1
2#pragma ident	"%Z%%M%	%I%	%E% SMI"
3
4/*
5** 2003 January 11
6**
7** The author disclaims copyright to this source code.  In place of
8** a legal notice, here is a blessing:
9**
10**    May you do good and not evil.
11**    May you find forgiveness for yourself and forgive others.
12**    May you share freely, never taking more than you give.
13**
14*************************************************************************
15** This file contains code used to implement the sqlite_set_authorizer()
16** API.  This facility is an optional feature of the library.  Embedded
17** systems that do not need this facility may omit it by recompiling
18** the library with -DSQLITE_OMIT_AUTHORIZATION=1
19**
20** $Id: auth.c,v 1.12.2.1 2004/06/14 11:58:37 drh Exp $
21*/
22#include "sqliteInt.h"
23
24/*
25** All of the code in this file may be omitted by defining a single
26** macro.
27*/
28#ifndef SQLITE_OMIT_AUTHORIZATION
29
30/*
31** Set or clear the access authorization function.
32**
33** The access authorization function is be called during the compilation
34** phase to verify that the user has read and/or write access permission on
35** various fields of the database.  The first argument to the auth function
36** is a copy of the 3rd argument to this routine.  The second argument
37** to the auth function is one of these constants:
38**
39**       SQLITE_COPY
40**       SQLITE_CREATE_INDEX
41**       SQLITE_CREATE_TABLE
42**       SQLITE_CREATE_TEMP_INDEX
43**       SQLITE_CREATE_TEMP_TABLE
44**       SQLITE_CREATE_TEMP_TRIGGER
45**       SQLITE_CREATE_TEMP_VIEW
46**       SQLITE_CREATE_TRIGGER
47**       SQLITE_CREATE_VIEW
48**       SQLITE_DELETE
49**       SQLITE_DROP_INDEX
50**       SQLITE_DROP_TABLE
51**       SQLITE_DROP_TEMP_INDEX
52**       SQLITE_DROP_TEMP_TABLE
53**       SQLITE_DROP_TEMP_TRIGGER
54**       SQLITE_DROP_TEMP_VIEW
55**       SQLITE_DROP_TRIGGER
56**       SQLITE_DROP_VIEW
57**       SQLITE_INSERT
58**       SQLITE_PRAGMA
59**       SQLITE_READ
60**       SQLITE_SELECT
61**       SQLITE_TRANSACTION
62**       SQLITE_UPDATE
63**
64** The third and fourth arguments to the auth function are the name of
65** the table and the column that are being accessed.  The auth function
66** should return either SQLITE_OK, SQLITE_DENY, or SQLITE_IGNORE.  If
67** SQLITE_OK is returned, it means that access is allowed.  SQLITE_DENY
68** means that the SQL statement will never-run - the sqlite_exec() call
69** will return with an error.  SQLITE_IGNORE means that the SQL statement
70** should run but attempts to read the specified column will return NULL
71** and attempts to write the column will be ignored.
72**
73** Setting the auth function to NULL disables this hook.  The default
74** setting of the auth function is NULL.
75*/
76int sqlite_set_authorizer(
77  sqlite *db,
78  int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
79  void *pArg
80){
81  db->xAuth = xAuth;
82  db->pAuthArg = pArg;
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, int rc){
91  sqliteErrorMsg(pParse, "illegal return value (%d) from the "
92    "authorization function - should be SQLITE_OK, SQLITE_IGNORE, "
93    "or SQLITE_DENY", rc);
94  pParse->rc = SQLITE_MISUSE;
95}
96
97/*
98** The pExpr should be a TK_COLUMN expression.  The table referred to
99** is in pTabList or else it is the NEW or OLD table of a trigger.
100** Check to see if it is OK to read this particular column.
101**
102** If the auth function returns SQLITE_IGNORE, change the TK_COLUMN
103** instruction into a TK_NULL.  If the auth function returns SQLITE_DENY,
104** then generate an error.
105*/
106void sqliteAuthRead(
107  Parse *pParse,        /* The parser context */
108  Expr *pExpr,          /* The expression to check authorization on */
109  SrcList *pTabList     /* All table that pExpr might refer to */
110){
111  sqlite *db = pParse->db;
112  int rc;
113  Table *pTab;          /* The table being read */
114  const char *zCol;     /* Name of the column of the table */
115  int iSrc;             /* Index in pTabList->a[] of table being read */
116  const char *zDBase;   /* Name of database being accessed */
117
118  if( db->xAuth==0 ) return;
119  assert( pExpr->op==TK_COLUMN );
120  for(iSrc=0; iSrc<pTabList->nSrc; iSrc++){
121    if( pExpr->iTable==pTabList->a[iSrc].iCursor ) break;
122  }
123  if( iSrc>=0 && iSrc<pTabList->nSrc ){
124    pTab = pTabList->a[iSrc].pTab;
125  }else{
126    /* This must be an attempt to read the NEW or OLD pseudo-tables
127    ** of a trigger.
128    */
129    TriggerStack *pStack; /* The stack of current triggers */
130    pStack = pParse->trigStack;
131    assert( pStack!=0 );
132    assert( pExpr->iTable==pStack->newIdx || pExpr->iTable==pStack->oldIdx );
133    pTab = pStack->pTab;
134  }
135  if( pTab==0 ) return;
136  if( pExpr->iColumn>=0 ){
137    assert( pExpr->iColumn<pTab->nCol );
138    zCol = pTab->aCol[pExpr->iColumn].zName;
139  }else if( pTab->iPKey>=0 ){
140    assert( pTab->iPKey<pTab->nCol );
141    zCol = pTab->aCol[pTab->iPKey].zName;
142  }else{
143    zCol = "ROWID";
144  }
145  assert( pExpr->iDb<db->nDb );
146  zDBase = db->aDb[pExpr->iDb].zName;
147  rc = db->xAuth(db->pAuthArg, SQLITE_READ, pTab->zName, zCol, zDBase,
148                 pParse->zAuthContext);
149  if( rc==SQLITE_IGNORE ){
150    pExpr->op = TK_NULL;
151  }else if( rc==SQLITE_DENY ){
152    if( db->nDb>2 || pExpr->iDb!=0 ){
153      sqliteErrorMsg(pParse, "access to %s.%s.%s is prohibited",
154         zDBase, pTab->zName, zCol);
155    }else{
156      sqliteErrorMsg(pParse, "access to %s.%s is prohibited", pTab->zName,zCol);
157    }
158    pParse->rc = SQLITE_AUTH;
159  }else if( rc!=SQLITE_OK ){
160    sqliteAuthBadReturnCode(pParse, rc);
161  }
162}
163
164/*
165** Do an authorization check using the code and arguments given.  Return
166** either SQLITE_OK (zero) or SQLITE_IGNORE or SQLITE_DENY.  If SQLITE_DENY
167** is returned, then the error count and error message in pParse are
168** modified appropriately.
169*/
170int sqliteAuthCheck(
171  Parse *pParse,
172  int code,
173  const char *zArg1,
174  const char *zArg2,
175  const char *zArg3
176){
177  sqlite *db = pParse->db;
178  int rc;
179
180  if( db->init.busy || db->xAuth==0 ){
181    return SQLITE_OK;
182  }
183  rc = db->xAuth(db->pAuthArg, code, zArg1, zArg2, zArg3, pParse->zAuthContext);
184  if( rc==SQLITE_DENY ){
185    sqliteErrorMsg(pParse, "not authorized");
186    pParse->rc = SQLITE_AUTH;
187  }else if( rc!=SQLITE_OK && rc!=SQLITE_IGNORE ){
188    rc = SQLITE_DENY;
189    sqliteAuthBadReturnCode(pParse, rc);
190  }
191  return rc;
192}
193
194/*
195** Push an authorization context.  After this routine is called, the
196** zArg3 argument to authorization callbacks will be zContext until
197** popped.  Or if pParse==0, this routine is a no-op.
198*/
199void sqliteAuthContextPush(
200  Parse *pParse,
201  AuthContext *pContext,
202  const char *zContext
203){
204  pContext->pParse = pParse;
205  if( pParse ){
206    pContext->zAuthContext = pParse->zAuthContext;
207    pParse->zAuthContext = zContext;
208  }
209}
210
211/*
212** Pop an authorization context that was previously pushed
213** by sqliteAuthContextPush
214*/
215void sqliteAuthContextPop(AuthContext *pContext){
216  if( pContext->pParse ){
217    pContext->pParse->zAuthContext = pContext->zAuthContext;
218    pContext->pParse = 0;
219  }
220}
221
222#endif /* SQLITE_OMIT_AUTHORIZATION */
223