upstream: Refactor creation of KEX proposal.

This adds kex_proposal_populate_entries (and corresponding free) which
populates the KEX proposal array with dynamically allocated strings.
This replaces the previous mix of static and dynamic that has been the
source of previous leaks and bugs.  Remove unused compat functions.
With & ok djm@.

OpenBSD-Commit-ID: f2f99da4aae2233cb18bf9c749320c5e040a9c7b

1 files changed, 12 insertions, 22 deletions

diff --git a/sshd.c b/sshd.c
index 748c15ee2..c45092ea4 100644
--- a/sshd.c
+++ b/sshd.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sshd.c,v 1.598 2023/03/03 03:12:24 dtucker Exp $ */
+/* $OpenBSD: sshd.c,v 1.599 2023/03/06 12:14:48 dtucker Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -104,7 +104,6 @@
 #include "digest.h"
 #include "sshkey.h"
 #include "kex.h"
-#include "myproposal.h"
 #include "authfile.h"
 #include "pathnames.h"
 #include "atomicio.h"
@@ -2389,30 +2388,23 @@ sshd_hostkey_sign(struct ssh *ssh, struct sshkey *privkey,
 static void
 do_ssh2_kex(struct ssh *ssh)
 {
-	char *myproposal[PROPOSAL_MAX] = { KEX_SERVER };
+	char *hkalgs = NULL, *myproposal[PROPOSAL_MAX];
+	const char *compression = NULL;
 	struct kex *kex;
-	char *prop_kex = NULL, *prop_enc = NULL, *prop_hostkey = NULL;
 	int r;
 
-	myproposal[PROPOSAL_KEX_ALGS] = prop_kex = compat_kex_proposal(ssh,
-	    options.kex_algorithms);
-	myproposal[PROPOSAL_ENC_ALGS_CTOS] =
-	    myproposal[PROPOSAL_ENC_ALGS_STOC] = prop_enc =
-	    compat_cipher_proposal(ssh, options.ciphers);
-	myproposal[PROPOSAL_MAC_ALGS_CTOS] =
-	    myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
-
-	if (options.compression == COMP_NONE) {
-		myproposal[PROPOSAL_COMP_ALGS_CTOS] =
-		    myproposal[PROPOSAL_COMP_ALGS_STOC] = "none";
-	}
-
 	if (options.rekey_limit || options.rekey_interval)
 		ssh_packet_set_rekey_limits(ssh, options.rekey_limit,
 		    options.rekey_interval);
 
-	myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = prop_hostkey =
-	   compat_pkalg_proposal(ssh, list_hostkey_types());
+	if (options.compression == COMP_NONE)
+		compression = "none";
+	hkalgs = list_hostkey_types();
+
+	kex_proposal_populate_entries(ssh, myproposal, options.kex_algorithms,
+	    options.ciphers, options.macs, compression, hkalgs);
+
+	free(hkalgs);
 
 	/* start key exchange */
 	if ((r = kex_setup(ssh, myproposal)) != 0)
@@ -2447,9 +2439,7 @@ do_ssh2_kex(struct ssh *ssh)
 	    (r = ssh_packet_write_wait(ssh)) != 0)
 		fatal_fr(r, "send test");
 #endif
-	free(prop_kex);
-	free(prop_enc);
-	free(prop_hostkey);
+	kex_proposal_free_entries(myproposal);
 	debug("KEX done");
 }