Bug 481146 - phosphor crashes due to derefencing NULL FILE*
phosphor crashes due to derefencing NULL FILE*
Status: CLOSED NEXTRELEASE
Product: Fedora
Classification: Fedora
Component: xscreensaver (Show other bugs)
9
All Linux
low Severity medium
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Assigned To: Mamoru TASAKA
Fedora Extras Quality Assurance
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Depends On:
Blocks:
  Show dependency treegraph
 
Reported: 2009-01-22 07:58 EST by John Sullivan
Modified: 2009-01-23 21:43 EST (History)
1 user (show)

See Also:
Fixed In Version:
Doc Type: Bug Fix
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Last Closed: 2009-01-23 21:43:12 EST
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Attachments (Terms of Use)
proposed fix (526 bytes, patch)
2009-01-22 07:58 EST, John Sullivan
no flags Details | Diff

  None (edit)
Description John Sullivan 2009-01-22 07:58:44 EST
Created attachment 329709 [details]
proposed fix

Description of problem:

When (without -pipe) the child exits, state->pipe is cleared but state->pid is not. Later on, state->pid is used to determine whether to send a message to the child (via state->pipe) it tests only the value of state->pid.

This can be forced by running with -window and resizing the window between child runs (which attempts to ioctl TIOCWINSZ on the pipe).

Version-Release number of selected component (if applicable):

xscreensaver-extras-5.08-1.fc9.x86_64

How reproducible:

The resize case, very. I think there's another semi-random crash case too though.

Steps to Reproduce:
1. Run phosphor with -window
2. Resize window
3.
  
Actual results:

SEGV

Expected results:

No SEGV

Additional info:

Attached patch does two things: clear state->pid once we know the child has exited, and check state->pipe before attempting to dereference it.
Comment 1 Mamoru TASAKA 2009-01-22 08:54:40 EST
Well, I can reproduce what you see and your proposal patch
seems reasonable. I will release the modified xscreensaver,
thanks.
Comment 2 Mamoru TASAKA 2009-01-22 10:45:11 EST
5.08-5.fc{11,10,9} is submitted:
For F-9:
http://koji.fedoraproject.org/koji/buildinfo?buildID=79778
Comment 3 Fedora Update System 2009-01-23 21:39:42 EST
xscreensaver-5.08-5.fc10 has been pushed to the Fedora 10 stable repository.  If problems still persist, please make note of it in this bug report.
Comment 4 Fedora Update System 2009-01-23 21:43:10 EST
xscreensaver-5.08-5.fc9 has been pushed to the Fedora 9 stable repository.  If problems still persist, please make note of it in this bug report.

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