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IDProjectCategoryView StatusDate SubmittedLast Update
0000083Main CAcert Websitecertificate issuingpublic2005-11-02 10:062013-01-13 15:34
ReporterSourcerer Assigned Toduane  
PrioritynormalSeverityminorReproducibilityalways
Status closedResolutionfixed 
Fixed in Version2006 
Summary0000083: Random Number exhaustion
DescriptionIn www/account/4.php line 0000127, there is a random number exhaustion problem:
       $rnd = fopen("/dev/urandom", "r");
        $hash = md5(fgets($rnd, 64));
        fclose($rnd);

The problem is that fgets() pre-buffers more bytes than actually necessary, which is exhausting the random number pool. Random numbers should be read from /dev/*random with dio_open (open/sysopen) and dio_read (read/sysread) instead.
TagsNo tags attached.
Reviewed by
Test Instructions

Relationships

related to 0000090 closedduane random numbers breach the CAcert CPS 

Activities

Sourcerer

2005-11-22 21:08

administrator   ~0000031

$rnd = dio_open("/dev/urandom",O_RDONLY);
        $hash = md5(dio_read($rnd,64));
        dio_close($rnd);

dio does not seem to be supported by all PHP versions, be careful.

2005-11-23 07:57

 

17.php.patch (659 bytes)    
--- 17.php.orig	2005-11-22 21:51:58.000000000 +0100
+++ 17.php	2005-11-22 21:52:10.000000000 +0100
@@ -124,9 +124,18 @@
 <form method="post" action="account.php">
 <input type="hidden" name="keytype" value="NS">
 <?
-	$rnd = fopen("/dev/urandom", "r");
-	$hash = md5(fgets($rnd, 64));
-	fclose($rnd);
+  if(function_exists("dio_open"))
+  {
+        $rnd = dio_open("/dev/urandom",O_RDONLY);
+        $hash = md5(dio_read($rnd,64));
+        dio_close($rnd);
+  }
+  else
+  {
+        $rnd = fopen("/dev/urandom", "r");
+        $hash = md5(fgets($rnd, 64));
+        fclose($rnd);
+  }
 ?>
 <?=_("Keysize:")?> <keygen name="SPKAC" challenge="<?=$hash?>">
17.php.patch (659 bytes)   

Sourcerer

2005-11-23 07:58

administrator   ~0000037

The patch automatically uses dio_open if they are available.
The same problem is in the following files:
includes/account.php
www/disputes.php
www/index.php
www/account/4.php

duane

2006-04-21 07:27

developer   ~0000173

function make_hash()
        {
                if(function_exists("dio_open"))
                {
                        $rnd = dio_open("/dev/urandom",O_RDONLY);
                        $hash = md5(dio_read($rnd,64));
                        dio_close($rnd);
                } else {
                        $rnd = fopen("/dev/urandom", "r");
                        $hash = md5(fgets($rnd, 64));
                        fclose($rnd);
                }
        }

Issue History

Date Modified Username Field Change
2005-11-02 10:06 Sourcerer New Issue
2005-11-22 21:08 Sourcerer Note Added: 0000031
2005-11-23 07:57 Sourcerer File Added: 17.php.patch
2005-11-23 07:58 Sourcerer Note Added: 0000037
2005-11-28 10:39 Sourcerer Status new => needs work
2005-11-28 10:39 Sourcerer Assigned To => duane
2005-12-08 20:38 evaldo Relationship added related to 0000090
2006-04-21 07:27 duane Status needs work => closed
2006-04-21 07:27 duane Note Added: 0000173
2006-04-21 07:27 duane Resolution open => fixed
2006-04-21 07:27 duane Fixed in Version => production
2013-01-13 15:34 Werner Dworak Fixed in Version => 2006