x509_get_sia() allocates this via a strndup() in x509_location().

Index: tak.c
===================================================================
RCS file: /cvs/src/usr.sbin/rpki-client/tak.c,v
diff -u -p -r1.19 tak.c
--- tak.c	21 Feb 2024 09:17:06 -0000	1.19
+++ tak.c	15 May 2024 06:01:45 -0000
@@ -308,6 +308,7 @@ tak_free(struct tak *t)
 
 	free(t->aia);
 	free(t->aki);
+	free(t->sia);
 	free(t->ski);
 	free(t);
 }