[BusyBox 0000604]: passwd doesnt use salt with md5 passwords

[bugs at busybox.net]

The following issue has been REOPENED. 
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http://busybox.net/bugs/view.php?id=604 
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Reported By:                taviso
Assigned To:                BusyBox
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Project:                    BusyBox
Issue ID:                   604
Category:                   Security
Reproducibility:            always
Severity:                   minor
Priority:                   normal
Status:                     feedback
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Date Submitted:             12-19-2005 02:30 PST
Last Modified:              06-11-2006 10:26 PDT
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Summary:                    passwd doesnt use salt with md5 passwords
Description: 
md5 encrypted passwords are usually generated using

crypt("password", "$1$SALT");

where SALT is some random characters, however the busybox passwd command
seems to use

crypt("password", "$1$"); (ie, no salt).

====================================================================== 

---------------------------------------------------------------------- 
 taviso - 12-19-05 05:43  
---------------------------------------------------------------------- 
obviously not using a salt is a bad idea as rainbow tables have been
demonstrated as an effective attack aginst unsalted passwords.

The fix is easy enough, just construct a salt that concatenates "$1$" and
crypt_make_salt() (/loginutils/passwd.c) 

---------------------------------------------------------------------- 
 robang74 - 01-10-06 01:59  
---------------------------------------------------------------------- 
This patch reduce size, fix the issue (standard 16bit and short SALT MD5
are both supported) and increase randomness about password generation and
i64c conversion. 

 Login/Password Management Utilities  --->    all yes, for both two:

[roberto at wsraf busybox]$ size busybox ../busybox.13222/busybox
   text    data     bss     dec     hex filename
 260328    2404   31716  294448   47e30 busybox
 260348    2408   31748  294504   47e68 ../busybox.13222/busybox

 patch at least compile, it is not tested (I have not a bb test suite
including passwd&co, yet).

 Information about MD5, SALT and password generation was found here:

 http://www.cafesoft.com/CSDigest/createDigest.do
 http://www.itl.nist.gov/fipspubs/fip46-2.htm
 http://perfec.to/gensalt

 

---------------------------------------------------------------------- 
 taviso - 03-29-06 14:25  
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this is CVE-2006-1058, please quote this reference in changelogs etc.

I'm attaching a minimal patch that's tested and works here. 

---------------------------------------------------------------------- 
 solar - 04-20-06 17:45  
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Fixed in revision 14930. 

---------------------------------------------------------------------- 
 solar - 04-21-06 01:10  
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closing bug for now with the patch from taviso applied.
Rob Landley has a planned rewrite for passwd handling which I expect 
we will see in the near future. 

---------------------------------------------------------------------- 
 bernhardf - 06-11-06 10:26  
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reopen to be able to close it.
Folks, please "close" bugs and not set their status to "fixed". If you do
the latter, then the bug will still show up as to be acted upon (will show
up in the overview page).

TIA 

Issue History 
Date Modified   Username       Field                    Change               
====================================================================== 
12-19-05 02:30  taviso         New Issue                                    
12-19-05 02:30  taviso         Status                   new => assigned     
12-19-05 02:30  taviso         Assigned To               => BusyBox         
12-19-05 05:43  taviso         Note Added: 0000800                          
01-10-06 01:55  robang74       File Added: passwd_1.patch                    
01-10-06 01:55  robang74       Issue Monitored: robang74                    
01-10-06 01:58  robang74       Note Added: 0000911                          
01-10-06 01:59  robang74       Note Edited: 0000911                         
01-17-06 01:25  mdeschamps     Issue Monitored: mdeschamps                    
03-29-06 14:25  taviso         Note Added: 0001205                          
03-29-06 14:25  taviso         File Added: passwd.diff                      
04-20-06 17:45  solar          Note Added: 0001310                          
04-21-06 01:10  solar          Status                   assigned => resolved
04-21-06 01:10  solar          Fixed in Version          => 1.2.x           
04-21-06 01:10  solar          Resolution               open => fixed       
04-21-06 01:10  solar          Note Added: 0001311                          
06-11-06 10:26  bernhardf      Status                   resolved => feedback
06-11-06 10:26  bernhardf      Resolution               fixed => reopened   
06-11-06 10:26  bernhardf      Note Added: 0001411                          
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