Bug 1311171

Summary: xfreerdp randomly segfaults in xf_gdi_memblt
Product: Red Hat Enterprise Linux 6 Reporter: Ondrej Holy <oholy>
Component: freerdpAssignee: Ondrej Holy <oholy>
Status: CLOSED ERRATA QA Contact: Desktop QE <desktop-qa-list>
Severity: unspecified Docs Contact:
Priority: unspecified    
Version: 6.7CC: desktop-qa-list, jkoten, thudziec, tpelka
Target Milestone: rc   
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard:
Fixed In Version: freerdp-1.0.2-5.el6 Doc Type: Bug Fix
Doc Text:
Cause: Servers may ask for bitmaps from a cache, which have never been defined. Consequence: Consequently, a client application might crash because a NULL pointer was used. Fix: An additional check is added to avoid further processing of the NULL pointer. Result: The client application is no more crashing if servers ask for missing bitmaps.
 Story Points: ---
Clone Of: 1311164 Environment:
Last Closed: 2016-05-10 19:44:15 UTC Type: Bug
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 1311164    
Bug Blocks:    

Description Ondrej Holy 2016-02-23 14:43:26 UTC 
+++ This bug was initially created as a clone of Bug #1311164 +++

Description of problem:

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7fffecae9700 (LWP 28342)]
0x0000000000408552 in xf_gdi_memblt (context=0x6c5b60, memblt=0x6b2d38) at FreeRDP/client/X11/xf_gdi.c:602
602		XCopyArea(xfi->display, bitmap->pixmap, xfi->drawing, xfi->gc,

#0  0x0000000000408552 in xf_gdi_memblt (context=0x6c5b60, memblt=0x6b2d38) at FreeRDP/client/X11/xf_gdi.c:602
#1  0x00007ffff68369ad in update_gdi_memblt (context=0x6c5b60, memblt=0x6b2d38) at libfreerdp-cache/bitmap.c:37
#2  0x00007ffff65fb189 in update_recv_primary_order (update=0x6b06b0, s=0x7fffe802cd10, flags=65 'A') at FreeRDP/libfreerdp-core/orders.c:1781
#3  0x00007ffff65fbef3 in update_recv_order (update=0x6b06b0, s=0x7fffe802cd10) at FreeRDP/libfreerdp-core/orders.c:2018
#4  0x00007ffff660bc44 in fastpath_recv_orders (fastpath=0x6b48f0, s=0x7fffe802cd10) at FreeRDP/libfreerdp-core/fastpath.c:132
#5  0x00007ffff660be20 in fastpath_recv_update (fastpath=0x6b48f0, updateCode=0 '\000', size=614, s=0x7fffe802cd10)
    at /home/oholy/Downloads/FreeRDP/libfreerdp-core/fastpath.c:173
#6  0x00007ffff660c34b in fastpath_recv_update_data (fastpath=0x6b48f0, s=0x7fffe802cd10) at FreeRDP/libfreerdp-core/fastpath.c:294
#7  0x00007ffff660c3d1 in fastpath_recv_updates (fastpath=0x6b48f0, s=0x7fffe802cd10) at FreeRDP/libfreerdp-core/fastpath.c:310
#8  0x00007ffff66094a6 in rdp_recv_fastpath_pdu (rdp=0x6a2200, s=0x7fffe802cd10) at FreeRDP/libfreerdp-core/rdp.c:763
#9  0x00007ffff66094f0 in rdp_recv_pdu (rdp=0x6a2200, s=0x7fffe802cd10) at FreeRDP/libfreerdp-core/rdp.c:771
#10 0x00007ffff66096a3 in rdp_recv_callback (transport=0x6a4080, s=0x7fffe802cd10, extra=0x6a2200) at FreeRDP/libfreerdp-core/rdp.c:831
#11 0x00007ffff660e6ab in transport_check_fds (ptransport=0x6a2250) at FreeRDP/libfreerdp-core/transport.c:359
#12 0x00007ffff660977f in rdp_check_fds (rdp=0x6a2200) at FreeRDP/libfreerdp-core/rdp.c:862
#13 0x00007ffff65fc263 in freerdp_check_fds (instance=0x6a2070) at FreeRDP/libfreerdp-core/freerdp.c:123
#14 0x0000000000414ac3 in xfreerdp_run (instance=0x6a2070) at FreeRDP/client/X11/xfreerdp.c:1054
#15 0x0000000000414c01 in thread_func (param=0x6c6830) at FreeRDP/client/X11/xfreerdp.c:1091
#16 0x00007ffff546860a in start_thread () from /lib64/libpthread.so.0
#17 0x00007ffff51a2a4d in clone () from /lib64/libc.so.6

How reproducible:

It happens randomly, usually immediately after xfreerdp window is shown. I saw this crashes only when connecting to Windows 2012, however according the upstream patch it is happening also for Windows XP at least. Any special cmd options aren't needed, however I see this more often (with less then 5 attempts) when connecting using rdp security without additional credentials...

Steps to Reproduce:
1. xfreerdp --sec rdp win2012server

Additional info:

It has been fixed upstream by the following commit:
https://github.com/FreeRDP/FreeRDP/commit/46a691db029912e5814b0c6fb36002a41e597825

The commit is easy backportable.

It seems that servers can ask for cached bitmaps that they haven't been defined. We can simply ignore such requests in order to fix this crashes.
Comment 7 errata-xmlrpc 2016-05-10 19:44:15 UTC 
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://rhn.redhat.com/errata/RHBA-2016-0756.html