diff options
Diffstat (limited to 'src/backend/catalog/pg_depend.c')
| -rw-r--r-- | src/backend/catalog/pg_depend.c | 74 |
1 files changed, 69 insertions, 5 deletions
diff --git a/src/backend/catalog/pg_depend.c b/src/backend/catalog/pg_depend.c index 9ffadbbc181..71c7cef2260 100644 --- a/src/backend/catalog/pg_depend.c +++ b/src/backend/catalog/pg_depend.c @@ -124,15 +124,23 @@ recordMultipleDependencies(const ObjectAddress *depender, /* * If we are executing a CREATE EXTENSION operation, mark the given object - * as being a member of the extension. Otherwise, do nothing. + * as being a member of the extension, or check that it already is one. + * Otherwise, do nothing. * * This must be called during creation of any user-definable object type * that could be a member of an extension. * - * If isReplace is true, the object already existed (or might have already - * existed), so we must check for a pre-existing extension membership entry. - * Passing false is a guarantee that the object is newly created, and so - * could not already be a member of any extension. + * isReplace must be true if the object already existed, and false if it is + * newly created. In the former case we insist that it already be a member + * of the current extension. In the latter case we can skip checking whether + * it is already a member of any extension. + * + * Note: isReplace = true is typically used when updating a object in + * CREATE OR REPLACE and similar commands. We used to allow the target + * object to not already be an extension member, instead silently absorbing + * it into the current extension. However, this was both error-prone + * (extensions might accidentally overwrite free-standing objects) and + * a security hazard (since the object would retain its previous ownership). */ void recordDependencyOnCurrentExtension(const ObjectAddress *object, @@ -150,6 +158,12 @@ recordDependencyOnCurrentExtension(const ObjectAddress *object, { Oid oldext; + /* + * Side note: these catalog lookups are safe only because the + * object is a pre-existing one. In the not-isReplace case, the + * caller has most likely not yet done a CommandCounterIncrement + * that would make the new object visible. + */ oldext = getExtensionOfObject(object->classId, object->objectId); if (OidIsValid(oldext)) { @@ -163,6 +177,13 @@ recordDependencyOnCurrentExtension(const ObjectAddress *object, getObjectDescription(object), get_extension_name(oldext)))); } + /* It's a free-standing object, so reject */ + ereport(ERROR, + (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("%s is not a member of extension \"%s\"", + getObjectDescription(object), + get_extension_name(CurrentExtensionObject)), + errdetail("An extension is not allowed to replace an object that it does not own."))); } /* OK, record it as a member of CurrentExtensionObject */ @@ -175,6 +196,49 @@ recordDependencyOnCurrentExtension(const ObjectAddress *object, } /* + * If we are executing a CREATE EXTENSION operation, check that the given + * object is a member of the extension, and throw an error if it isn't. + * Otherwise, do nothing. + * + * This must be called whenever a CREATE IF NOT EXISTS operation (for an + * object type that can be an extension member) has found that an object of + * the desired name already exists. It is insecure for an extension to use + * IF NOT EXISTS except when the conflicting object is already an extension + * member; otherwise a hostile user could substitute an object with arbitrary + * properties. + */ +void +checkMembershipInCurrentExtension(const ObjectAddress *object) +{ + /* + * This is actually the same condition tested in + * recordDependencyOnCurrentExtension; but we want to issue a + * differently-worded error, and anyway it would be pretty confusing to + * call recordDependencyOnCurrentExtension in these circumstances. + */ + + /* Only whole objects can be extension members */ + Assert(object->objectSubId == 0); + + if (creating_extension) + { + Oid oldext; + + oldext = getExtensionOfObject(object->classId, object->objectId); + /* If already a member of this extension, OK */ + if (oldext == CurrentExtensionObject) + return; + /* Else complain */ + ereport(ERROR, + (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("%s is not a member of extension \"%s\"", + getObjectDescription(object), + get_extension_name(CurrentExtensionObject)), + errdetail("An extension may only use CREATE ... IF NOT EXISTS to skip object creation if the conflicting object is one that it already owns."))); + } +} + +/* * deleteDependencyRecordsFor -- delete all records with given depender * classId/objectId. Returns the number of records deleted. * |