
+#include <linux/nfs_idmap.h>
+#include <linux/keyctl.h>
+#include <linux/key-type.h>
+#include <linux/rcupdate.h>
+#include <linux/kernel.h>
+#include <linux/err.h>
+
+#include <keys/user-type.h>
+
+#define NFS_UINT_MAXLEN 11
+
+const struct cred *id_resolver_cache;
+
+struct key_type key_type_id_resolver = {
+ .name = "id_resolver",
+ .instantiate = user_instantiate,
+ .match = user_match,
+ .revoke = user_revoke,
+ .destroy = user_destroy,
+ .describe = user_describe,
+ .read = user_read,
+};
+
+int nfs_idmap_init(void)
+{
+ struct cred *cred;
+ struct key *keyring;
+ int ret = 0;
+
+ printk(KERN_NOTICE "Registering the %s key type\n", key_type_id_resolver.name);
+
+ cred = prepare_kernel_cred(NULL);
+ if (!cred)
+ return -ENOMEM;
+
+ keyring = key_alloc(&key_type_keyring, ".id_resolver", 0, 0, cred,
+ (KEY_POS_ALL & ~KEY_POS_SETATTR) |
+ KEY_USR_VIEW | KEY_USR_READ,
+ KEY_ALLOC_NOT_IN_QUOTA);
+ if (IS_ERR(keyring)) {
+ ret = PTR_ERR(keyring);
+ goto failed_put_cred;
+ }
+
+ ret = key_instantiate_and_link(keyring, NULL, 0, NULL, NULL);
+ if (ret < 0)
+ goto failed_put_key;
+
+ ret = register_key_type(&key_type_id_resolver);
+ if (ret < 0)
+ goto failed_put_key;
+
+ cred->thread_keyring = keyring;
+ cred->jit_keyring = KEY_REQKEY_DEFL_THREAD_KEYRING;
+ id_resolver_cache = cred;
+ return 0;
+
+failed_put_key:
+ key_put(keyring);
+failed_put_cred:
+ put_cred(cred);
+ return ret;
+}
+
+void nfs_idmap_quit(void)
+{
+ key_revoke(id_resolver_cache->thread_keyring);
+ unregister_key_type(&key_type_id_resolver);
+ put_cred(id_resolver_cache);
+}
+
+/*
+ * Assemble the description to pass to request_key()
+ * This function will allocate a new string and update dest to point
+ * at it. The caller is responsible for freeing dest.
+ *
+ * On error 0 is returned. Otherwise, the length of dest is returned.
+ */
+static ssize_t nfs_idmap_get_desc(const char *name, size_t namelen,
+ const char *type, size_t typelen, char **desc)
+{
+ char *cp;
+ size_t desclen = typelen + namelen + 2;
+
+ *desc = kmalloc(desclen, GFP_KERNEL);
+ if (!desc)
+ return -ENOMEM;
+
+ cp = *desc;
+ memcpy(cp, type, typelen);
+ cp += typelen;
+ *cp++ = ':';
+
+ memcpy(cp, name, namelen);
+ cp += namelen;
+ *cp = '\0';
+ return desclen;
+}
+
+static ssize_t nfs_idmap_request_key(const char *name, size_t namelen,
+ const char *type, void *data, size_t data_size)
+{
+ const struct cred *saved_cred;
+ struct key *rkey;
+ char *desc;
+ struct user_key_payload *payload;
+ ssize_t ret;
+
+ ret = nfs_idmap_get_desc(name, namelen, type, strlen(type), &desc);
+ if (ret <= 0)
+ goto out;
+
+ saved_cred = override_creds(id_resolver_cache);
+ rkey = request_key(&key_type_id_resolver, desc, "");
+ revert_creds(saved_cred);
+ kfree(desc);
+ if (IS_ERR(rkey)) {
+ ret = PTR_ERR(rkey);
+ goto out;
+ }
+
+ rcu_read_lock();
+ rkey->perm |= KEY_USR_VIEW;
+
+ ret = key_validate(rkey);
+ if (ret < 0)
+ goto out_up;
+
+ payload = rcu_dereference(rkey->payload.data);
+ if (IS_ERR_OR_NULL(payload)) {
+ ret = PTR_ERR(payload);
+ goto out_up;
+ }
+
+ ret = payload->datalen;
+ if (ret > 0 && ret <= data_size)
+ memcpy(data, payload->data, ret);
+ else
+ ret = -EINVAL;
+
+out_up:
+ rcu_read_unlock();
+ key_put(rkey);
+out:
+ return ret;
+}
+
+
+/* ID -> Name */
+static ssize_t nfs_idmap_lookup_name(__u32 id, const char *type, char *buf, size_t buflen)
+{
+ char id_str[NFS_UINT_MAXLEN];
+ int id_len;
+ ssize_t ret;
+
+ id_len = snprintf(id_str, sizeof(id_str), "%u", id);
+ ret = nfs_idmap_request_key(id_str, id_len, type, buf, buflen);
+ if (ret < 0)
+ return -EINVAL;
+ return ret;
+}
+
+/* Name -> ID */
+static int nfs_idmap_lookup_id(const char *name, size_t namelen,
+ const char *type, __u32 *id)
+{
+ char id_str[NFS_UINT_MAXLEN];
+ long id_long;
+ ssize_t data_size;
+ int ret = 0;
+
+ data_size = nfs_idmap_request_key(name, namelen, type, id_str, NFS_UINT_MAXLEN);
+ if (data_size <= 0) {
+ ret = -EINVAL;
+ } else {
+ ret = strict_strtol(id_str, 10, &id_long);
+ *id = (__u32)id_long;
+ }
+ return ret;
+}
+
+int nfs_map_name_to_uid(struct nfs_client *clp, const char *name, size_t namelen, __u32 *uid)
+{
+ return nfs_idmap_lookup_id(name, namelen, "uid", uid);
+}
+
+int nfs_map_group_to_gid(struct nfs_client *clp, const char *name, size_t namelen, __u32 *gid)
+{
+ return nfs_idmap_lookup_id(name, namelen, "gid", gid);
+}
+
+int nfs_map_uid_to_name(struct nfs_client *clp, __u32 uid, char *buf, size_t buflen)
+{
+ return nfs_idmap_lookup_name(uid, "user", buf, buflen);
+}
+int nfs_map_gid_to_group(struct nfs_client *clp, __u32 gid, char *buf, size_t buflen)
+{
+ return nfs_idmap_lookup_name(gid, "group", buf, buflen);
+}
+
+#else /* CONFIG_NFS_USE_IDMAPPER not defined */
+
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/init.h>
return nfs_idmap_id(idmap, &idmap->idmap_group_hash, name, namelen, uid);
}
-int nfs_map_uid_to_name(struct nfs_client *clp, __u32 uid, char *buf)
+int nfs_map_uid_to_name(struct nfs_client *clp, __u32 uid, char *buf, size_t buflen)
{
struct idmap *idmap = clp->cl_idmap;
return nfs_idmap_name(idmap, &idmap->idmap_user_hash, uid, buf);
}
-int nfs_map_gid_to_group(struct nfs_client *clp, __u32 uid, char *buf)
+int nfs_map_gid_to_group(struct nfs_client *clp, __u32 uid, char *buf, size_t buflen)
{
struct idmap *idmap = clp->cl_idmap;
return nfs_idmap_name(idmap, &idmap->idmap_group_hash, uid, buf);
}
+#endif /* CONFIG_NFS_USE_NEW_IDMAPPER */
/* Forward declaration to make this header independent of others */
struct nfs_client;
+#ifdef CONFIG_NFS_USE_NEW_IDMAPPER
+
+int nfs_idmap_init(void);
+void nfs_idmap_quit(void);
+
+static inline int nfs_idmap_new(struct nfs_client *clp)
+{
+ return 0;
+}
+
+static inline void nfs_idmap_delete(struct nfs_client *clp)
+{
+}
+
+#else /* CONFIG_NFS_USE_NEW_IDMAPPER not set */
+
+static inline int nfs_idmap_init(void)
+{
+ return 0;
+}
+
+static inline void nfs_idmap_quit(void)
+{
+}
+
int nfs_idmap_new(struct nfs_client *);
void nfs_idmap_delete(struct nfs_client *);
+#endif /* CONFIG_NFS_USE_NEW_IDMAPPER */
+
int nfs_map_name_to_uid(struct nfs_client *, const char *, size_t, __u32 *);
int nfs_map_group_to_gid(struct nfs_client *, const char *, size_t, __u32 *);
-int nfs_map_uid_to_name(struct nfs_client *, __u32, char *);
-int nfs_map_gid_to_group(struct nfs_client *, __u32, char *);
+int nfs_map_uid_to_name(struct nfs_client *, __u32, char *, size_t);
+int nfs_map_gid_to_group(struct nfs_client *, __u32, char *, size_t);
extern unsigned int nfs_idmap_cache_timeout;
#endif /* __KERNEL__ */
git.openpandora.org / pandora-kernel.git / commitdiff