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 */ 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 #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 */ 90 static 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 */ 104 int 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 */ 140 void 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 */ 197 int 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 */ 246 void 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 */ 261 void 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