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2023-04-28Fix crashes with CREATE SCHEMA AUTHORIZATION and schema elementsMichael Paquier
CREATE SCHEMA AUTHORIZATION with appended schema elements can lead to crashes when comparing the schema name of the query with the schemas used in the qualification of some clauses in the elements' queries. The origin of the problem is that the transformation routine for the elements listed in a CREATE SCHEMA query uses as new, expected, schema name the one listed in CreateSchemaStmt itself. However, depending on the query, CreateSchemaStmt.schemaname may be NULL, being computed instead from the role specification of the query given by the AUTHORIZATION clause, that could be either: - A user name string, with the new schema name being set to the same value as the role given. - Guessed from CURRENT_ROLE, SESSION_ROLE or CURRENT_ROLE, with a new schema name computed from the security context where CREATE SCHEMA is running. Regression tests are added for CREATE SCHEMA with some appended elements (some of them with schema qualifications), covering also some role specification patterns. While on it, this simplifies the context structure used during the transformation of the elements listed in a CREATE SCHEMA query by removing the fields for the role specification and the role type. They were not used, and for the role specification this could be confusing as the schema name may by extracted from that at the beginning of CreateSchemaCommand(). This issue exists for a long time, so backpatch down to all the versions supported. Reported-by: Song Hongyu Author: Michael Paquier Reviewed-by: Richard Guo Discussion: https://postgr.es/m/17909-f65c12dfc5f0451d@postgresql.org Backpatch-through: 11
2023-03-31Fix List memory issue in transformColumnDefinitionDavid Rowley
When calling generateSerialExtraStmts(), we would pass in the constraint->options. In some cases, generateSerialExtraStmts() would modify the referenced List to remove elements from it, but doing so is invalid without assigning the list back to all variables that point to it. In the particular reported problem case, the List became empty, in which cases it became NIL, but the passed in constraint->options didn't get to find out about that and was left pointing to free'd memory. To fix this, just perform a list_copy() inside generateSerialExtraStmts(). We could just do a list_copy() just before we perform the delete from the list, however, that seems less robust. Let's make sure the generated CreateSeqStmt gets a completely different copy of the list to be safe. Bug: #17879 Reported-by: Fei Changhong Diagnosed-by: Fei Changhong Discussion: https://postgr.es/m/17879-b7dfb5debee58ff5@postgresql.org Backpatch-through: 11, all supported versions
2023-03-13Fix failure to detect some cases of improperly-nested aggregates.Tom Lane
check_agg_arguments_walker() supposed that it needn't descend into the arguments of a lower-level aggregate function, but this is just wrong in the presence of multiple levels of sub-select. The oversight would lead to executor failures on queries that should be rejected. (Prior to v11, they actually were rejected, thanks to a "redundant" execution-time check.) Per bug #17835 from Anban Company. Back-patch to all supported branches. Discussion: https://postgr.es/m/17835-4f29f3098b2d0ba4@postgresql.org
2023-03-07Fix more bugs caused by adding columns to the end of a view.Tom Lane
If a view is defined atop another view, and then CREATE OR REPLACE VIEW is used to add columns to the lower view, then when the upper view's referencing RTE is expanded by ApplyRetrieveRule we will have a subquery RTE with fewer eref->colnames than output columns. This confuses various code that assumes those lists are always in sync, as they are in plain parser output. We have seen such problems before (cf commit d5b760ecb), and now I think the time has come to do what was speculated about in that commit: let's make ApplyRetrieveRule synthesize some column names to preserve the invariant that holds in parser output. Otherwise we'll be chasing this class of bugs indefinitely. Moreover, it appears from testing that this actually gives us better results in the test case d5b760ecb added, and likely in other corner cases that we lack coverage for. In HEAD, I replaced d5b760ecb's hack to make expandRTE exit early with an elog(ERROR) call, since the case is now presumably unreachable. But it seems like changing that in back branches would bring more risk than benefit, so there I just updated the comment. Per bug #17811 from Alexander Lakhin. Back-patch to all supported branches. Discussion: https://postgr.es/m/17811-d31686b78f0dffc9@postgresql.org
2022-10-16Rename parser token REF to REF_P to avoid a symbol conflict.Tom Lane
In the latest version of Apple's macOS SDK, <sys/socket.h> fails to compile if "REF" is #define'd as something. Apple may or may not agree that this is a bug, and even if they do accept the bug report I filed, they probably won't fix it very quickly. In the meantime, our back branches will all fail to compile gram.y. v15 and HEAD currently escape the problem thanks to the refactoring done in 98e93a1fc, but that's purely accidental. Moreover, since that patch removed a widely-visible inclusion of <netdb.h>, back-patching it seems too likely to break third-party code. Instead, change the token's code name to REF_P, following our usual convention for naming parser tokens that are likely to have symbol conflicts. The effects of that should be localized to the grammar and immediately surrounding files, so it seems like a safer answer. Per project policy that we want to keep recently-out-of-support branches buildable on modern systems, back-patch all the way to 9.2. Discussion: https://postgr.es/m/1803927.1665938411@sss.pgh.pa.us
2022-09-20Suppress variable-set-but-not-used warnings from clang 15.Tom Lane
clang 15+ will issue a set-but-not-used warning when the only use of a variable is in autoincrements (e.g., "foo++;"). That's perfectly sensible, but it detects a few more cases that we'd not noticed before. Silence the warnings with our usual methods, such as PG_USED_FOR_ASSERTS_ONLY, or in one case by actually removing a useless variable. One thing that we can't nicely get rid of is that with %pure-parser, Bison emits "yynerrs" as a local variable that falls foul of this warning. To silence those, I inserted "(void) yynerrs;" in the top-level productions of affected grammars. Per recently-established project policy, this is a candidate for back-patching into out-of-support branches: it suppresses annoying compiler warnings but changes no behavior. Hence, back-patch to 9.5, which is as far as these patches go without issues. (A preliminary check shows that the prior branches need some other set-but-not-used cleanups too, so I'll leave them for another day.) Discussion: https://postgr.es/m/514615.1663615243@sss.pgh.pa.us
2022-08-13Catch stack overflow when recursing in transformFromClauseItem().Tom Lane
Most parts of the parser can expect that the stack overflow check in transformExprRecurse() will trigger before things get desperate. However, transformFromClauseItem() can recurse directly to self without having analyzed any expressions, so it's possible to drive it to a stack-overrun crash. Add a check to prevent that. Per bug #17583 from Egor Chindyaskin. Back-patch to all supported branches. Richard Guo Discussion: https://postgr.es/m/17583-33be55b9f981f75c@postgresql.org
2022-08-08In extensions, don't replace objects not belonging to the extension.Tom Lane
Previously, if an extension script did CREATE OR REPLACE and there was an existing object not belonging to the extension, it would overwrite the object and adopt it into the extension. This is problematic, first because the overwrite is probably unintentional, and second because we didn't change the object's ownership. Thus a hostile user could create an object in advance of an expected CREATE EXTENSION command, and would then have ownership rights on an extension object, which could be modified for trojan-horse-type attacks. Hence, forbid CREATE OR REPLACE of an existing object unless it already belongs to the extension. (Note that we've always forbidden replacing an object that belongs to some other extension; only the behavior for previously-free-standing objects changes here.) For the same reason, also fail CREATE IF NOT EXISTS when there is an existing object that doesn't belong to the extension. Our thanks to Sven Klemm for reporting this problem. Security: CVE-2022-2625
2022-08-01Check maximum number of columns in function RTEs, too.Tom Lane
I thought commit fd96d14d9 had plugged all the holes of this sort, but no, function RTEs could produce oversize tuples too, either via long coldeflists or just from multiple functions in one RTE. (I'm pretty sure the other variants of base RTEs aren't a problem, because they ultimately refer to either a table or a sub-SELECT, whose widths are enforced elsewhere. But we explicitly allow join RTEs to be overwidth, as long as you don't try to form their tuple result.) Per further discussion of bug #17561. As before, patch all branches. Discussion: https://postgr.es/m/17561-80350151b9ad2ad4@postgresql.org
2022-07-29In transformRowExpr(), check for too many columns in the row.Tom Lane
A RowExpr with more than MaxTupleAttributeNumber columns would fail at execution anyway, since we cannot form a tuple datum with more than that many columns. While heap_form_tuple() has a check for too many columns, it emerges that there are some intermediate bits of code that don't check and can be driven to failure with sufficiently many columns. Checking this at parse time seems like the most appropriate place to install a defense, since we already check SELECT list length there. While at it, make the SELECT-list-length error use the same errcode (TOO_MANY_COLUMNS) as heap_form_tuple does, rather than the generic PROGRAM_LIMIT_EXCEEDED. Per bug #17561 from Egor Chindyaskin. The given test case crashes in all supported branches (and probably a lot further back), so patch all. Discussion: https://postgr.es/m/17561-80350151b9ad2ad4@postgresql.org
2022-07-21Fix ruleutils issues with dropped cols in functions-returning-composite.Tom Lane
Due to lack of concern for the case in the dependency code, it's possible to drop a column of a composite type even though stored queries have references to the dropped column via functions-in-FROM that return the composite type. There are "soft" references, namely FROM-clause aliases for such columns, and "hard" references, that is actual Vars referring to them. The right fix for hard references is to add dependencies preventing the drop; something we've known for many years and not done (and this commit still doesn't address it). A "soft" reference shouldn't prevent a drop though. We've been around on this before (cf. 9b35ddce9, 2c4debbd0), but nobody had noticed that the current behavior can result in dump/reload failures, because ruleutils.c can print more column aliases than the underlying composite type now has. So we need to rejigger the column-alias-handling code to treat such columns as dropped and not print aliases for them. Rather than writing new code for this, I used expandRTE() which already knows how to figure out which function result columns are dropped. I'd initially thought maybe we could use expandRTE() in all cases, but that fails for EXPLAIN's purposes, because the planner strips a lot of RTE infrastructure that expandRTE() needs. So this patch just uses it for unplanned function RTEs and otherwise does things the old way. If there is a hard reference (Var), then removing the column alias causes us to fail to print the Var, since there's no longer a name to print. Failing seems less desirable than printing a made-up name, so I made it print "?dropped?column?" instead. Per report from Timo Stolz. Back-patch to all supported branches. Discussion: https://postgr.es/m/5c91267e-3b6d-5795-189c-d15a55d61dbb@nullachtvierzehn.de
2022-07-07Fix alias matching in transformLockingClause().Dean Rasheed
When locking a specific named relation for a FOR [KEY] UPDATE/SHARE clause, transformLockingClause() finds the relation to lock by scanning the rangetable for an RTE with a matching eref->aliasname. However, it failed to account for the visibility rules of a join RTE. If a join RTE doesn't have a user-supplied alias, it will have a generated eref->aliasname of "unnamed_join" that is not visible as a relation name in the parse namespace. Such an RTE needs to be skipped, otherwise it might be found in preference to a regular base relation with a user-supplied alias of "unnamed_join", preventing it from being locked. In addition, if a join RTE doesn't have a user-supplied alias, but does have a join_using_alias, then the RTE needs to be matched using that alias rather than the generated eref->aliasname, otherwise a misleading "relation not found" error will be reported rather than a "join cannot be locked" error. Backpatch all the way, except for the second part which only goes back to 14, where JOIN USING aliases were added. Dean Rasheed, reviewed by Tom Lane. Discussion: https://postgr.es/m/CAEZATCUY_KOBnqxbTSPf=7fz9HWPnZ5Xgb9SwYzZ8rFXe7nb=w@mail.gmail.com
2022-05-18Check column list length in XMLTABLE/JSON_TABLE aliasAlvaro Herrera
We weren't checking the length of the column list in the alias clause of an XMLTABLE or JSON_TABLE function (a "tablefunc" RTE), and it was possible to make the server crash by passing an overly long one. Fix it by throwing an error in that case, like the other places that deal with alias lists. In passing, modify the equivalent test used for join RTEs to look like the other ones, which was different for no apparent reason. This bug came in when XMLTABLE was born in version 10; backpatch to all stable versions. Reported-by: Wang Ke <krking@zju.edu.cn> Discussion: https://postgr.es/m/17480-1c9d73565bb28e90@postgresql.org
2022-05-09Fix core dump in transformValuesClause when there are no columns.Tom Lane
The parser code that transformed VALUES from row-oriented to column-oriented lists failed if there were zero columns. You can't write that straightforwardly (though probably you should be able to), but the case can be reached by expanding a "tab.*" reference to a zero-column table. Per bug #17477 from Wang Ke. Back-patch to all supported branches. Discussion: https://postgr.es/m/17477-0af3c6ac6b0a6ae0@postgresql.org
2022-04-18Avoid invalid array reference in transformAlterTableStmt().Tom Lane
Don't try to look at the attidentity field of system attributes, because they're not there in the TupleDescAttr array. Sometimes this is harmless because we accidentally pick up a zero, but otherwise we'll report "no owned sequence found" from an attempt to alter a system attribute. (It seems possible that a SIGSEGV could occur, too, though I've not seen it in testing.) It's not in this function's charter to complain that you can't alter a system column, so instead just hard-wire an assumption that system attributes aren't identities. I didn't bother with a regression test because the appearance of the bug is very erratic. Per bug #17465 from Roman Zharkov. Back-patch to all supported branches. (There's not actually a live bug before v12, because before that get_attidentity() did the right thing anyway. But for consistency I changed the test in the older branches too.) Discussion: https://postgr.es/m/17465-f2a554a6cb5740d3@postgresql.org
2022-01-29Fix failure to validate the result of select_common_type().Tom Lane
Although select_common_type() has a failure-return convention, an apparent successful return just provides a type OID that *might* work as a common supertype; we've not validated that the required casts actually exist. In the mainstream use-cases that doesn't matter, because we'll proceed to invoke coerce_to_common_type() on each input, which will fail appropriately if the proposed common type doesn't actually work. However, a few callers didn't read the (nonexistent) fine print, and thought that if they got back a nonzero OID then the coercions were sure to work. This affects in particular the recently-added "anycompatible" polymorphic types; we might think that a function/operator using such types matches cases it really doesn't. A likely end result of that is unexpected "ambiguous operator" errors, as for example in bug #17387 from James Inform. Another, much older, case is that the parser might try to transform an "x IN (list)" construct to a ScalarArrayOpExpr even when the list elements don't actually have a common supertype. It doesn't seem desirable to add more checking to select_common_type itself, as that'd just slow down the mainstream use-cases. Instead, write a separate function verify_common_type that performs the missing checks, and add a call to that where necessary. Likewise add verify_common_type_from_oids to go with select_common_type_from_oids. Back-patch to v13 where the "anycompatible" types came in. (The symptom complained of in bug #17387 doesn't appear till v14, but that's just because we didn't get around to converting || to use anycompatible till then.) In principle the "x IN (list)" fix could go back all the way, but I'm not currently convinced that it makes much difference in real-world cases, so I won't bother for now. Discussion: https://postgr.es/m/17387-5dfe54b988444963@postgresql.org
2021-12-16Ensure casting to typmod -1 generates a RelabelType.Tom Lane
Fix the code changed by commit 5c056b0c2 so that we always generate RelabelType, not something else, for a cast to unspecified typmod. Otherwise planner optimizations might not happen. It appears we missed this point because the previous experiments were done on type numeric: the parser undesirably generates a call on the numeric() length-coercion function, but then numeric_support() optimizes that down to a RelabelType, so that everything seems fine. It misbehaves for types that have a non-optimized length coercion function, such as bpchar. Per report from John Naylor. Back-patch to all supported branches, as the previous patch eventually was. Unfortunately, that no longer includes 9.6 ... we really shouldn't put this type of change into a nearly-EOL branch. Discussion: https://postgr.es/m/CAFBsxsEfbFHEkouc+FSj+3K1sHipLPbEC67L0SAe-9-da8QtYg@mail.gmail.com
2021-11-02Avoid O(N^2) behavior in SyncPostCheckpoint().Tom Lane
As in commits 6301c3ada and e9d9ba2a4, avoid doing repetitive list_delete_first() operations, since that would be expensive when there are many files waiting to be unlinked. This is a slightly larger change than in those cases. We have to keep the list state valid for calls to AbsorbSyncRequests(), so it's necessary to invent a "canceled" field instead of immediately deleting PendingUnlinkEntry entries. Also, because we might not be able to process all the entries, we need a new list primitive list_delete_first_n(). list_delete_first_n() is almost list_copy_tail(), but it modifies the input List instead of making a new copy. I found a couple of existing uses of the latter that could profitably use the new function. (There might be more, but the other callers look like they probably shouldn't overwrite the input List.) As before, back-patch to v13. Discussion: https://postgr.es/m/CD2F0E7F-9822-45EC-A411-AE56F14DEA9F@amazon.com
2021-10-19Remove bogus assertion in transformExpressionList().Tom Lane
I think when I added this assertion (in commit 8f889b108), I was only thinking of the use of transformExpressionList at top level of INSERT and VALUES. But it's also called by transformRowExpr(), which can certainly occur in an UPDATE targetlist, so it's inappropriate to suppose that p_multiassign_exprs must be empty. Besides, since the input is not expected to contain ResTargets, there's no reason it should contain MultiAssignRefs either. Hence this code need not be concerned about the state of p_multiassign_exprs, and we should just drop the assertion. Per bug #17236 from ocean_li_996. It's been wrong for years, so back-patch to all supported branches. Discussion: https://postgr.es/m/17236-3210de9bcba1d7ca@postgresql.org
2021-10-01Error out if SKIP LOCKED and WITH TIES are both specifiedAlvaro Herrera
Both bugs #16676[1] and #17141[2] illustrate that the combination of SKIP LOCKED and FETCH FIRST WITH TIES break expectations when it comes to rows returned to other sessions accessing the same row. Since this situation is detectable from the syntax and hard to fix otherwise, forbid for now, with the potential to fix in the future. [1] https://postgr.es/m/16676-fd62c3c835880da6@postgresql.org [2] https://postgr.es/m/17141-913d78b9675aac8e@postgresql.org Backpatch-through: 13, where WITH TIES was introduced Author: David Christensen <david.christensen@crunchydata.com> Discussion: https://postgr.es/m/CAOxo6XLPccCKru3xPMaYDpa+AXyPeWFs+SskrrL+HKwDjJnLhg@mail.gmail.com
2021-09-20Don't elide casting to typmod -1.Tom Lane
Casting a value that's already of a type with a specific typmod to an unspecified typmod doesn't do anything so far as run-time behavior is concerned. However, it really ought to change the exposed type of the expression to match. Up to now, coerce_type_typmod hasn't bothered with that, which creates gotchas in contexts such as recursive unions. If for example one side of the union is numeric(18,3), but it needs to be plain numeric to match the other side, there's no direct way to express that. This is easy enough to fix, by inserting a RelabelType to update the exposed type of the expression. However, it's a bit nervous-making to change this behavior, because it's stood for a really long time. But no complaints have emerged about 14beta3, so go ahead and back-patch. Back-patch of 5c056b0c2 into previous supported branches. Discussion: https://postgr.es/m/CABNQVagu3bZGqiTjb31a8D5Od3fUMs7Oh3gmZMQZVHZ=uWWWfQ@mail.gmail.com Discussion: https://postgr.es/m/1488389.1631984807@sss.pgh.pa.us
2021-08-25Avoid using ambiguous word "positive" in error message.Fujii Masao
There are two identical error messages about valid value of modulus for hash partition, in PostgreSQL source code. Commit 0e1275fb07 improved only one of them so that ambiguous word "positive" was avoided there, and forgot to improve the other. This commit improves the other. Which would reduce translator burden. Back-pach to v11 where the error message exists. Author: Kyotaro Horiguchi Reviewed-by: Fujii Masao Discussion: https://postgr.es/m/20210819.170315.1413060634876301811.horikyota.ntt@gmail.com
2021-08-19Avoid trying to lock OLD/NEW in a rule with FOR UPDATE.Tom Lane
transformLockingClause neglected to exclude the pseudo-RTEs for OLD/NEW when processing a rule's query. This led to odd errors or even crashes later on. This bug is very ancient, but it's not terribly surprising that nobody noticed, since the use-case for SELECT FOR UPDATE in a non-view rule is somewhere between thin and non-existent. Still, crashing is not OK. Per bug #17151 from Zhiyong Wu. Thanks to Masahiko Sawada for analysis of the problem. Discussion: https://postgr.es/m/17151-c03a3e6e4ec9aadb@postgresql.org
2021-08-18Fix check_agg_arguments' examination of aggregate FILTER clauses.Tom Lane
Recursion into the FILTER clause was mis-implemented, such that a relevant Var or Aggref at the very top of the FILTER clause would be ignored. (Of course, that'd have to be a plain boolean Var or boolean-returning aggregate.) The consequence would be mis-identification of the correct semantic level of the aggregate, which could lead to not-per-spec query behavior. If the FILTER expression is an aggregate, this could also lead to failure to issue an expected "aggregate function calls cannot be nested" error, which would likely result in a core dump later on, since the planner and executor aren't expecting such cases to appear. The root cause is that commit b560ec1b0 blindly copied some code that assumed it's recursing into a List, and thus didn't examine the top-level node. To forestall questions about why this call doesn't look like the others, as well as possible future copy-and-paste mistakes, let's change all three check_agg_arguments_walker calls in check_agg_arguments, even though only the one for the filter clause is really broken. Per bug #17152 from Zhiyong Wu. This has been wrong since we implemented FILTER, so back-patch to all supported versions. (Testing suggests that pre-v11 branches manage to avoid crashing in the bad-Aggref case, thanks to "redundant" checks in ExecInitAgg. But I'm not sure how thorough that protection is, and anyway the wrong-behavior issue remains, so fix 9.6 and 10 too.) Discussion: https://postgr.es/m/17152-c7f906cc1a88e61b@postgresql.org
2021-06-01Reject SELECT ... GROUP BY GROUPING SETS (()) FOR UPDATE.Tom Lane
This case should be disallowed, just as FOR UPDATE with a plain GROUP BY is disallowed; FOR UPDATE only makes sense when each row of the query result can be identified with a single table row. However, we missed teaching CheckSelectLocking() to check groupingSets as well as groupClause, so that it would allow degenerate grouping sets. That resulted in a bad plan and a null-pointer dereference in the executor. Looking around for other instances of the same bug, the only one I found was in examine_simple_variable(). That'd just lead to silly estimates, but it should be fixed too. Per private report from Yaoguang Chen. Back-patch to all supported branches.
2021-04-12Fix old bug with coercing the result of a COLLATE expression.Tom Lane
There are hacks in parse_coerce.c to push down a requested coercion to below any CollateExpr that may appear. However, we did that even if the requested data type is non-collatable, leading to an invalid expression tree in which CollateExpr is applied to a non-collatable type. The fix is just to drop the CollateExpr altogether, reasoning that it's useless. This bug is ten years old, dating to the original addition of COLLATE support. The lack of field complaints suggests that there aren't a lot of user-visible consequences. We noticed the problem because it would trigger an assertion in DefineVirtualRelation if the invalid structure appears as an output column of a view; however, in a non-assert build, you don't see a crash just a (subtly incorrect) complaint about applying collation to a non-collatable type. I found that by putting the incorrect structure further down in a view, I could make a view definition that would fail dump/reload, per the added regression test case. But CollateExpr doesn't do anything at run-time, so this likely doesn't lead to any really exciting consequences. Per report from Yulin Pei. Back-patch to all supported branches. Discussion: https://postgr.es/m/HK0PR01MB22744393C474D503E16C8509F4709@HK0PR01MB2274.apcprd01.prod.exchangelabs.com
2021-03-12Forbid marking an identity column as nullable.Tom Lane
GENERATED ALWAYS AS IDENTITY implies NOT NULL, but the code failed to complain if you overrode that with "GENERATED ALWAYS AS IDENTITY NULL". One might think the old behavior was a feature, but it was inconsistent because the outcome varied depending on the order of the clauses, so it seems to have been just an oversight. Per bug #16913 from Pavel Boev. Back-patch to v10 where identity columns were introduced. Vik Fearing (minor tweaks by me) Discussion: https://postgr.es/m/16913-3b5198410f67d8c6@postgresql.org
2021-02-25Fix list-manipulation bug in WITH RECURSIVE processing.Tom Lane
makeDependencyGraphWalker and checkWellFormedRecursionWalker thought they could hold onto a pointer to a list's first cons cell while the list was modified by recursive calls. That was okay when the cons cell was actually separately palloc'd ... but since commit 1cff1b95a, it's quite unsafe, leading to core dumps or incorrect complaints of faulty WITH nesting. In the field this'd require at least a seven-deep WITH nest to cause an issue, but enabling DEBUG_LIST_MEMORY_USAGE allows the bug to be seen with lesser nesting depths. Per bug #16801 from Alexander Lakhin. Back-patch to v13. Michael Paquier and Tom Lane Discussion: https://postgr.es/m/16801-393c7922143eaa4d@postgresql.org
2021-02-08Fix mishandling of column-level SELECT privileges for join aliases.Tom Lane
scanNSItemForColumn, expandNSItemAttrs, and ExpandSingleTable would pass the wrong RTE to markVarForSelectPriv when dealing with a join ParseNamespaceItem: they'd pass the join RTE, when what we need to mark is the base table that the join column came from. The end result was to not fill the base table's selectedCols bitmap correctly, resulting in an understatement of the set of columns that are read by the query. The executor would still insist on there being at least one selectable column; but with a correctly crafted query, a user having SELECT privilege on just one column of a table would nonetheless be allowed to read all its columns. To fix, make markRTEForSelectPriv fetch the correct RTE for itself, ignoring the possibly-mismatched RTE passed by the caller. Later, we'll get rid of some now-unused RTE arguments, but that risks API breaks so we won't do it in released branches. This problem was introduced by commit 9ce77d75c, so back-patch to v13 where that came in. Thanks to Sven Klemm for reporting the problem. Security: CVE-2021-20229
2020-12-01Ensure that expandTableLikeClause() re-examines the same table.Tom Lane
As it stood, expandTableLikeClause() re-did the same relation_openrv call that transformTableLikeClause() had done. However there are scenarios where this would not find the same table as expected. We hold lock on the LIKE source table, so it can't be renamed or dropped, but another table could appear before it in the search path. This explains the odd behavior reported in bug #16758 when cloning a table as a temp table of the same name. This case worked as expected before commit 502898192 introduced the need to open the source table twice, so we should fix it. To make really sure we get the same table, let's re-open it by OID not name. That requires adding an OID field to struct TableLikeClause, which is a little nervous-making from an ABI standpoint, but as long as it's at the end I don't think there's any serious risk. Per bug #16758 from Marc Boeren. Like the previous patch, back-patch to all supported branches. Discussion: https://postgr.es/m/16758-840e84a6cfab276d@postgresql.org
2020-11-19Further fixes for CREATE TABLE LIKE: cope with self-referential FKs.Tom Lane
Commit 502898192 was too careless about the order of execution of the additional ALTER TABLE operations generated by expandTableLikeClause. It just stuck them all at the end, which seems okay for most purposes. But it falls down in the case where LIKE is importing a primary key or unique index and the outer CREATE TABLE includes a FOREIGN KEY constraint that needs to depend on that index. Weird as that is, it used to work, so we ought to keep it working. To fix, make parse_utilcmd.c insert LIKE clauses between index-creation and FK-creation commands in the transformed list of commands, and change utility.c so that the commands generated by expandTableLikeClause are executed immediately not at the end. One could imagine scenarios where this wouldn't work either; but currently expandTableLikeClause only makes column default expressions, CHECK constraints, and indexes, and this ordering seems fine for those. Per bug #16730 from Sofoklis Papasofokli. Like the previous patch, back-patch to all supported branches. Discussion: https://postgr.es/m/16730-b902f7e6e0276b30@postgresql.org
2020-10-28Calculate extraUpdatedCols in query rewriter, not parser.Tom Lane
It's unsafe to do this at parse time because addition of generated columns to a table would not invalidate stored rules containing UPDATEs on the table ... but there might now be dependent generated columns that were not there when the rule was made. This also fixes an oversight that rewriteTargetView failed to update extraUpdatedCols when transforming an UPDATE on an updatable view. (Since the new calculation is downstream of that, rewriteTargetView doesn't actually need to do anything; but before, there was a demonstrable bug there.) In v13 and HEAD, this leads to easily-visible bugs because (since commit c6679e4fc) we won't recalculate generated columns that aren't listed in extraUpdatedCols. In v12 this bitmap is mostly just used for trigger-firing decisions, so you'd only notice a problem if a trigger cared whether a generated column had been updated. I'd complained about this back in May, but then forgot about it until bug #16671 from Michael Paul Killian revived the issue. Back-patch to v12 where this field was introduced. If existing stored rules contain any extraUpdatedCols values, they'll be ignored because the rewriter will overwrite them, so the bug will be fixed even for existing rules. (But note that if someone were to update to 13.1 or 12.5, store some rules with UPDATEs on tables having generated columns, and then downgrade to a prior minor version, they might observe issues similar to what this patch fixes. That seems unlikely enough to not be worth going to a lot of effort to fix.) Discussion: https://postgr.es/m/10206.1588964727@sss.pgh.pa.us Discussion: https://postgr.es/m/16671-2fa55851859fb166@postgresql.org
2020-10-07Fix optimization hazard in gram.y's makeOrderedSetArgs(), redux.Tom Lane
It appears that commit cf63c641c, which intended to prevent misoptimization of the result-building step in makeOrderedSetArgs, didn't go far enough: buildfarm member hornet's version of xlc is now optimizing back to the old, broken behavior in which list_length(directargs) is fetched only after list_concat() has changed that value. I'm not entirely convinced whether that's an undeniable compiler bug or whether it can be justified by a sufficiently aggressive interpretation of C sequence points. So let's just change the code to make it harder to misinterpret. Back-patch to all supported versions, just in case. Discussion: https://postgr.es/m/1830491.1601944935@sss.pgh.pa.us
2020-09-28Add for_each_from, to simplify loops starting from non-first list cells.Tom Lane
We have a dozen or so places that need to iterate over all but the first cell of a List. Prior to v13 this was typically written as for_each_cell(lc, lnext(list_head(list))) Commit 1cff1b95a changed these to for_each_cell(lc, list, list_second_cell(list)) This patch introduces a new macro for_each_from() which expresses the start point as a list index, allowing these to be written as for_each_from(lc, list, 1) This is marginally more efficient, since ForEachState.i can be initialized directly instead of backing into it from a ListCell address. It also seems clearer and less typo-prone. Some of the remaining uses of for_each_cell() look like they could profitably be changed to for_each_from(), but here I confined myself to changing uses of list_second_cell(). Also, fix for_each_cell_setup() and for_both_cell_setup() to const-ify their arguments; that's a simple oversight in 1cff1b95a. Back-patch into v13, on the grounds that (1) the const-ification is a minor bug fix, and (2) it's better for back-patching purposes if we only have two ways to write these loops rather than three. In HEAD, also remove list_third_cell() and list_fourth_cell(), which were also introduced in 1cff1b95a, and are unused as of cc99baa43. It seems unlikely that any third-party code would have started to use them already; anyone who has can be directed to list_nth_cell instead. Discussion: https://postgr.es/m/CAApHDvpo1zj9KhEpU2cCRZfSM3Q6XGdhzuAS2v79PH7WJBkYVA@mail.gmail.com
2020-09-28Assign collations in partition bound expressions.Tom Lane
Failure to do this can result in errors during evaluation of the bound expression, as illustrated by the new regression test. Back-patch to v12 where the ability for partition bounds to be expressions was added. Discussion: https://postgr.es/m/CAJV4CdrZ5mKuaEsRSbLf2URQ3h6iMtKD=hik8MaF5WwdmC9uZw@mail.gmail.com
2020-09-14Message fixes and style improvementsPeter Eisentraut
2020-09-07Clarify comments in enforce_generic_type_consistency().Tom Lane
Some of the pre-existing comments were vague about whether they referred to all polymorphic types or only the old-style ones. Also be more consistent about using the "family 1" vs "family 2" terminology. Himanshu Upadhyaya and Tom Lane Discussion: https://postgr.es/m/CAPF61jBUg9XoMPNuLpoZ+h6UZ2VxKdNt3rQL1xw1GOBwjWzAXQ@mail.gmail.com
2020-08-21Fix handling of CREATE TABLE LIKE with inheritance.Tom Lane
If a CREATE TABLE command uses both LIKE and traditional inheritance, Vars in CHECK constraints and expression indexes that are absorbed from a LIKE parent table tended to get mis-numbered, resulting in wrong answers and/or bizarre error messages (though probably not any actual crashes, thanks to validation occurring in the executor). In v12 and up, the same could happen to Vars in GENERATED expressions, even in cases with no LIKE clause but multiple traditional-inheritance parents. The cause of the problem for LIKE is that parse_utilcmd.c supposed it could renumber such Vars correctly during transformCreateStmt(), which it cannot since we have not yet accounted for columns added via inheritance. Fix that by postponing processing of LIKE INCLUDING CONSTRAINTS, DEFAULTS, GENERATED, INDEXES till after we've performed DefineRelation(). The error with GENERATED and multiple inheritance is a simple oversight in MergeAttributes(); it knows it has to renumber Vars in inherited CHECK constraints, but forgot to apply the same processing to inherited GENERATED expressions (a/k/a defaults). Per bug #16272 from Tom Gottfried. The non-GENERATED variants of the issue are ancient, presumably dating right back to the addition of CREATE TABLE LIKE; hence back-patch to all supported branches. Discussion: https://postgr.es/m/16272-6e32da020e9a9381@postgresql.org
2020-05-19part_strategy does not need its very own keyword classification.Tom Lane
This should be plain old ColId. Making it so makes the grammar less complicated, and makes the compiled tables a kilobyte or so smaller (likely because they don't have to deal with a keyword classification that's not used anyplace else).
2020-05-18WITH TIES: number of rows is optional and defaults to oneAlvaro Herrera
FETCH FIRST .. ONLY implements this correctly, but we missed to include it for FETCH FIRST .. WITH TIES in commit 357889eb17bb. Author: Vik Fearing Discussion: https://postgr.es/m/6aa690ef-551d-e24f-2690-c38c2442947c@postgresfriends.org
2020-05-16Run pgindent with new pg_bsd_indent version 2.1.1.Tom Lane
Thomas Munro fixed a longstanding annoyance in pg_bsd_indent, that it would misformat lines containing IsA() macros on the assumption that the IsA() call should be treated like a cast. This improves some other cases involving field/variable names that match typedefs, too. The only places that get worse are a couple of uses of the OpenSSL macro STACK_OF(); we'll gladly take that trade-off. Discussion: https://postgr.es/m/20200114221814.GA19630@alvherre.pgsql
2020-05-14Initial pgindent and pgperltidy run for v13.Tom Lane
Includes some manual cleanup of places that pgindent messed up, most of which weren't per project style anyway. Notably, it seems some people didn't absorb the style rules of commit c9d297751, because there were a bunch of new occurrences of function calls with a newline just after the left paren, all with faulty expectations about how the rest of the call would get indented.
2020-05-13Dial back -Wimplicit-fallthrough to level 3Alvaro Herrera
The additional pain from level 4 is excessive for the gain. Also revert all the source annotation changes to their original wordings, to avoid back-patching pain. Discussion: https://postgr.es/m/31166.1589378554@sss.pgh.pa.us
2020-05-12Add -Wimplicit-fallthrough to CFLAGS and CXXFLAGSAlvaro Herrera
Use it at level 4, a bit more restrictive than the default level, and tweak our commanding comments to FALLTHROUGH. (However, leave zic.c alone, since it's external code; to avoid the warnings that would appear there, change CFLAGS for that file in the Makefile.) Author: Julien Rouhaud <rjuju123@gmail.com> Author: Álvaro Herrera <alvherre@alvh.no-ip.org> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/20200412081825.qyo5vwwco3fv4gdo@nol Discussion: https://postgr.es/m/flat/E1fDenm-0000C8-IJ@gemulon.postgresql.org
2020-04-20Add ALTER .. NO DEPENDS ONAlvaro Herrera
Commit f2fcad27d59c (9.6 era) added the ability to mark objects as dependent an extension, but forgot to add a way for such dependencies to be removed. This commit fixes that oversight. Strictly speaking this should be backpatched to 9.6, but due to lack of demand we're not doing so at this time. Discussion: https://postgr.es/m/20200217225333.GA30974@alvherre.pgsql Reviewed-by: ahsan hadi <ahsan.hadi@gmail.com> Reviewed-by: Ibrar Ahmed <ibrar.ahmad@gmail.com> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
2020-04-09Fix CREATE TABLE LIKE INCLUDING GENERATED column order issuePeter Eisentraut
CREATE TABLE LIKE INCLUDING GENERATED would fail if a generated column referred to a column with a higher attribute number. This is because the column mapping mechanism created the mapping incrementally as columns are added. This was sufficient for previous uses of that mechanism (omitting dropped columns), and it also happened to work if generated columns only referred to columns with lower attribute numbers, but here it failed. This fix is to build the attribute mapping in a separate loop before processing the columns in detail. Bug: #16342 Reported-by: Ethan Waldo <ewaldo@healthetechs.com> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
2020-04-08Revert 0f5ca02f53Alexander Korotkov
0f5ca02f53 introduces 3 new keywords. It appears to be too much for relatively small feature. Given now we past feature freeze, it's already late for discussion of the new syntax. So, revert. Discussion: https://postgr.es/m/28209.1586294824%40sss.pgh.pa.us
2020-04-08Fix crash when using COLLATE in partition bound expressionsMichael Paquier
Attempting to use a COLLATE clause with a type that it not collatable in a partition bound expression could crash the server. This commit fixes the code by adding more checks similar to what is done when computing index or partition attributes by making sure that there is a collation iff the type is collatable. Backpatch down to 12, as 7c079d7 introduced this problem. Reported-by: Alexander Lakhin Author: Dmitry Dolgov Discussion: https://postgr.es/m/16325-809194cf742313ab@postgresql.org Backpatch-through: 12
2020-04-08Put back mistakenly removed #include.Tom Lane
In commit 4dbcb3f84 I removed some code from parse_coerce.c, and also removed some apparently-no-longer-needed #includes. But removing datum.h broke some not-compiled-by-default code. Discussion: https://postgr.es/m/20200407205436.pyjhddw5bn5upvsu@development
2020-04-07Implement waiting for given lsn at transaction startAlexander Korotkov
This commit adds following optional clause to BEGIN and START TRANSACTION commands. WAIT FOR LSN lsn [ TIMEOUT timeout ] New clause pospones transaction start till given lsn is applied on standby. This clause allows user be sure, that changes previously made on primary would be visible on standby. New shared memory struct is used to track awaited lsn per backend. Recovery process wakes up backend once required lsn is applied. Author: Ivan Kartyshov, Anna Akenteva Reviewed-by: Craig Ringer, Thomas Munro, Robert Haas, Kyotaro Horiguchi Reviewed-by: Masahiko Sawada, Ants Aasma, Dmitry Ivanov, Simon Riggs Reviewed-by: Amit Kapila, Alexander Korotkov Discussion: https://postgr.es/m/0240c26c-9f84-30ea-fca9-93ab2df5f305%40postgrespro.ru