ipsecctl(8): handle non-null-terminated strings

[Tobias Heider]

ipsecctl wrongly assumes that strings like the pf tag or
the identities are always null terminated.
The diff below fixes the cases that always kill my
ipsecctl -m when running a fuzzer.

ok?

Index: pfkdump.c
===================================================================
RCS file: /mount/openbsd/cvs/src/sbin/ipsecctl/pfkdump.c,v
retrieving revision 1.57
diff -u -p -r1.57 pfkdump.c
--- pfkdump.c   7 Aug 2023 04:10:08 -0000       1.57
+++ pfkdump.c   9 Oct 2023 20:41:54 -0000
@@ -406,9 +406,11 @@ print_tag(struct sadb_ext *ext, struct s
 {
        struct sadb_x_tag *stag = (struct sadb_x_tag *)ext;
        char *p;
+       int plen;
 
        p = (char *)(stag + 1);
-       printf("%s", p);
+       plen = (stag->sadb_x_tag_len * 8) - sizeof(*stag);
+       printf("%.*s", plen, p);
 }
 
 static void
@@ -590,10 +592,12 @@ static void
 print_ident(struct sadb_ext *ext, struct sadb_msg *msg, int opts)
 {
        struct sadb_ident *ident = (struct sadb_ident *)ext;
+       int ilen;
 
-       printf("type %s id %llu: %s",
+       ilen = (ident->sadb_ident_len * 8) - sizeof(*ident);
+       printf("type %s id %llu: %.*s",
            lookup_name(identity_types, ident->sadb_ident_type),
-           ident->sadb_ident_id, (char *)(ident + 1));
+           ident->sadb_ident_id, ilen, (char *)(ident + 1));
 }
 
 static void