FAS started using the python-migrate package to update its db. This is a good thing for third-parties that want to install their own FAS server as it lets us ship the database changes in a way that is easy for those users to apply to their own production databases.
However, it doesn't work very well in our particular environment because we're a bit more strict about our permissions than the migrate authors envision. In order to perform migrations, you need to have a user that can modify the schema for the db. This is either hte owner of the db or the superuser. In our setup, we create the db with the superuser and then run our web apps with another user. This prevents the normal web app from modifying the db schema.
To work around this I propose writing a script that does this: # 1) Create a db user. # 2) grant access to all the values in the specified db # 3) run the migrate commands to create the manage.py script and run it with the new username and password # 4) Reassign any new tables to the postgres user # 5) Remove the temporary db user
The command line to invoke it would then look like this:
sudo -u postgres migrate-runner -h DBHOST -d DBNAME MIGRATE_REPO
Does this look: 1) Doable -- loupgaroublond I'm looking at you to tell me what the migrate commands will be and if there's any caveats to this
2) Secure -- the point of this would be to keep protecting the db superuser with a sudo account on db2 and not being able to use it without a shell on db2. If the security of this solution is less than what giving a password to a superuser account would be then we might as well do that instead.
If this looks good, I'll work on coding something up.
-Toshio
On Fri, 8 Aug 2008, Toshio Kuratomi wrote:
FAS started using the python-migrate package to update its db. This is a good thing for third-parties that want to install their own FAS server as it lets us ship the database changes in a way that is easy for those users to apply to their own production databases.
However, it doesn't work very well in our particular environment because we're a bit more strict about our permissions than the migrate authors envision. In order to perform migrations, you need to have a user that can modify the schema for the db. This is either hte owner of the db or the superuser. In our setup, we create the db with the superuser and then run our web apps with another user. This prevents the normal web app from modifying the db schema.
A classic complaint I have between dev's and sysadmin's. I think what you have below is good, generally sysadmins don't want to install a bunch of python libraries on the database for a specific application.
To work around this I propose writing a script that does this: # 1) Create a db user. # 2) grant access to all the values in the specified db # 3) run the migrate commands to create the manage.py script and run it with the new username and password # 4) Reassign any new tables to the postgres user # 5) Remove the temporary db user
The command line to invoke it would then look like this:
sudo -u postgres migrate-runner -h DBHOST -d DBNAME MIGRATE_REPO
Does this look:
- Doable -- loupgaroublond I'm looking at you to tell me what the migrate
commands will be and if there's any caveats to this
- Secure -- the point of this would be to keep protecting the db superuser
with a sudo account on db2 and not being able to use it without a shell on db2. If the security of this solution is less than what giving a password to a superuser account would be then we might as well do that instead.
If this looks good, I'll work on coding something up.
I'd almost have the sysadmins run a command on one of the app servers that has workflow like this
1) pre upgrade check 2) Prompt the user to run a command on the database server, cut and paste. 3) click OK or agree or something 4) Perform upgrade 5) If possible, have the upgrade script remove the user created in step 2, otherwise prompt 6) win.
I think those steps work with the steps you outlined above. I'm curious what others think?
-Mike
Mike McGrath wrote:
On Fri, 8 Aug 2008, Toshio Kuratomi wrote:
# 1) Create a db user. # 2) grant access to all the values in the specified db # 3) run the migrate commands to create the manage.py script and run it with the new username and password # 4) Reassign any new tables to the postgres user # 5) Remove the temporary db user
The command line to invoke it would then look like this:
sudo -u postgres migrate-runner -h DBHOST -d DBNAME MIGRATE_REPO
Does this look:
- Doable -- loupgaroublond I'm looking at you to tell me what the migrate
commands will be and if there's any caveats to this
- Secure -- the point of this would be to keep protecting the db superuser
with a sudo account on db2 and not being able to use it without a shell on db2. If the security of this solution is less than what giving a password to a superuser account would be then we might as well do that instead.
If this looks good, I'll work on coding something up.
I'd almost have the sysadmins run a command on one of the app servers that has workflow like this
- pre upgrade check
- Prompt the user to run a command on the database server, cut and paste.
- click OK or agree or something
- Perform upgrade
- If possible, have the upgrade script remove the user created in step 2,
otherwise prompt 6) win.
I think those steps work with the steps you outlined above. I'm curious what others think?
The additions sound reasonable::
app2 $ migrate-runner -h db2 -d fas2 /usr/share/fas/database This script must create a temporary db user, fas2temp on db2. That user will have permission to modify anything in the fas2 database. If you stop this script in the middle of running you will want to remove the created user from the db. To continue, enter your password for sudo on db2:
Running: ssh db2 pg_temp_user --verbose --create fas2 pg_temp_user: checking for db fas2... yes [sudo -u postgres psql select from pg_users where name = 'fas2temp'] pg_temp_user: checking for existing fas2temp... no [if yes, then abort and have the admin remove the account, check for other issues, etc] pg_temp_user: generating password... success pg_temp_user: create fas2temp... success [sudo -u postgres cat temppasswdfile | sudo -u postgres createuser fas2temp -P -E && sudo -u postgres rm temppasswdfile || sudo -u postgres rm temppasswdfile] pg_temp_user: setting fas2temp permissions on fas2 [echo "grant all on fas2 to fas2temp" | sudo -u postgres psql fas2] [print fas2temp passwd to stdout which migrate-runner captures] Received password for fas2temp Running migrate [various script invocations that loupgaroublond helps me create] Running: ssh db2 pg_temp_user --verbose --remove fas2 pg_temp_user: checking for db fas2... yes pg_temp_user: checking for existing fas2temp... yes pg_temp_user: removing fas2temp... success Successfully upgraded database
-Toshio
2008/8/9 Toshio Kuratomi a.badger@gmail.com:
FAS started using the python-migrate package to update its db. This is a good thing for third-parties that want to install their own FAS server as it lets us ship the database changes in a way that is easy for those users to apply to their own production databases.
However, it doesn't work very well in our particular environment because we're a bit more strict about our permissions than the migrate authors envision. In order to perform migrations, you need to have a user that can modify the schema for the db. This is either hte owner of the db or the superuser. In our setup, we create the db with the superuser and then run our web apps with another user. This prevents the normal web app from modifying the db schema.
To work around this I propose writing a script that does this: # 1) Create a db user. # 2) grant access to all the values in the specified db # 3) run the migrate commands to create the manage.py script and run it with the new username and password # 4) Reassign any new tables to the postgres user # 5) Remove the temporary db user
The command line to invoke it would then look like this:
sudo -u postgres migrate-runner -h DBHOST -d DBNAME MIGRATE_REPO
Does this look:
- Doable -- loupgaroublond I'm looking at you to tell me what the migrate
commands will be and if there's any caveats to this
- Secure -- the point of this would be to keep protecting the db superuser
with a sudo account on db2 and not being able to use it without a shell on db2. If the security of this solution is less than what giving a password to a superuser account would be then we might as well do that instead.
If this looks good, I'll work on coding something up.
I don't see how this is any more secure than just either granting some user sudo or creating a long term admin DB role just for the FAS DB that is well protected.
As I see it:
1) the FAS run time itself has not been security audited and vetted, therefore the least damage it can do to the DB the better. 2) Most of the admins, or rather the people in charge of upgrading FAS on our servers have been security audited and vetted through a system of mutual respect in a meritocracy. Why do we need a temporary superuser account every time we upgrade? 3) If we store the long term superuser account for FAS somewhere so upgrade scripts can be done automatically, then all I think we need is some SELinux / file perm policy that prevents FAS from accessing those files itself.
As for feasibility, I don't think the migrate scripts themselves can create new users on the fly, nor do I think that's where we want to do it. We probably want to create per project wrappers that get called instead of manage.py. Have we spoken to upstream about this yet too?
Or maybe I just need to wake up more, and I'll get it.
-Yaakov
On Mon, 11 Aug 2008, Yaakov Nemoy wrote:
2008/8/9 Toshio Kuratomi a.badger@gmail.com:
FAS started using the python-migrate package to update its db. This is a good thing for third-parties that want to install their own FAS server as it lets us ship the database changes in a way that is easy for those users to apply to their own production databases.
However, it doesn't work very well in our particular environment because we're a bit more strict about our permissions than the migrate authors envision. In order to perform migrations, you need to have a user that can modify the schema for the db. This is either hte owner of the db or the superuser. In our setup, we create the db with the superuser and then run our web apps with another user. This prevents the normal web app from modifying the db schema.
To work around this I propose writing a script that does this: # 1) Create a db user. # 2) grant access to all the values in the specified db # 3) run the migrate commands to create the manage.py script and run it with the new username and password # 4) Reassign any new tables to the postgres user # 5) Remove the temporary db user
The command line to invoke it would then look like this:
sudo -u postgres migrate-runner -h DBHOST -d DBNAME MIGRATE_REPO
Does this look:
- Doable -- loupgaroublond I'm looking at you to tell me what the migrate
commands will be and if there's any caveats to this
- Secure -- the point of this would be to keep protecting the db superuser
with a sudo account on db2 and not being able to use it without a shell on db2. If the security of this solution is less than what giving a password to a superuser account would be then we might as well do that instead.
If this looks good, I'll work on coding something up.
I don't see how this is any more secure than just either granting some user sudo or creating a long term admin DB role just for the FAS DB that is well protected.
You must be a developer ;-)
As I see it:
- the FAS run time itself has not been security audited and vetted,
therefore the least damage it can do to the DB the better.
Even if it had... You shouldn't consider it 'secure'. We've done plenty of audits. AFAIK there is no industry standard for vetting.
- Most of the admins, or rather the people in charge of upgrading FAS
on our servers have been security audited and vetted through a system of mutual respect in a meritocracy. Why do we need a temporary superuser account every time we upgrade?
Those users don't have db accounts, fas does. And we don't want to give the fas user more rights then it needs.
- If we store the long term superuser account for FAS somewhere so
upgrade scripts can be done automatically, then all I think we need is some SELinux / file perm policy that prevents FAS from accessing those files itself.
If the upgrade script can create a temporary user and get rid of it. Why risk having that account used during a non-upgrade time. I'm fine with using SElinux as a backup to primary security policies. But using SELinux as a primary security of some kind. No thanks, we've had to disable it in the past for various reasons before we were able to re-enable it even in permissive mode.
-Mike
On Mon, Aug 11, 2008 at 4:31 PM, Mike McGrath mmcgrath@redhat.com wrote:
On Mon, 11 Aug 2008, Yaakov Nemoy wrote:
2008/8/9 Toshio Kuratomi a.badger@gmail.com:
FAS started using the python-migrate package to update its db. This is a good thing for third-parties that want to install their own FAS server as it lets us ship the database changes in a way that is easy for those users to apply to their own production databases.
However, it doesn't work very well in our particular environment because we're a bit more strict about our permissions than the migrate authors envision. In order to perform migrations, you need to have a user that can modify the schema for the db. This is either hte owner of the db or the superuser. In our setup, we create the db with the superuser and then run our web apps with another user. This prevents the normal web app from modifying the db schema.
To work around this I propose writing a script that does this: # 1) Create a db user. # 2) grant access to all the values in the specified db # 3) run the migrate commands to create the manage.py script and run it with the new username and password # 4) Reassign any new tables to the postgres user # 5) Remove the temporary db user
The command line to invoke it would then look like this:
sudo -u postgres migrate-runner -h DBHOST -d DBNAME MIGRATE_REPO
Does this look:
- Doable -- loupgaroublond I'm looking at you to tell me what the migrate
commands will be and if there's any caveats to this
- Secure -- the point of this would be to keep protecting the db superuser
with a sudo account on db2 and not being able to use it without a shell on db2. If the security of this solution is less than what giving a password to a superuser account would be then we might as well do that instead.
If this looks good, I'll work on coding something up.
I don't see how this is any more secure than just either granting some user sudo or creating a long term admin DB role just for the FAS DB that is well protected.
You must be a developer ;-)
As I see it:
- the FAS run time itself has not been security audited and vetted,
therefore the least damage it can do to the DB the better.
Even if it had... You shouldn't consider it 'secure'. We've done plenty of audits. AFAIK there is no industry standard for vetting.
- Most of the admins, or rather the people in charge of upgrading FAS
on our servers have been security audited and vetted through a system of mutual respect in a meritocracy. Why do we need a temporary superuser account every time we upgrade?
Those users don't have db accounts, fas does. And we don't want to give the fas user more rights then it needs.
- If we store the long term superuser account for FAS somewhere so
upgrade scripts can be done automatically, then all I think we need is some SELinux / file perm policy that prevents FAS from accessing those files itself.
If the upgrade script can create a temporary user and get rid of it. Why risk having that account used during a non-upgrade time. I'm fine with using SElinux as a backup to primary security policies. But using SELinux as a primary security of some kind. No thanks, we've had to disable it in the past for various reasons before we were able to re-enable it even in permissive mode.
I see then. My recommendation is to have an outside wrapper that just takes random db url stuff, including a superuser username and password, creates a new superuser, passes the new user to migrate.py and lets migrate.py take over from there. It's doable, I just don't see what security we gain, over having certain dedicated users (namely toshio and/or ricky) who are the only ones who can run migrate.py, using the superuser password.
-Yaakov
Toshio Kuratomi wrote:
app2 $ migrate-runner -h db2 -d fas2 /usr/share/fas/database This script must create a temporary db user, fas2temp on db2. That user will have permission to modify anything in the fas2 database. If you stop this script in the middle of running you will want to remove the created user from the db. To continue, enter your password for sudo on db2:
Running: ssh db2 pg_temp_user --verbose --create fas2 pg_temp_user: checking for db fas2... yes [sudo -u postgres psql select from pg_users where name = 'fas2temp'] pg_temp_user: checking for existing fas2temp... no [if yes, then abort and have the admin remove the account, check for other issues, etc] pg_temp_user: generating password... success pg_temp_user: create fas2temp... success [sudo -u postgres cat temppasswdfile | sudo -u postgres createuser fas2temp -P -E && sudo -u postgres rm temppasswdfile || sudo -u postgres rm temppasswdfile] pg_temp_user: setting fas2temp permissions on fas2 [echo "grant all on fas2 to fas2temp" | sudo -u postgres psql fas2] [print fas2temp passwd to stdout which migrate-runner captures] Received password for fas2temp Running migrate [various script invocations that loupgaroublond helps me create] Running: ssh db2 pg_temp_user --verbose --remove fas2 pg_temp_user: checking for db fas2... yes pg_temp_user: checking for existing fas2temp... yes
[One more step needed here:] pg_temp_user: updating table ownership to postgres... success [This detects all the tables in the fas2 db and reassigns ownership from the fas2temp user to the database superuser.]
pg_temp_user: removing fas2temp... success Successfully upgraded database
-Toshio
infrastructure@lists.fedoraproject.org
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Mike McGrath -
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Yaakov Nemoy