From 5a101fcc08ec031e10c8727ee73975f450e8c424 Mon Sep 17 00:00:00 2001 From: Jo-Philipp Wich Date: Tue, 10 Sep 2013 19:41:29 +0200 Subject: [PATCH] session: setup a persistent NULL section and implement login procedure --- CMakeLists.txt | 13 +- include/rpcd/session.h | 2 + session.c | 366 ++++++++++++++++++++++++++++++++++++++++- unauthenticated.json | 13 ++ 4 files changed, 392 insertions(+), 2 deletions(-) create mode 100644 unauthenticated.json diff --git a/CMakeLists.txt b/CMakeLists.txt index b5b164a..8c0a4ef 100644 --- a/CMakeLists.txt +++ b/CMakeLists.txt @@ -1,5 +1,7 @@ cmake_minimum_required(VERSION 2.6) +INCLUDE(CheckFunctionExists) + PROJECT(rpcd C) ADD_DEFINITIONS(-Os -Wall -Werror --std=gnu99 -g3 -Wmissing-declarations -Iinclude) @@ -13,10 +15,19 @@ IF(APPLE) LINK_DIRECTORIES(/opt/local/lib) ENDIF() +CHECK_FUNCTION_EXISTS(getspnam HAVE_SHADOW) +IF(HAVE_SHADOW) + ADD_DEFINITIONS(-DHAVE_SHADOW) +ENDIF() + FIND_LIBRARY(json NAMES json-c json) +FIND_LIBRARY(crypt NAMES crypt) +IF(crypt STREQUAL "LIBS-NOTFOUND") + SET(crypt "") +ENDIF() ADD_EXECUTABLE(rpcd main.c exec.c session.c uci.c plugin.c) -TARGET_LINK_LIBRARIES(rpcd ubox ubus uci dl blobmsg_json ${json}) +TARGET_LINK_LIBRARIES(rpcd ubox ubus uci dl blobmsg_json ${json} ${crypt}) SET(PLUGINS "") diff --git a/include/rpcd/session.h b/include/rpcd/session.h index 7fa388e..7c3b270 100644 --- a/include/rpcd/session.h +++ b/include/rpcd/session.h @@ -32,7 +32,9 @@ #define RPC_SID_LEN 32 #define RPC_DEFAULT_SESSION_TIMEOUT 300 +#define RPC_DEFAULT_SESSION_ID "00000000000000000000000000000000" #define RPC_SESSION_DIRECTORY "/var/run/rpcd/sessions" +#define RPC_SESSION_ACL_DIR "/usr/share/rpcd/acl.d" struct rpc_session { struct avl_node avl; diff --git a/session.c b/session.c index e390a9b..9ad1552 100644 --- a/session.c +++ b/session.c @@ -17,10 +17,19 @@ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ +#define _GNU_SOURCE /* crypt() */ + #include +#include #include #include #include +#include +#include + +#ifdef HAVE_SHADOW +#include +#endif #include @@ -100,6 +109,18 @@ static const struct blobmsg_policy dump_policy[__RPC_DUMP_MAX] = { [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 @@ -215,7 +236,8 @@ rpc_session_dump(struct rpc_session *ses, struct ubus_context *ctx, 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 @@ -739,6 +761,332 @@ rpc_handle_destroy(struct ubus_context *ctx, struct ubus_object *obj, } +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(hash, password); + + 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; + 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; + + /* 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) +{ + 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; + + uci_foreach_element(&o->v.list, l) + if (l->name && !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. + * + * "": { + * "": [ + * "", + * "", + * ... + * ] + * } + */ + if (blob_id(acl_scope) == BLOBMSG_TYPE_TABLE) { + blobmsg_for_each_attr(acl_obj, acl_scope, rem) { + if (blob_id(acl_obj) != BLOBMSG_TYPE_ARRAY) + continue; + + blobmsg_for_each_attr(acl_func, acl_obj, rem2) { + if (blob_id(acl_func) != BLOBMSG_TYPE_STRING) + continue; + + rpc_session_grant(ses, NULL, 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. + * + * "": [ + * "", + * "", + * ... + * ] + */ + else if (blob_id(acl_scope) == BLOBMSG_TYPE_ARRAY) { + blobmsg_for_each_attr(acl_obj, acl_scope, rem) { + if (blob_id(acl_obj) != BLOBMSG_TYPE_STRING) + continue; + + rpc_session_grant(ses, NULL, 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 (blob_id(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 + * "": { + * "": { + * "": ... + * } + * } + * becomes + * "access-group": { + * "": [ + * "" + * ] + * } + * + * This allows session clients to easily query the allowed + * access groups without having to test access of each single + * // tuple defined in a group. + */ + rpc_session_grant(ses, NULL, "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(acl_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) { @@ -868,6 +1216,8 @@ rpc_session_from_blob(struct blob_attr *attr) 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), @@ -878,6 +1228,7 @@ 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 = @@ -892,6 +1243,15 @@ 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); } @@ -928,6 +1288,10 @@ void rpc_session_freeze(void) 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); rpc_blob_to_file(path, buf.head); diff --git a/unauthenticated.json b/unauthenticated.json new file mode 100644 index 0000000..baded9d --- /dev/null +++ b/unauthenticated.json @@ -0,0 +1,13 @@ +{ + "unauthenticated": { + "description": "Access controls for unauthenticated requests", + "read": { + "ubus": { + "session": [ + "access", + "login" + ] + } + } + } +}