strutils: fix unsigned integer overflows [AddressSanitizer]

include/strutils.h:174:10: runtime error: unsigned integer overflow: 0 -
1 cannot be represented in type 'size_t' (aka 'unsigned long')

include/strutils.h:178:6: runtime error: unsigned integer overflow:
18446744073709551615 + 1 cannot be represented in type 'size_t' (aka
'unsigned long')

Signed-off-by: Sami Kerola <kerolasa@iki.fi>

1 files changed, 6 insertions, 3 deletions

diff --git a/include/strutils.h b/include/strutils.h
index cfe8a9560..4d8463a6d 100644
--- a/include/strutils.h
+++ b/include/strutils.h
@@ -171,11 +171,14 @@ static inline size_t rtrim_whitespace(unsigned char *str)
 {
 	size_t i = strlen((char *) str);
 
-	while (i--) {
-		if (!isspace(str[i]))
+	while (i) {
+		i--;
+		if (!isspace(str[i])) {
+			i++;
 			break;
+		}
 	}
-	str[++i] = '\0';
+	str[i] = '\0';
 	return i;
 }