[asterisk-bugs] [Zaptel 0011471]: [patch] unsafe use of strncpy

[noreply at bugs.digium.com]

A NOTE has been added to this issue. 
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http://bugs.digium.com/view.php?id=11471 
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Reported By:                flefoll
Assigned To:                tzafrir
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Project:                    Zaptel
Issue ID:                   11471
Category:                   General
Reproducibility:            always
Severity:                   minor
Priority:                   normal
Status:                     assigned
Zaptel Version:              SVN 
SVN Branch (only for SVN checkouts, not tarball releases):  1.4  
SVN Revision (number only!): 3317 
Disclaimer on File?:        N/A 
Request Review:              
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Date Submitted:             12-05-2007 03:15 CST
Last Modified:              01-22-2008 07:05 CST
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Summary:                    [patch] unsafe use of strncpy
Description: 
strncpy(dst, src, len) makes a copy of src towards dst, limited to len
characters, but does NOT guarantee a final null character. So if you want
to obtain a "traditional" null-terminated string, extra work is required.

Zaptel uses strncpy in many places, but most often does not do this extra
work, while destination initial contents is undetermined (stack, ...).

I suggest to use snprintf() instead of strncpy(), since snprintf does
guarantee a final null character. Constraint : snprintf requires including
stdio.h, while strncpy requires including strings.h.

See additional information for the list of files that use strncpy.

I will upload patches for a number of them (not all at the moment).

The same work should be done on SVN Trunk, but it did not compile
yesterday for me (Fedora 7)
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---------------------------------------------------------------------- 
 flefoll - 01-22-08 07:05  
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Because many files are involved in this issue, what about ...
- first, defining zap_copy_string() function in zaptel.h,
- next, fixing incorrect strncpy() calls progressively, file by file ?
I have uploaded "zaptel.h.br14.3708.patch-zap_copy_string" for zaptel.h
rev 3708 in SVN zaptel/branches/1.4. zap_copy_string() is a
quasi-copy/paste (doxygen comments included) of Asterisk ast_copy_string(). 

Issue History 
Date Modified   Username       Field                    Change               
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01-22-08 07:05  flefoll        Note Added: 0080992                          
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