Bug 7210 - ssh crash on Kerberos errors on Windows
Summary: ssh crash on Kerberos errors on Windows
Status: CLOSED FIXED
Alias: None
Product: ThinLinc
Classification: Unclassified
Component: Client (show other bugs)
Version: 1.3.1
Hardware: PC Unknown
: P2 Normal
Target Milestone: 4.10.0
Assignee: Pierre Ossman
URL:
Keywords: prosaic
Depends on:
Blocks: 4532
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Reported: 2018-07-10 13:10 CEST by Pierre Ossman
Modified: 2019-02-18 12:27 CET (History)
1 user (show)

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Description Pierre Ossman cendio 2018-07-10 13:10:11 CEST 
If there is an error in the GSS-API/Kerberos routines, then our ssh will crash. Windows doesn't seem to show the crash dialog for stripped binaries, so the practical issue is that the user sees a "SSH terminated" message rather than "Kerberos auth failed".
Comment 2 Pierre Ossman cendio 2018-07-10 13:11:01 CEST 
Fix:

Index: openssh/openbsd-compat/win32-sspi.c
===================================================================
--- openssh/openbsd-compat/win32-sspi.c (revision 33497)
+++ openssh/openbsd-compat/win32-sspi.c (working copy)
@@ -190,7 +192,7 @@
                                msg = "No minor code available";
                }
                status_string->length = strlen(msg);
-               status_string->value = msg;
+               status_string->value = xstrdup(msg);
 
                return GSS_S_COMPLETE;
        }
Comment 3 Pierre Ossman cendio 2019-01-24 15:10:32 CET 
The bug can be provoked by connecting to a realm for which you have no ticket (same realm but wrong user works fine). So basically just connect to any non-Kerberos server and the bug happens.

I tried it on our Windows 2008R2 server, and I even got a crash dialog for ssh.
Comment 4 Pierre Ossman cendio 2019-01-24 15:12:50 CET 
This was with an unstripped binary, so I guess that explains the error dialog.
Comment 6 Pierre Ossman cendio 2019-01-24 15:15:47 CET 
Above fix applied and works well.

This code is only in the error handling, so the tester only needs to test this failure scenario.
Comment 7 Peter Åstrand cendio 2019-02-18 12:27:47 CET 
Tested both x64 and x86 version of the Windows client, build 6045. The error message is correctly displayed.
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