From: NRK <nrk@disroot.org>
Date: Fri, 18 Mar 2022 10:20:54 +0000 (+0600)
Subject: avoid potential UB when using isprint()
X-Git-Tag: 0.9~6
X-Git-Url: http://www.git.stargrave.org/?a=commitdiff_plain;h=af3bb68add1c40d19d0dee382009e21b0870a38f;hp=2aefa348baf4b702fdce98eb105bcba175d8283f;p=st.git

avoid potential UB when using isprint()

all the ctype.h functions' argument must be representable as an unsigned
char or as EOF, otherwise the behavior is undefined.
---

diff --git a/st.c b/st.c
index c71fa06..1307fdf 100644
--- a/st.c
+++ b/st.c
@@ -367,7 +367,7 @@ static const char base64_digits[] = {
 char
 base64dec_getc(const char **src)
 {
-	while (**src && !isprint(**src))
+	while (**src && !isprint((unsigned char)**src))
 		(*src)++;
 	return **src ? *((*src)++) : '=';  /* emulate padding if string ends */
 }