session.c: use blobmsg_type() instead of blob_id()
[project/rpcd.git] / session.c
index d970d45..6d27ff6 100644 (file)
--- a/session.c
+++ b/session.c
  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
+#define _GNU_SOURCE    /* crypt() */
+
 #include <libubox/avl-cmp.h>
+#include <libubox/blobmsg.h>
 #include <libubox/utils.h>
 #include <libubus.h>
 #include <fnmatch.h>
+#include <glob.h>
+#include <uci.h>
+
+#ifdef HAVE_SHADOW
+#include <shadow.h>
+#endif
 
-#include "session.h"
+#include <rpcd/session.h>
 
 static struct avl_tree sessions;
 static struct blob_buf buf;
 
+static LIST_HEAD(create_callbacks);
+static LIST_HEAD(destroy_callbacks);
+
 static const struct blobmsg_policy new_policy = {
        .name = "timeout", .type = BLOBMSG_TYPE_INT32
 };
@@ -81,6 +93,32 @@ static const struct blobmsg_policy perm_policy[__RPC_SP_MAX] = {
        [RPC_SP_FUNCTION] = { .name = "function", .type = BLOBMSG_TYPE_STRING },
 };
 
+enum {
+       RPC_DUMP_SID,
+       RPC_DUMP_TIMEOUT,
+       RPC_DUMP_EXPIRES,
+       RPC_DUMP_DATA,
+       __RPC_DUMP_MAX,
+};
+static const struct blobmsg_policy dump_policy[__RPC_DUMP_MAX] = {
+       [RPC_DUMP_SID] = { .name = "sid", .type = BLOBMSG_TYPE_STRING },
+       [RPC_DUMP_TIMEOUT] = { .name = "timeout", .type = BLOBMSG_TYPE_INT32 },
+       [RPC_DUMP_EXPIRES] = { .name = "expires", .type = BLOBMSG_TYPE_INT32 },
+       [RPC_DUMP_DATA] = { .name = "data", .type = BLOBMSG_TYPE_TABLE },
+};
+
+enum {
+       RPC_L_USERNAME,
+       RPC_L_PASSWORD,
+       RPC_L_TIMEOUT,
+       __RPC_L_MAX,
+};
+static const struct blobmsg_policy login_policy[__RPC_L_MAX] = {
+       [RPC_L_USERNAME] = { .name = "username", .type = BLOBMSG_TYPE_STRING },
+       [RPC_L_PASSWORD] = { .name = "password", .type = BLOBMSG_TYPE_STRING },
+       [RPC_L_TIMEOUT]  = { .name = "timeout", .type = BLOBMSG_TYPE_INT32 },
+};
+
 /*
  * Keys in the AVL tree contain all pattern characters up to the first wildcard.
  * To look up entries, start with the last entry that has a key less than or
@@ -165,9 +203,7 @@ rpc_session_dump_acls(struct rpc_session *ses, struct blob_buf *b)
 }
 
 static void
-rpc_session_dump(struct rpc_session *ses,
-                                        struct ubus_context *ctx,
-                                        struct ubus_request_data *req)
+rpc_session_to_blob(struct rpc_session *ses, bool acls)
 {
        void *c;
 
@@ -177,13 +213,22 @@ rpc_session_dump(struct rpc_session *ses,
        blobmsg_add_u32(&buf, "timeout", ses->timeout);
        blobmsg_add_u32(&buf, "expires", uloop_timeout_remaining(&ses->t) / 1000);
 
-       c = blobmsg_open_table(&buf, "acls");
-       rpc_session_dump_acls(ses, &buf);
-       blobmsg_close_table(&buf, c);
+       if (acls) {
+               c = blobmsg_open_table(&buf, "acls");
+               rpc_session_dump_acls(ses, &buf);
+               blobmsg_close_table(&buf, c);
+       }
 
        c = blobmsg_open_table(&buf, "data");
        rpc_session_dump_data(ses, &buf);
        blobmsg_close_table(&buf, c);
+}
+
+static void
+rpc_session_dump(struct rpc_session *ses, struct ubus_context *ctx,
+                 struct ubus_request_data *req)
+{
+       rpc_session_to_blob(ses, true);
 
        ubus_send_reply(ctx, req, buf.head);
 }
@@ -191,7 +236,8 @@ rpc_session_dump(struct rpc_session *ses,
 static void
 rpc_touch_session(struct rpc_session *ses)
 {
-       uloop_timeout_set(&ses->t, ses->timeout * 1000);
+       if (ses->timeout > 0)
+               uloop_timeout_set(&ses->t, ses->timeout * 1000);
 }
 
 static void
@@ -200,6 +246,10 @@ rpc_session_destroy(struct rpc_session *ses)
        struct rpc_session_acl *acl, *nacl;
        struct rpc_session_acl_scope *acl_scope, *nacl_scope;
        struct rpc_session_data *data, *ndata;
+       struct rpc_session_cb *cb;
+
+       list_for_each_entry(cb, &destroy_callbacks, list)
+               cb->cb(ses, cb->priv);
 
        uloop_timeout_cancel(&ses->t);
 
@@ -227,25 +277,47 @@ static void rpc_session_timeout(struct uloop_timeout *t)
 }
 
 static struct rpc_session *
-rpc_session_create(int timeout)
+rpc_session_new(void)
 {
        struct rpc_session *ses;
 
        ses = calloc(1, sizeof(*ses));
+
        if (!ses)
                return NULL;
 
-       ses->timeout  = timeout;
-       ses->avl.key  = ses->id;
-       rpc_random(ses->id);
+       ses->avl.key = ses->id;
 
-       avl_insert(&sessions, &ses->avl);
        avl_init(&ses->acls, avl_strcmp, true, NULL);
        avl_init(&ses->data, avl_strcmp, false, NULL);
 
        ses->t.cb = rpc_session_timeout;
+
+       return ses;
+}
+
+static struct rpc_session *
+rpc_session_create(int timeout)
+{
+       struct rpc_session *ses;
+       struct rpc_session_cb *cb;
+
+       ses = rpc_session_new();
+
+       if (!ses)
+               return NULL;
+
+       rpc_random(ses->id);
+
+       ses->timeout = timeout;
+
+       avl_insert(&sessions, &ses->avl);
+
        rpc_touch_session(ses);
 
+       list_for_each_entry(cb, &create_callbacks, list)
+               cb->cb(ses, cb->priv);
+
        return ses;
 }
 
@@ -314,7 +386,7 @@ uh_id_len(const char *str)
 }
 
 static int
-rpc_session_grant(struct rpc_session *ses, struct ubus_context *ctx,
+rpc_session_grant(struct rpc_session *ses,
                   const char *scope, const char *object, const char *function)
 {
        struct rpc_session_acl *acl;
@@ -365,7 +437,7 @@ rpc_session_grant(struct rpc_session *ses, struct ubus_context *ctx,
 }
 
 static int
-rpc_session_revoke(struct rpc_session *ses, struct ubus_context *ctx,
+rpc_session_revoke(struct rpc_session *ses,
                    const char *scope, const char *object, const char *function)
 {
        struct rpc_session_acl *acl, *next;
@@ -430,8 +502,8 @@ rpc_handle_acl(struct ubus_context *ctx, struct ubus_object *obj,
        const char *scope = "ubus";
        int rem1, rem2;
 
-       int (*cb)(struct rpc_session *ses, struct ubus_context *ctx,
-                 const char *scope, const char *object, const char *function);
+       int (*cb)(struct rpc_session *ses,
+                 const char *scope, const char *object, const char *function);
 
        blobmsg_parse(acl_policy, __RPC_SA_MAX, tb, blob_data(msg), blob_len(msg));
 
@@ -451,17 +523,17 @@ rpc_handle_acl(struct ubus_context *ctx, struct ubus_object *obj,
                cb = rpc_session_revoke;
 
        if (!tb[RPC_SA_OBJECTS])
-               return cb(ses, ctx, scope, NULL, NULL);
+               return cb(ses, scope, NULL, NULL);
 
        blobmsg_for_each_attr(attr, tb[RPC_SA_OBJECTS], rem1) {
-               if (blob_id(attr) != BLOBMSG_TYPE_ARRAY)
+               if (blobmsg_type(attr) != BLOBMSG_TYPE_ARRAY)
                        continue;
 
                object = NULL;
                function = NULL;
 
                blobmsg_for_each_attr(sattr, attr, rem2) {
-                       if (blob_id(sattr) != BLOBMSG_TYPE_STRING)
+                       if (blobmsg_type(sattr) != BLOBMSG_TYPE_STRING)
                                continue;
 
                        if (!object)
@@ -473,7 +545,7 @@ rpc_handle_acl(struct ubus_context *ctx, struct ubus_object *obj,
                }
 
                if (object && function)
-                       cb(ses, ctx, scope, object, function);
+                       cb(ses, scope, object, function);
        }
 
        return 0;
@@ -529,14 +601,33 @@ rpc_handle_access(struct ubus_context *ctx, struct ubus_object *obj,
        return 0;
 }
 
+static void
+rpc_session_set(struct rpc_session *ses, const char *key, struct blob_attr *val)
+{
+       struct rpc_session_data *data;
+
+       data = avl_find_element(&ses->data, key, data, avl);
+       if (data) {
+               avl_delete(&ses->data, &data->avl);
+               free(data);
+       }
+
+       data = calloc(1, sizeof(*data) + blob_pad_len(val));
+       if (!data)
+               return;
+
+       memcpy(data->attr, val, blob_pad_len(val));
+       data->avl.key = blobmsg_name(data->attr);
+       avl_insert(&ses->data, &data->avl);
+}
+
 static int
 rpc_handle_set(struct ubus_context *ctx, struct ubus_object *obj,
                struct ubus_request_data *req, const char *method,
                struct blob_attr *msg)
 {
        struct rpc_session *ses;
-       struct rpc_session_data *data;
-       struct blob_attr *tb[__RPC_SA_MAX];
+       struct blob_attr *tb[__RPC_SS_MAX];
        struct blob_attr *attr;
        int rem;
 
@@ -553,19 +644,7 @@ rpc_handle_set(struct ubus_context *ctx, struct ubus_object *obj,
                if (!blobmsg_name(attr)[0])
                        continue;
 
-               data = avl_find_element(&ses->data, blobmsg_name(attr), data, avl);
-               if (data) {
-                       avl_delete(&ses->data, &data->avl);
-                       free(data);
-               }
-
-               data = calloc(1, sizeof(*data) + blob_pad_len(attr));
-               if (!data)
-                       break;
-
-               memcpy(data->attr, attr, blob_pad_len(attr));
-               data->avl.key = blobmsg_name(data->attr);
-               avl_insert(&ses->data, &data->avl);
+               rpc_session_set(ses, blobmsg_name(attr), attr);
        }
 
        return 0;
@@ -578,7 +657,7 @@ rpc_handle_get(struct ubus_context *ctx, struct ubus_object *obj,
 {
        struct rpc_session *ses;
        struct rpc_session_data *data;
-       struct blob_attr *tb[__RPC_SA_MAX];
+       struct blob_attr *tb[__RPC_SG_MAX];
        struct blob_attr *attr;
        void *c;
        int rem;
@@ -597,7 +676,7 @@ rpc_handle_get(struct ubus_context *ctx, struct ubus_object *obj,
 
        if (tb[RPC_SG_KEYS])
                blobmsg_for_each_attr(attr, tb[RPC_SG_KEYS], rem) {
-                       if (blob_id(attr) != BLOBMSG_TYPE_STRING)
+                       if (blobmsg_type(attr) != BLOBMSG_TYPE_STRING)
                                continue;
 
                        data = avl_find_element(&ses->data, blobmsg_data(attr), data, avl);
@@ -645,7 +724,7 @@ rpc_handle_unset(struct ubus_context *ctx, struct ubus_object *obj,
        }
 
        blobmsg_for_each_attr(attr, tb[RPC_SG_KEYS], rem) {
-               if (blob_id(attr) != BLOBMSG_TYPE_STRING)
+               if (blobmsg_type(attr) != BLOBMSG_TYPE_STRING)
                        continue;
 
                data = avl_find_element(&ses->data, blobmsg_data(attr), data, avl);
@@ -672,6 +751,9 @@ rpc_handle_destroy(struct ubus_context *ctx, struct ubus_object *obj,
        if (!tb)
                return UBUS_STATUS_INVALID_ARGUMENT;
 
+       if (!strcmp(blobmsg_get_string(tb), RPC_DEFAULT_SESSION_ID))
+               return UBUS_STATUS_PERMISSION_DENIED;
+
        ses = rpc_session_get(blobmsg_data(tb));
        if (!ses)
                return UBUS_STATUS_NOT_FOUND;
@@ -681,8 +763,492 @@ rpc_handle_destroy(struct ubus_context *ctx, struct ubus_object *obj,
        return 0;
 }
 
+
+static bool
+rpc_login_test_password(const char *hash, const char *password)
+{
+       char *crypt_hash;
+
+       /* password is not set */
+       if (!hash || !*hash || !strcmp(hash, "!") || !strcmp(hash, "x"))
+       {
+               return true;
+       }
+
+       /* password hash refers to shadow/passwd */
+       else if (!strncmp(hash, "$p$", 3))
+       {
+#ifdef HAVE_SHADOW
+               struct spwd *sp = getspnam(hash + 3);
+
+               if (!sp)
+                       return false;
+
+               return rpc_login_test_password(sp->sp_pwdp, password);
+#else
+               struct passwd *pw = getpwnam(hash + 3);
+
+               if (!pw)
+                       return false;
+
+               return rpc_login_test_password(pw->pw_passwd, password);
+#endif
+       }
+
+       crypt_hash = crypt(password, hash);
+
+       return !strcmp(crypt_hash, hash);
+}
+
+static struct uci_section *
+rpc_login_test_login(struct uci_context *uci,
+                     const char *username, const char *password)
+{
+       struct uci_package *p = NULL;
+       struct uci_section *s;
+       struct uci_element *e;
+       struct uci_ptr ptr = { .package = "rpcd" };
+
+       uci_load(uci, ptr.package, &p);
+
+       if (!p)
+               return false;
+
+       uci_foreach_element(&p->sections, e)
+       {
+               s = uci_to_section(e);
+
+               if (strcmp(s->type, "login"))
+                       continue;
+
+               ptr.section = s->e.name;
+               ptr.s = NULL;
+
+               /* test for matching username */
+               ptr.option = "username";
+               ptr.o = NULL;
+
+               if (uci_lookup_ptr(uci, &ptr, NULL, true))
+                       continue;
+
+               if (ptr.o->type != UCI_TYPE_STRING)
+                       continue;
+
+               if (strcmp(ptr.o->v.string, username))
+                       continue;
+
+               /* If password is NULL, we're restoring ACLs for an existing session,
+                * in this case do not check the password again. */
+               if (!password)
+                       return ptr.s;
+
+               /* test for matching password */
+               ptr.option = "password";
+               ptr.o = NULL;
+
+               if (uci_lookup_ptr(uci, &ptr, NULL, true))
+                       continue;
+
+               if (ptr.o->type != UCI_TYPE_STRING)
+                       continue;
+
+               if (rpc_login_test_password(ptr.o->v.string, password))
+                       return ptr.s;
+       }
+
+       return NULL;
+}
+
+static bool
+rpc_login_test_permission(struct uci_section *s,
+                          const char *perm, const char *group)
+{
+       const char *p;
+       struct uci_option *o;
+       struct uci_element *e, *l;
+
+       /* If the login section is not provided, we're setting up acls for the
+        * default session, in this case uncondionally allow access to the
+        * "unauthenticated" access group */
+       if (!s) {
+               return !strcmp(group, "unauthenticated");
+       }
+
+       uci_foreach_element(&s->options, e)
+       {
+               o = uci_to_option(e);
+
+               if (o->type != UCI_TYPE_LIST)
+                       continue;
+
+               if (strcmp(o->e.name, perm))
+                       continue;
+
+               /* Match negative expressions first. If a negative expression matches
+                * the current group name then deny access. */
+               uci_foreach_element(&o->v.list, l) {
+                       p = l->name;
+
+                       if (!p || *p != '!')
+                               continue;
+
+                       while (isspace(*++p));
+
+                       if (!*p)
+                               continue;
+
+                       if (!fnmatch(p, group, 0))
+                               return false;
+               }
+
+               uci_foreach_element(&o->v.list, l) {
+                       if (!l->name || !*l->name || *l->name == '!')
+                               continue;
+
+                       if (!fnmatch(l->name, group, 0))
+                               return true;
+               }
+       }
+
+       /* make sure that write permission implies read permission */
+       if (!strcmp(perm, "read"))
+               return rpc_login_test_permission(s, "write", group);
+
+       return false;
+}
+
+static void
+rpc_login_setup_acl_scope(struct rpc_session *ses,
+                          struct blob_attr *acl_perm,
+                          struct blob_attr *acl_scope)
+{
+       struct blob_attr *acl_obj, *acl_func;
+       int rem, rem2;
+
+       /*
+        * Parse ACL scopes in table notation.
+        *
+        *      "<scope>": {
+        *              "<object>": [
+        *                      "<function>",
+        *                      "<function>",
+        *                      ...
+        *              ]
+        *      }
+        */
+       if (blobmsg_type(acl_scope) == BLOBMSG_TYPE_TABLE) {
+               blobmsg_for_each_attr(acl_obj, acl_scope, rem) {
+                       if (blobmsg_type(acl_obj) != BLOBMSG_TYPE_ARRAY)
+                               continue;
+
+                       blobmsg_for_each_attr(acl_func, acl_obj, rem2) {
+                               if (blobmsg_type(acl_func) != BLOBMSG_TYPE_STRING)
+                                       continue;
+
+                               rpc_session_grant(ses, blobmsg_name(acl_scope),
+                                                      blobmsg_name(acl_obj),
+                                                      blobmsg_data(acl_func));
+                       }
+               }
+       }
+
+       /*
+        * Parse ACL scopes in array notation. The permission ("read" or "write")
+        * will be used as function name for each object.
+        *
+        *      "<scope>": [
+        *              "<object>",
+        *              "<object>",
+        *              ...
+        *      ]
+        */
+       else if (blobmsg_type(acl_scope) == BLOBMSG_TYPE_ARRAY) {
+               blobmsg_for_each_attr(acl_obj, acl_scope, rem) {
+                       if (blobmsg_type(acl_obj) != BLOBMSG_TYPE_STRING)
+                               continue;
+
+                       rpc_session_grant(ses, blobmsg_name(acl_scope),
+                                              blobmsg_data(acl_obj),
+                                              blobmsg_name(acl_perm));
+               }
+       }
+}
+
+static void
+rpc_login_setup_acl_file(struct rpc_session *ses, struct uci_section *login,
+                         const char *path)
+{
+       struct blob_buf acl = { 0 };
+       struct blob_attr *acl_group, *acl_perm, *acl_scope;
+       int rem, rem2, rem3;
+
+       blob_buf_init(&acl, 0);
+
+       if (!blobmsg_add_json_from_file(&acl, path)) {
+               fprintf(stderr, "Failed to parse %s\n", path);
+               goto out;
+       }
+
+       /* Iterate access groups in toplevel object */
+       blob_for_each_attr(acl_group, acl.head, rem) {
+               /* Iterate permission objects in each access group object */
+               blobmsg_for_each_attr(acl_perm, acl_group, rem2) {
+                       if (blobmsg_type(acl_perm) != BLOBMSG_TYPE_TABLE)
+                               continue;
+
+                       /* Only "read" and "write" permissions are defined */
+                       if (strcmp(blobmsg_name(acl_perm), "read") &&
+                               strcmp(blobmsg_name(acl_perm), "write"))
+                               continue;
+
+                       /*
+                        * Check if the current user context specifies the current
+                        * "read" or "write" permission in the given access group.
+                        */
+                       if (!rpc_login_test_permission(login, blobmsg_name(acl_perm),
+                                                             blobmsg_name(acl_group)))
+                               continue;
+
+                       /* Iterate scope objects within the permission object */
+                       blobmsg_for_each_attr(acl_scope, acl_perm, rem3) {
+                               /* Setup the scopes of the access group */
+                               rpc_login_setup_acl_scope(ses, acl_perm, acl_scope);
+
+                               /*
+                                * Add the access group itself as object to the "access-group"
+                                * meta scope and the the permission level ("read" or "write")
+                                * as function, so
+                                *      "<group>": {
+                                *              "<permission>": {
+                                *                      "<scope>": ...
+                                *              }
+                                *      }
+                                * becomes
+                                *      "access-group": {
+                                *              "<group>": [
+                                *                      "<permission>"
+                                *              ]
+                                *      }
+                                *
+                                * This allows session clients to easily query the allowed
+                                * access groups without having to test access of each single
+                                * <scope>/<object>/<function> tuple defined in a group.
+                                */
+                               rpc_session_grant(ses, "access-group",
+                                                      blobmsg_name(acl_group),
+                                                      blobmsg_name(acl_perm));
+                       }
+               }
+       }
+
+out:
+       blob_buf_free(&acl);
+}
+
+static void
+rpc_login_setup_acls(struct rpc_session *ses, struct uci_section *login)
+{
+       int i;
+       glob_t gl;
+
+       if (glob(RPC_SESSION_ACL_DIR "/*.json", 0, NULL, &gl))
+               return;
+
+       for (i = 0; i < gl.gl_pathc; i++)
+               rpc_login_setup_acl_file(ses, login, gl.gl_pathv[i]);
+
+       globfree(&gl);
+}
+
+static int
+rpc_handle_login(struct ubus_context *ctx, struct ubus_object *obj,
+                 struct ubus_request_data *req, const char *method,
+                 struct blob_attr *msg)
+{
+       struct uci_context *uci = NULL;
+       struct uci_section *login;
+       struct rpc_session *ses;
+       struct blob_attr *tb[__RPC_L_MAX];
+       int timeout = RPC_DEFAULT_SESSION_TIMEOUT;
+       int rv = 0;
+
+       blobmsg_parse(login_policy, __RPC_L_MAX, tb, blob_data(msg), blob_len(msg));
+
+       if (!tb[RPC_L_USERNAME] || !tb[RPC_L_PASSWORD]) {
+               rv = UBUS_STATUS_INVALID_ARGUMENT;
+               goto out;
+       }
+
+       uci = uci_alloc_context();
+
+       if (!uci) {
+               rv = UBUS_STATUS_UNKNOWN_ERROR;
+               goto out;
+       }
+
+       login = rpc_login_test_login(uci, blobmsg_get_string(tb[RPC_L_USERNAME]),
+                                         blobmsg_get_string(tb[RPC_L_PASSWORD]));
+
+       if (!login) {
+               rv = UBUS_STATUS_PERMISSION_DENIED;
+               goto out;
+       }
+
+       if (tb[RPC_L_TIMEOUT])
+               timeout = blobmsg_get_u32(tb[RPC_L_TIMEOUT]);
+
+       ses = rpc_session_create(timeout);
+
+       if (!ses) {
+               rv = UBUS_STATUS_UNKNOWN_ERROR;
+               goto out;
+       }
+
+       rpc_login_setup_acls(ses, login);
+
+       rpc_session_set(ses, "user", tb[RPC_L_USERNAME]);
+       rpc_session_dump(ses, ctx, req);
+
+out:
+       if (uci)
+               uci_free_context(uci);
+
+       return rv;
+}
+
+
+static bool
+rpc_validate_sid(const char *id)
+{
+       if (!id)
+               return false;
+
+       if (strlen(id) != RPC_SID_LEN)
+               return false;
+
+       while (*id)
+               if (!isxdigit(*id++))
+                       return false;
+
+       return true;
+}
+
+static int
+rpc_blob_to_file(const char *path, struct blob_attr *attr)
+{
+       int fd, len;
+
+       fd = open(path, O_WRONLY | O_CREAT | O_EXCL, 0600);
+
+       if (fd < 0)
+               return fd;
+
+       len = write(fd, attr, blob_pad_len(attr));
+
+       close(fd);
+
+       if (len != blob_pad_len(attr))
+       {
+               unlink(path);
+               return -1;
+       }
+
+       return len;
+}
+
+static struct blob_attr *
+rpc_blob_from_file(const char *path)
+{
+       int fd = -1, len;
+       struct stat s;
+       struct blob_attr head, *attr = NULL;
+
+       if (stat(path, &s) || !S_ISREG(s.st_mode))
+               return NULL;
+
+       fd = open(path, O_RDONLY);
+
+       if (fd < 0)
+               goto fail;
+
+       len = read(fd, &head, sizeof(head));
+
+       if (len != sizeof(head) || blob_pad_len(&head) != s.st_size)
+               goto fail;
+
+       attr = calloc(1, s.st_size);
+
+       if (!attr)
+               goto fail;
+
+       memcpy(attr, &head, sizeof(head));
+
+       len += read(fd, (char *)attr + sizeof(head), s.st_size - sizeof(head));
+
+       if (len != blob_pad_len(&head))
+               goto fail;
+
+       return attr;
+
+fail:
+       if (fd >= 0)
+               close(fd);
+
+       if (attr)
+               free(attr);
+
+       return NULL;
+}
+
+static bool
+rpc_session_from_blob(struct uci_context *uci, struct blob_attr *attr)
+{
+       int i, rem;
+       const char *user = NULL;
+       struct rpc_session *ses;
+       struct uci_section *login;
+       struct blob_attr *tb[__RPC_DUMP_MAX], *data;
+
+       blobmsg_parse(dump_policy, __RPC_DUMP_MAX, tb,
+                     blob_data(attr), blob_len(attr));
+
+       for (i = 0; i < __RPC_DUMP_MAX; i++)
+               if (!tb[i])
+                       return false;
+
+       ses = rpc_session_new();
+
+       if (!ses)
+               return false;
+
+       memcpy(ses->id, blobmsg_data(tb[RPC_DUMP_SID]), RPC_SID_LEN);
+
+       ses->timeout = blobmsg_get_u32(tb[RPC_DUMP_TIMEOUT]);
+
+       blobmsg_for_each_attr(data, tb[RPC_DUMP_DATA], rem) {
+               rpc_session_set(ses, blobmsg_name(data), data);
+
+               if (!strcmp(blobmsg_name(data), "username"))
+                       user = blobmsg_get_string(data);
+       }
+
+       if (uci && user) {
+               login = rpc_login_test_login(uci, user, NULL);
+               if (login)
+                       rpc_login_setup_acls(ses, login);
+       }
+
+       avl_insert(&sessions, &ses->avl);
+
+       uloop_timeout_set(&ses->t, blobmsg_get_u32(tb[RPC_DUMP_EXPIRES]) * 1000);
+
+       return true;
+}
+
 int rpc_session_api_init(struct ubus_context *ctx)
 {
+       struct rpc_session *ses;
+
        static const struct ubus_method session_methods[] = {
                UBUS_METHOD("create",  rpc_handle_create,  &new_policy),
                UBUS_METHOD("list",    rpc_handle_list,    &sid_policy),
@@ -693,6 +1259,7 @@ int rpc_session_api_init(struct ubus_context *ctx)
                UBUS_METHOD("get",     rpc_handle_get,     get_policy),
                UBUS_METHOD("unset",   rpc_handle_unset,   get_policy),
                UBUS_METHOD("destroy", rpc_handle_destroy, &sid_policy),
+               UBUS_METHOD("login",   rpc_handle_login,   login_policy),
        };
 
        static struct ubus_object_type session_type =
@@ -707,6 +1274,15 @@ int rpc_session_api_init(struct ubus_context *ctx)
 
        avl_init(&sessions, avl_strcmp, false, NULL);
 
+       /* setup the default session */
+       ses = rpc_session_new();
+
+       if (ses) {
+               strcpy(ses->id, RPC_DEFAULT_SESSION_ID);
+               rpc_login_setup_acls(ses, NULL);
+               avl_insert(&sessions, &ses->avl);
+       }
+
        return ubus_add_object(ctx, &obj);
 }
 
@@ -720,3 +1296,75 @@ bool rpc_session_access(const char *sid, const char *scope,
 
        return rpc_session_acl_allowed(ses, scope, object, function);
 }
+
+void rpc_session_create_cb(struct rpc_session_cb *cb)
+{
+       if (cb && cb->cb)
+               list_add(&cb->list, &create_callbacks);
+}
+
+void rpc_session_destroy_cb(struct rpc_session_cb *cb)
+{
+       if (cb && cb->cb)
+               list_add(&cb->list, &destroy_callbacks);
+}
+
+void rpc_session_freeze(void)
+{
+       struct stat s;
+       struct rpc_session *ses;
+       char path[PATH_MAX];
+
+       if (stat(RPC_SESSION_DIRECTORY, &s))
+               mkdir(RPC_SESSION_DIRECTORY, 0700);
+
+       avl_for_each_element(&sessions, ses, avl) {
+               /* skip default session */
+               if (!strcmp(ses->id, RPC_DEFAULT_SESSION_ID))
+                       continue;
+
+               snprintf(path, sizeof(path) - 1, RPC_SESSION_DIRECTORY "/%s", ses->id);
+               rpc_session_to_blob(ses, false);
+               rpc_blob_to_file(path, buf.head);
+       }
+}
+
+void rpc_session_thaw(void)
+{
+       DIR *d;
+       char path[PATH_MAX];
+       struct dirent *e;
+       struct blob_attr *attr;
+       struct uci_context *uci;
+
+       d = opendir(RPC_SESSION_DIRECTORY);
+
+       if (!d)
+               return;
+
+       uci = uci_alloc_context();
+
+       if (!uci)
+               return;
+
+       while ((e = readdir(d)) != NULL) {
+               if (!rpc_validate_sid(e->d_name))
+                       continue;
+
+               snprintf(path, sizeof(path) - 1,
+                        RPC_SESSION_DIRECTORY "/%s", e->d_name);
+
+               attr = rpc_blob_from_file(path);
+
+               if (attr) {
+                       rpc_session_from_blob(uci, attr);
+                       free(attr);
+               }
+
+               unlink(path);
+       }
+
+       closedir(d);
+
+       uci_free_context(uci);
+}