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Make standard maintenance operations (including VACUUM, ANALYZE, REINDEX,

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and CLUSTER) execute as the table owner rather than the calling user, using
the same privilege-switching mechanism already used for SECURITY DEFINER
functions.  The purpose of this change is to ensure that user-defined
functions used in index definitions cannot acquire the privileges of a
superuser account that is performing routine maintenance.  While a function
used in an index is supposed to be IMMUTABLE and thus not able to do anything
very interesting, there are several easy ways around that restriction; and
even if we could plug them all, there would remain a risk of reading sensitive
information and broadcasting it through a covert channel such as CPU usage.

To prevent bypassing this security measure, execution of SET SESSION
AUTHORIZATION and SET ROLE is now forbidden within a SECURITY DEFINER context.

Thanks to Itagaki Takahiro for reporting this vulnerability.

Security: CVE-2007-6600
This commit is contained in:
Tom Lane
2008-01-03 21:23:15 +00:00
parent 98f27aaef3
commit eedb068c0a
13 changed files with 237 additions and 127 deletions
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31
src/backend/commands/analyze.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/commands/analyze.c,v 1.113 2008/01/01 19:45:48 momjian Exp $
* $PostgreSQL: pgsql/src/backend/commands/analyze.c,v 1.114 2008/01/03 21:23:15 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -119,6 +119,8 @@ analyze_rel(Oid relid, VacuumStmt *vacstmt,
HeapTuple *rows;
PGRUsage ru0;
TimestampTz starttime = 0;
Oid save_userid;
bool save_secdefcxt;
if (vacstmt->verbose)
elevel = INFO;
@ -202,6 +204,18 @@ analyze_rel(Oid relid, VacuumStmt *vacstmt,
return;
}
ereport(elevel,
(errmsg("analyzing \"%s.%s\"",
get_namespace_name(RelationGetNamespace(onerel)),
RelationGetRelationName(onerel))));
/*
* Switch to the table owner's userid, so that any index functions are
* run as that user.
*/
GetUserIdAndContext(&save_userid, &save_secdefcxt);
SetUserIdAndContext(onerel->rd_rel->relowner, true);
/* let others know what I'm doing */
LWLockAcquire(ProcArrayLock, LW_EXCLUSIVE);
MyProc->vacuumFlags |= PROC_IN_ANALYZE;
@ -215,11 +229,6 @@ analyze_rel(Oid relid, VacuumStmt *vacstmt,
starttime = GetCurrentTimestamp();
}
ereport(elevel,
(errmsg("analyzing \"%s.%s\"",
get_namespace_name(RelationGetNamespace(onerel)),
RelationGetRelationName(onerel))));
/*
* Determine which columns to analyze
*
@ -344,9 +353,7 @@ analyze_rel(Oid relid, VacuumStmt *vacstmt,
onerel->rd_rel->relisshared,
0, 0);
vac_close_indexes(nindexes, Irel, AccessShareLock);
relation_close(onerel, ShareUpdateExclusiveLock);
return;
goto cleanup;
}
/*
@ -466,6 +473,9 @@ analyze_rel(Oid relid, VacuumStmt *vacstmt,
totalrows, totaldeadrows);
}
/* We skip to here if there were no analyzable columns */
cleanup:
/* Done with indexes */
vac_close_indexes(nindexes, Irel, NoLock);
@ -498,6 +508,9 @@ analyze_rel(Oid relid, VacuumStmt *vacstmt,
LWLockAcquire(ProcArrayLock, LW_EXCLUSIVE);
MyProc->vacuumFlags &= ~PROC_IN_ANALYZE;
LWLockRelease(ProcArrayLock);
/* Restore userid */
SetUserIdAndContext(save_userid, save_secdefcxt);
}
/*