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Repair incorrect check for coercion of unknown literal to ANYARRAY, a bug

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I introduced in 7.4.1 :-(.  It's correct to allow unknown to be coerced to
ANY or ANYELEMENT, since it's a real-enough data type, but it most certainly
isn't an array datatype.  This can cause a backend crash but AFAICT is not
exploitable as a security hole.  Per report from Michael Fuhr.

Note: as fixed in HEAD, this changes a constant in the pg_stats view,
resulting in a change in the expected regression outputs.  The back-branch
patches have been hacked to avoid that, so that pre-existing installations
won't start failing their regression tests.
This commit is contained in:
Tom Lane 2006-10-11 20:21:19 +00:00
parent 8608aa9534
commit dc167085f3
1 changed files with 22 additions and 5 deletions
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27
src/backend/parser/parse_coerce.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/parser/parse_coerce.c,v 2.126.4.2 2006/01/17 17:33:34 tgl Exp $
* $PostgreSQL: pgsql/src/backend/parser/parse_coerce.c,v 2.126.4.3 2006/10/11 20:21:19 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -130,11 +130,28 @@ coerce_type(ParseState *pstate, Node *node,
return node;
}
if (targetTypeId == ANYOID ||
targetTypeId == ANYARRAYOID ||
targetTypeId == ANYELEMENTOID)
targetTypeId == ANYELEMENTOID ||
(targetTypeId == ANYARRAYOID &&
(inputTypeId != UNKNOWNOID ||
(IsA(node, Const) && ((Const *) node)->constisnull)))) /* HACK */
{
/* assume can_coerce_type verified that implicit coercion is okay */
/* NB: we do NOT want a RelabelType here */
/*
* Assume can_coerce_type verified that implicit coercion is okay.
*
* Note: by returning the unmodified node here, we are saying that
* it's OK to treat an UNKNOWN constant as a valid input for a
* function accepting ANY or ANYELEMENT. This should be all right,
* since an UNKNOWN value is still a perfectly valid Datum. However
* an UNKNOWN value is definitely *not* an array, and so we mustn't
* accept it for ANYARRAY. (Instead, we will call anyarray_in below,
* which will produce an error.)
*
* HACK: if it's a NULL UNKNOWN constant, return it as-is, same as
* before. This is just to avoid changing the pg_stats view and thus
* the expected regression test results in back branches.
*
* NB: we do NOT want a RelabelType here.
*/
return node;
}
if (inputTypeId == UNKNOWNOID && IsA(node, Const))