Fix icedtea Cannot grant permissions to unsigned jars error

I banged my head on a wall for a while before I finally found a fix to this one. OpenJDK8 has new security features that break compatibility with the IPMI interfaces of my older servers. The problem in my case stemmed from the fact that the java applet is signed, just with an algorhythm that JDK8 blacklists. So, I had to remove MD5 from the blacklisted algorhythms to get this to work. Thanks to this site for guidance on how to do this.

Per that site, this is what I did to fix the issue:

Find the java.security file. In my case it is located in /usr/lib/jvm/java-8-openjdk-amd64/jre/lib/security/java.security

Then find the row:

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jdk.jar.disabledAlgorithms=MD2, MD5, RSA keySize < 1024

Comment it out, copy it, delete the MD5 string.

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#jdk.jar.disabledAlgorithms=MD2, MD5, RSA keySize < 1024
jdk.jar.disabledAlgorithms=MD2, RSA keySize < 1024

12 thoughts on “Fix icedtea Cannot grant permissions to unsigned jars error”

  1. Very helpful blog, I’ve made a similar post but recently updated mine as the java.security file is now located here in the newer versions like openjdk 11: /usr/lib/jvm/java-11-openjdk-amd64/conf/security/java.security

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