De Mysteriis Dom jemalloc
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unmask_jemalloc - De Mysteriis Dom jemalloc

A gdb/Python extension to unmask and bring to light the internals of the various jemalloc flavors.

This new release of unmask_jemalloc specifically targets Mozilla Firefox and is a complete rewrite of the initial version of the utility as published in our Phrack paper on exploiting jemalloc:

The original slide deck from our Black USA 2012 presentation on the subject of exploiting Firefox/jemalloc is available at:

The updated slide deck is at:

We have extensively tested unmask_jemalloc with various versions of Mozilla Firefox (including the latest release at the time of this writing, 33.0) on OS X (x86_64) and Linux (both x86 and x86_64) with gdb 7.7 (which embeds Python3).

You can load unmask_jemalloc by including the following in your gdbinit (or issuing them at the gdb prompt):

python import sys
python sys.path.append("/path/to/unmask_jemalloc")
source /path/to/unmask_jemalloc/

Then from gdb use the jehelp command to get details on the commands provided by unmask_jemalloc:

gdb $ jehelp
[unmask_jemalloc] De Mysteriis Dom jemalloc
[unmask_jemalloc] v0.8

[unmask_jemalloc] available commands:
[unmask_jemalloc]   jechunks               : dump info on all available chunks
[unmask_jemalloc]   jearenas               : dump info on jemalloc arenas
[unmask_jemalloc]   jeruns [-c]            : dump info on jemalloc runs (-c for current runs only)
[unmask_jemalloc]   jebins                 : dump info on jemalloc bins
[unmask_jemalloc]   jeregions <size class> : dump all current regions of the given size class
[unmask_jemalloc]   jesearch [-c] <hex>    : search the heap for the given hex value (-c for current runs only)
[unmask_jemalloc]   jedump [filename]      : dump all available info to screen (default) or file
[unmask_jemalloc]   jeparse                : (re)parse jemalloc structures from memory
[unmask_jemalloc]   jeversion              : output version number
[unmask_jemalloc]   jehelp                 : this help message

The development of unmask_jemalloc will continue at:

Feel free to contribute!

argp & huku, Mon Oct 6 15:06:32 EEST 2014