From: Hiltjo Posthuma <hiltjo@codemadness.org>
Date: Wed, 5 May 2021 23:09:21 +0000 (+0200)
Subject: fix undefined behaviour of using isspace ctype function
X-Git-Url: https://git.armaanb.net/?p=sic.git;a=commitdiff_plain;h=d9bda20849c464eff0adb56414da1840abc6ef6a

fix undefined behaviour of using isspace ctype function

cast all ctype(3) functions argument to (unsigned char) to avoid UB

POSIX says:
"The c argument is an int, the value of which the application shall ensure is a
character representable as an unsigned char or equal to the value of the macro
EOF. If the argument has any other value, the behavior is undefined."

Many libc cast implicitly the value, but NetBSD for example does not, which is
probably the correct thing to interpret it.
---

diff --git a/sic.c b/sic.c
index 774f357..c1e428e 100644
--- a/sic.c
+++ b/sic.c
@@ -74,7 +74,7 @@ parsein(char *s) {
 		return;
 	}
 	c = *++s;
-	if(c != '\0' && isspace(s[1])) {
+	if(c != '\0' && isspace((unsigned char)s[1])) {
 		p = s + 2;
 		switch(c) {
 		case 'j':
diff --git a/util.c b/util.c
index 2567812..0869cca 100644
--- a/util.c
+++ b/util.c
@@ -42,7 +42,7 @@ dial(char *host, char *port) {
 
 static char *
 eat(char *s, int (*p)(int), int r) {
-	while(*s != '\0' && p(*s) == r)
+	while(*s != '\0' && p((unsigned char)*s) == r)
 		s++;
 	return s;
 }
@@ -61,7 +61,7 @@ trim(char *s) {
 	char *e;
 
 	e = s + strlen(s) - 1;
-	while(e > s && isspace(*e))
+	while(e > s && isspace((unsigned char)*e))
 		e--;
 	*(e + 1) = '\0';
 }