Re: New default role- 'pg_read_all_data'

Le 28/08/2020 à 16:52, Stephen Frost a écrit :
> Greetings,
>
> * Gilles Darold (gilles(at)darold(dot)net) wrote:
>> Le 28/08/2020 à 15:26, Stephen Frost a écrit :
>>> * Magnus Hagander (magnus(at)hagander(dot)net) wrote:
>>>> On Fri, Aug 28, 2020 at 2:38 PM Stephen Frost <sfrost(at)snowman(dot)net> wrote:
>>>>> * Magnus Hagander (magnus(at)hagander(dot)net) wrote:
>>>>>> Without having actually looked at the code, definite +1 for this feature.
>>>>>> It's much requested...
>>>>> Thanks.
>>>>>
>>>>>> But, should we also have a pg_write_all_data to go along with it?
>>>>> Perhaps, but could certainly be a different patch, and it'd need to be
>>>>> better defined, it seems to me... read_all is pretty straight-forward
>>>>> (the general goal being "make pg_dumpall/pg_dump work"), what would
>>>>> write mean? INSERT? DELETE? TRUNCATE? ALTER TABLE? System catalogs?
>>>> Well, it's pg_write_all_*data*, so it certainly wouldn't be alter table or
>>>> system catalogs.
>>>>
>>>> I'd say insert/update/delete yes.
>>>>
>>>> TRUNCATE is always an outlier.Given it's generally classified as DDL, I
>>>> wouldn't include it.
>>> Alright, that seems like it'd be pretty easy. We already have a check
>>> in pg_class_aclmask to disallow modification of system catalogs w/o
>>> being a superuser, so we should be alright to add a similar check for
>>> insert/update/delete just below where I added the SELECT check.
>>>
>>>>> Doesn't seem like you could just declare it to be 'allow pg_restore'
>>>>> either, as that might include creating untrusted functions, et al.
>>>> No definitely not. That wouldn't be the usecase at all :)
>>> Good. :)
>>>
>>>> (and fwiw to me the main use case for read_all_data also isn't pg_dump,
>>>> because most people using pg_dump are already db owner or higher in my
>>>> experience. But it is nice that it helps with that too)
>>> Glad to have confirmation that there's other use-cases this helps with.
>>>
>>> I'll post an updated patch with that added in a day or two.
>> Looking at this thread I was thinking about the FDW. Does role
>> pg_read_all_data will allow to execute pg_dump with --include-foreign-data
>> option? If this is the case how about priviledge on fdw and foreign server?
>> If this is the behavior we want I guess that the modification should be
>> applied to pg_foreign_data_wrapper_aclmask() and pg_foreign_server_aclmask()
>> too.
> Using an FDW will often also require having a user mapping and there's
> no way for that to be accomplished through only GRANT'ing a default
> role, so I don't think we should mix this specific role with the FDW
> permissions system.

I'm fine with that, perhaps it should be mentioned in the documentation
that foreign tables are not covered by this role.

--
Gilles Darold