[asterisk-dev] [Code Review] MALLOC_DEBUG enhancements.

[rmudgett]

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This is an automatically generated e-mail. To reply, visit:
https://reviewboard.asterisk.org/r/2182/
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(Updated Nov. 7, 2012, 2:48 p.m.)


Review request for Asterisk Developers.


Changes
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Address wdoekes and David's comments.

* Fixed the memory overwrite when wiping the region memory in region_data_wipe()/region_data_check().
* Fixed a potential alignment issue on 64 bit systems.  struct ast_region.data[] should now be aligned correctly for all platforms.
* Extracted region_check_fences() from __ast_free_region() and handle_memory_show().
* Updated handle_memory_show() CLI usage help.


Summary
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MALLOC_DEBUG enhancements.

* Makes malloc() behave like calloc().  It will return a memory block
filled with 0x55.  A nonzero value.

* Makes free() fill the released memory block and boundary fence's with
0xdeaddead.  Any pointer use after free is going to have a pointer
pointing to 0xdeaddead.  The 0xdeaddead pointer is usually an invalid
memory address so a crash is expected.

* Puts the freed memory block into a circular array so it is not reused
immediately.

* When the circular array rotates out a memory block to the heap it checks
that the memory has not been altered from 0xdeaddead.

* Made the astmm_log message wording better.

* Made crash if the DO_CRASH menuselect option is enabled and something is
found.


Diffs (updated)
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  /branches/1.8/include/asterisk/astmm.h 376023 
  /branches/1.8/include/asterisk/utils.h 376023 
  /branches/1.8/main/asterisk.c 376023 
  /branches/1.8/main/astmm.c 376023 
  /branches/1.8/main/utils.c 376023 

Diff: https://reviewboard.asterisk.org/r/2182/diff


Testing
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The MALLOC_DEBUG enhancements were instrumental in pointing out a memory corruption problem.


Thanks,

rmudgett

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