Disallow '/' characters in LC_* environment variables which might

be used to point to a bad locale file. This is only believed to be a
minor security risk - the only risk is if some program uses the result
of a localized string as a format specifier in a vulnerable function
like sprintf(). No such code is believed to exist in the FreeBSD base
system, although it is possible that badly written third party code
would do that.

Submitted by:	imp
Approved by:	ache

lib/libc/locale/setlocale.c

@@ -129,7 +129,7 @@ setlocale(category, locale)
 		if (!env || !*env)
 			env = getenv("LANG");
 
-		if (!env || !*env)
+		if (!env || !*env || strchr(env, '/'))
 			env = "C";
 
 		(void) strncpy(new_categories[category], env, ENCODING_LEN);