| Summary: |
null pointer dereference in ProcXTestFakeInput when all input devices are disabled |
| Product: |
xorg
|
Reporter: |
Andy Lutomirski <luto> |
| Component: |
Server/General | Assignee: |
Xorg Project Team <xorg-team> |
| Status: |
RESOLVED
FIXED
|
QA Contact: |
Xorg Project Team <xorg-team> |
| Severity: |
normal
|
|
|
| Priority: |
medium
|
CC: |
peter.hutterer
|
| Version: |
unspecified | |
|
| Hardware: |
Other | |
|
| OS: |
All | |
|
| Whiteboard: |
|
|
i915 platform:
|
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i915 features:
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|---|
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This is xorg-x11-server-1.11.3-1.fc16 from Fedora 16. I want to use x11vnc or vino-server in a way that's reasonably secure against attackers sitting at the keyboard. The best idea I have is to turn off local input devices, like this: for dev in `xinput list |perl -ane '$_ =~ /id=(\d+)\s/ and print "$1\n"'`; do xinput set-prop "$dev" 'Device Enabled' "$1" done This works until a remote user actually tries to send input. Then I get an instant segfault in the server. gdb says: Program received signal SIGSEGV, Segmentation fault. 0x00000000004db52e in ProcXTestFakeInput (client=0x2057c60) at xtest.c:375 375 if (!dev->valuator) (gdb) bt #0 0x00000000004db52e in ProcXTestFakeInput (client=0x2057c60) at xtest.c:375 #1 0x0000000000433ae1 in Dispatch () at dispatch.c:447 #2 0x0000000000422e15 in main (argc=<optimized out>, argv=0x7fff821baa48, envp=<optimized out>) at main.c:287 (gdb) list 370 } 371 372 need_ptr_update = 0; 373 break; 374 case MotionNotify: 375 if (!dev->valuator) 376 return BadDevice; 377 378 if (!(extension || ev->u.keyButtonPointer.root == None)) 379 { (gdb) print dev $1 = (DeviceIntPtr) 0x0 (It would be nice to have a better way to do this. For example, turning off all non-Xtest input and setting dpms off *without telling client software that dpms is off* so that the compositor continues to draw things.)