#include "nodes/parsenodes.h"
#include "utils/array.h"
#include "utils/relcache.h"

Include dependency graph for rowsecurity.h:

This graph shows which files directly or indirectly include this file:

Data Structures
struct	RowSecurityPolicy

struct	RowSecurityDesc

Typedefs
typedef struct RowSecurityPolicy	RowSecurityPolicy

typedef struct RowSecurityDesc	RowSecurityDesc

typedef List (	row_security_policy_hook_type) (CmdType cmdtype, Relation relation)

Functions
void	get_row_security_policies (Query root, RangeTblEntry rte, int rt_index, List securityQuals, List withCheckOptions, bool hasRowSecurity, bool hasSubLinks)

Variables
PGDLLIMPORT row_security_policy_hook_type	row_security_policy_hook_permissive

PGDLLIMPORT row_security_policy_hook_type	row_security_policy_hook_restrictive

Typedef Documentation

◆ row_security_policy_hook_type

typedef List *(* row_security_policy_hook_type) (CmdType cmdtype, Relation relation)

Definition at line 37 of file rowsecurity.h.

◆ RowSecurityDesc

typedef struct RowSecurityDesc RowSecurityDesc

◆ RowSecurityPolicy

typedef struct RowSecurityPolicy RowSecurityPolicy

Function Documentation

◆ get_row_security_policies()

void get_row_security_policies	(	Query *	root,
		RangeTblEntry *	rte,
		int	rt_index,
		List **	securityQuals,
		List **	withCheckOptions,
		bool *	hasRowSecurity,
		bool *	hasSubLinks
	)

Definition at line 98 of file rowsecurity.c.

{
    Oid         user_id;
    int         rls_status;
    Relation    rel;
    CmdType     commandType;
    List       *permissive_policies;
    List       *restrictive_policies;
    RTEPermissionInfo *perminfo;
 
    /* Defaults for the return values */
    *securityQuals = NIL;
    *withCheckOptions = NIL;
    *hasRowSecurity = false;
    *hasSubLinks = false;
 
    Assert(rte->rtekind == RTE_RELATION);
 
    /* If this is not a normal relation, just return immediately */
    if (rte->relkind != RELKIND_RELATION &&
        rte->relkind != RELKIND_PARTITIONED_TABLE)
        return;
 
    perminfo = getRTEPermissionInfo(root->rteperminfos, rte);
 
    /* Switch to checkAsUser if it's set */
    user_id = OidIsValid(perminfo->checkAsUser) ?
        perminfo->checkAsUser : GetUserId();
 
    /* Determine the state of RLS for this, pass checkAsUser explicitly */
    rls_status = check_enable_rls(rte->relid, perminfo->checkAsUser, false);
 
    /* If there is no RLS on this table at all, nothing to do */
    if (rls_status == RLS_NONE)
        return;
 
    /*
     * RLS_NONE_ENV means we are not doing any RLS now, but that may change
     * with changes to the environment, so we mark it as hasRowSecurity to
     * force a re-plan when the environment changes.
     */
    if (rls_status == RLS_NONE_ENV)
    {
        /*
         * Indicate that this query may involve RLS and must therefore be
         * replanned if the environment changes (GUCs, role), but we are not
         * adding anything here.
         */
        *hasRowSecurity = true;
 
        return;
    }
 
    /*
     * RLS is enabled for this relation.
     *
     * Get the security policies that should be applied, based on the command
     * type.  Note that if this isn't the target relation, we actually want
     * the relation's SELECT policies, regardless of the query command type,
     * for example in UPDATE t1 ... FROM t2 we need to apply t1's UPDATE
     * policies and t2's SELECT policies.
     */
    rel = table_open(rte->relid, NoLock);
 
    commandType = rt_index == root->resultRelation ?
        root->commandType : CMD_SELECT;
 
    /*
     * In some cases, we need to apply USING policies (which control the
     * visibility of records) associated with multiple command types (see
     * specific cases below).
     *
     * When considering the order in which to apply these USING policies, we
     * prefer to apply higher privileged policies, those which allow the user
     * to lock records (UPDATE and DELETE), first, followed by policies which
     * don't (SELECT).
     *
     * Note that the optimizer is free to push down and reorder quals which
     * use leakproof functions.
     *
     * In all cases, if there are no policy clauses allowing access to rows in
     * the table for the specific type of operation, then a single
     * always-false clause (a default-deny policy) will be added (see
     * add_security_quals).
     */
 
    /*
     * For a SELECT, if UPDATE privileges are required (eg: the user has
     * specified FOR [KEY] UPDATE/SHARE), then add the UPDATE USING quals
     * first.
     *
     * This way, we filter out any records from the SELECT FOR SHARE/UPDATE
     * which the user does not have access to via the UPDATE USING policies,
     * similar to how we require normal UPDATE rights for these queries.
     */
    if (commandType == CMD_SELECT && perminfo->requiredPerms & ACL_UPDATE)
    {
        List       *update_permissive_policies;
        List       *update_restrictive_policies;
 
        get_policies_for_relation(rel, CMD_UPDATE, user_id,
                                  &update_permissive_policies,
                                  &update_restrictive_policies);
 
        add_security_quals(rt_index,
                           update_permissive_policies,
                           update_restrictive_policies,
                           securityQuals,
                           hasSubLinks);
    }
 
    /*
     * For SELECT, UPDATE and DELETE, add security quals to enforce the USING
     * policies.  These security quals control access to existing table rows.
     * Restrictive policies are combined together using AND, and permissive
     * policies are combined together using OR.
     */
 
    get_policies_for_relation(rel, commandType, user_id, &permissive_policies,
                              &restrictive_policies);
 
    if (commandType == CMD_SELECT ||
        commandType == CMD_UPDATE ||
        commandType == CMD_DELETE)
        add_security_quals(rt_index,
                           permissive_policies,
                           restrictive_policies,
                           securityQuals,
                           hasSubLinks);
 
    /*
     * Similar to above, during an UPDATE, DELETE, or MERGE, if SELECT rights
     * are also required (eg: when a RETURNING clause exists, or the user has
     * provided a WHERE clause which involves columns from the relation), we
     * collect up CMD_SELECT policies and add them via add_security_quals
     * first.
     *
     * This way, we filter out any records which are not visible through an
     * ALL or SELECT USING policy.
     */
    if ((commandType == CMD_UPDATE || commandType == CMD_DELETE ||
         commandType == CMD_MERGE) &&
        perminfo->requiredPerms & ACL_SELECT)
    {
        List       *select_permissive_policies;
        List       *select_restrictive_policies;
 
        get_policies_for_relation(rel, CMD_SELECT, user_id,
                                  &select_permissive_policies,
                                  &select_restrictive_policies);
 
        add_security_quals(rt_index,
                           select_permissive_policies,
                           select_restrictive_policies,
                           securityQuals,
                           hasSubLinks);
    }
 
    /*
     * For INSERT and UPDATE, add withCheckOptions to verify that any new
     * records added are consistent with the security policies.  This will use
     * each policy's WITH CHECK clause, or its USING clause if no explicit
     * WITH CHECK clause is defined.
     */
    if (commandType == CMD_INSERT || commandType == CMD_UPDATE)
    {
        /* This should be the target relation */
        Assert(rt_index == root->resultRelation);
 
        add_with_check_options(rel, rt_index,
                               commandType == CMD_INSERT ?
                               WCO_RLS_INSERT_CHECK : WCO_RLS_UPDATE_CHECK,
                               permissive_policies,
                               restrictive_policies,
                               withCheckOptions,
                               hasSubLinks,
                               false);
 
        /*
         * Get and add ALL/SELECT policies, if SELECT rights are required for
         * this relation (eg: when RETURNING is used).  These are added as WCO
         * policies rather than security quals to ensure that an error is
         * raised if a policy is violated; otherwise, we might end up silently
         * dropping rows to be added.
         */
        if (perminfo->requiredPerms & ACL_SELECT)
        {
            List       *select_permissive_policies = NIL;
            List       *select_restrictive_policies = NIL;
 
            get_policies_for_relation(rel, CMD_SELECT, user_id,
                                      &select_permissive_policies,
                                      &select_restrictive_policies);
            add_with_check_options(rel, rt_index,
                                   commandType == CMD_INSERT ?
                                   WCO_RLS_INSERT_CHECK : WCO_RLS_UPDATE_CHECK,
                                   select_permissive_policies,
                                   select_restrictive_policies,
                                   withCheckOptions,
                                   hasSubLinks,
                                   true);
        }
 
        /*
         * For INSERT ... ON CONFLICT DO UPDATE we need additional policy
         * checks for the UPDATE which may be applied to the same RTE.
         */
        if (commandType == CMD_INSERT &&
            root->onConflict && root->onConflict->action == ONCONFLICT_UPDATE)
        {
            List       *conflict_permissive_policies;
            List       *conflict_restrictive_policies;
            List       *conflict_select_permissive_policies = NIL;
            List       *conflict_select_restrictive_policies = NIL;
 
            /* Get the policies that apply to the auxiliary UPDATE */
            get_policies_for_relation(rel, CMD_UPDATE, user_id,
                                      &conflict_permissive_policies,
                                      &conflict_restrictive_policies);
 
            /*
             * Enforce the USING clauses of the UPDATE policies using WCOs
             * rather than security quals.  This ensures that an error is
             * raised if the conflicting row cannot be updated due to RLS,
             * rather than the change being silently dropped.
             */
            add_with_check_options(rel, rt_index,
                                   WCO_RLS_CONFLICT_CHECK,
                                   conflict_permissive_policies,
                                   conflict_restrictive_policies,
                                   withCheckOptions,
                                   hasSubLinks,
                                   true);
 
            /*
             * Get and add ALL/SELECT policies, as WCO_RLS_CONFLICT_CHECK WCOs
             * to ensure they are considered when taking the UPDATE path of an
             * INSERT .. ON CONFLICT DO UPDATE, if SELECT rights are required
             * for this relation, also as WCO policies, again, to avoid
             * silently dropping data.  See above.
             */
            if (perminfo->requiredPerms & ACL_SELECT)
            {
                get_policies_for_relation(rel, CMD_SELECT, user_id,
                                          &conflict_select_permissive_policies,
                                          &conflict_select_restrictive_policies);
                add_with_check_options(rel, rt_index,
                                       WCO_RLS_CONFLICT_CHECK,
                                       conflict_select_permissive_policies,
                                       conflict_select_restrictive_policies,
                                       withCheckOptions,
                                       hasSubLinks,
                                       true);
            }
 
            /* Enforce the WITH CHECK clauses of the UPDATE policies */
            add_with_check_options(rel, rt_index,
                                   WCO_RLS_UPDATE_CHECK,
                                   conflict_permissive_policies,
                                   conflict_restrictive_policies,
                                   withCheckOptions,
                                   hasSubLinks,
                                   false);
 
            /*
             * Add ALL/SELECT policies as WCO_RLS_UPDATE_CHECK WCOs, to ensure
             * that the final updated row is visible when taking the UPDATE
             * path of an INSERT .. ON CONFLICT DO UPDATE, if SELECT rights
             * are required for this relation.
             */
            if (perminfo->requiredPerms & ACL_SELECT)
                add_with_check_options(rel, rt_index,
                                       WCO_RLS_UPDATE_CHECK,
                                       conflict_select_permissive_policies,
                                       conflict_select_restrictive_policies,
                                       withCheckOptions,
                                       hasSubLinks,
                                       true);
        }
    }
 
    /*
     * FOR MERGE, we fetch policies for UPDATE, DELETE and INSERT (and ALL)
     * and set them up so that we can enforce the appropriate policy depending
     * on the final action we take.
     *
     * We already fetched the SELECT policies above, to check existing rows,
     * but we must also check that new rows created by INSERT/UPDATE actions
     * are visible, if SELECT rights are required. For INSERT actions, we only
     * do this if RETURNING is specified, to be consistent with a plain INSERT
     * command, which can only require SELECT rights when RETURNING is used.
     *
     * We don't push the UPDATE/DELETE USING quals to the RTE because we don't
     * really want to apply them while scanning the relation since we don't
     * know whether we will be doing an UPDATE or a DELETE at the end. We
     * apply the respective policy once we decide the final action on the
     * target tuple.
     *
     * XXX We are setting up USING quals as WITH CHECK. If RLS prohibits
     * UPDATE/DELETE on the target row, we shall throw an error instead of
     * silently ignoring the row. This is different than how normal
     * UPDATE/DELETE works and more in line with INSERT ON CONFLICT DO UPDATE
     * handling.
     */
    if (commandType == CMD_MERGE)
    {
        List       *merge_update_permissive_policies;
        List       *merge_update_restrictive_policies;
        List       *merge_delete_permissive_policies;
        List       *merge_delete_restrictive_policies;
        List       *merge_insert_permissive_policies;
        List       *merge_insert_restrictive_policies;
        List       *merge_select_permissive_policies = NIL;
        List       *merge_select_restrictive_policies = NIL;
 
        /*
         * Fetch the UPDATE policies and set them up to execute on the
         * existing target row before doing UPDATE.
         */
        get_policies_for_relation(rel, CMD_UPDATE, user_id,
                                  &merge_update_permissive_policies,
                                  &merge_update_restrictive_policies);
 
        /*
         * WCO_RLS_MERGE_UPDATE_CHECK is used to check UPDATE USING quals on
         * the existing target row.
         */
        add_with_check_options(rel, rt_index,
                               WCO_RLS_MERGE_UPDATE_CHECK,
                               merge_update_permissive_policies,
                               merge_update_restrictive_policies,
                               withCheckOptions,
                               hasSubLinks,
                               true);
 
        /* Enforce the WITH CHECK clauses of the UPDATE policies */
        add_with_check_options(rel, rt_index,
                               WCO_RLS_UPDATE_CHECK,
                               merge_update_permissive_policies,
                               merge_update_restrictive_policies,
                               withCheckOptions,
                               hasSubLinks,
                               false);
 
        /*
         * Add ALL/SELECT policies as WCO_RLS_UPDATE_CHECK WCOs, to ensure
         * that the updated row is visible when executing an UPDATE action, if
         * SELECT rights are required for this relation.
         */
        if (perminfo->requiredPerms & ACL_SELECT)
        {
            get_policies_for_relation(rel, CMD_SELECT, user_id,
                                      &merge_select_permissive_policies,
                                      &merge_select_restrictive_policies);
            add_with_check_options(rel, rt_index,
                                   WCO_RLS_UPDATE_CHECK,
                                   merge_select_permissive_policies,
                                   merge_select_restrictive_policies,
                                   withCheckOptions,
                                   hasSubLinks,
                                   true);
        }
 
        /*
         * Fetch the DELETE policies and set them up to execute on the
         * existing target row before doing DELETE.
         */
        get_policies_for_relation(rel, CMD_DELETE, user_id,
                                  &merge_delete_permissive_policies,
                                  &merge_delete_restrictive_policies);
 
        /*
         * WCO_RLS_MERGE_DELETE_CHECK is used to check DELETE USING quals on
         * the existing target row.
         */
        add_with_check_options(rel, rt_index,
                               WCO_RLS_MERGE_DELETE_CHECK,
                               merge_delete_permissive_policies,
                               merge_delete_restrictive_policies,
                               withCheckOptions,
                               hasSubLinks,
                               true);
 
        /*
         * No special handling is required for INSERT policies. They will be
         * checked and enforced during ExecInsert(). But we must add them to
         * withCheckOptions.
         */
        get_policies_for_relation(rel, CMD_INSERT, user_id,
                                  &merge_insert_permissive_policies,
                                  &merge_insert_restrictive_policies);
 
        add_with_check_options(rel, rt_index,
                               WCO_RLS_INSERT_CHECK,
                               merge_insert_permissive_policies,
                               merge_insert_restrictive_policies,
                               withCheckOptions,
                               hasSubLinks,
                               false);
 
        /*
         * Add ALL/SELECT policies as WCO_RLS_INSERT_CHECK WCOs, to ensure
         * that the inserted row is visible when executing an INSERT action,
         * if RETURNING is specified and SELECT rights are required for this
         * relation.
         */
        if (perminfo->requiredPerms & ACL_SELECT && root->returningList)
            add_with_check_options(rel, rt_index,
                                   WCO_RLS_INSERT_CHECK,
                                   merge_select_permissive_policies,
                                   merge_select_restrictive_policies,
                                   withCheckOptions,
                                   hasSubLinks,
                                   true);
    }
 
    table_close(rel, NoLock);
 
    /*
     * Copy checkAsUser to the row security quals and WithCheckOption checks,
     * in case they contain any subqueries referring to other relations.
     */
    setRuleCheckAsUser((Node *) *securityQuals, perminfo->checkAsUser);
    setRuleCheckAsUser((Node *) *withCheckOptions, perminfo->checkAsUser);
 
    /*
     * Mark this query as having row security, so plancache can invalidate it
     * when necessary (eg: role changes)
     */
    *hasRowSecurity = true;
}