Improve certificate sanity checks
This patch aims to enforce more stricter certificate sanity checks and make gnutls more RFC 5280 compliant. Some of the sanity checks require --enable-strict-x509 option to be enabled.
- (strict-x509) parse all certificate extensions when loading the certificate to prohibit random octet strings
- prohibit any garbage bits in key usage extension
- prohibit empty DirectoryString in Distinguished name structures of Issuer and Subject name
Closes #1218
Checklist
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Commits have Signed-off-by:
with name/author being identical to the commit author -
Code modified for feature -
Test suite updated with functionality tests -
Test suite updated with negative tests -
Documentation updated / NEWS entry present (for non-trivial changes) -
CI timeout is 2h or higher (see Settings/CICD/General pipelines/Timeout)
Reviewer's checklist:
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Any issues marked for closing are addressed -
There is a test suite reasonably covering new functionality or modifications -
Function naming, parameters, return values, types, etc., are consistent and according to CONTRIBUTION.md
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This feature/change has adequate documentation added -
No obvious mistakes in the code
Edited by Daiki Ueno