+ in secret_key can cause problems

Since it looks like knox is no longer maintained, I thought I'd write about this issue I ran into with keystone and S3 that may help other people out.

We were getting 403 errors when uploading to S3 through keystone, but with the same credentials we could upload using s3cmd. It wasn't a region issue, the bucket was in the US standard region, and I tried explicitly setting the region with no luck.

I noticed there was a plus sign in the AWS secret key, so on a whim, I created another separate user with the same credentials as the original account, and I was able to upload with the new account on both s3cmd and keystone/knox. The new secret key did not have a + sign in it.

It's probably an encoding issue.

No source files or tests are identified in the report. Start by reproducing an S3 upload through keystone/knox with a secret key containing a plus sign and compare it with s3cmd, then trace where the credentials are encoded. Done means the cause is confirmed and uploads work correctly with such keys, with regression coverage added where the relevant code is found.

Written by the indexing model from the issue text.