upstream: scrub keyboard-interactive authentication prompts coming

from the server through asmprintf() prior to display; suggested by and ok
dtucker@

OpenBSD-Commit-ID: 31fe93367645c37fbfe4691596bf6cf1e3972a58

diff --git a/sshconnect2.c b/sshconnect2.c
index 6c31eeaf23f941be528df1f5737a3a6724804c84..149bb8d6e88343a73565ea0c0aac17a49f1f36b2 100644 (file)
--- a/sshconnect2.c
+++ b/sshconnect2.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sshconnect2.c,v 1.335 2020/11/13 04:53:12 djm Exp $ */
+/* $OpenBSD: sshconnect2.c,v 1.336 2020/11/13 07:30:44 djm Exp $ */
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
  * Copyright (c) 2008 Damien Miller.  All rights reserved.
@@ -33,6 +33,7 @@
 
 #include <errno.h>
 #include <fcntl.h>
+#include <limits.h>
 #include <netdb.h>
 #include <pwd.h>
 #include <signal.h>
@@ -1924,9 +1925,10 @@ input_userauth_info_req(int type, u_int32_t seq, struct ssh *ssh)
                if ((r = sshpkt_get_cstring(ssh, &prompt, NULL)) != 0 ||
                    (r = sshpkt_get_u8(ssh, &echo)) != 0)
                        goto out;
-               xasprintf(&display_prompt, "(%s@%s) %s",
+               if (asmprintf(&display_prompt, INT_MAX, NULL, "(%s@%s) %s",
                    authctxt->server_user, options.host_key_alias ?
-                   options.host_key_alias : authctxt->host, prompt);
+                   options.host_key_alias : authctxt->host, prompt) == -1)
+                       fatal_f("asmprintf failed");
                response = read_passphrase(display_prompt, echo ? RP_ECHO : 0);
                if ((r = sshpkt_put_cstring(ssh, response)) != 0)
                        goto out;