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Module Signing and Kernel Taint

A kernel can be told to accept only modules signed with a trusted key, so that nobody loads arbitrary code into the most privileged part of the system. When you load your own unsigned or out-of-tree module, the kernel marks itself tainted, which is a note in the log saying 'from here on, bug reports may not be my fault'. It is not an error and usually not a problem for development. Knowing this stops you from chasing a warning that is simply telling the truth.

Questions this Concept answers

  • Why does the kernel record a taint flag when an out-of-tree module is loaded?

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A kernel can be told to accept only modules signed with a trusted key, so that nobody loads arbitrary code into the most privileged part of the system. When you load your own unsigned or out-of-tree module, the kernel marks itself tainted, which is a note in the log saying 'from here on, bug reports may not be my fault'. It is not an error and usually not a problem for development. Knowing this stops you from chasing a warning that is simply telling the truth.

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