Simon Levermann created CODEC-245:
-------------------------------------

             Summary: RegEx for verifying salts in ShaCrypt is incorrect
                 Key: CODEC-245
                 URL: https://issues.apache.org/jira/browse/CODEC-245
             Project: Commons Codec
          Issue Type: Bug
    Affects Versions: 1.11
            Reporter: Simon Levermann


The regex/code that extracts the salt from a given salt string in Sha2Crypt 
treats some invalid salt formats as valid:
{code:java}
^\$([56])\$(rounds=(\d+)\$)?([\.\/a-zA-Z0-9]{1,16}).*
{code}
The code then goes on to use capture group 3 (the round count) to determine how 
many rounds are used, and capture group 4 (the actual salt) to use as salt data.

However, for an input that contains an invalid salt specification like this:
{code:java}
$5$notrounds=1000$asdfasdf
{code}
This string is treated as valid. The operation then uses "notrounds" as the 
salt for hashing:
{code:java}
System.out.println(Sha2Crypt.sha256Crypt(new byte[100], 
"$5$notrounds=1000$asdfasdf"));
{code}
The above code prints
{code:java}
$5$notrounds$aAEx6EzUBfc.aIIeiItVjUREbj/ar4xlb/qcMxD90NA
{code}
This code should probably throw an exceptions. Additionally, other invalid salt 
strings like

 
{code:java}
$6$rounds=1000$äöüäöü
{code}
Result in hashes like:
{code:java}
$5$rounds$ZIRdMgi25kK5Zmi1whKjcnFN/Pe8QCAOlTmxMfwAoq5
{code}
Completely ignoring the rounds parameter, and using the literal string "rounds" 
as the salt for hashing.

 



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