fix utf and rune handling in preparation for 32bit runes

1 files changed, 7 insertions, 3 deletions

diff --git a/sys/src/cmd/cc/dpchk.c b/sys/src/cmd/cc/dpchk.c
index 99a49ee5a..aa7d468b8 100644
--- a/sys/src/cmd/cc/dpchk.c
+++ b/sys/src/cmd/cc/dpchk.c
@@ -67,13 +67,14 @@ getflag(char *s)
 {
 	Bits flag;
 	int f;
-	char *fmt;
+	char *fmt, *e;
 	Rune c;
 
 	fmt = fmtbuf;
+	e = fmtbuf + sizeof(fmtbuf)-1;
 	flag = zbits;
 	nstar = 0;
-	for(;;) {
+	while(fmt < e){
 		s += chartorune(&c, s);
 		fmt += runetochar(fmt, &c);
 		if(c == 0 || c >= nelem(flagbits))
@@ -175,7 +176,7 @@ pragvararg(void)
 {
 	Sym *s;
 	int n, c;
-	char *t;
+	char *t, *e;
 	Rune r;
 	Type *ty;
 
@@ -225,12 +226,15 @@ cktype:
 	if(c != '"')
 		goto bad;
 	t = fmtbuf;
+	e = t + sizeof(fmtbuf)-1;
 	for(;;) {
 		r = getr();
 		if(r == ' ' || r == '\n')
 			goto bad;
 		if(r == '"')
 			break;
+		if(t >= e)
+			goto bad;
 		t += runetochar(t, &r);
 	}
 	*t = 0;