fix: harden small core containers

dict.c

@@ -64,13 +64,15 @@ dictopen(char *path)
 	Biobuf *b;
 	Str key;
 	char *line, *tab;
-	int len;
+	int len, lineno;
 
 	b = Bopen(path, OREAD);
 	if(b == nil)
 		die("can't open: %s", path);
 	h = hmapalloc(4096);
+	lineno = 0;
 	while((line = Brdstr(b, '\n', 1)) != nil){
+		lineno++;
 		len = strlen(line);
 		if(len > 0 && line[len-1] == '\r')
 			line[--len] = '\0';
@@ -84,6 +86,8 @@ dictopen(char *path)
 			continue;
 		}
 		*tab = '\0';
+		if(utflen(line) > Maxrunes)
+			die("dictionary key too long: %s:%d", path, lineno);
 		sinit(&key, line, tab - line);
 		hmapset(&h, &key, tab+1, len - (tab - line) - 1);
 		free(line);
@@ -101,7 +105,10 @@ dictinit(char *dir)
 	for(i = 0; i < nlang; i++){
 		if(langs[i].dictname == nil)
 			continue;
-		snprint(path, sizeof(path), "%s/%s.dict", dir, langs[i].dictname);
+		if(snprint(path, sizeof(path), "%s/%s.dict", dir,
+		   langs[i].dictname) >= (int)sizeof path)
+			die("dictionary path too long: %s/%s.dict",
+				dir, langs[i].dictname);
 		langs[i].dict = dictopen(path);
 	}
 }