[SRU] Fix CSR version in python-acme, focal
| Affects | Status | Importance | Assigned to | Milestone | |
|---|---|---|---|---|---|
| python-acme (Ubuntu) |
New
|
Undecided
|
Unassigned | ||
Bug Description
[ Impact ]
This bug causes certbot to generate CSRs which are invalid. These CSRs are then sent to ACME servers or otherwise parsed. Some software validate CSR validity more aggressively, whichmeans it will reject these CSRs.
The principle motivation for backporting this fix is to stop certbot from generating CSRs. This will both alleviate bugs experienced by users, as well as reduce pressure on CSR parsers to accept _invalid_ CSRs.
[ Test plan ]
The patch contains a unit test that verifies the patch itself works correctly. It has been present in certbot upstream since the 1.29.0 release. Further, the fix was backported to both Debian and RHEL. Therefore, it has received substantial burn-in and is extremely unlikely to regress anything.
[ Where problems could occur ]
For a problem to occur, it would require software that not only accepted, but in fact _required_, an invalid CSR, and which also did not process CSRs from recent versions of certbot or versions from Debian or RHEL containing the backport.
The worst-case scenario for such software would be something that copied the version value from a CSR into a certificate it was issuing (CSRs have only a single valid version, v1. X.509 certificates can be either v1 or v3, however in practice v3 is the only version in use.). Such software would end up producing different (and less correct/compatible) certificates. I am not aware of any software with this behavior.
A more likely (though still improbable) bug would be software which merely asserts that the CSR's version is something incorrect.
This relates to LP#: 2004073.
