[asterisk-dev] [Code Review] 3898: Fix memory Corruption in __ast_string_field_ptr_build_va

[wdoekes]

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https://reviewboard.asterisk.org/r/3898/
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(Updated Aug. 11, 2014, 5:24 a.m.)


Status
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This change has been marked as submitted.


Review request for Asterisk Developers.


Changes
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Committed in revision 420680


Bugs: ASTERISK-23508
    https://issues.asterisk.org/jira/browse/ASTERISK-23508


Repository: Asterisk


Description
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Reporter has observed memory corruption in __ast_string_field_ptr_build_va.

Cause:
- when all space in a stringfield is used (used==size), then space==0
- in that case, the "available" space would become below zero and overflow (size_t)
- result, avaiable space is huge, and memory corruption ensues


Diffs
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  /branches/1.8/main/utils.c 420566 

Diff: https://reviewboard.asterisk.org/r/3898/diff/


Testing
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Problem and cause has been described by Arnd Schmitter and tested by him and JoshE.

The tested patch was against 11. This review is a backport to 1.8.


File Attachments
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branches-11
  https://reviewboard.asterisk.org/media/uploaded/files/2014/08/08/4d51862e-4661-49f2-92be-e6a17feebfd3__issueA23508_stringfieldptr_corruption-11.x.patch


Thanks,

wdoekes

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