IT17202: DP:SUBSTRING-BASE64() MIGHT RESTART DATAPOWER WITH OFFSET PARAMETER OUTSIDE VALID RANGE

Fix packs for DataPower Service Gateway version 7.0
Fix packs for DataPower B2B Appliance version 7.0
Fix packs for DataPower Integration Appliance version 7.0
Fix packs for DataPower Gateway version 7.1
Fix packs for DataPower Gateway version 7.2
Fix packs for DataPower Gateway version 7.5
Fix packs for DataPower Gateway version 7.5.1
Fix packs for DataPower Gateway version 7.5.2

APAR status

• Closed as program error.

Error description

• dp:substring-base64() might restart device with offset
  parameter outside valid range
  

Local fix

• Workaround crash avoidance by replacing all occurences of
  "dp:substing-base64()" with provided "func:substring-base64()",
  see (A), attached as well.
  
  
  (A)
  <!-- func:substring-base64() workaround for
  dp:substring-base64() -->
  <xsl:stylesheet version="1.0"
    xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
    xmlns:func="http://exslt.org/functions"
    xmlns:dp="http://www.datapower.com/extensions"
    extension-element-prefixes="dp"
  >
    <xsl:template match="/">
        <xsl:copy-of select="'' = func:substring-base64('', 6,
  29)"/>
  <!--  <xsl:copy-of select="'' = dp:substring-base64('', 6,
  29)"/> -->
    </xsl:template>
  
    <func:function name="func:substring-base64">
      <xsl:param name="string"/>
      <xsl:param name="offset"/>
      <xsl:param name="length"/>
  
      <func:result>
        <xsl:choose>
          <xsl:when test="($offset &lt; 1) or
                          ($offset >
  func:base64-length($string))" />
          <xsl:otherwise>
            <xsl:value-of
              select="dp:substring-base64($string, $offset,
  $length)" />
          </xsl:otherwise>
        </xsl:choose>
      </func:result>
    </func:function>
  
    <func:function name="func:base64-length">
      <xsl:param name="bytes"/>
  
      <xsl:choose>
        <xsl:when test="contains($bytes,'==')">
          <func:result select="(string-length($bytes) div 4) * 3
  - 2"/>
        </xsl:when>
        <xsl:when test="contains($bytes,'=')">
          <func:result select="(string-length($bytes) div 4) * 3
  - 1"/>
        </xsl:when>
        <xsl:otherwise>
          <func:result select="(string-length($bytes) div 4) *
  3"/>
        </xsl:otherwise>
      </xsl:choose>
    </func:function>
  
  </xsl:stylesheet>
  

Problem summary

• All users of dp:substring-base64() extension function are
  affected with a potential restart when the offset is set out of
  bounds of the input size.
  

Problem conclusion

• Fix is available in 7.0.0.17, 7.1.0.14, 7.2.0.11, 7.5.0.5,
  7.5.1.4 and 7.5.2.2
  
  For a list of the latest fix packs available, please see:
  http://www-01.ibm.com/support/docview.wss?uid=swg21237631
  

Temporary fix

• Explictly check the boundaries in the stylesheet or use the
  preapred workaround function "func:substring-base64" in the
  original description of this APAR.
  

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

Fix information

• Fixed component name

  DATAPOWER

• Fixed component ID

  DP1234567

Applicable component levels

• R700 PSN

     UP

• R710 PSN

     UP

• R720 PSN

     UP

• R750 PSN

     UP

• R751 PSN

     UP

• R752 PSN

     UP