Overflow prevention in str_to_unsigned

1 files changed, 9 insertions, 1 deletions

diff --git a/utils.c b/utils.c
index 10079d2..db0df78 100644
--- a/utils.c
+++ b/utils.c
@@ -49,8 +49,16 @@ uint64_t str_to_unsigned(struct string str, char *err) {
 		case '7':
 		case '8':
 		case '9':
+			if (val > ((uint64_t)-1)/10) {
+				*err = 1;
+				return 0;
+			}
 			val *= 10;
-			val += (uint8_t)(str.data[0] - 0x30);
+			if (val > (-((uint64_t)((uint8_t)str.data[0] - 0x30) + 1))) {
+				*err = 1;
+				return 0;
+			}
+			val += (uint8_t)str.data[0] - 0x30;
 			break;
 		default:
 			*err = 1;