TLA Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * rls.c
4 : * RLS-related utility functions.
5 : *
6 : * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
7 : * Portions Copyright (c) 1994, Regents of the University of California
8 : *
9 : *
10 : * IDENTIFICATION
11 : * src/backend/utils/misc/rls.c
12 : *
13 : *-------------------------------------------------------------------------
14 : */
15 : #include "postgres.h"
16 :
17 : #include "access/htup.h"
18 : #include "access/htup_details.h"
19 : #include "access/transam.h"
20 : #include "catalog/namespace.h"
21 : #include "catalog/pg_class.h"
22 : #include "miscadmin.h"
23 : #include "utils/acl.h"
24 : #include "utils/builtins.h"
25 : #include "utils/lsyscache.h"
26 : #include "utils/rls.h"
27 : #include "utils/syscache.h"
28 : #include "utils/varlena.h"
29 :
30 :
31 : /*
32 : * check_enable_rls
33 : *
34 : * Determine, based on the relation, row_security setting, and current role,
35 : * if RLS is applicable to this query. RLS_NONE_ENV indicates that, while
36 : * RLS is not to be added for this query, a change in the environment may change
37 : * that. RLS_NONE means that RLS is not on the relation at all and therefore
38 : * we don't need to worry about it. RLS_ENABLED means RLS should be implemented
39 : * for the table and the plan cache needs to be invalidated if the environment
40 : * changes.
41 : *
42 : * Handle checking as another role via checkAsUser (for views, etc). Pass
43 : * InvalidOid to check the current user.
44 : *
45 : * If noError is set to 'true' then we just return RLS_ENABLED instead of doing
46 : * an ereport() if the user has attempted to bypass RLS and they are not
47 : * allowed to. This allows users to check if RLS is enabled without having to
48 : * deal with the actual error case (eg: error cases which are trying to decide
49 : * if the user should get data from the relation back as part of the error).
50 : */
51 : int
52 CBC 421562 : check_enable_rls(Oid relid, Oid checkAsUser, bool noError)
53 : {
54 GNC 421562 : Oid user_id = OidIsValid(checkAsUser) ? checkAsUser : GetUserId();
55 : HeapTuple tuple;
56 : Form_pg_class classform;
57 : bool relrowsecurity;
58 : bool relforcerowsecurity;
59 : bool amowner;
60 :
61 : /* Nothing to do for built-in relations */
62 CBC 421562 : if (relid < (Oid) FirstNormalObjectId)
63 116837 : return RLS_NONE;
64 :
65 : /* Fetch relation's relrowsecurity and relforcerowsecurity flags */
66 304725 : tuple = SearchSysCache1(RELOID, ObjectIdGetDatum(relid));
67 304725 : if (!HeapTupleIsValid(tuple))
68 UBC 0 : return RLS_NONE;
69 CBC 304725 : classform = (Form_pg_class) GETSTRUCT(tuple);
70 :
71 304725 : relrowsecurity = classform->relrowsecurity;
72 304725 : relforcerowsecurity = classform->relforcerowsecurity;
73 :
74 304725 : ReleaseSysCache(tuple);
75 :
76 : /* Nothing to do if the relation does not have RLS */
77 304725 : if (!relrowsecurity)
78 303093 : return RLS_NONE;
79 :
80 : /*
81 : * BYPASSRLS users always bypass RLS. Note that superusers are always
82 : * considered to have BYPASSRLS.
83 : *
84 : * Return RLS_NONE_ENV to indicate that this decision depends on the
85 : * environment (in this case, the user_id).
86 : */
87 1632 : if (has_bypassrls_privilege(user_id))
88 252 : return RLS_NONE_ENV;
89 :
90 : /*
91 : * Table owners generally bypass RLS, except if the table has been set (by
92 : * an owner) to FORCE ROW SECURITY, and this is not a referential
93 : * integrity check.
94 : *
95 : * Return RLS_NONE_ENV to indicate that this decision depends on the
96 : * environment (in this case, the user_id).
97 : */
98 GNC 1380 : amowner = object_ownercheck(RelationRelationId, relid, user_id);
99 CBC 1380 : if (amowner)
100 : {
101 : /*
102 : * If FORCE ROW LEVEL SECURITY has been set on the relation then we
103 : * should return RLS_ENABLED to indicate that RLS should be applied.
104 : * If not, or if we are in an InNoForceRLSOperation context, we return
105 : * RLS_NONE_ENV.
106 : *
107 : * InNoForceRLSOperation indicates that we should not apply RLS even
108 : * if the table has FORCE RLS set - IF the current user is the owner.
109 : * This is specifically to ensure that referential integrity checks
110 : * are able to still run correctly.
111 : *
112 : * This is intentionally only done after we have checked that the user
113 : * is the table owner, which should always be the case for referential
114 : * integrity checks.
115 : */
116 195 : if (!relforcerowsecurity || InNoForceRLSOperation())
117 114 : return RLS_NONE_ENV;
118 : }
119 :
120 : /*
121 : * We should apply RLS. However, the user may turn off the row_security
122 : * GUC to get a forced error instead.
123 : */
124 1266 : if (!row_security && !noError)
125 33 : ereport(ERROR,
126 : (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
127 : errmsg("query would be affected by row-level security policy for table \"%s\"",
128 : get_rel_name(relid)),
129 : amowner ? errhint("To disable the policy for the table's owner, use ALTER TABLE NO FORCE ROW LEVEL SECURITY.") : 0));
130 :
131 : /* RLS should be fully enabled for this relation. */
132 1233 : return RLS_ENABLED;
133 : }
134 :
135 : /*
136 : * row_security_active
137 : *
138 : * check_enable_rls wrapped as a SQL callable function except
139 : * RLS_NONE_ENV and RLS_NONE are the same for this purpose.
140 : */
141 : Datum
142 6 : row_security_active(PG_FUNCTION_ARGS)
143 : {
144 : /* By OID */
145 6 : Oid tableoid = PG_GETARG_OID(0);
146 : int rls_status;
147 :
148 6 : rls_status = check_enable_rls(tableoid, InvalidOid, true);
149 6 : PG_RETURN_BOOL(rls_status == RLS_ENABLED);
150 : }
151 :
152 : Datum
153 6 : row_security_active_name(PG_FUNCTION_ARGS)
154 : {
155 : /* By qualified name */
156 6 : text *tablename = PG_GETARG_TEXT_PP(0);
157 : RangeVar *tablerel;
158 : Oid tableoid;
159 : int rls_status;
160 :
161 : /* Look up table name. Can't lock it - we might not have privileges. */
162 6 : tablerel = makeRangeVarFromNameList(textToQualifiedNameList(tablename));
163 6 : tableoid = RangeVarGetRelid(tablerel, NoLock, false);
164 :
165 6 : rls_status = check_enable_rls(tableoid, InvalidOid, true);
166 6 : PG_RETURN_BOOL(rls_status == RLS_ENABLED);
167 : }
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