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path: root/src/backend/optimizer/prep/prepsecurity.c
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* Improve RLS planning by marking individual quals with security levels.Tom Lane2017-01-18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In an RLS query, we must ensure that security filter quals are evaluated before ordinary query quals, in case the latter contain "leaky" functions that could expose the contents of sensitive rows. The original implementation of RLS planning ensured this by pushing the scan of a secured table into a sub-query that it marked as a security-barrier view. Unfortunately this results in very inefficient plans in many cases, because the sub-query cannot be flattened and gets planned independently of the rest of the query. To fix, drop the use of sub-queries to enforce RLS qual order, and instead mark each qual (RestrictInfo) with a security_level field establishing its priority for evaluation. Quals must be evaluated in security_level order, except that "leakproof" quals can be allowed to go ahead of quals of lower security_level, if it's helpful to do so. This has to be enforced within the ordering of any one list of quals to be evaluated at a table scan node, and we also have to ensure that quals are not chosen for early evaluation (i.e., use as an index qual or TID scan qual) if they're not allowed to go ahead of other quals at the scan node. This is sufficient to fix the problem for RLS quals, since we only support RLS policies on simple tables and thus RLS quals will always exist at the table scan level only. Eventually these qual ordering rules should be enforced for join quals as well, which would permit improving planning for explicit security-barrier views; but that's a task for another patch. Note that FDWs would need to be aware of these rules --- and not, for example, send an insecure qual for remote execution --- but since we do not yet allow RLS policies on foreign tables, the case doesn't arise. This will need to be addressed before we can allow such policies. Patch by me, reviewed by Stephen Frost and Dean Rasheed. Discussion: https://postgr.es/m/8185.1477432701@sss.pgh.pa.us
* Update copyright via script for 2017Bruce Momjian2017-01-03
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* Fix incorrect varlevelsup in security_barrier_replace_vars().Dean Rasheed2016-02-29
| | | | | | | | | | | | | | | | | | | When converting an RTE with securityQuals into a security barrier subquery RTE, ensure that the Vars in the new subquery's targetlist all have varlevelsup = 0 so that they correctly refer to the underlying base relation being wrapped. The original code was creating new Vars by copying them from existing Vars referencing the base relation found elsewhere in the query, but failed to account for the fact that such Vars could come from sublink subqueries, and hence have varlevelsup > 0. In practice it looks like this could only happen with nested security barrier views, where the outer view has a WHERE clause containing a correlated subquery, due to the order in which the Vars are processed. Bug: #13988 Reported-by: Adam Guthrie Backpatch-to: 9.4, where updatable SB views were introduced
* Update copyright for 2016Bruce Momjian2016-01-02
| | | | Backpatch certain files through 9.1
* Handle append_rel_list in expand_security_qualStephen Frost2015-10-09
| | | | | | | | | | | | | | | | | During expand_security_quals, we take the security barrier quals on an RTE and create a subquery which evaluates the quals. During this, we have to replace any variables in the outer query which refer to the original RTE with references to the columns from the subquery. We need to also perform that replacement for any Vars in the append_rel_list. Only backpatching to 9.5 as we only go through this process in 9.4 for auto-updatable security barrier views, which UNION ALL queries aren't. Discovered by Haribabu Kommi Patch by Dean Rasheed
* Represent columns requiring insert and update privileges indentently.Andres Freund2015-05-08
| | | | | | | | | | | | | | | | | | | Previously, relation range table entries used a single Bitmapset field representing which columns required either UPDATE or INSERT privileges, despite the fact that INSERT and UPDATE privileges are separately cataloged, and may be independently held. As statements so far required either insert or update privileges but never both, that was sufficient. The required permission could be inferred from the top level statement run. The upcoming INSERT ... ON CONFLICT UPDATE feature needs to independently check for both privileges in one statement though, so that is not sufficient anymore. Bumps catversion as stored rules change. Author: Peter Geoghegan Reviewed-By: Andres Freund
* Improve representation of PlanRowMark.Tom Lane2015-03-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch fixes two inadequacies of the PlanRowMark representation. First, that the original LockingClauseStrength isn't stored (and cannot be inferred for foreign tables, which always get ROW_MARK_COPY). Since some PlanRowMarks are created out of whole cloth and don't actually have an ancestral RowMarkClause, this requires adding a dummy LCS_NONE value to enum LockingClauseStrength, which is fairly annoying but the alternatives seem worse. This fix allows getting rid of the use of get_parse_rowmark() in FDWs (as per the discussion around commits 462bd95705a0c23b and 8ec8760fc87ecde0), and it simplifies some things elsewhere. Second, that the representation assumed that all child tables in an inheritance hierarchy would use the same RowMarkType. That's true today but will soon not be true. We add an "allMarkTypes" field that identifies the union of mark types used in all a parent table's children, and use that where appropriate (currently, only in preprocess_targetlist()). In passing fix a couple of minor infelicities left over from the SKIP LOCKED patch, notably that _outPlanRowMark still thought waitPolicy is a bool. Catversion bump is required because the numeric values of enum LockingClauseStrength can appear in on-disk rules. Extracted from a much larger patch to support foreign table inheritance; it seemed worth breaking this out, since it's a separable concern. Shigeru Hanada and Etsuro Fujita, somewhat modified by me
* Fix targetRelation initializiation in prepsecurityStephen Frost2015-03-01
| | | | | | | | | | | | | | | In 6f9bd50eabb0a4960e94c83dac8855771c9f340d, we modified expand_security_quals() to tell expand_security_qual() about when the current RTE was the targetRelation. Unfortunately, that commit initialized the targetRelation variable used outside of the loop over the RTEs instead of at the start of it. This patch moves the variable and the initialization of it into the loop, where it should have been to begin with. Pointed out by Dean Rasheed. Back-patch to 9.4 as the original commit was.
* Add locking clause for SB views for update/deleteStephen Frost2015-02-25
| | | | | | | | | | | | | | | | In expand_security_qual(), we were handling locking correctly when a PlanRowMark existed, but not when we were working with the target relation (which doesn't have any PlanRowMarks, but the subquery created for the security barrier quals still needs to lock the rows under it). Noted by Etsuro Fujita when working with the Postgres FDW, which wasn't properly issuing a SELECT ... FOR UPDATE to the remote side under a DELETE. Back-patch to 9.4 where updatable security barrier views were introduced. Per discussion with Etsuro and Dean Rasheed.
* Update copyright for 2015Bruce Momjian2015-01-06
| | | | Backpatch certain files through 9.0
* Implement SKIP LOCKED for row-level locksAlvaro Herrera2014-10-07
| | | | | | | | | | | | | | | | | | This clause changes the behavior of SELECT locking clauses in the presence of locked rows: instead of causing a process to block waiting for the locks held by other processes (or raise an error, with NOWAIT), SKIP LOCKED makes the new reader skip over such rows. While this is not appropriate behavior for general purposes, there are some cases in which it is useful, such as queue-like tables. Catalog version bumped because this patch changes the representation of stored rules. Reviewed by Craig Ringer (based on a previous attempt at an implementation by Simon Riggs, who also provided input on the syntax used in the current patch), David Rowley, and Álvaro Herrera. Author: Thomas Munro
* Fix bogus variable-mangling in security_barrier_replace_vars().Tom Lane2014-09-24
| | | | | | | | | | | | | | This function created new Vars with varno different from varnoold, which is a condition that should never prevail before setrefs.c does the final variable-renumbering pass. The created Vars could not be seen as equal() to normal Vars, which among other things broke equivalence-class processing for them. The consequences of this were indeed visible in the regression tests, in the form of failure to propagate constants as one would expect. I stumbled across it while poking at bug #11457 --- after intentionally disabling join equivalence processing, the security-barrier regression tests started falling over with fun errors like "could not find pathkey item to sort", because of failure to match the corrupted Vars to normal ones.
* Fix Var handling for security barrier viewsStephen Frost2014-08-26
| | | | | | | | | | | | | | | In some cases, not all Vars were being correctly marked as having been modified for updatable security barrier views, which resulted in invalid plans (eg: when security barrier views were created over top of inheiritance structures). In passing, be sure to update both varattno and varonattno, as _equalVar won't consider the Vars identical otherwise. This isn't known to cause any issues with updatable security barrier views, but was noticed as missing while working on RLS and makes sense to get fixed. Back-patch to 9.4 where updatable security barrier views were introduced.
* pgindent run for 9.4Bruce Momjian2014-05-06
| | | | | This includes removing tabs after periods in C comments, which was applied to back branches, so this change should not effect backpatching.
* Make security barrier views automatically updatableStephen Frost2014-04-12
Views which are marked as security_barrier must have their quals applied before any user-defined quals are called, to prevent user-defined functions from being able to see rows which the security barrier view is intended to prevent them from seeing. Remove the restriction on security barrier views being automatically updatable by adding a new securityQuals list to the RTE structure which keeps track of the quals from security barrier views at each level, independently of the user-supplied quals. When RTEs are later discovered which have securityQuals populated, they are turned into subquery RTEs which are marked as security_barrier to prevent any user-supplied quals being pushed down (modulo LEAKPROOF quals). Dean Rasheed, reviewed by Craig Ringer, Simon Riggs, KaiGai Kohei