Update session token only once per minute
this is simmilar to #28952
if Rails.application.config.redmine_verify_sessions is enabled, basically each read request triggers an update to tokens table. This is bad for performance because it blocks the database.
My patch transforms the update query into a select query that doesn't block on heavy load. We could actually update the token only once per hour which is the minimum available setting for Setting.session_lifetime and Setting.session_timeout, but redmine modifications could use smaller values, so I choose 1 minute interval. Smaller session_timeout then 1 minute won't work now, but I think such small timeout doesn't make much sense.
Updated by Pavel Rosický almost 5 years ago
if you have time, could you review? https://www.redmine.org/attachments/20901/user.rb.patch
GET requests shouldn't update a database all the time. It's even more relevant for #29513
disabling Rails.application.config.redmine_verify_sessions isn't an option because it makes Redmine vulnerable
are there any security concerns about this change?
Updated by Holger Just over 1 year ago
I support the approach to reduce write traffic to the database. With this patch, the write contention on the tokens table and the Redmine database in general should be reduced quite a bit.
At first, I though that we would need to check whether we have only one valid token for the
maximum query too. Turns out that there is a unique index on the
tokens.value column in the database. As such, we are guaranteed to have only exactly zero or one token with a given value in the database. As both of these cases are checked by the patch, I think it should be fine and as secure as the previous version.
The slight reduction in accuracy is acceptable as the value is only used for session expiration where the difference of at most one minute is negligible. Enforcing session timeouts of less than one minute is not useful and does not need to be supported as it would effectively reduce the session to be only useful for (more-or-less) a single request.