upstream: allow sshpkt_fatal() to take a varargs format; we'll

use this to give packet-related fatal error messages more context (esp. the
remote endpoint) ok markus@

OpenBSD-Commit-ID: de57211f9543426b515a8a10a4f481666b2b2a50

1 files changed, 23 insertions, 6 deletions

diff --git a/packet.c b/packet.c
index ded5a3201..aa8be8c94 100644
--- a/packet.c
+++ b/packet.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: packet.c,v 1.279 2019/01/04 03:23:00 djm Exp $ */
+/* $OpenBSD: packet.c,v 1.280 2019/01/19 21:33:14 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -1809,10 +1809,10 @@ sshpkt_fmt_connection_id(struct ssh *ssh, char *s, size_t l)
 /*
  * Pretty-print connection-terminating errors and exit.
  */
-void
-sshpkt_fatal(struct ssh *ssh, const char *tag, int r)
+static void
+sshpkt_vfatal(struct ssh *ssh, int r, const char *fmt, va_list ap)
 {
-        char remote_id[512];
+        char *tag = NULL, remote_id[512];
 
         sshpkt_fmt_connection_id(ssh, remote_id, sizeof(remote_id));
 
@@ -1846,6 +1846,11 @@ sshpkt_fatal(struct ssh *ssh, const char *tag, int r)
                 }
                 /* FALLTHROUGH */
         default:
+                if (vasprintf(&tag, fmt, ap) == -1) {
+                        ssh_packet_clear_keys(ssh);
+                        logdie("%s: could not allocate failure message",
+                            __func__);
+                }
                 ssh_packet_clear_keys(ssh);
                 logdie("%s%sConnection %s %s: %s",
                     tag != NULL ? tag : "", tag != NULL ? ": " : "",
@@ -1854,6 +1859,18 @@ sshpkt_fatal(struct ssh *ssh, const char *tag, int r)
         }
 }
 
+void
+sshpkt_fatal(struct ssh *ssh, int r, const char *fmt, ...)
+{
+        va_list ap;
+
+        va_start(ap, fmt);
+        sshpkt_vfatal(ssh, r, fmt, ap);
+        /* NOTREACHED */
+        va_end(ap);
+        logdie("%s: should have exited", __func__);
+}
+
 /*
  * Logs the error plus constructs and sends a disconnect packet, closes the
  * connection, and exits.  This function never returns. The error message
@@ -1889,10 +1906,10 @@ ssh_packet_disconnect(struct ssh *ssh, const char *fmt,...)
          * for it to get sent.
          */
         if ((r = sshpkt_disconnect(ssh, "%s", buf)) != 0)
-                sshpkt_fatal(ssh, __func__, r);
+                sshpkt_fatal(ssh, r, "%s", __func__);
 
         if ((r = ssh_packet_write_wait(ssh)) != 0)
-                sshpkt_fatal(ssh, __func__, r);
+                sshpkt_fatal(ssh, r, "%s", __func__);
 
         /* Close the connection. */
         ssh_packet_close(ssh);