Re: proposal: hide application_name from other users

On Wed, Jan 22, 2014 at 1:03 PM, Josh Berkus <josh(at)agliodbs(dot)com> wrote:
> Probably Heroku has some more specific exploit case to be concerned
> about here; if so, might I suggest taking it up with the -security list?

I don't think there's a specific vulnerability that needs to be kept
secret here.

Here's an example. I just created a new "hobby" database which is on a
multi-tenant cluster and ran select * from pg_stat_activity. Here are
two of the more interesting examples:

463752 | de5nmf0gbii3u5 | 32250 | 463751 | qspfkgrwgqtbcu | unicorn
worker[1] -p 30390 -c ./config/unicorn.rb | |
| | |
| |
| | | <insufficient privilege>
463752 | de5nmf0gbii3u5 | 32244 | 463751 | qspfkgrwgqtbcu | unicorn
worker[0] -p 30390 -c ./config/unicorn.rb | |
| | |
| |
| | | <insufficient privilege>

Note that the contents of the ARGV array are being set by the
"unicorn" task queuing library. It knows it's making this information
visible to other users with shell access on this machine. But the
decision to stuff the ARGV information into the application_name is
being made by the Pg driver. Neither is under the control of the
application author who may not even be aware this is happening.
Neither component has the complete information to make a competent
decision about whether this information is safe to be in
application_name or not.

Note that the query is showing as "<insufficient privilege>" even
though it is listed in the ps output -- the same ps output that is
listing the unicorn ARGV that is being shown in the
application_name....

You might say that the Pg gem is at fault for making a blanket policy
decision for applications that the ARGV is safe to show to other
database users but realistically it's so useful to see this
information for your own connections that it's probably the right
decision. Without it it's awfully hard to tell which worker is on
which connection. It would just be nice to be able to treat
application_name the same as query.