2 files changed, 24 insertions, 11 deletions

diff --git a/ChangeLog b/ChangeLog
index 72d5a21e1..0ece9c09d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -61,6 +61,12 @@
      [clientloop.c]
      fix incorrect exit status when multiplexing and channel ID 0 is recycled
      bz#1570 reported by peter.oliver AT eon-is.co.uk; ok dtucker
+   - djm@cvs.openbsd.org 2009/11/19 23:39:50
+     [session.c]
+     bz#1606: error when an attempt is made to connect to a server
+     with ForceCommand=internal-sftp with a shell session (i.e. not a
+     subsystem session). Avoids stuck client when attempting to ssh to such a
+     service. ok dtucker@
 
 20091226
  - (tim) [contrib/cygwin/Makefile] Install ssh-copy-id and ssh-copy-id.1
diff --git a/session.c b/session.c
index 78192314a..cc205386f 100644
--- a/session.c
+++ b/session.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: session.c,v 1.247 2009/10/06 04:46:40 djm Exp $ */
+/* $OpenBSD: session.c,v 1.248 2009/11/19 23:39:50 djm Exp $ */
 /*
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
  *                    All rights reserved
@@ -142,9 +142,10 @@ static int sessions_first_unused = -1;
 static int sessions_nalloc = 0;
 static Session *sessions = NULL;
 
-#define SUBSYSTEM_NONE          0
-#define SUBSYSTEM_EXT           1
-#define SUBSYSTEM_INT_SFTP      2
+#define SUBSYSTEM_NONE                  0
+#define SUBSYSTEM_EXT                   1
+#define SUBSYSTEM_INT_SFTP              2
+#define SUBSYSTEM_INT_SFTP_ERROR        3
 
 #ifdef HAVE_LOGIN_CAP
 login_cap_t *lc;
@@ -785,17 +786,19 @@ do_exec(Session *s, const char *command)
         if (options.adm_forced_command) {
                 original_command = command;
                 command = options.adm_forced_command;
-                if (IS_INTERNAL_SFTP(command))
-                        s->is_subsystem = SUBSYSTEM_INT_SFTP;
-                else if (s->is_subsystem)
+                if (IS_INTERNAL_SFTP(command)) {
+                        s->is_subsystem = s->is_subsystem ?
+                            SUBSYSTEM_INT_SFTP : SUBSYSTEM_INT_SFTP_ERROR;
+                } else if (s->is_subsystem)
                         s->is_subsystem = SUBSYSTEM_EXT;
                 debug("Forced command (config) '%.900s'", command);
         } else if (forced_command) {
                 original_command = command;
                 command = forced_command;
-                if (IS_INTERNAL_SFTP(command))
-                        s->is_subsystem = SUBSYSTEM_INT_SFTP;
-                else if (s->is_subsystem)
+                if (IS_INTERNAL_SFTP(command)) {
+                        s->is_subsystem = s->is_subsystem ?
+                            SUBSYSTEM_INT_SFTP : SUBSYSTEM_INT_SFTP_ERROR;
+                } else if (s->is_subsystem)
                         s->is_subsystem = SUBSYSTEM_EXT;
                 debug("Forced command (key option) '%.900s'", command);
         }
@@ -1783,7 +1786,11 @@ do_child(Session *s, const char *command)
         /* restore SIGPIPE for child */
         signal(SIGPIPE, SIG_DFL);
 
-        if (s->is_subsystem == SUBSYSTEM_INT_SFTP) {
+        if (s->is_subsystem == SUBSYSTEM_INT_SFTP_ERROR) {
+                printf("This service allows sftp connections only.\n");
+                fflush(NULL);
+                exit(1);
+        } else if (s->is_subsystem == SUBSYSTEM_INT_SFTP) {
                 extern int optind, optreset;
                 int i;
                 char *p, *args;