000001 /*
000002 ** 2003 January 11
000003 **
000004 ** The author disclaims copyright to this source code. In place of
000005 ** a legal notice, here is a blessing:
000006 **
000007 ** May you do good and not evil.
000008 ** May you find forgiveness for yourself and forgive others.
000009 ** May you share freely, never taking more than you give.
000010 **
000011 *************************************************************************
000012 ** This file contains code used to implement the sqlite3_set_authorizer()
000013 ** API. This facility is an optional feature of the library. Embedded
000014 ** systems that do not need this facility may omit it by recompiling
000015 ** the library with -DSQLITE_OMIT_AUTHORIZATION=1
000016 */
000017 #include "sqliteInt.h"
000018
000019 /*
000020 ** All of the code in this file may be omitted by defining a single
000021 ** macro.
000022 */
000023 #ifndef SQLITE_OMIT_AUTHORIZATION
000024
000025 /*
000026 ** Set or clear the access authorization function.
000027 **
000028 ** The access authorization function is be called during the compilation
000029 ** phase to verify that the user has read and/or write access permission on
000030 ** various fields of the database. The first argument to the auth function
000031 ** is a copy of the 3rd argument to this routine. The second argument
000032 ** to the auth function is one of these constants:
000033 **
000034 ** SQLITE_CREATE_INDEX
000035 ** SQLITE_CREATE_TABLE
000036 ** SQLITE_CREATE_TEMP_INDEX
000037 ** SQLITE_CREATE_TEMP_TABLE
000038 ** SQLITE_CREATE_TEMP_TRIGGER
000039 ** SQLITE_CREATE_TEMP_VIEW
000040 ** SQLITE_CREATE_TRIGGER
000041 ** SQLITE_CREATE_VIEW
000042 ** SQLITE_DELETE
000043 ** SQLITE_DROP_INDEX
000044 ** SQLITE_DROP_TABLE
000045 ** SQLITE_DROP_TEMP_INDEX
000046 ** SQLITE_DROP_TEMP_TABLE
000047 ** SQLITE_DROP_TEMP_TRIGGER
000048 ** SQLITE_DROP_TEMP_VIEW
000049 ** SQLITE_DROP_TRIGGER
000050 ** SQLITE_DROP_VIEW
000051 ** SQLITE_INSERT
000052 ** SQLITE_PRAGMA
000053 ** SQLITE_READ
000054 ** SQLITE_SELECT
000055 ** SQLITE_TRANSACTION
000056 ** SQLITE_UPDATE
000057 **
000058 ** The third and fourth arguments to the auth function are the name of
000059 ** the table and the column that are being accessed. The auth function
000060 ** should return either SQLITE_OK, SQLITE_DENY, or SQLITE_IGNORE. If
000061 ** SQLITE_OK is returned, it means that access is allowed. SQLITE_DENY
000062 ** means that the SQL statement will never-run - the sqlite3_exec() call
000063 ** will return with an error. SQLITE_IGNORE means that the SQL statement
000064 ** should run but attempts to read the specified column will return NULL
000065 ** and attempts to write the column will be ignored.
000066 **
000067 ** Setting the auth function to NULL disables this hook. The default
000068 ** setting of the auth function is NULL.
000069 */
000070 int sqlite3_set_authorizer(
000071 sqlite3 *db,
000072 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
000073 void *pArg
000074 ){
000075 #ifdef SQLITE_ENABLE_API_ARMOR
000076 if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
000077 #endif
000078 sqlite3_mutex_enter(db->mutex);
000079 db->xAuth = (sqlite3_xauth)xAuth;
000080 db->pAuthArg = pArg;
000081 if( db->xAuth ) sqlite3ExpirePreparedStatements(db, 1);
000082 sqlite3_mutex_leave(db->mutex);
000083 return SQLITE_OK;
000084 }
000085
000086 /*
000087 ** Write an error message into pParse->zErrMsg that explains that the
000088 ** user-supplied authorization function returned an illegal value.
000089 */
000090 static void sqliteAuthBadReturnCode(Parse *pParse){
000091 sqlite3ErrorMsg(pParse, "authorizer malfunction");
000092 pParse->rc = SQLITE_ERROR;
000093 }
000094
000095 /*
000096 ** Invoke the authorization callback for permission to read column zCol from
000097 ** table zTab in database zDb. This function assumes that an authorization
000098 ** callback has been registered (i.e. that sqlite3.xAuth is not NULL).
000099 **
000100 ** If SQLITE_IGNORE is returned and pExpr is not NULL, then pExpr is changed
000101 ** to an SQL NULL expression. Otherwise, if pExpr is NULL, then SQLITE_IGNORE
000102 ** is treated as SQLITE_DENY. In this case an error is left in pParse.
000103 */
000104 int sqlite3AuthReadCol(
000105 Parse *pParse, /* The parser context */
000106 const char *zTab, /* Table name */
000107 const char *zCol, /* Column name */
000108 int iDb /* Index of containing database. */
000109 ){
000110 sqlite3 *db = pParse->db; /* Database handle */
000111 char *zDb = db->aDb[iDb].zDbSName; /* Schema name of attached database */
000112 int rc; /* Auth callback return code */
000113
000114 if( db->init.busy ) return SQLITE_OK;
000115 rc = db->xAuth(db->pAuthArg, SQLITE_READ, zTab,zCol,zDb,pParse->zAuthContext
000116 #ifdef SQLITE_USER_AUTHENTICATION
000117 ,db->auth.zAuthUser
000118 #endif
000119 );
000120 if( rc==SQLITE_DENY ){
000121 char *z = sqlite3_mprintf("%s.%s", zTab, zCol);
000122 if( db->nDb>2 || iDb!=0 ) z = sqlite3_mprintf("%s.%z", zDb, z);
000123 sqlite3ErrorMsg(pParse, "access to %z is prohibited", z);
000124 pParse->rc = SQLITE_AUTH;
000125 }else if( rc!=SQLITE_IGNORE && rc!=SQLITE_OK ){
000126 sqliteAuthBadReturnCode(pParse);
000127 }
000128 return rc;
000129 }
000130
000131 /*
000132 ** The pExpr should be a TK_COLUMN expression. The table referred to
000133 ** is in pTabList or else it is the NEW or OLD table of a trigger.
000134 ** Check to see if it is OK to read this particular column.
000135 **
000136 ** If the auth function returns SQLITE_IGNORE, change the TK_COLUMN
000137 ** instruction into a TK_NULL. If the auth function returns SQLITE_DENY,
000138 ** then generate an error.
000139 */
000140 void sqlite3AuthRead(
000141 Parse *pParse, /* The parser context */
000142 Expr *pExpr, /* The expression to check authorization on */
000143 Schema *pSchema, /* The schema of the expression */
000144 SrcList *pTabList /* All table that pExpr might refer to */
000145 ){
000146 Table *pTab = 0; /* The table being read */
000147 const char *zCol; /* Name of the column of the table */
000148 int iSrc; /* Index in pTabList->a[] of table being read */
000149 int iDb; /* The index of the database the expression refers to */
000150 int iCol; /* Index of column in table */
000151
000152 assert( pExpr->op==TK_COLUMN || pExpr->op==TK_TRIGGER );
000153 assert( !IN_RENAME_OBJECT );
000154 assert( pParse->db->xAuth!=0 );
000155 iDb = sqlite3SchemaToIndex(pParse->db, pSchema);
000156 if( iDb<0 ){
000157 /* An attempt to read a column out of a subquery or other
000158 ** temporary table. */
000159 return;
000160 }
000161
000162 if( pExpr->op==TK_TRIGGER ){
000163 pTab = pParse->pTriggerTab;
000164 }else{
000165 assert( pTabList );
000166 for(iSrc=0; iSrc<pTabList->nSrc; iSrc++){
000167 if( pExpr->iTable==pTabList->a[iSrc].iCursor ){
000168 pTab = pTabList->a[iSrc].pTab;
000169 break;
000170 }
000171 }
000172 }
000173 iCol = pExpr->iColumn;
000174 if( pTab==0 ) return;
000175
000176 if( iCol>=0 ){
000177 assert( iCol<pTab->nCol );
000178 zCol = pTab->aCol[iCol].zCnName;
000179 }else if( pTab->iPKey>=0 ){
000180 assert( pTab->iPKey<pTab->nCol );
000181 zCol = pTab->aCol[pTab->iPKey].zCnName;
000182 }else{
000183 zCol = "ROWID";
000184 }
000185 assert( iDb>=0 && iDb<pParse->db->nDb );
000186 if( SQLITE_IGNORE==sqlite3AuthReadCol(pParse, pTab->zName, zCol, iDb) ){
000187 pExpr->op = TK_NULL;
000188 }
000189 }
000190
000191 /*
000192 ** Do an authorization check using the code and arguments given. Return
000193 ** either SQLITE_OK (zero) or SQLITE_IGNORE or SQLITE_DENY. If SQLITE_DENY
000194 ** is returned, then the error count and error message in pParse are
000195 ** modified appropriately.
000196 */
000197 int sqlite3AuthCheck(
000198 Parse *pParse,
000199 int code,
000200 const char *zArg1,
000201 const char *zArg2,
000202 const char *zArg3
000203 ){
000204 sqlite3 *db = pParse->db;
000205 int rc;
000206
000207 /* Don't do any authorization checks if the database is initializing
000208 ** or if the parser is being invoked from within sqlite3_declare_vtab.
000209 */
000210 assert( !IN_RENAME_OBJECT || db->xAuth==0 );
000211 if( db->xAuth==0 || db->init.busy || IN_SPECIAL_PARSE ){
000212 return SQLITE_OK;
000213 }
000214
000215 /* EVIDENCE-OF: R-43249-19882 The third through sixth parameters to the
000216 ** callback are either NULL pointers or zero-terminated strings that
000217 ** contain additional details about the action to be authorized.
000218 **
000219 ** The following testcase() macros show that any of the 3rd through 6th
000220 ** parameters can be either NULL or a string. */
000221 testcase( zArg1==0 );
000222 testcase( zArg2==0 );
000223 testcase( zArg3==0 );
000224 testcase( pParse->zAuthContext==0 );
000225
000226 rc = db->xAuth(db->pAuthArg, code, zArg1, zArg2, zArg3, pParse->zAuthContext
000227 #ifdef SQLITE_USER_AUTHENTICATION
000228 ,db->auth.zAuthUser
000229 #endif
000230 );
000231 if( rc==SQLITE_DENY ){
000232 sqlite3ErrorMsg(pParse, "not authorized");
000233 pParse->rc = SQLITE_AUTH;
000234 }else if( rc!=SQLITE_OK && rc!=SQLITE_IGNORE ){
000235 rc = SQLITE_DENY;
000236 sqliteAuthBadReturnCode(pParse);
000237 }
000238 return rc;
000239 }
000240
000241 /*
000242 ** Push an authorization context. After this routine is called, the
000243 ** zArg3 argument to authorization callbacks will be zContext until
000244 ** popped. Or if pParse==0, this routine is a no-op.
000245 */
000246 void sqlite3AuthContextPush(
000247 Parse *pParse,
000248 AuthContext *pContext,
000249 const char *zContext
000250 ){
000251 assert( pParse );
000252 pContext->pParse = pParse;
000253 pContext->zAuthContext = pParse->zAuthContext;
000254 pParse->zAuthContext = zContext;
000255 }
000256
000257 /*
000258 ** Pop an authorization context that was previously pushed
000259 ** by sqlite3AuthContextPush
000260 */
000261 void sqlite3AuthContextPop(AuthContext *pContext){
000262 if( pContext->pParse ){
000263 pContext->pParse->zAuthContext = pContext->zAuthContext;
000264 pContext->pParse = 0;
000265 }
000266 }
000267
000268 #endif /* SQLITE_OMIT_AUTHORIZATION */