auth: lua - Passdb/userdb lookups can no longer return a single string on success

The second return value must be either a table or nil. Returning a single
string was a bit unsafe since its values could accidentally become expanded
to spaces, causing unsafe behavior.

If the first return value indicates an error, the second can still be a
string.

diff --git a/src/auth/db-lua.c b/src/auth/db-lua.c
index 057661bd15c4419b77ae76bf1848f545f8fbe8cd..591d76c5da11695458c73b212766a1a708d67b36 100644 (file)
--- a/src/auth/db-lua.c
+++ b/src/auth/db-lua.c
@@ -371,10 +371,10 @@ static void auth_lua_dovecot_auth_register(lua_State *L)
        lua_pop(L, 1);
 }
 
-static int auth_lua_call_lookup(lua_State *L, const char *fn,
+static int auth_lua_call_lookup(lua_State *L, const char *fn, int ret_success,
                                struct auth_request *req, const char **error_r)
 {
-       int err = 0;
+       int ret, err = 0;
 
        e_debug(authdb_event(req), "Calling %s", fn);
 
@@ -388,11 +388,22 @@ static int auth_lua_call_lookup(lua_State *L, const char *fn,
                                           "(expected number got %s)",
                                           fn, luaL_typename(L, -2));
                err = -1;
-       } else if (!lua_isstring(L, -1) && !lua_istable(L, -1) && !lua_isnil(L, -1)) {
-               *error_r = t_strdup_printf("db-lua: %s(req) invalid return value "
-                                          "(expected nil, string or table, got %s)",
-                                          fn, luaL_typename(L, -1));
-               err = -1;
+       } else if ((ret = lua_tointeger(L, -2)) != ret_success) {
+               if (!lua_isstring(L, -1) && !lua_isnil(L, -1)) {
+                       *error_r = t_strdup_printf(
+                               "db-lua: %s(req) invalid error return value "
+                               "(expected nil or string, got %s)",
+                               fn, luaL_typename(L, -1));
+                       err = -1;
+               }
+       } else {
+               if (!lua_istable(L, -1) && !lua_isnil(L, -1)) {
+                       *error_r = t_strdup_printf(
+                               "db-lua: %s(req) invalid return value "
+                               "(expected nil or table, got %s)",
+                               fn, luaL_typename(L, -1));
+                       err = -1;
+               }
        }
 
        if (err != 0) {
@@ -483,38 +494,17 @@ auth_lua_script_get_default_cache_key(const struct auth_lua_script_parameters *p
        return 0;
 }
 
-static void
-auth_lua_export_fields(struct auth_request *req,
-                      const char *str,
-                      const char **scheme_r, const char **password_r)
-{
-       const char *const *fields = t_strsplit_spaces(str, " ");
-       while(*fields != NULL) {
-               const char *value = strchr(*fields, '=');
-               const char *key;
-
-               if (value == NULL) {
-                       key = *fields;
-                       value = "";
-               } else {
-                       key = t_strdup_until(*fields, value++);
-               }
-
-               if (password_r != NULL && strcmp(key, "password") == 0) {
-                       *scheme_r = password_get_scheme(&value);
-                       *password_r = value;
-               } else if (req->userdb_lookup) {
-                       auth_request_set_userdb_field(req, key, value);
-               } else {
-                       auth_request_set_field(req, key, value, STATIC_PASS_SCHEME);
-               }
-               fields++;
-       }
-}
-
 static void auth_lua_export_table(lua_State *L, struct auth_request *req,
                                 const char **scheme_r, const char **password_r)
 {
+       if (lua_isnil(L, -1)) {
+               lua_pop(L, 2);
+               lua_gc(L, LUA_GCCOLLECT, 0);
+               i_assert(lua_gettop(L) == 0);
+               return;
+       }
+       i_assert(lua_istable(L, -1));
+
        lua_pushvalue(L, -1);
        lua_pushnil(L);
        while (lua_next(L, -2) != 0) {
@@ -584,9 +574,12 @@ auth_lua_export_userdb_table(lua_State *L, struct auth_request *req,
        enum userdb_result ret = lua_tointeger(L, -2);
 
        if (ret != USERDB_RESULT_OK) {
+               if (lua_isnil(L, -1))
+                       *error_r = "userdb failed";
+               else
+                       *error_r = t_strdup(lua_tostring(L, -1));
                lua_pop(L, 2);
                lua_gc(L, LUA_GCCOLLECT, 0);
-               *error_r = "userdb failed";
                return ret;
        }
 
@@ -602,9 +595,12 @@ auth_lua_export_passdb_table(lua_State *L, struct auth_request *req,
        enum passdb_result ret = lua_tointeger(L, -2);
 
        if (ret != PASSDB_RESULT_OK) {
+               if (lua_isnil(L, -1))
+                       *error_r = "passdb failed";
+               else
+                       *error_r = t_strdup(lua_tostring(L, -1));
                lua_pop(L, 2);
                lua_gc(L, LUA_GCCOLLECT, 0);
-               *error_r = "passb failed";
                return ret;
        }
 
@@ -612,40 +608,12 @@ auth_lua_export_passdb_table(lua_State *L, struct auth_request *req,
        return PASSDB_RESULT_OK;
 }
 
-static enum passdb_result
-auth_lua_call_lookup_finish(lua_State *L, struct auth_request *req,
-                           const char **scheme_r, const char **password_r,
-                           const char **error_r)
-{
-       if (lua_istable(L, -1)) {
-               return auth_lua_export_passdb_table(L, req, scheme_r,
-                                                   password_r, error_r);
-       }
-
-       enum passdb_result ret = lua_tointeger(L, -2);
-       const char *str = t_strdup(lua_tostring(L, -1));
-       lua_pop(L, 2);
-       lua_gc(L, LUA_GCCOLLECT, 0);
-       /* stack should be empty now */
-       i_assert(lua_gettop(L) == 0);
-
-       if (ret != PASSDB_RESULT_OK && ret != PASSDB_RESULT_NEXT) {
-               *error_r = str;
-       } else if (str != NULL) {
-               auth_lua_export_fields(req, str, scheme_r, password_r);
-       }
-
-       if (scheme_r != NULL && *scheme_r == NULL)
-               *scheme_r = "PLAIN";
-
-       return ret;
-}
-
 enum passdb_result
 auth_lua_call_password_verify(struct dlua_script *script,
                              struct auth_request *req, const char *password, const char **error_r)
 {
        lua_State *L = script->L;
+       enum passdb_result ret;
        int err = 0;
 
        e_debug(authdb_event(req), "Calling %s", AUTH_LUA_PASSWORD_VERIFY);
@@ -663,12 +631,22 @@ auth_lua_call_password_verify(struct dlua_script *script,
                                           AUTH_LUA_PASSWORD_VERIFY,
                                           luaL_typename(L, -2));
                err = -1;
-       } else if (!lua_isstring(L, -1) && !lua_istable(L, -1) && !lua_isnil(L, -1)) {
-               *error_r = t_strdup_printf("db-lua: %s invalid return value "
-                                          "(expected nil, string or table, got %s)",
-                                          AUTH_LUA_PASSWORD_VERIFY,
-                                          luaL_typename(L, -1));
-               err = -1;
+       } else if ((ret = lua_tointeger(L, -2)) != PASSDB_RESULT_OK) {
+               if (!lua_isstring(L, -1) && !lua_isnil(L, -1)) {
+                       *error_r = t_strdup_printf(
+                               "db-lua: %s invalid error return value "
+                               "(expected nil or string, got %s)",
+                               AUTH_LUA_PASSWORD_VERIFY, luaL_typename(L, -1));
+                       err = -1;
+               }
+       } else {
+               if (!lua_istable(L, -1) && !lua_isnil(L, -1)) {
+                       *error_r = t_strdup_printf(
+                               "db-lua: %s invalid return value "
+                               "(expected nil or table, got %s)",
+                               AUTH_LUA_PASSWORD_VERIFY, luaL_typename(L, -1));
+                       err = -1;
+               }
        }
 
        if (err != 0) {
@@ -678,8 +656,7 @@ auth_lua_call_password_verify(struct dlua_script *script,
                return PASSDB_RESULT_INTERNAL_FAILURE;
        }
 
-
-       return auth_lua_call_lookup_finish(L, req, NULL, NULL, error_r);
+       return auth_lua_export_passdb_table(L, req, NULL, NULL, error_r);
 }
 
 
@@ -691,13 +668,15 @@ auth_lua_call_passdb_lookup(struct dlua_script *script,
        lua_State *L = script->L;
 
        *scheme_r = *password_r = NULL;
-       if (auth_lua_call_lookup(L, AUTH_LUA_PASSDB_LOOKUP, req, error_r) < 0) {
+       if (auth_lua_call_lookup(L, AUTH_LUA_PASSDB_LOOKUP, PASSDB_RESULT_OK,
+                                req, error_r) < 0) {
                lua_gc(L, LUA_GCCOLLECT, 0);
                i_assert(lua_gettop(L) == 0);
                return PASSDB_RESULT_INTERNAL_FAILURE;
        }
 
-       return auth_lua_call_lookup_finish(L, req, scheme_r, password_r, error_r);
+       return auth_lua_export_passdb_table(L, req, scheme_r, password_r,
+                                           error_r);
 }
 
 
@@ -707,29 +686,14 @@ auth_lua_call_userdb_lookup(struct dlua_script *script,
 {
        lua_State *L = script->L;
 
-       if (auth_lua_call_lookup(L, AUTH_LUA_USERDB_LOOKUP, req, error_r) < 0) {
+       if (auth_lua_call_lookup(L, AUTH_LUA_USERDB_LOOKUP, USERDB_RESULT_OK,
+                                req, error_r) < 0) {
                lua_gc(L, LUA_GCCOLLECT, 0);
                i_assert(lua_gettop(L) == 0);
                return USERDB_RESULT_INTERNAL_FAILURE;
        }
 
-       if (lua_istable(L, -1))
-               return auth_lua_export_userdb_table(L, req, error_r);
-
-       enum userdb_result ret = lua_tointeger(L, -2);
-       const char *str = t_strdup(lua_tostring(L, -1));
-       lua_pop(L, 2);
-       lua_gc(L, LUA_GCCOLLECT, 0);
-       i_assert(lua_gettop(L) == 0);
-
-       if (ret != USERDB_RESULT_OK) {
-               *error_r = str;
-               return ret;
-       }
-       if (str != NULL)
-               auth_lua_export_fields(req, str, NULL, NULL);
-
-       return USERDB_RESULT_OK;
+       return auth_lua_export_userdb_table(L, req, error_r);
 }
 
 struct userdb_iterate_context *