config: Fix panic when parsing invalid %{ variable program

For example:
login_greeting = %{

Fixes:
Panic: %{: syntax error, unexpected end of file, expecting CCBRACE or PIPE or NAME

diff --git a/src/config/config-parser.c b/src/config/config-parser.c
index a5b91c0a8c1a84c2aa8469385bf4e07951f472b9..198555043f9767a4f670feb7b4487cc4923384c2 100644 (file)
--- a/src/config/config-parser.c
+++ b/src/config/config-parser.c
@@ -571,6 +571,35 @@ setting_value_can_check(const char *value, bool expand_values)
        return TRUE;
 }
 
+static int settings_value_check_vars(struct config_parser_context *ctx,
+                                    const char *value)
+{
+       if (strstr(value, "%{") != NULL) {
+               /* Verify that the program can be parsed. The expansion is done
+                  by config clients. */
+               struct var_expand_program *program;
+               const char *error;
+               int ret = var_expand_program_create(value, &program, &error);
+               if (ret < 0) {
+                       ctx->error = p_strdup_printf(ctx->pool, "%s: %s",
+                                                    value, error);
+                       return -1;
+               }
+               var_expand_program_free(&program);
+       }
+       return 0;
+}
+
+static int settings_value_check_common(struct config_parser_context *ctx,
+                                      const char *value)
+{
+       if (settings_value_check_vars(ctx, value) < 0)
+               return -1;
+       if (!setting_value_can_check(value, ctx->expand_values))
+               return 0;
+       return 1;
+}
+
 static int
 settings_value_check(struct config_parser_context *ctx,
                     const struct setting_parser_info *info,
@@ -582,12 +611,13 @@ settings_value_check(struct config_parser_context *ctx,
        if (prefixed_value[0] != CONFIG_VALUE_PREFIX_EXPANDED)
                return 0;
        const char *value = prefixed_value + 1;
+       int ret;
 
        switch (def->type) {
        case SET_BOOL: {
                bool b;
-               if (!setting_value_can_check(value, ctx->expand_values))
-                       break;
+               if ((ret = settings_value_check_common(ctx, value)) <= 0)
+                       return ret;
                if (str_parse_get_bool(value, &b, &error) < 0) {
                        ctx->error = p_strdup(ctx->pool, error);
                        return -1;
@@ -597,8 +627,8 @@ settings_value_check(struct config_parser_context *ctx,
        case SET_UINTMAX: {
                uintmax_t num;
 
-               if (!setting_value_can_check(value, ctx->expand_values))
-                       break;
+               if ((ret = settings_value_check_common(ctx, value)) <= 0)
+                       return ret;
                if (str_to_uintmax(value, &num) < 0) {
                        ctx->error = p_strdup_printf(ctx->pool,
                                "Invalid number %s: %s", value,
@@ -610,8 +640,8 @@ settings_value_check(struct config_parser_context *ctx,
        case SET_UINT_OCT:
                if (*value == '0') {
                        unsigned long long octal;
-                       if (!setting_value_can_check(value, ctx->expand_values))
-                               break;
+                       if ((ret = settings_value_check_common(ctx, value)) <= 0)
+                               return ret;
                        if (str_to_ullong_oct(value, &octal) < 0) {
                                ctx->error = p_strconcat(ctx->pool,
                                        "Invalid number: ", value, NULL);
@@ -623,8 +653,8 @@ settings_value_check(struct config_parser_context *ctx,
        case SET_UINT: {
                unsigned int num;
 
-               if (!setting_value_can_check(value, ctx->expand_values))
-                       break;
+               if ((ret = settings_value_check_common(ctx, value)) <= 0)
+                       return ret;
                if (settings_value_is_unlimited(value))
                        break;
                if (str_to_uint(value, &num) < 0) {
@@ -637,8 +667,8 @@ settings_value_check(struct config_parser_context *ctx,
        }
        case SET_TIME: {
                unsigned int interval;
-               if (!setting_value_can_check(value, ctx->expand_values))
-                       break;
+               if ((ret = settings_value_check_common(ctx, value)) <= 0)
+                       return ret;
                if (settings_value_is_unlimited(value))
                        break;
                if (str_parse_get_interval(value, &interval, &error) < 0) {
@@ -649,8 +679,8 @@ settings_value_check(struct config_parser_context *ctx,
        }
        case SET_TIME_MSECS: {
                unsigned int interval;
-               if (!setting_value_can_check(value, ctx->expand_values))
-                       break;
+               if ((ret = settings_value_check_common(ctx, value)) <= 0)
+                       return ret;
                if (settings_value_is_unlimited(value))
                        break;
                if (str_parse_get_interval_msecs(value, &interval, &error) < 0) {
@@ -661,8 +691,8 @@ settings_value_check(struct config_parser_context *ctx,
        }
        case SET_SIZE: {
                uoff_t size;
-               if (!setting_value_can_check(value, ctx->expand_values))
-                       break;
+               if ((ret = settings_value_check_common(ctx, value)) <= 0)
+                       return ret;
                if (settings_value_is_unlimited(value))
                        break;
                if (str_parse_get_size(value, &size, &error) < 0) {
@@ -673,8 +703,8 @@ settings_value_check(struct config_parser_context *ctx,
        }
        case SET_IN_PORT: {
                in_port_t port;
-               if (!setting_value_can_check(value, ctx->expand_values))
-                       break;
+               if ((ret = settings_value_check_common(ctx, value)) <= 0)
+                       return ret;
                if (net_str2port_zero(value, &port) < 0) {
                        ctx->error = p_strdup_printf(ctx->pool,
                                "Invalid port number %s", value);
@@ -683,12 +713,15 @@ settings_value_check(struct config_parser_context *ctx,
                break;
        }
        case SET_STR:
+               if (settings_value_check_vars(ctx, value) < 0)
+                       return -1;
+               break;
        case SET_STR_NOVARS:
                break;
        case SET_ENUM:
                /* get the available values from default string */
-               if (!setting_value_can_check(value, ctx->expand_values))
-                       break;
+               if ((ret = settings_value_check_common(ctx, value)) <= 0)
+                       return ret;
                i_assert(info->defaults != NULL);
                const char *const *default_value =
                        CONST_PTR_OFFSET(info->defaults, def->offset);
@@ -700,10 +733,11 @@ settings_value_check(struct config_parser_context *ctx,
                }
                break;
        case SET_FILE:
-               break;
        case SET_STRLIST:
        case SET_BOOLLIST:
        case SET_FILTER_ARRAY:
+               if (settings_value_check_vars(ctx, value) < 0)
+                       return -1;
                break;
        case SET_FILTER_NAME:
                ctx->error = p_strdup_printf(ctx->pool,