bugThe FreeType Project - Bugs: bug #54858, parse_buildchar can timeout fuzzer...

 
 

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bug #54858: parse_buildchar can timeout fuzzer in debug build.

Submitter:  bungeman <bungeman>
Submitted:  Wed 17 Oct 2018 06:24:42 PM UTC
   
 
Severity:  3 - Normal Item Group:  None
Status:  Fixed Privacy:  Public
Assigned to:  wl Open/Closed:  Closed
Planned Release:  2.10.0

Sun 21 Oct 2018 05:34:05 PM UTC, comment #1: 

Thanks!  Now fixed in git (with a slightly different patch).

Werner LEMBERG <wl>
Group administrator
Wed 17 Oct 2018 06:24:42 PM UTC, original submission:  

Originally reported at https://crbug.com/889216 .

It appears that FreeType change 8ed53468772ec0bc70d121cc1af2c77b1a15e8d0 "[psaux, type1] Trace PostScript dictionaries and other things." has caused the debug build of the fuzzer to find a way to timeout. This change hid almost everything behind FT_DEBUG_LEVEL_TRACE except for one 'for' loop. This 'for' loop will have a body which does nothing, so in a release build the compiler should simply remove it. However, in a debug build this do-nothing loop remains, and the fuzzer finds a way to set "face->len_buildchar" to 0xFFFFFFFF making this empty loop take quite some time.

Attached is a small diff which puts this 'for' loop behind the FT_DEBUG_LEVEL_TRACE flag, which keeps the debug fuzzer from timing out.

bungeman <bungeman>

 

(Note: upload size limit is set to 16384 kB, after insertion of the required escape characters.)

Attached Files
file #45225:  trace.diff added by bungeman (627B - text/x-patch)

 

Depends on the following items: None found

Items that depend on this one: None found

 

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    Follow 5 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    2018-10-21 wl StatusNone Fixed
        Assigned toNone wl
        Open/ClosedOpen Closed
        Planned ReleaseNone 2.10.0
    2018-10-17 bungeman Attached File- Added trace.diff, #45225

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