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 */
sqlite3_set_authorizer(sqlite3 * db,int (* xAuth)(void *,int,const char *,const char *,const char *,const char *),void * pArg)70 int sqlite3_set_authorizer(
71 sqlite3 *db,
72 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
73 void *pArg
74 ){
75 sqlite3_mutex_enter(db->mutex);
76 db->xAuth = xAuth;
77 db->pAuthArg = pArg;
78 sqlite3ExpirePreparedStatements(db);
79 sqlite3_mutex_leave(db->mutex);
80 return SQLITE_OK;
81 }
82
83 /*
84 ** Write an error message into pParse->zErrMsg that explains that the
85 ** user-supplied authorization function returned an illegal value.
86 */
sqliteAuthBadReturnCode(Parse * pParse)87 static void sqliteAuthBadReturnCode(Parse *pParse){
88 sqlite3ErrorMsg(pParse, "authorizer malfunction");
89 pParse->rc = SQLITE_ERROR;
90 }
91
92 /*
93 ** Invoke the authorization callback for permission to read column zCol from
94 ** table zTab in database zDb. This function assumes that an authorization
95 ** callback has been registered (i.e. that sqlite3.xAuth is not NULL).
96 **
97 ** If SQLITE_IGNORE is returned and pExpr is not NULL, then pExpr is changed
98 ** to an SQL NULL expression. Otherwise, if pExpr is NULL, then SQLITE_IGNORE
99 ** is treated as SQLITE_DENY. In this case an error is left in pParse.
100 */
sqlite3AuthReadCol(Parse * pParse,const char * zTab,const char * zCol,int iDb)101 int sqlite3AuthReadCol(
102 Parse *pParse, /* The parser context */
103 const char *zTab, /* Table name */
104 const char *zCol, /* Column name */
105 int iDb /* Index of containing database. */
106 ){
107 sqlite3 *db = pParse->db; /* Database handle */
108 char *zDb = db->aDb[iDb].zName; /* Name of attached database */
109 int rc; /* Auth callback return code */
110
111 rc = db->xAuth(db->pAuthArg, SQLITE_READ, zTab,zCol,zDb,pParse->zAuthContext);
112 if( rc==SQLITE_DENY ){
113 if( db->nDb>2 || iDb!=0 ){
114 sqlite3ErrorMsg(pParse, "access to %s.%s.%s is prohibited",zDb,zTab,zCol);
115 }else{
116 sqlite3ErrorMsg(pParse, "access to %s.%s is prohibited", zTab, zCol);
117 }
118 pParse->rc = SQLITE_AUTH;
119 }else if( rc!=SQLITE_IGNORE && rc!=SQLITE_OK ){
120 sqliteAuthBadReturnCode(pParse);
121 }
122 return rc;
123 }
124
125 /*
126 ** The pExpr should be a TK_COLUMN expression. The table referred to
127 ** is in pTabList or else it is the NEW or OLD table of a trigger.
128 ** Check to see if it is OK to read this particular column.
129 **
130 ** If the auth function returns SQLITE_IGNORE, change the TK_COLUMN
131 ** instruction into a TK_NULL. If the auth function returns SQLITE_DENY,
132 ** then generate an error.
133 */
sqlite3AuthRead(Parse * pParse,Expr * pExpr,Schema * pSchema,SrcList * pTabList)134 void sqlite3AuthRead(
135 Parse *pParse, /* The parser context */
136 Expr *pExpr, /* The expression to check authorization on */
137 Schema *pSchema, /* The schema of the expression */
138 SrcList *pTabList /* All table that pExpr might refer to */
139 ){
140 sqlite3 *db = pParse->db;
141 Table *pTab = 0; /* The table being read */
142 const char *zCol; /* Name of the column of the table */
143 int iSrc; /* Index in pTabList->a[] of table being read */
144 int iDb; /* The index of the database the expression refers to */
145 int iCol; /* Index of column in table */
146
147 if( db->xAuth==0 ) return;
148 iDb = sqlite3SchemaToIndex(pParse->db, pSchema);
149 if( iDb<0 ){
150 /* An attempt to read a column out of a subquery or other
151 ** temporary table. */
152 return;
153 }
154
155 assert( pExpr->op==TK_COLUMN || pExpr->op==TK_TRIGGER );
156 if( pExpr->op==TK_TRIGGER ){
157 pTab = pParse->pTriggerTab;
158 }else{
159 assert( pTabList );
160 for(iSrc=0; ALWAYS(iSrc<pTabList->nSrc); iSrc++){
161 if( pExpr->iTable==pTabList->a[iSrc].iCursor ){
162 pTab = pTabList->a[iSrc].pTab;
163 break;
164 }
165 }
166 }
167 iCol = pExpr->iColumn;
168 if( NEVER(pTab==0) ) return;
169
170 if( iCol>=0 ){
171 assert( iCol<pTab->nCol );
172 zCol = pTab->aCol[iCol].zName;
173 }else if( pTab->iPKey>=0 ){
174 assert( pTab->iPKey<pTab->nCol );
175 zCol = pTab->aCol[pTab->iPKey].zName;
176 }else{
177 zCol = "ROWID";
178 }
179 assert( iDb>=0 && iDb<db->nDb );
180 if( SQLITE_IGNORE==sqlite3AuthReadCol(pParse, pTab->zName, zCol, iDb) ){
181 pExpr->op = TK_NULL;
182 }
183 }
184
185 /*
186 ** Do an authorization check using the code and arguments given. Return
187 ** either SQLITE_OK (zero) or SQLITE_IGNORE or SQLITE_DENY. If SQLITE_DENY
188 ** is returned, then the error count and error message in pParse are
189 ** modified appropriately.
190 */
sqlite3AuthCheck(Parse * pParse,int code,const char * zArg1,const char * zArg2,const char * zArg3)191 int sqlite3AuthCheck(
192 Parse *pParse,
193 int code,
194 const char *zArg1,
195 const char *zArg2,
196 const char *zArg3
197 ){
198 sqlite3 *db = pParse->db;
199 int rc;
200
201 /* Don't do any authorization checks if the database is initialising
202 ** or if the parser is being invoked from within sqlite3_declare_vtab.
203 */
204 if( db->init.busy || IN_DECLARE_VTAB ){
205 return SQLITE_OK;
206 }
207
208 if( db->xAuth==0 ){
209 return SQLITE_OK;
210 }
211 rc = db->xAuth(db->pAuthArg, code, zArg1, zArg2, zArg3, pParse->zAuthContext);
212 if( rc==SQLITE_DENY ){
213 sqlite3ErrorMsg(pParse, "not authorized");
214 pParse->rc = SQLITE_AUTH;
215 }else if( rc!=SQLITE_OK && rc!=SQLITE_IGNORE ){
216 rc = SQLITE_DENY;
217 sqliteAuthBadReturnCode(pParse);
218 }
219 return rc;
220 }
221
222 /*
223 ** Push an authorization context. After this routine is called, the
224 ** zArg3 argument to authorization callbacks will be zContext until
225 ** popped. Or if pParse==0, this routine is a no-op.
226 */
sqlite3AuthContextPush(Parse * pParse,AuthContext * pContext,const char * zContext)227 void sqlite3AuthContextPush(
228 Parse *pParse,
229 AuthContext *pContext,
230 const char *zContext
231 ){
232 assert( pParse );
233 pContext->pParse = pParse;
234 pContext->zAuthContext = pParse->zAuthContext;
235 pParse->zAuthContext = zContext;
236 }
237
238 /*
239 ** Pop an authorization context that was previously pushed
240 ** by sqlite3AuthContextPush
241 */
sqlite3AuthContextPop(AuthContext * pContext)242 void sqlite3AuthContextPop(AuthContext *pContext){
243 if( pContext->pParse ){
244 pContext->pParse->zAuthContext = pContext->zAuthContext;
245 pContext->pParse = 0;
246 }
247 }
248
249 #endif /* SQLITE_OMIT_AUTHORIZATION */
250