PostgreSQL Source Code  git master
rowsecurity.h File Reference
#include "nodes/parsenodes.h"
#include "utils/array.h"
#include "utils/relcache.h"
Include dependency graph for rowsecurity.h:
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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

◆ 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 108 of file rowsecurity.c.

References ACL_SELECT, ACL_UPDATE, OnConflictExpr::action, add_security_quals(), add_with_check_options(), Assert, check_enable_rls(), RangeTblEntry::checkAsUser, CMD_DELETE, CMD_INSERT, CMD_SELECT, CMD_UPDATE, Query::commandType, get_policies_for_relation(), GetUserId(), NIL, NoLock, Query::onConflict, ONCONFLICT_UPDATE, RangeTblEntry::relid, RangeTblEntry::relkind, RangeTblEntry::requiredPerms, Query::resultRelation, RLS_NONE, RLS_NONE_ENV, setRuleCheckAsUser(), table_close(), table_open(), WCO_RLS_CONFLICT_CHECK, WCO_RLS_INSERT_CHECK, and WCO_RLS_UPDATE_CHECK.

Referenced by fireRIRrules().

111 {
112  Oid user_id;
113  int rls_status;
114  Relation rel;
115  CmdType commandType;
116  List *permissive_policies;
117  List *restrictive_policies;
118 
119  /* Defaults for the return values */
120  *securityQuals = NIL;
121  *withCheckOptions = NIL;
122  *hasRowSecurity = false;
123  *hasSubLinks = false;
124 
125  /* If this is not a normal relation, just return immediately */
126  if (rte->relkind != RELKIND_RELATION &&
127  rte->relkind != RELKIND_PARTITIONED_TABLE)
128  return;
129 
130  /* Switch to checkAsUser if it's set */
131  user_id = rte->checkAsUser ? rte->checkAsUser : GetUserId();
132 
133  /* Determine the state of RLS for this, pass checkAsUser explicitly */
134  rls_status = check_enable_rls(rte->relid, rte->checkAsUser, false);
135 
136  /* If there is no RLS on this table at all, nothing to do */
137  if (rls_status == RLS_NONE)
138  return;
139 
140  /*
141  * RLS_NONE_ENV means we are not doing any RLS now, but that may change
142  * with changes to the environment, so we mark it as hasRowSecurity to
143  * force a re-plan when the environment changes.
144  */
145  if (rls_status == RLS_NONE_ENV)
146  {
147  /*
148  * Indicate that this query may involve RLS and must therefore be
149  * replanned if the environment changes (GUCs, role), but we are not
150  * adding anything here.
151  */
152  *hasRowSecurity = true;
153 
154  return;
155  }
156 
157  /*
158  * RLS is enabled for this relation.
159  *
160  * Get the security policies that should be applied, based on the command
161  * type. Note that if this isn't the target relation, we actually want
162  * the relation's SELECT policies, regardless of the query command type,
163  * for example in UPDATE t1 ... FROM t2 we need to apply t1's UPDATE
164  * policies and t2's SELECT policies.
165  */
166  rel = table_open(rte->relid, NoLock);
167 
168  commandType = rt_index == root->resultRelation ?
169  root->commandType : CMD_SELECT;
170 
171  /*
172  * In some cases, we need to apply USING policies (which control the
173  * visibility of records) associated with multiple command types (see
174  * specific cases below).
175  *
176  * When considering the order in which to apply these USING policies, we
177  * prefer to apply higher privileged policies, those which allow the user
178  * to lock records (UPDATE and DELETE), first, followed by policies which
179  * don't (SELECT).
180  *
181  * Note that the optimizer is free to push down and reorder quals which
182  * use leakproof functions.
183  *
184  * In all cases, if there are no policy clauses allowing access to rows in
185  * the table for the specific type of operation, then a single
186  * always-false clause (a default-deny policy) will be added (see
187  * add_security_quals).
188  */
189 
190  /*
191  * For a SELECT, if UPDATE privileges are required (eg: the user has
192  * specified FOR [KEY] UPDATE/SHARE), then add the UPDATE USING quals
193  * first.
194  *
195  * This way, we filter out any records from the SELECT FOR SHARE/UPDATE
196  * which the user does not have access to via the UPDATE USING policies,
197  * similar to how we require normal UPDATE rights for these queries.
198  */
199  if (commandType == CMD_SELECT && rte->requiredPerms & ACL_UPDATE)
200  {
201  List *update_permissive_policies;
202  List *update_restrictive_policies;
203 
205  &update_permissive_policies,
206  &update_restrictive_policies);
207 
208  add_security_quals(rt_index,
209  update_permissive_policies,
210  update_restrictive_policies,
211  securityQuals,
212  hasSubLinks);
213  }
214 
215  /*
216  * For SELECT, UPDATE and DELETE, add security quals to enforce the USING
217  * policies. These security quals control access to existing table rows.
218  * Restrictive policies are combined together using AND, and permissive
219  * policies are combined together using OR.
220  */
221 
222  get_policies_for_relation(rel, commandType, user_id, &permissive_policies,
223  &restrictive_policies);
224 
225  if (commandType == CMD_SELECT ||
226  commandType == CMD_UPDATE ||
227  commandType == CMD_DELETE)
228  add_security_quals(rt_index,
229  permissive_policies,
230  restrictive_policies,
231  securityQuals,
232  hasSubLinks);
233 
234  /*
235  * Similar to above, during an UPDATE or DELETE, if SELECT rights are also
236  * required (eg: when a RETURNING clause exists, or the user has provided
237  * a WHERE clause which involves columns from the relation), we collect up
238  * CMD_SELECT policies and add them via add_security_quals first.
239  *
240  * This way, we filter out any records which are not visible through an
241  * ALL or SELECT USING policy.
242  */
243  if ((commandType == CMD_UPDATE || commandType == CMD_DELETE) &&
244  rte->requiredPerms & ACL_SELECT)
245  {
246  List *select_permissive_policies;
247  List *select_restrictive_policies;
248 
250  &select_permissive_policies,
251  &select_restrictive_policies);
252 
253  add_security_quals(rt_index,
254  select_permissive_policies,
255  select_restrictive_policies,
256  securityQuals,
257  hasSubLinks);
258  }
259 
260  /*
261  * For INSERT and UPDATE, add withCheckOptions to verify that any new
262  * records added are consistent with the security policies. This will use
263  * each policy's WITH CHECK clause, or its USING clause if no explicit
264  * WITH CHECK clause is defined.
265  */
266  if (commandType == CMD_INSERT || commandType == CMD_UPDATE)
267  {
268  /* This should be the target relation */
269  Assert(rt_index == root->resultRelation);
270 
271  add_with_check_options(rel, rt_index,
272  commandType == CMD_INSERT ?
274  permissive_policies,
275  restrictive_policies,
276  withCheckOptions,
277  hasSubLinks,
278  false);
279 
280  /*
281  * Get and add ALL/SELECT policies, if SELECT rights are required for
282  * this relation (eg: when RETURNING is used). These are added as WCO
283  * policies rather than security quals to ensure that an error is
284  * raised if a policy is violated; otherwise, we might end up silently
285  * dropping rows to be added.
286  */
287  if (rte->requiredPerms & ACL_SELECT)
288  {
289  List *select_permissive_policies = NIL;
290  List *select_restrictive_policies = NIL;
291 
293  &select_permissive_policies,
294  &select_restrictive_policies);
295  add_with_check_options(rel, rt_index,
296  commandType == CMD_INSERT ?
298  select_permissive_policies,
299  select_restrictive_policies,
300  withCheckOptions,
301  hasSubLinks,
302  true);
303  }
304 
305  /*
306  * For INSERT ... ON CONFLICT DO UPDATE we need additional policy
307  * checks for the UPDATE which may be applied to the same RTE.
308  */
309  if (commandType == CMD_INSERT &&
310  root->onConflict && root->onConflict->action == ONCONFLICT_UPDATE)
311  {
312  List *conflict_permissive_policies;
313  List *conflict_restrictive_policies;
314  List *conflict_select_permissive_policies = NIL;
315  List *conflict_select_restrictive_policies = NIL;
316 
317  /* Get the policies that apply to the auxiliary UPDATE */
319  &conflict_permissive_policies,
320  &conflict_restrictive_policies);
321 
322  /*
323  * Enforce the USING clauses of the UPDATE policies using WCOs
324  * rather than security quals. This ensures that an error is
325  * raised if the conflicting row cannot be updated due to RLS,
326  * rather than the change being silently dropped.
327  */
328  add_with_check_options(rel, rt_index,
330  conflict_permissive_policies,
331  conflict_restrictive_policies,
332  withCheckOptions,
333  hasSubLinks,
334  true);
335 
336  /*
337  * Get and add ALL/SELECT policies, as WCO_RLS_CONFLICT_CHECK WCOs
338  * to ensure they are considered when taking the UPDATE path of an
339  * INSERT .. ON CONFLICT DO UPDATE, if SELECT rights are required
340  * for this relation, also as WCO policies, again, to avoid
341  * silently dropping data. See above.
342  */
343  if (rte->requiredPerms & ACL_SELECT)
344  {
346  &conflict_select_permissive_policies,
347  &conflict_select_restrictive_policies);
348  add_with_check_options(rel, rt_index,
350  conflict_select_permissive_policies,
351  conflict_select_restrictive_policies,
352  withCheckOptions,
353  hasSubLinks,
354  true);
355  }
356 
357  /* Enforce the WITH CHECK clauses of the UPDATE policies */
358  add_with_check_options(rel, rt_index,
360  conflict_permissive_policies,
361  conflict_restrictive_policies,
362  withCheckOptions,
363  hasSubLinks,
364  false);
365 
366  /*
367  * Add ALL/SELECT policies as WCO_RLS_UPDATE_CHECK WCOs, to ensure
368  * that the final updated row is visible when taking the UPDATE
369  * path of an INSERT .. ON CONFLICT DO UPDATE, if SELECT rights
370  * are required for this relation.
371  */
372  if (rte->requiredPerms & ACL_SELECT)
373  add_with_check_options(rel, rt_index,
375  conflict_select_permissive_policies,
376  conflict_select_restrictive_policies,
377  withCheckOptions,
378  hasSubLinks,
379  true);
380  }
381  }
382 
383  table_close(rel, NoLock);
384 
385  /*
386  * Copy checkAsUser to the row security quals and WithCheckOption checks,
387  * in case they contain any subqueries referring to other relations.
388  */
389  setRuleCheckAsUser((Node *) *securityQuals, rte->checkAsUser);
390  setRuleCheckAsUser((Node *) *withCheckOptions, rte->checkAsUser);
391 
392  /*
393  * Mark this query as having row security, so plancache can invalidate it
394  * when necessary (eg: role changes)
395  */
396  *hasRowSecurity = true;
397 }
#define NIL
Definition: pg_list.h:65
void table_close(Relation relation, LOCKMODE lockmode)
Definition: table.c:133
void setRuleCheckAsUser(Node *node, Oid userid)
Oid GetUserId(void)
Definition: miscinit.c:380
OnConflictExpr * onConflict
Definition: parsenodes.h:144
int resultRelation
Definition: parsenodes.h:122
Definition: nodes.h:525
AclMode requiredPerms
Definition: parsenodes.h:1096
unsigned int Oid
Definition: postgres_ext.h:31
static void add_security_quals(int rt_index, List *permissive_policies, List *restrictive_policies, List **securityQuals, bool *hasSubLinks)
Definition: rowsecurity.c:559
#define NoLock
Definition: lockdefs.h:34
static void add_with_check_options(Relation rel, int rt_index, WCOKind kind, List *permissive_policies, List *restrictive_policies, List **withCheckOptions, bool *hasSubLinks, bool force_using)
Definition: rowsecurity.c:655
OnConflictAction action
Definition: primnodes.h:1512
#define ACL_UPDATE
Definition: parsenodes.h:76
#define ACL_SELECT
Definition: parsenodes.h:75
CmdType commandType
Definition: parsenodes.h:112
int check_enable_rls(Oid relid, Oid checkAsUser, bool noError)
Definition: rls.c:52
#define Assert(condition)
Definition: c.h:739
Relation table_open(Oid relationId, LOCKMODE lockmode)
Definition: table.c:39
Definition: rls.h:43
Definition: pg_list.h:50
CmdType
Definition: nodes.h:668
static void get_policies_for_relation(Relation relation, CmdType cmd, Oid user_id, List **permissive_policies, List **restrictive_policies)
Definition: rowsecurity.c:408

Variable Documentation

◆ row_security_policy_hook_permissive

PGDLLIMPORT row_security_policy_hook_type row_security_policy_hook_permissive

Definition at line 96 of file rowsecurity.c.

Referenced by _PG_fini(), _PG_init(), and get_policies_for_relation().

◆ row_security_policy_hook_restrictive

PGDLLIMPORT row_security_policy_hook_type row_security_policy_hook_restrictive

Definition at line 97 of file rowsecurity.c.

Referenced by _PG_fini(), _PG_init(), and get_policies_for_relation().