1/*
2** 2003 January 11
3**
4** The author disclaims copyright to this source code. In place of
5** a legal notice, here is a blessing:
6**
7** May you do good and not evil.
8** May you find forgiveness for yourself and forgive others.
9** May you share freely, never taking more than you give.
10**
11*************************************************************************
12** This file contains code used to implement the sqlite3_set_authorizer()
13** API. This facility is an optional feature of the library. Embedded
14** systems that do not need this facility may omit it by recompiling
15** the library with -DSQLITE_OMIT_AUTHORIZATION=1
16*/
17#include "sqliteInt.h"
18
19/*
20** All of the code in this file may be omitted by defining a single
21** macro.
22*/
23#ifndef SQLITE_OMIT_AUTHORIZATION
24
25/*
26** Set or clear the access authorization function.
27**
28** The access authorization function is be called during the compilation
29** phase to verify that the user has read and/or write access permission on
30** various fields of the database. The first argument to the auth function
31** is a copy of the 3rd argument to this routine. The second argument
32** to the auth function is one of these constants:
33**
34** SQLITE_CREATE_INDEX
35** SQLITE_CREATE_TABLE
36** SQLITE_CREATE_TEMP_INDEX
37** SQLITE_CREATE_TEMP_TABLE
38** SQLITE_CREATE_TEMP_TRIGGER
39** SQLITE_CREATE_TEMP_VIEW
40** SQLITE_CREATE_TRIGGER
41** SQLITE_CREATE_VIEW
42** SQLITE_DELETE
43** SQLITE_DROP_INDEX
44** SQLITE_DROP_TABLE
45** SQLITE_DROP_TEMP_INDEX
46** SQLITE_DROP_TEMP_TABLE
47** SQLITE_DROP_TEMP_TRIGGER
48** SQLITE_DROP_TEMP_VIEW
49** SQLITE_DROP_TRIGGER
50** SQLITE_DROP_VIEW
51** SQLITE_INSERT
52** SQLITE_PRAGMA
53** SQLITE_READ
54** SQLITE_SELECT
55** SQLITE_TRANSACTION
56** SQLITE_UPDATE
57**
58** The third and fourth arguments to the auth function are the name of
59** the table and the column that are being accessed. The auth function
60** should return either SQLITE_OK, SQLITE_DENY, or SQLITE_IGNORE. If
61** SQLITE_OK is returned, it means that access is allowed. SQLITE_DENY
62** means that the SQL statement will never-run - the sqlite3_exec() call
63** will return with an error. SQLITE_IGNORE means that the SQL statement
64** should run but attempts to read the specified column will return NULL
65** and attempts to write the column will be ignored.
66**
67** Setting the auth function to NULL disables this hook. The default
68** setting of the auth function is NULL.
69*/
70int sqlite3_set_authorizer(
71 sqlite3 *db,
72 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
73 void *pArg
74){
75#ifdef SQLITE_ENABLE_API_ARMOR
76 if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
77#endif
78 sqlite3_mutex_enter(db->mutex);
79 db->xAuth = (sqlite3_xauth)xAuth;
80 db->pAuthArg = pArg;
81 if( db->xAuth ) sqlite3ExpirePreparedStatements(db, 1);
82 sqlite3_mutex_leave(db->mutex);
83 return SQLITE_OK;
84}
85
86/*
87** Write an error message into pParse->zErrMsg that explains that the
88** user-supplied authorization function returned an illegal value.
89*/
90static void sqliteAuthBadReturnCode(Parse *pParse){
91 sqlite3ErrorMsg(pParse, "authorizer malfunction");
92 pParse->rc = SQLITE_ERROR;
93}
94
95/*
96** Invoke the authorization callback for permission to read column zCol from
97** table zTab in database zDb. This function assumes that an authorization
98** callback has been registered (i.e. that sqlite3.xAuth is not NULL).
99**
100** If SQLITE_IGNORE is returned and pExpr is not NULL, then pExpr is changed
101** to an SQL NULL expression. Otherwise, if pExpr is NULL, then SQLITE_IGNORE
102** is treated as SQLITE_DENY. In this case an error is left in pParse.
103*/
104int sqlite3AuthReadCol(
105 Parse *pParse, /* The parser context */
106 const char *zTab, /* Table name */
107 const char *zCol, /* Column name */
108 int iDb /* Index of containing database. */
109){
110 sqlite3 *db = pParse->db; /* Database handle */
111 char *zDb = db->aDb[iDb].zDbSName; /* Schema name of attached database */
112 int rc; /* Auth callback return code */
113
114 if( db->init.busy ) return SQLITE_OK;
115 rc = db->xAuth(db->pAuthArg, SQLITE_READ, zTab,zCol,zDb,pParse->zAuthContext
116#ifdef SQLITE_USER_AUTHENTICATION
117 ,db->auth.zAuthUser
118#endif
119 );
120 if( rc==SQLITE_DENY ){
121 char *z = sqlite3_mprintf("%s.%s", zTab, zCol);
122 if( db->nDb>2 || iDb!=0 ) z = sqlite3_mprintf("%s.%z", zDb, z);
123 sqlite3ErrorMsg(pParse, "access to %z is prohibited", z);
124 pParse->rc = SQLITE_AUTH;
125 }else if( rc!=SQLITE_IGNORE && rc!=SQLITE_OK ){
126 sqliteAuthBadReturnCode(pParse);
127 }
128 return rc;
129}
130
131/*
132** The pExpr should be a TK_COLUMN expression. The table referred to
133** is in pTabList or else it is the NEW or OLD table of a trigger.
134** Check to see if it is OK to read this particular column.
135**
136** If the auth function returns SQLITE_IGNORE, change the TK_COLUMN
137** instruction into a TK_NULL. If the auth function returns SQLITE_DENY,
138** then generate an error.
139*/
140void sqlite3AuthRead(
141 Parse *pParse, /* The parser context */
142 Expr *pExpr, /* The expression to check authorization on */
143 Schema *pSchema, /* The schema of the expression */
144 SrcList *pTabList /* All table that pExpr might refer to */
145){
146 Table *pTab = 0; /* The table being read */
147 const char *zCol; /* Name of the column of the table */
148 int iSrc; /* Index in pTabList->a[] of table being read */
149 int iDb; /* The index of the database the expression refers to */
150 int iCol; /* Index of column in table */
151
152 assert( pExpr->op==TK_COLUMN || pExpr->op==TK_TRIGGER );
153 assert( !IN_RENAME_OBJECT );
154 assert( pParse->db->xAuth!=0 );
155 iDb = sqlite3SchemaToIndex(pParse->db, pSchema);
156 if( iDb<0 ){
157 /* An attempt to read a column out of a subquery or other
158 ** temporary table. */
159 return;
160 }
161
162 if( pExpr->op==TK_TRIGGER ){
163 pTab = pParse->pTriggerTab;
164 }else{
165 assert( pTabList );
166 for(iSrc=0; iSrc<pTabList->nSrc; iSrc++){
167 if( pExpr->iTable==pTabList->a[iSrc].iCursor ){
168 pTab = pTabList->a[iSrc].pTab;
169 break;
170 }
171 }
172 }
173 iCol = pExpr->iColumn;
174 if( pTab==0 ) return;
175
176 if( iCol>=0 ){
177 assert( iCol<pTab->nCol );
178 zCol = pTab->aCol[iCol].zCnName;
179 }else if( pTab->iPKey>=0 ){
180 assert( pTab->iPKey<pTab->nCol );
181 zCol = pTab->aCol[pTab->iPKey].zCnName;
182 }else{
183 zCol = "ROWID";
184 }
185 assert( iDb>=0 && iDb<pParse->db->nDb );
186 if( SQLITE_IGNORE==sqlite3AuthReadCol(pParse, pTab->zName, zCol, iDb) ){
187 pExpr->op = TK_NULL;
188 }
189}
190
191/*
192** Do an authorization check using the code and arguments given. Return
193** either SQLITE_OK (zero) or SQLITE_IGNORE or SQLITE_DENY. If SQLITE_DENY
194** is returned, then the error count and error message in pParse are
195** modified appropriately.
196*/
197int sqlite3AuthCheck(
198 Parse *pParse,
199 int code,
200 const char *zArg1,
201 const char *zArg2,
202 const char *zArg3
203){
204 sqlite3 *db = pParse->db;
205 int rc;
206
207 /* Don't do any authorization checks if the database is initialising
208 ** or if the parser is being invoked from within sqlite3_declare_vtab.
209 */
210 assert( !IN_RENAME_OBJECT || db->xAuth==0 );
211 if( db->xAuth==0 || db->init.busy || IN_SPECIAL_PARSE ){
212 return SQLITE_OK;
213 }
214
215 /* EVIDENCE-OF: R-43249-19882 The third through sixth parameters to the
216 ** callback are either NULL pointers or zero-terminated strings that
217 ** contain additional details about the action to be authorized.
218 **
219 ** The following testcase() macros show that any of the 3rd through 6th
220 ** parameters can be either NULL or a string. */
221 testcase( zArg1==0 );
222 testcase( zArg2==0 );
223 testcase( zArg3==0 );
224 testcase( pParse->zAuthContext==0 );
225
226 rc = db->xAuth(db->pAuthArg, code, zArg1, zArg2, zArg3, pParse->zAuthContext
227#ifdef SQLITE_USER_AUTHENTICATION
228 ,db->auth.zAuthUser
229#endif
230 );
231 if( rc==SQLITE_DENY ){
232 sqlite3ErrorMsg(pParse, "not authorized");
233 pParse->rc = SQLITE_AUTH;
234 }else if( rc!=SQLITE_OK && rc!=SQLITE_IGNORE ){
235 rc = SQLITE_DENY;
236 sqliteAuthBadReturnCode(pParse);
237 }
238 return rc;
239}
240
241/*
242** Push an authorization context. After this routine is called, the
243** zArg3 argument to authorization callbacks will be zContext until
244** popped. Or if pParse==0, this routine is a no-op.
245*/
246void sqlite3AuthContextPush(
247 Parse *pParse,
248 AuthContext *pContext,
249 const char *zContext
250){
251 assert( pParse );
252 pContext->pParse = pParse;
253 pContext->zAuthContext = pParse->zAuthContext;
254 pParse->zAuthContext = zContext;
255}
256
257/*
258** Pop an authorization context that was previously pushed
259** by sqlite3AuthContextPush
260*/
261void sqlite3AuthContextPop(AuthContext *pContext){
262 if( pContext->pParse ){
263 pContext->pParse->zAuthContext = pContext->zAuthContext;
264 pContext->pParse = 0;
265 }
266}
267
268#endif /* SQLITE_OMIT_AUTHORIZATION */
269