bugfindutils - Bugs: bug #19923, root-only buffer overrun in locate...

 
 

bug #19923: root-only buffer overrun in locate from findutils-4.3.x

Submitter:  James Youngman <jay>
Submitted:  Mon 21 May 2007 09:44:05 PM UTC
   
 
Category:  locate Severity:  6 - Security
Item Group:  Wrong result Status:  Fixed
Privacy:  Public Assigned to:  jay
Originator Name:  Nix Open/Closed:  Closed
Release:  4.3.5 Fixed Release:  4.3.6
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Mon 21 May 2007 10:13:36 PM UTC, comment #1: 

Um, if one byte of `what' was always what was overwritten, then -fstack-protector wouldn't have caught this problem. The guard (adjacent to `what') must have been smashed. (This won't smash the return address on 32-bit hosts and will probably not do so on 64-bit hosts either: I'd say `certainly not' only I don't have any 64-bit hosts here to test against.)

(However, I seem to recall that -fstack-protector reorders variables as well as canarying them, in which case your statement is correct when the stack protector is off. I can't recall. Sorry.)

Anonymous
Mon 21 May 2007 09:44:05 PM UTC, original submission:  

If root invokes locate, their group ID is set to a random value.  The same bug also causes an array overrun past the end of the local array groups[].  The variable which gets overwritten by the buffer overrun on x86 is 'what'.  The value of that variable is always changed before it is used, and so I believe that this buffer overrun will not cause a crash.  The only effect of the bug therefore would be for locate to change group to a random group ID since groups[0] is uninitialised. On my test system this random group ID is 0 anyway.  The effect does not depend on any externally-controllable information, so it is unlikely this is exploitable. 

James Youngman <jay>
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    Follow 5 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    2007-05-21 jay PrivacyPrivate Public
        Open/ClosedOpen Closed
    2007-05-21 jay StatusIn Progress Fixed
        Assigned toNone jay
        Fixed ReleaseNone 4.3.6

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