diff options
Diffstat (limited to 'src/backend/utils/adt')
| -rw-r--r-- | src/backend/utils/adt/selfuncs.c | 486 |
1 files changed, 263 insertions, 223 deletions
diff --git a/src/backend/utils/adt/selfuncs.c b/src/backend/utils/adt/selfuncs.c index 17fbfa9b410..1c480cfaaf7 100644 --- a/src/backend/utils/adt/selfuncs.c +++ b/src/backend/utils/adt/selfuncs.c @@ -5288,8 +5288,8 @@ ReleaseDummy(HeapTuple tuple) * unique for this query. (Caution: this should be trusted for * statistical purposes only, since we do not check indimmediate nor * verify that the exact same definition of equality applies.) - * acl_ok: true if current user has permission to read the column(s) - * underlying the pg_statistic entry. This is consulted by + * acl_ok: true if current user has permission to read all table rows from + * the column(s) underlying the pg_statistic entry. This is consulted by * statistic_proc_security_check(). * * Caller is responsible for doing ReleaseVariableStats() before exiting. @@ -5408,7 +5408,6 @@ examine_variable(PlannerInfo *root, Node *node, int varRelid, */ ListCell *ilist; ListCell *slist; - Oid userid; /* * The nullingrels bits within the expression could prevent us from @@ -5418,17 +5417,6 @@ examine_variable(PlannerInfo *root, Node *node, int varRelid, if (bms_overlap(varnos, root->outer_join_rels)) node = remove_nulling_relids(node, root->outer_join_rels, NULL); - /* - * Determine the user ID to use for privilege checks: either - * onerel->userid if it's set (e.g., in case we're accessing the table - * via a view), or the current user otherwise. - * - * If we drill down to child relations, we keep using the same userid: - * it's going to be the same anyway, due to how we set up the relation - * tree (q.v. build_simple_rel). - */ - userid = OidIsValid(onerel->userid) ? onerel->userid : GetUserId(); - foreach(ilist, onerel->indexlist) { IndexOptInfo *index = (IndexOptInfo *) lfirst(ilist); @@ -5496,69 +5484,32 @@ examine_variable(PlannerInfo *root, Node *node, int varRelid, if (HeapTupleIsValid(vardata->statsTuple)) { - /* Get index's table for permission check */ - RangeTblEntry *rte; - - rte = planner_rt_fetch(index->rel->relid, root); - Assert(rte->rtekind == RTE_RELATION); - /* + * Test if user has permission to access all + * rows from the index's table. + * * For simplicity, we insist on the whole * table being selectable, rather than trying * to identify which column(s) the index - * depends on. Also require all rows to be - * selectable --- there must be no - * securityQuals from security barrier views - * or RLS policies. + * depends on. + * + * Note that for an inheritance child, + * permissions are checked on the inheritance + * root parent, and whole-table select + * privilege on the parent doesn't quite + * guarantee that the user could read all + * columns of the child. But in practice it's + * unlikely that any interesting security + * violation could result from allowing access + * to the expression index's stats, so we + * allow it anyway. See similar code in + * examine_simple_variable() for additional + * comments. */ vardata->acl_ok = - rte->securityQuals == NIL && - (pg_class_aclcheck(rte->relid, userid, - ACL_SELECT) == ACLCHECK_OK); - - /* - * If the user doesn't have permissions to - * access an inheritance child relation, check - * the permissions of the table actually - * mentioned in the query, since most likely - * the user does have that permission. Note - * that whole-table select privilege on the - * parent doesn't quite guarantee that the - * user could read all columns of the child. - * But in practice it's unlikely that any - * interesting security violation could result - * from allowing access to the expression - * index's stats, so we allow it anyway. See - * similar code in examine_simple_variable() - * for additional comments. - */ - if (!vardata->acl_ok && - root->append_rel_array != NULL) - { - AppendRelInfo *appinfo; - Index varno = index->rel->relid; - - appinfo = root->append_rel_array[varno]; - while (appinfo && - planner_rt_fetch(appinfo->parent_relid, - root)->rtekind == RTE_RELATION) - { - varno = appinfo->parent_relid; - appinfo = root->append_rel_array[varno]; - } - if (varno != index->rel->relid) - { - /* Repeat access check on this rel */ - rte = planner_rt_fetch(varno, root); - Assert(rte->rtekind == RTE_RELATION); - - vardata->acl_ok = - rte->securityQuals == NIL && - (pg_class_aclcheck(rte->relid, - userid, - ACL_SELECT) == ACLCHECK_OK); - } - } + all_rows_selectable(root, + index->rel->relid, + NULL); } else { @@ -5628,58 +5579,26 @@ examine_variable(PlannerInfo *root, Node *node, int varRelid, vardata->freefunc = ReleaseDummy; /* + * Test if user has permission to access all rows from the + * table. + * * For simplicity, we insist on the whole table being * selectable, rather than trying to identify which - * column(s) the statistics object depends on. Also - * require all rows to be selectable --- there must be no - * securityQuals from security barrier views or RLS - * policies. + * column(s) the statistics object depends on. + * + * Note that for an inheritance child, permissions are + * checked on the inheritance root parent, and whole-table + * select privilege on the parent doesn't quite guarantee + * that the user could read all columns of the child. But + * in practice it's unlikely that any interesting security + * violation could result from allowing access to the + * expression stats, so we allow it anyway. See similar + * code in examine_simple_variable() for additional + * comments. */ - vardata->acl_ok = - rte->securityQuals == NIL && - (pg_class_aclcheck(rte->relid, userid, - ACL_SELECT) == ACLCHECK_OK); - - /* - * If the user doesn't have permissions to access an - * inheritance child relation, check the permissions of - * the table actually mentioned in the query, since most - * likely the user does have that permission. Note that - * whole-table select privilege on the parent doesn't - * quite guarantee that the user could read all columns of - * the child. But in practice it's unlikely that any - * interesting security violation could result from - * allowing access to the expression stats, so we allow it - * anyway. See similar code in examine_simple_variable() - * for additional comments. - */ - if (!vardata->acl_ok && - root->append_rel_array != NULL) - { - AppendRelInfo *appinfo; - Index varno = onerel->relid; - - appinfo = root->append_rel_array[varno]; - while (appinfo && - planner_rt_fetch(appinfo->parent_relid, - root)->rtekind == RTE_RELATION) - { - varno = appinfo->parent_relid; - appinfo = root->append_rel_array[varno]; - } - if (varno != onerel->relid) - { - /* Repeat access check on this rel */ - rte = planner_rt_fetch(varno, root); - Assert(rte->rtekind == RTE_RELATION); - - vardata->acl_ok = - rte->securityQuals == NIL && - (pg_class_aclcheck(rte->relid, - userid, - ACL_SELECT) == ACLCHECK_OK); - } - } + vardata->acl_ok = all_rows_selectable(root, + onerel->relid, + NULL); break; } @@ -5734,109 +5653,20 @@ examine_simple_variable(PlannerInfo *root, Var *var, if (HeapTupleIsValid(vardata->statsTuple)) { - RelOptInfo *onerel = find_base_rel_noerr(root, var->varno); - Oid userid; - /* - * Check if user has permission to read this column. We require - * all rows to be accessible, so there must be no securityQuals - * from security barrier views or RLS policies. + * Test if user has permission to read all rows from this column. * - * Normally the Var will have an associated RelOptInfo from which - * we can find out which userid to do the check as; but it might - * not if it's a RETURNING Var for an INSERT target relation. In - * that case use the RTEPermissionInfo associated with the RTE. + * This requires that the user has the appropriate SELECT + * privileges and that there are no securityQuals from security + * barrier views or RLS policies. If that's not the case, then we + * only permit leakproof functions to be passed pg_statistic data + * in vardata, otherwise the functions might reveal data that the + * user doesn't have permission to see --- see + * statistic_proc_security_check(). */ - if (onerel) - userid = onerel->userid; - else - { - RTEPermissionInfo *perminfo; - - perminfo = getRTEPermissionInfo(root->parse->rteperminfos, rte); - userid = perminfo->checkAsUser; - } - if (!OidIsValid(userid)) - userid = GetUserId(); - vardata->acl_ok = - rte->securityQuals == NIL && - ((pg_class_aclcheck(rte->relid, userid, - ACL_SELECT) == ACLCHECK_OK) || - (pg_attribute_aclcheck(rte->relid, var->varattno, userid, - ACL_SELECT) == ACLCHECK_OK)); - - /* - * If the user doesn't have permissions to access an inheritance - * child relation or specifically this attribute, check the - * permissions of the table/column actually mentioned in the - * query, since most likely the user does have that permission - * (else the query will fail at runtime), and if the user can read - * the column there then he can get the values of the child table - * too. To do that, we must find out which of the root parent's - * attributes the child relation's attribute corresponds to. - */ - if (!vardata->acl_ok && var->varattno > 0 && - root->append_rel_array != NULL) - { - AppendRelInfo *appinfo; - Index varno = var->varno; - int varattno = var->varattno; - bool found = false; - - appinfo = root->append_rel_array[varno]; - - /* - * Partitions are mapped to their immediate parent, not the - * root parent, so must be ready to walk up multiple - * AppendRelInfos. But stop if we hit a parent that is not - * RTE_RELATION --- that's a flattened UNION ALL subquery, not - * an inheritance parent. - */ - while (appinfo && - planner_rt_fetch(appinfo->parent_relid, - root)->rtekind == RTE_RELATION) - { - int parent_varattno; - - found = false; - if (varattno <= 0 || varattno > appinfo->num_child_cols) - break; /* safety check */ - parent_varattno = appinfo->parent_colnos[varattno - 1]; - if (parent_varattno == 0) - break; /* Var is local to child */ - - varno = appinfo->parent_relid; - varattno = parent_varattno; - found = true; - - /* If the parent is itself a child, continue up. */ - appinfo = root->append_rel_array[varno]; - } - - /* - * In rare cases, the Var may be local to the child table, in - * which case, we've got to live with having no access to this - * column's stats. - */ - if (!found) - return; - - /* Repeat the access check on this parent rel & column */ - rte = planner_rt_fetch(varno, root); - Assert(rte->rtekind == RTE_RELATION); - - /* - * Fine to use the same userid as it's the same in all - * relations of a given inheritance tree. - */ - vardata->acl_ok = - rte->securityQuals == NIL && - ((pg_class_aclcheck(rte->relid, userid, - ACL_SELECT) == ACLCHECK_OK) || - (pg_attribute_aclcheck(rte->relid, varattno, userid, - ACL_SELECT) == ACLCHECK_OK)); - } + all_rows_selectable(root, var->varno, + bms_make_singleton(var->varattno - FirstLowInvalidHeapAttributeNumber)); } else { @@ -6034,6 +5864,214 @@ examine_simple_variable(PlannerInfo *root, Var *var, } /* + * all_rows_selectable + * Test whether the user has permission to select all rows from a given + * relation. + * + * Inputs: + * root: the planner info + * varno: the index of the relation (assumed to be an RTE_RELATION) + * varattnos: the attributes for which permission is required, or NULL if + * whole-table access is required + * + * Returns true if the user has the required select permissions, and there are + * no securityQuals from security barrier views or RLS policies. + * + * Note that if the relation is an inheritance child relation, securityQuals + * and access permissions are checked against the inheritance root parent (the + * relation actually mentioned in the query) --- see the comments in + * expand_single_inheritance_child() for an explanation of why it has to be + * done this way. + * + * If varattnos is non-NULL, its attribute numbers should be offset by + * FirstLowInvalidHeapAttributeNumber so that system attributes can be + * checked. If varattnos is NULL, only table-level SELECT privileges are + * checked, not any column-level privileges. + * + * Note: if the relation is accessed via a view, this function actually tests + * whether the view owner has permission to select from the relation. To + * ensure that the current user has permission, it is also necessary to check + * that the current user has permission to select from the view, which we do + * at planner-startup --- see subquery_planner(). + * + * This is exported so that other estimation functions can use it. + */ +bool +all_rows_selectable(PlannerInfo *root, Index varno, Bitmapset *varattnos) +{ + RelOptInfo *rel = find_base_rel_noerr(root, varno); + RangeTblEntry *rte = planner_rt_fetch(varno, root); + Oid userid; + int varattno; + + Assert(rte->rtekind == RTE_RELATION); + + /* + * Determine the user ID to use for privilege checks (either the current + * user or the view owner, if we're accessing the table via a view). + * + * Normally the relation will have an associated RelOptInfo from which we + * can find the userid, but it might not if it's a RETURNING Var for an + * INSERT target relation. In that case use the RTEPermissionInfo + * associated with the RTE. + * + * If we navigate up to a parent relation, we keep using the same userid, + * since it's the same in all relations of a given inheritance tree. + */ + if (rel) + userid = rel->userid; + else + { + RTEPermissionInfo *perminfo; + + perminfo = getRTEPermissionInfo(root->parse->rteperminfos, rte); + userid = perminfo->checkAsUser; + } + if (!OidIsValid(userid)) + userid = GetUserId(); + + /* + * Permissions and securityQuals must be checked on the table actually + * mentioned in the query, so if this is an inheritance child, navigate up + * to the inheritance root parent. If the user can read the whole table + * or the required columns there, then they can read from the child table + * too. For per-column checks, we must find out which of the root + * parent's attributes the child relation's attributes correspond to. + */ + if (root->append_rel_array != NULL) + { + AppendRelInfo *appinfo; + + appinfo = root->append_rel_array[varno]; + + /* + * Partitions are mapped to their immediate parent, not the root + * parent, so must be ready to walk up multiple AppendRelInfos. But + * stop if we hit a parent that is not RTE_RELATION --- that's a + * flattened UNION ALL subquery, not an inheritance parent. + */ + while (appinfo && + planner_rt_fetch(appinfo->parent_relid, + root)->rtekind == RTE_RELATION) + { + Bitmapset *parent_varattnos = NULL; + + /* + * For each child attribute, find the corresponding parent + * attribute. In rare cases, the attribute may be local to the + * child table, in which case, we've got to live with having no + * access to this column. + */ + varattno = -1; + while ((varattno = bms_next_member(varattnos, varattno)) >= 0) + { + AttrNumber attno; + AttrNumber parent_attno; + + attno = varattno + FirstLowInvalidHeapAttributeNumber; + + if (attno == InvalidAttrNumber) + { + /* + * Whole-row reference, so must map each column of the + * child to the parent table. + */ + for (attno = 1; attno <= appinfo->num_child_cols; attno++) + { + parent_attno = appinfo->parent_colnos[attno - 1]; + if (parent_attno == 0) + return false; /* attr is local to child */ + parent_varattnos = + bms_add_member(parent_varattnos, + parent_attno - FirstLowInvalidHeapAttributeNumber); + } + } + else + { + if (attno < 0) + { + /* System attnos are the same in all tables */ + parent_attno = attno; + } + else + { + if (attno > appinfo->num_child_cols) + return false; /* safety check */ + parent_attno = appinfo->parent_colnos[attno - 1]; + if (parent_attno == 0) + return false; /* attr is local to child */ + } + parent_varattnos = + bms_add_member(parent_varattnos, + parent_attno - FirstLowInvalidHeapAttributeNumber); + } + } + + /* If the parent is itself a child, continue up */ + varno = appinfo->parent_relid; + varattnos = parent_varattnos; + appinfo = root->append_rel_array[varno]; + } + + /* Perform the access check on this parent rel */ + rte = planner_rt_fetch(varno, root); + Assert(rte->rtekind == RTE_RELATION); + } + + /* + * For all rows to be accessible, there must be no securityQuals from + * security barrier views or RLS policies. + */ + if (rte->securityQuals != NIL) + return false; + + /* + * Test for table-level SELECT privilege. + * + * If varattnos is non-NULL, this is sufficient to give access to all + * requested attributes, even for a child table, since we have verified + * that all required child columns have matching parent columns. + * + * If varattnos is NULL (whole-table access requested), this doesn't + * necessarily guarantee that the user can read all columns of a child + * table, but we allow it anyway (see comments in examine_variable()) and + * don't bother checking any column privileges. + */ + if (pg_class_aclcheck(rte->relid, userid, ACL_SELECT) == ACLCHECK_OK) + return true; + + if (varattnos == NULL) + return false; /* whole-table access requested */ + + /* + * Don't have table-level SELECT privilege, so check per-column + * privileges. + */ + varattno = -1; + while ((varattno = bms_next_member(varattnos, varattno)) >= 0) + { + AttrNumber attno = varattno + FirstLowInvalidHeapAttributeNumber; + + if (attno == InvalidAttrNumber) + { + /* Whole-row reference, so must have access to all columns */ + if (pg_attribute_aclcheck_all(rte->relid, userid, ACL_SELECT, + ACLMASK_ALL) != ACLCHECK_OK) + return false; + } + else + { + if (pg_attribute_aclcheck(rte->relid, attno, userid, + ACL_SELECT) != ACLCHECK_OK) + return false; + } + } + + /* If we reach here, have all required column privileges */ + return true; +} + +/* * examine_indexcol_variable * Try to look up statistical data about an index column/expression. * Fill in a VariableStatData struct to describe the column. @@ -6121,15 +6159,17 @@ examine_indexcol_variable(PlannerInfo *root, IndexOptInfo *index, /* * Check whether it is permitted to call func_oid passing some of the - * pg_statistic data in vardata. We allow this either if the user has SELECT - * privileges on the table or column underlying the pg_statistic data or if - * the function is marked leakproof. + * pg_statistic data in vardata. We allow this if either of the following + * conditions is met: (1) the user has SELECT privileges on the table or + * column underlying the pg_statistic data and there are no securityQuals from + * security barrier views or RLS policies, or (2) the function is marked + * leakproof. */ bool statistic_proc_security_check(VariableStatData *vardata, Oid func_oid) { if (vardata->acl_ok) - return true; + return true; /* have SELECT privs and no securityQuals */ if (!OidIsValid(func_oid)) return false; |