banned.h: mark strcat() as banned

peff · gitster · commit 1b11b64b815d · 2018-07-26T10:12:50.000-07:00
The strcat() function has all of the same overflow problems as strcpy(). And as a bonus, it's easy to end up accidentally quadratic, as each subsequent call has to walk through the existing string. The last strcat() call went away in f063d38 (daemon: use cld->env_array when re-spawning, 2015-09-24). In general, strcat() can be replaced either with a dynamic string (strbuf or xstrfmt), or with xsnprintf if you know the length is bounded. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/banned.h b/banned.h
@@ -12,5 +12,7 @@
 
 #undef strcpy
 #define strcpy(x,y) BANNED(strcpy)
+#undef strcat
+#define strcat(x,y) BANNED(strcat)
 
 #endif /* BANNED_H */
