plugins: use stricter parsing for option values

also: convert the stored int value from 'int' to 's64'

atoi fails silently, returning a zero. instead we use the more robust
strtoll which will allow us fail with an error.

we also make the parsing for bools stricter, only allowing plausibly
boolean values to parse.

lightningd/plugin.c

@@ -466,13 +466,37 @@ struct io_plan *plugin_stdout_conn_init(struct io_conn *conn,
 
 char *plugin_opt_set(const char *arg, struct plugin_opt *popt)
 {
+	char *endp;
+	long long l;
+
 	tal_free(popt->value->as_str);
+
 	popt->value->as_str = tal_strdup(popt, arg);
-	if (streq(popt->type, "int"))
-		*popt->value->as_int = atoi(arg);
-	else if (streq(popt->type, "bool"))
-		*popt->value->as_bool = streq(arg, "true") || streq(arg, "True")
-			|| streq(arg, "1");
+	if (streq(popt->type, "int")) {
+		errno = 0;
+		l = strtoll(arg, &endp, 0);
+		if (errno || *endp)
+			return tal_fmt(tmpctx, "%s does not parse as type %s",
+				       popt->value->as_str, popt->type);
+		*popt->value->as_int = l;
+
+		/* Check if the number did not fit in `s64` (in case `long long`
+		 * is a bigger type). */
+		if (*popt->value->as_int != l)
+			return tal_fmt(tmpctx, "%s does not parse as type %s (overflowed)",
+				       popt->value->as_str, popt->type);
+	} else if (streq(popt->type, "bool")) {
+		/* valid values are 'true', 'True', '1', '0', 'false', 'False', or '' */
+		if (streq(arg, "true") || streq(arg, "True") || streq(arg, "1")) {
+			*popt->value->as_bool = true;
+		} else if (streq(arg, "false") || streq(arg, "False")
+				|| streq(arg, "0") || streq(arg, "")) {
+			*popt->value->as_bool = false;
+		} else
+			return tal_fmt(tmpctx, "%s does not parse as type %s",
+				       popt->value->as_str, popt->type);
+	}
+
 	return NULL;
 }
 
@@ -509,12 +533,12 @@ static bool plugin_opt_add(struct plugin *plugin, const char *buffer,
 		}
 	} else if (json_tok_streq(buffer, typetok, "int")) {
 		popt->type = "int";
-		popt->value->as_int = talz(popt->value, int);
+		popt->value->as_int = talz(popt->value, s64);
 		if (defaulttok) {
-			json_to_int(buffer, defaulttok, popt->value->as_int);
-			popt->value->as_str = tal_fmt(popt->value, "%d", *popt->value->as_int);
+			json_to_s64(buffer, defaulttok, popt->value->as_int);
+			popt->value->as_str = tal_fmt(popt->value, "%"PRIu64, *popt->value->as_int);
 			popt->description = tal_fmt(
-					popt, "%.*s (default: %i)", desctok->end - desctok->start,
+					popt, "%.*s (default: %"PRIu64")", desctok->end - desctok->start,
 					buffer + desctok->start, *popt->value->as_int);
 		}
 	} else if (json_tok_streq(buffer, typetok, "bool")) {
@@ -535,7 +559,7 @@ static bool plugin_opt_add(struct plugin *plugin, const char *buffer,
 		popt->description = json_strdup(popt, buffer, desctok);
 	list_add_tail(&plugin->plugin_opts, &popt->list);
 	opt_register_arg(popt->name, plugin_opt_set, NULL, popt,
-				popt->description);
+			 popt->description);
 	return true;
 }
 
@@ -1185,7 +1209,7 @@ void json_add_opt_plugins(struct json_stream *response,
 				if (opt->value->as_bool) {
 					json_add_bool(response, opt_name, opt->value->as_bool);
 				} else if (opt->value->as_int) {
-					json_add_s32(response, opt_name, *opt->value->as_int);
+					json_add_s64(response, opt_name, *opt->value->as_int);
 				} else if (opt->value->as_str) {
 					json_add_string(response, opt_name, opt->value->as_str);
 				} else {

lightningd/plugin.h

@@ -114,7 +114,7 @@ struct plugins {
  */
 struct plugin_opt_value {
 	char *as_str;
-	int *as_int;
+	s64 *as_int;
 	bool *as_bool;
 };