]> git.ipfire.org Git - thirdparty/postgresql.git/commitdiff
Harden _int_matchsel() against being attached to the wrong operator.
authorTom Lane <tgl@sss.pgh.pa.us>
Mon, 9 Feb 2026 15:14:22 +0000 (10:14 -0500)
committerTom Lane <tgl@sss.pgh.pa.us>
Mon, 9 Feb 2026 15:14:22 +0000 (10:14 -0500)
While the preceding commit prevented such attachments from occurring
in future, this one aims to prevent further abuse of any already-
created operator that exposes _int_matchsel to the wrong data types.
(No other contrib module has a vulnerable selectivity estimator.)

We need only check that the Const we've found in the query is indeed
of the type we expect (query_int), but there's a difficulty: as an
extension type, query_int doesn't have a fixed OID that we could
hard-code into the estimator.

Therefore, the bulk of this patch consists of infrastructure to let
an extension function securely look up the OID of a datatype
belonging to the same extension.  (Extension authors have requested
such functionality before, so we anticipate that this code will
have additional non-security uses, and may soon be extended to allow
looking up other kinds of SQL objects.)

This is done by first finding the extension that owns the calling
function (there can be only one), and then thumbing through the
objects owned by that extension to find a type that has the desired
name.  This is relatively expensive, especially for large extensions,
so a simple cache is put in front of these lookups.

Reported-by: Daniel Firer as part of zeroday.cloud
Author: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Noah Misch <noah@leadboat.com>
Security: CVE-2026-2004
Backpatch-through: 14

contrib/intarray/_int_selfuncs.c
src/backend/catalog/pg_depend.c
src/backend/commands/extension.c
src/include/catalog/dependency.h
src/include/commands/extension.h
src/tools/pgindent/typedefs.list

index 4a7053028c6249958aa7733e60cb644834a799ba..7fce743632fbb805ee3ffbf077b9aff129a2c1cd 100644 (file)
@@ -19,6 +19,7 @@
 #include "catalog/pg_operator.h"
 #include "catalog/pg_statistic.h"
 #include "catalog/pg_type.h"
+#include "commands/extension.h"
 #include "miscadmin.h"
 #include "utils/fmgrprotos.h"
 #include "utils/lsyscache.h"
@@ -170,7 +171,18 @@ _int_matchsel(PG_FUNCTION_ARGS)
                PG_RETURN_FLOAT8(0.0);
        }
 
-       /* The caller made sure the const is a query, so get it now */
+       /*
+        * Verify that the Const is a query_int, else return a default estimate.
+        * (This could only fail if someone attached this estimator to the wrong
+        * operator.)
+        */
+       if (((Const *) other)->consttype !=
+               get_function_sibling_type(fcinfo->flinfo->fn_oid, "query_int"))
+       {
+               ReleaseVariableStats(vardata);
+               PG_RETURN_FLOAT8(DEFAULT_EQ_SEL);
+       }
+
        query = DatumGetQueryTypeP(((Const *) other)->constvalue);
 
        /* Empty query matches nothing */
index 55309d16f1566a41ed8746c9ea568db497b0f219..07c2d41c189685d452d893cb51cae3974ead1e5d 100644 (file)
 #include "catalog/pg_constraint.h"
 #include "catalog/pg_depend.h"
 #include "catalog/pg_extension.h"
+#include "catalog/pg_type.h"
 #include "catalog/partition.h"
 #include "commands/extension.h"
 #include "miscadmin.h"
 #include "utils/fmgroids.h"
 #include "utils/lsyscache.h"
 #include "utils/rel.h"
+#include "utils/syscache.h"
 
 
 static bool isObjectPinned(const ObjectAddress *object);
@@ -813,6 +815,77 @@ getAutoExtensionsOfObject(Oid classId, Oid objectId)
        return result;
 }
 
+/*
+ * Look up a type belonging to an extension.
+ *
+ * Returns the type's OID, or InvalidOid if not found.
+ *
+ * Notice that the type is specified by name only, without a schema.
+ * That's because this will typically be used by relocatable extensions
+ * which can't make a-priori assumptions about which schema their objects
+ * are in.  As long as the extension only defines one type of this name,
+ * the answer is unique anyway.
+ *
+ * We might later add the ability to look up functions, operators, etc.
+ */
+Oid
+getExtensionType(Oid extensionOid, const char *typname)
+{
+       Oid                     result = InvalidOid;
+       Relation        depRel;
+       ScanKeyData key[3];
+       SysScanDesc scan;
+       HeapTuple       tup;
+
+       depRel = table_open(DependRelationId, AccessShareLock);
+
+       ScanKeyInit(&key[0],
+                               Anum_pg_depend_refclassid,
+                               BTEqualStrategyNumber, F_OIDEQ,
+                               ObjectIdGetDatum(ExtensionRelationId));
+       ScanKeyInit(&key[1],
+                               Anum_pg_depend_refobjid,
+                               BTEqualStrategyNumber, F_OIDEQ,
+                               ObjectIdGetDatum(extensionOid));
+       ScanKeyInit(&key[2],
+                               Anum_pg_depend_refobjsubid,
+                               BTEqualStrategyNumber, F_INT4EQ,
+                               Int32GetDatum(0));
+
+       scan = systable_beginscan(depRel, DependReferenceIndexId, true,
+                                                         NULL, 3, key);
+
+       while (HeapTupleIsValid(tup = systable_getnext(scan)))
+       {
+               Form_pg_depend depform = (Form_pg_depend) GETSTRUCT(tup);
+
+               if (depform->classid == TypeRelationId &&
+                       depform->deptype == DEPENDENCY_EXTENSION)
+               {
+                       Oid                     typoid = depform->objid;
+                       HeapTuple       typtup;
+
+                       typtup = SearchSysCache1(TYPEOID, ObjectIdGetDatum(typoid));
+                       if (!HeapTupleIsValid(typtup))
+                               continue;               /* should we throw an error? */
+                       if (strcmp(NameStr(((Form_pg_type) GETSTRUCT(typtup))->typname),
+                                          typname) == 0)
+                       {
+                               result = typoid;
+                               ReleaseSysCache(typtup);
+                               break;                  /* no need to keep searching */
+                       }
+                       ReleaseSysCache(typtup);
+               }
+       }
+
+       systable_endscan(scan);
+
+       table_close(depRel, AccessShareLock);
+
+       return result;
+}
+
 /*
  * Detect whether a sequence is marked as "owned" by a column
  *
index 688f1874f31f0931f4b9b2dea8728a1168567b1f..72fdd7511bdd255dfa7efae8d44d0e06af1055ff 100644 (file)
@@ -45,6 +45,7 @@
 #include "catalog/pg_depend.h"
 #include "catalog/pg_extension.h"
 #include "catalog/pg_namespace.h"
+#include "catalog/pg_proc.h"
 #include "catalog/pg_type.h"
 #include "commands/alter.h"
 #include "commands/comment.h"
@@ -62,6 +63,7 @@
 #include "utils/builtins.h"
 #include "utils/conffiles.h"
 #include "utils/fmgroids.h"
+#include "utils/inval.h"
 #include "utils/lsyscache.h"
 #include "utils/memutils.h"
 #include "utils/rel.h"
@@ -141,7 +143,26 @@ typedef struct
        char       *loc;
 } ExtensionLocation;
 
+/*
+ * Cache structure for get_function_sibling_type (and maybe later,
+ * allied lookup functions).
+ */
+typedef struct ExtensionSiblingCache
+{
+       struct ExtensionSiblingCache *next; /* list link */
+       /* lookup key: requesting function's OID and type name */
+       Oid                     reqfuncoid;
+       const char *typname;
+       bool            valid;                  /* is entry currently valid? */
+       uint32          exthash;                /* cache hash of owning extension's OID */
+       Oid                     typeoid;                /* OID associated with typname */
+} ExtensionSiblingCache;
+
+/* Head of linked list of ExtensionSiblingCache structs */
+static ExtensionSiblingCache *ext_sibling_list = NULL;
+
 /* Local functions */
+static void ext_sibling_callback(Datum arg, int cacheid, uint32 hashvalue);
 static List *find_update_path(List *evi_list,
                                                          ExtensionVersionInfo *evi_start,
                                                          ExtensionVersionInfo *evi_target,
@@ -263,6 +284,114 @@ get_extension_schema(Oid ext_oid)
        return result;
 }
 
+/*
+ * get_function_sibling_type - find a type belonging to same extension as func
+ *
+ * Returns the type's OID, or InvalidOid if not found.
+ *
+ * This is useful in extensions, which won't have fixed object OIDs.
+ * We work from the calling function's own OID, which it can get from its
+ * FunctionCallInfo parameter, and look up the owning extension and thence
+ * a type belonging to the same extension.
+ *
+ * Notice that the type is specified by name only, without a schema.
+ * That's because this will typically be used by relocatable extensions
+ * which can't make a-priori assumptions about which schema their objects
+ * are in.  As long as the extension only defines one type of this name,
+ * the answer is unique anyway.
+ *
+ * We might later add the ability to look up functions, operators, etc.
+ *
+ * This code is simply a frontend for some pg_depend lookups.  Those lookups
+ * are fairly expensive, so we provide a simple cache facility.  We assume
+ * that the passed typname is actually a C constant, or at least permanently
+ * allocated, so that we need not copy that string.
+ */
+Oid
+get_function_sibling_type(Oid funcoid, const char *typname)
+{
+       ExtensionSiblingCache *cache_entry;
+       Oid                     extoid;
+       Oid                     typeoid;
+
+       /*
+        * See if we have the answer cached.  Someday there may be enough callers
+        * to justify a hash table, but for now, a simple linked list is fine.
+        */
+       for (cache_entry = ext_sibling_list; cache_entry != NULL;
+                cache_entry = cache_entry->next)
+       {
+               if (funcoid == cache_entry->reqfuncoid &&
+                       strcmp(typname, cache_entry->typname) == 0)
+                       break;
+       }
+       if (cache_entry && cache_entry->valid)
+               return cache_entry->typeoid;
+
+       /*
+        * Nope, so do the expensive lookups.  We do not expect failures, so we do
+        * not cache negative results.
+        */
+       extoid = getExtensionOfObject(ProcedureRelationId, funcoid);
+       if (!OidIsValid(extoid))
+               return InvalidOid;
+       typeoid = getExtensionType(extoid, typname);
+       if (!OidIsValid(typeoid))
+               return InvalidOid;
+
+       /*
+        * Build, or revalidate, cache entry.
+        */
+       if (cache_entry == NULL)
+       {
+               /* Register invalidation hook if this is first entry */
+               if (ext_sibling_list == NULL)
+                       CacheRegisterSyscacheCallback(EXTENSIONOID,
+                                                                                 ext_sibling_callback,
+                                                                                 (Datum) 0);
+
+               /* Momentarily zero the space to ensure valid flag is false */
+               cache_entry = (ExtensionSiblingCache *)
+                       MemoryContextAllocZero(CacheMemoryContext,
+                                                                  sizeof(ExtensionSiblingCache));
+               cache_entry->next = ext_sibling_list;
+               ext_sibling_list = cache_entry;
+       }
+
+       cache_entry->reqfuncoid = funcoid;
+       cache_entry->typname = typname;
+       cache_entry->exthash = GetSysCacheHashValue1(EXTENSIONOID,
+                                                                                                ObjectIdGetDatum(extoid));
+       cache_entry->typeoid = typeoid;
+       /* Mark it valid only once it's fully populated */
+       cache_entry->valid = true;
+
+       return typeoid;
+}
+
+/*
+ * ext_sibling_callback
+ *             Syscache inval callback function for EXTENSIONOID cache
+ *
+ * It seems sufficient to invalidate ExtensionSiblingCache entries when
+ * the owning extension's pg_extension entry is modified or deleted.
+ * Neither a requesting function's OID, nor the OID of the object it's
+ * looking for, could change without an extension update or drop/recreate.
+ */
+static void
+ext_sibling_callback(Datum arg, int cacheid, uint32 hashvalue)
+{
+       ExtensionSiblingCache *cache_entry;
+
+       for (cache_entry = ext_sibling_list; cache_entry != NULL;
+                cache_entry = cache_entry->next)
+       {
+               if (hashvalue == 0 ||
+                       cache_entry->exthash == hashvalue)
+                       cache_entry->valid = false;
+       }
+}
+
 /*
  * Utility functions to check validity of extension and version names
  */
index 969fd8b23f935fbb85ef27c1239d5076d1f76371..2f3c1eae3c71d62c1f83af4926129680c57e865e 100644 (file)
@@ -186,6 +186,8 @@ extern long changeDependenciesOn(Oid refClassId, Oid oldRefObjectId,
 extern Oid     getExtensionOfObject(Oid classId, Oid objectId);
 extern List *getAutoExtensionsOfObject(Oid classId, Oid objectId);
 
+extern Oid     getExtensionType(Oid extensionOid, const char *typname);
+
 extern bool sequenceIsOwned(Oid seqId, char deptype, Oid *tableId, int32 *colId);
 extern List *getOwnedSequences(Oid relid);
 extern Oid     getIdentitySequence(Relation rel, AttrNumber attnum, bool missing_ok);
index 4ebc2bac223a86993b775cdfb0e8f1199f2e1f80..7a76bdebcfa7fb8ccd1a7e7c8ddb7646185ee450 100644 (file)
@@ -52,6 +52,8 @@ extern char *get_extension_name(Oid ext_oid);
 extern Oid     get_extension_schema(Oid ext_oid);
 extern bool extension_file_exists(const char *extensionName);
 
+extern Oid     get_function_sibling_type(Oid funcoid, const char *typname);
+
 extern ObjectAddress AlterExtensionNamespace(const char *extensionName, const char *newschema,
                                                                                         Oid *oldschema);
 
index 775184894122bc2d808202eec9c3ec579cc7ae34..7619845fba952631c93e05a5757bd7f3ff3beb28 100644 (file)
@@ -803,6 +803,7 @@ ExtensibleNodeMethods
 ExtensionControlFile
 ExtensionInfo
 ExtensionLocation
+ExtensionSiblingCache
 ExtensionVersionInfo
 FDWCollateState
 FD_SET