test/fuzzinvariants.c

   1 /*
   2 ** 2022-06-14
   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 **
  13 ** This library is used by fuzzcheck to test query invariants.
  14 **
  15 ** An sqlite3_stmt is passed in that has just returned SQLITE_ROW.  This
  16 ** routine does:
  17 **
  18 **     *   Record the output of the current row
  19 **     *   Construct an alternative query that should return the same row
  20 **     *   Run the alternative query and verify that it does in fact return
  21 **         the same row
  22 **
  23 */
  24 #include "sqlite3.h"
  25 #include <stdio.h>
  26 #include <stdlib.h>
  27 #include <string.h>
  28 #include <ctype.h>
  29
  30 /* Forward references */
  31 static char *fuzz_invariant_sql(sqlite3_stmt*, int);
  32 static int sameValue(sqlite3_stmt*,int,sqlite3_stmt*,int,sqlite3_stmt*);
  33 static void reportInvariantFailed(sqlite3_stmt*,sqlite3_stmt*,int);
  34
  35 /*
  36 ** Do an invariant check on pStmt.  iCnt determines which invariant check to
  37 ** perform.  The first check is iCnt==0.
  38 **
  39 ** *pbCorrupt is a flag that, if true, indicates that the database file
  40 ** is known to be corrupt.  A value of non-zero means "yes, the database
  41 ** is corrupt".  A zero value means "we do not know whether or not the
  42 ** database is corrupt".  The value might be set prior to entry, or this
  43 ** routine might set the value.
  44 **
  45 ** Return values:
  46 **
  47 **     SQLITE_OK          This check was successful.
  48 **
  49 **     SQLITE_DONE        iCnt is out of range.  The caller typically sets
  50 **                        up a loop on iCnt starting with zero, and increments
  51 **                        iCnt until this code is returned.
  52 **
  53 **     SQLITE_CORRUPT     The invariant failed, but the underlying database
  54 **                        file is indicating that it is corrupt, which might
  55 **                        be the cause of the malfunction.  The *pCorrupt
  56 **                        value will also be set.
  57 **
  58 **     SQLITE_INTERNAL    The invariant failed, and the database file is not
  59 **                        corrupt.  (This never happens because this function
  60 **                        will call abort() following an invariant failure.)
  61 **
  62 **     (other)            Some other kind of error occurred.
  63 */
  64 int fuzz_invariant(
  65   sqlite3 *db,            /* The database connection */
  66   sqlite3_stmt *pStmt,    /* Test statement stopped on an SQLITE_ROW */
  67   int iCnt,               /* Invariant sequence number, starting at 0 */
  68   int iRow,               /* Current row number */
  69   int nRow,               /* Number of output rows from pStmt */
  70   int *pbCorrupt,         /* IN/OUT: Flag indicating a corrupt database file */
  71   int eVerbosity          /* How much debugging output */
  72 ){
  73   char *zTest;
  74   sqlite3_stmt *pTestStmt = 0;
  75   int rc;
  76   int i;
  77   int nCol;
  78   int nParam;
  79
  80   if( *pbCorrupt ) return SQLITE_DONE;
  81   nParam = sqlite3_bind_parameter_count(pStmt);
  82   if( nParam>100 ) return SQLITE_DONE;
  83   zTest = fuzz_invariant_sql(pStmt, iCnt);
  84   if( zTest==0 ) return SQLITE_DONE;
  85   rc = sqlite3_prepare_v2(db, zTest, -1, &pTestStmt, 0);
  86   if( rc ){
  87     if( eVerbosity ){
  88       printf("invariant compile failed: %s\n%s\n",
  89              sqlite3_errmsg(db), zTest);
  90     }
  91     sqlite3_free(zTest);
  92     sqlite3_finalize(pTestStmt);
  93     return rc;
  94   }
  95   sqlite3_free(zTest);
  96   nCol = sqlite3_column_count(pStmt);
  97   for(i=0; i<nCol; i++){
  98     rc = sqlite3_bind_value(pTestStmt,i+1+nParam,sqlite3_column_value(pStmt,i));
  99     if( rc!=SQLITE_OK && rc!=SQLITE_RANGE ){
 100       sqlite3_finalize(pTestStmt);
 101       return rc;
 102     }
 103   }
 104   if( eVerbosity>=2 ){
 105     char *zSql = sqlite3_expanded_sql(pTestStmt);
 106     printf("invariant-sql #%d:\n%s\n", iCnt, zSql);
 107     sqlite3_free(zSql);
 108   }
 109   while( (rc = sqlite3_step(pTestStmt))==SQLITE_ROW ){
 110     for(i=0; i<nCol; i++){
 111       if( !sameValue(pStmt, i, pTestStmt, i, 0) ) break;
 112     }
 113     if( i>=nCol ) break;
 114   }
 115   if( rc==SQLITE_DONE ){
 116     /* No matching output row found */
 117     sqlite3_stmt *pCk = 0;
 118
 119     /* This is not a fault if the database file is corrupt, because anything
 120     ** can happen with a corrupt database file */
 121     rc = sqlite3_prepare_v2(db, "PRAGMA integrity_check", -1, &pCk, 0);
 122     if( rc ){
 123       sqlite3_finalize(pCk);
 124       sqlite3_finalize(pTestStmt);
 125       return rc;
 126     }
 127     rc = sqlite3_step(pCk);
 128     if( rc!=SQLITE_ROW
 129      || sqlite3_column_text(pCk, 0)==0
 130      || strcmp((const char*)sqlite3_column_text(pCk,0),"ok")!=0
 131     ){
 132       *pbCorrupt = 1;
 133       sqlite3_finalize(pCk);
 134       sqlite3_finalize(pTestStmt);
 135       return SQLITE_CORRUPT;
 136     }
 137     sqlite3_finalize(pCk);
 138
 139     if( sqlite3_strlike("%group%by%order%by%desc%",sqlite3_sql(pStmt),0)==0 ){
 140       /* dbsqlfuzz crash-647c162051c9b23ce091b7bbbe5125ce5f00e922
 141       ** Original statement is:
 142       **
 143       **    SELECT a,c,d,b,'' FROM t1 GROUP BY 1 HAVING d<>345 ORDER BY a DESC;
 144       **
 145       ** The values of c, d, and b are indeterminate and change when the
 146       ** enclosed in the test query because the DESC is dropped.
 147       **
 148       **    SELECT * FROM (...) WHERE "a"==0
 149       */
 150       goto not_a_fault;
 151     }
 152
 153     if( sqlite3_strlike("%limit%)%order%by%", sqlite3_sql(pTestStmt),0)==0 ){
 154       /* crash-89bd6a6f8c6166e9a4c5f47b3e70b225f69b76c6
 155       ** Original statement is:
 156       **
 157       **    SELECT a,b,c* FROM t1 LIMIT 1%5<4
 158       **
 159       ** When running:
 160       **
 161       **    SELECT * FROM (...) ORDER BY 1
 162       **
 163       ** A different subset of the rows come out
 164       */
 165       goto not_a_fault;
 166     }
 167
 168     /* The original sameValue() comparison assumed a collating sequence
 169     ** of "binary".  It can sometimes get an incorrect result for different
 170     ** collating sequences.  So rerun the test with no assumptions about
 171     ** collations.
 172     */
 173     rc = sqlite3_prepare_v2(db,
 174        "SELECT ?1=?2 OR ?1=?2 COLLATE nocase OR ?1=?2 COLLATE rtrim",
 175        -1, &pCk, 0);
 176     if( rc==SQLITE_OK ){
 177       sqlite3_reset(pTestStmt);
 178       while( (rc = sqlite3_step(pTestStmt))==SQLITE_ROW ){
 179         for(i=0; i<nCol; i++){
 180           if( !sameValue(pStmt, i, pTestStmt, i, pCk) ) break;
 181         }
 182         if( i>=nCol ){
 183           sqlite3_finalize(pCk);
 184           goto not_a_fault;
 185         }
 186       }
 187     }
 188     sqlite3_finalize(pCk);
 189
 190     /* Invariants do not necessarily work if there are virtual tables
 191     ** involved in the query */
 192     rc = sqlite3_prepare_v2(db,
 193             "SELECT 1 FROM bytecode(?1) WHERE opcode='VOpen'", -1, &pCk, 0);
 194     if( rc==SQLITE_OK ){
 195       sqlite3_bind_pointer(pCk, 1, pStmt, "stmt-pointer", 0);
 196       rc = sqlite3_step(pCk);
 197     }
 198     sqlite3_finalize(pCk);
 199     if( rc==SQLITE_DONE ){
 200       reportInvariantFailed(pStmt, pTestStmt, iRow);
 201       return SQLITE_INTERNAL;
 202     }else if( eVerbosity>0 ){
 203       printf("invariant-error ignored due to the use of virtual tables\n");
 204     }
 205   }
 206 not_a_fault:
 207   sqlite3_finalize(pTestStmt);
 208   return SQLITE_OK;
 209 }
 210
 211
 212 /*
 213 ** Generate SQL used to test a statement invariant.
 214 **
 215 ** Return 0 if the iCnt is out of range.
 216 **
 217 ** iCnt meanings:
 218 **
 219 **   0     SELECT * FROM (<query>)
 220 **   1     SELECT DISTINCT * FROM (<query>)
 221 **   2     SELECT * FROM (<query>) WHERE ORDER BY 1
 222 **   3     SELECT DISTINCT * FROM (<query>) ORDER BY 1
 223 **   4     SELECT * FROM (<query>) WHERE <all-columns>=<all-values>
 224 **   5     SELECT DISTINCT * FROM (<query>) WHERE <all-columns=<all-values
 225 **   6     SELECT * FROM (<query>) WHERE <all-column>=<all-value> ORDER BY 1
 226 **   7     SELECT DISTINCT * FROM (<query>) WHERE <all-column>=<all-value>
 227 **                           ORDER BY 1
 228 **   N+0   SELECT * FROM (<query>) WHERE <nth-column>=<value>
 229 **   N+1   SELECT DISTINCT * FROM (<query>) WHERE <Nth-column>=<value>
 230 **   N+2   SELECT * FROM (<query>) WHERE <Nth-column>=<value> ORDER BY 1
 231 **   N+3   SELECT DISTINCT * FROM (<query>) WHERE <Nth-column>=<value>
 232 **                           ORDER BY N
 233 **
 234 */
 235 static char *fuzz_invariant_sql(sqlite3_stmt *pStmt, int iCnt){
 236   const char *zIn;
 237   size_t nIn;
 238   const char *zAnd = "WHERE";
 239   int i;
 240   sqlite3_str *pTest;
 241   sqlite3_stmt *pBase = 0;
 242   sqlite3 *db = sqlite3_db_handle(pStmt);
 243   int rc;
 244   int nCol = sqlite3_column_count(pStmt);
 245   int mxCnt;
 246   int bDistinct = 0;
 247   int bOrderBy = 0;
 248   int nParam = sqlite3_bind_parameter_count(pStmt);
 249
 250   switch( iCnt % 4 ){
 251     case 1:  bDistinct = 1;              break;
 252     case 2:  bOrderBy = 1;               break;
 253     case 3:  bDistinct = bOrderBy = 1;   break;
 254   }
 255   iCnt /= 4;
 256   mxCnt = nCol;
 257   if( iCnt<0 || iCnt>mxCnt ) return 0;
 258   zIn = sqlite3_sql(pStmt);
 259   if( zIn==0 ) return 0;
 260   nIn = strlen(zIn);
 261   while( nIn>0 && (isspace(zIn[nIn-1]) || zIn[nIn-1]==';') ) nIn--;
 262   if( strchr(zIn, '?') ) return 0;
 263   pTest = sqlite3_str_new(0);
 264   sqlite3_str_appendf(pTest, "SELECT %s* FROM (",
 265                       bDistinct ? "DISTINCT " : "");
 266   sqlite3_str_append(pTest, zIn, (int)nIn);
 267   sqlite3_str_append(pTest, ")", 1);
 268   rc = sqlite3_prepare_v2(db, sqlite3_str_value(pTest), -1, &pBase, 0);
 269   if( rc ){
 270     sqlite3_finalize(pBase);
 271     pBase = pStmt;
 272   }
 273   for(i=0; i<sqlite3_column_count(pStmt); i++){
 274     const char *zColName = sqlite3_column_name(pBase,i);
 275     const char *zSuffix = zColName ? strrchr(zColName, ':') : 0;
 276     if( zSuffix
 277      && isdigit(zSuffix[1])
 278      && (zSuffix[1]>'3' || isdigit(zSuffix[2]))
 279     ){
 280       /* This is a randomized column name and so cannot be used in the
 281       ** WHERE clause. */
 282       continue;
 283     }
 284     if( iCnt==0 ) continue;
 285     if( iCnt>1 && i+2!=iCnt ) continue;
 286     if( zColName==0 ) continue;
 287     if( sqlite3_column_type(pStmt, i)==SQLITE_NULL ){
 288       sqlite3_str_appendf(pTest, " %s \"%w\" ISNULL", zAnd, zColName);
 289     }else{
 290       sqlite3_str_appendf(pTest, " %s \"%w\"=?%d", zAnd, zColName,
 291                           i+1+nParam);
 292     }
 293     zAnd = "AND";
 294   }
 295   if( pBase!=pStmt ) sqlite3_finalize(pBase);
 296   if( bOrderBy ){
 297     sqlite3_str_appendf(pTest, " ORDER BY %d", iCnt>2 ? iCnt-1 : 1);
 298   }
 299   return sqlite3_str_finish(pTest);
 300 }
 301
 302 /*
 303 ** Return true if and only if v1 and is the same as v2.
 304 */
 305 static int sameValue(
 306   sqlite3_stmt *pS1, int i1,       /* Value to text on the left */
 307   sqlite3_stmt *pS2, int i2,       /* Value to test on the right */
 308   sqlite3_stmt *pTestCompare       /* COLLATE comparison statement or NULL */
 309 ){
 310   int x = 1;
 311   int t1 = sqlite3_column_type(pS1,i1);
 312   int t2 = sqlite3_column_type(pS2,i2);
 313   if( t1!=t2 ){
 314     if( (t1==SQLITE_INTEGER && t2==SQLITE_FLOAT)
 315      || (t1==SQLITE_FLOAT && t2==SQLITE_INTEGER)
 316     ){
 317       /* Comparison of numerics is ok */
 318     }else{
 319       return 0;
 320     }
 321   }
 322   switch( sqlite3_column_type(pS1,i1) ){
 323     case SQLITE_INTEGER: {
 324       x =  sqlite3_column_int64(pS1,i1)==sqlite3_column_int64(pS2,i2);
 325       break;
 326     }
 327     case SQLITE_FLOAT: {
 328       x = sqlite3_column_double(pS1,i1)==sqlite3_column_double(pS2,i2);
 329       break;
 330     }
 331     case SQLITE_TEXT: {
 332       int e1 = sqlite3_value_encoding(sqlite3_column_value(pS1,i1));
 333       int e2 = sqlite3_value_encoding(sqlite3_column_value(pS2,i2));
 334       if( e1!=e2 ){
 335         const char *z1 = (const char*)sqlite3_column_text(pS1,i1);
 336         const char *z2 = (const char*)sqlite3_column_text(pS2,i2);
 337         x = ((z1==0 && z2==0) || (z1!=0 && z2!=0 && strcmp(z1,z1)==0));
 338         printf("Encodings differ.  %d on left and %d on right\n", e1, e2);
 339         abort();
 340       }
 341       if( pTestCompare ){
 342         sqlite3_bind_value(pTestCompare, 1, sqlite3_column_value(pS1,i1));
 343         sqlite3_bind_value(pTestCompare, 2, sqlite3_column_value(pS2,i2));
 344         x = sqlite3_step(pTestCompare)==SQLITE_ROW
 345                       && sqlite3_column_int(pTestCompare,0)!=0;
 346         sqlite3_reset(pTestCompare);
 347         break;
 348       }
 349       if( e1!=SQLITE_UTF8 ){
 350         int len1 = sqlite3_column_bytes16(pS1,i1);
 351         const unsigned char *b1 = sqlite3_column_blob(pS1,i1);
 352         int len2 = sqlite3_column_bytes16(pS2,i2);
 353         const unsigned char *b2 = sqlite3_column_blob(pS2,i2);
 354         if( len1!=len2 ){
 355           x = 0;
 356         }else if( len1==0 ){
 357           x = 1;
 358         }else{
 359           x = (b1!=0 && b2!=0 && memcmp(b1,b2,len1)==0);
 360         }
 361         break;
 362       }
 363       /* Fall through into the SQLITE_BLOB case */
 364     }
 365     case SQLITE_BLOB: {
 366       int len1 = sqlite3_column_bytes(pS1,i1);
 367       const unsigned char *b1 = sqlite3_column_blob(pS1,i1);
 368       int len2 = sqlite3_column_bytes(pS2,i2);
 369       const unsigned char *b2 = sqlite3_column_blob(pS2,i2);
 370       if( len1!=len2 ){
 371         x = 0;
 372       }else if( len1==0 ){
 373         x = 1;
 374       }else{
 375         x = (b1!=0 && b2!=0 && memcmp(b1,b2,len1)==0);
 376       }
 377       break;
 378     }
 379   }
 380   return x;
 381 }
 382
 383 /*
 384 ** Print binary data as hex
 385 */
 386 static void printHex(const unsigned char *a, int n, int mx){
 387   int j;
 388   for(j=0; j<mx && j<n; j++){
 389     printf("%02x", a[j]);
 390   }
 391   if( j<n ) printf("...");
 392 }
 393
 394 /*
 395 ** Print a single row from the prepared statement
 396 */
 397 static void printRow(sqlite3_stmt *pStmt, int iRow){
 398   int i, n, nCol;
 399   unsigned const char *data;
 400   nCol = sqlite3_column_count(pStmt);
 401   for(i=0; i<nCol; i++){
 402     printf("row%d.col%d = ", iRow, i);
 403     switch( sqlite3_column_type(pStmt, i) ){
 404       case SQLITE_NULL: {
 405         printf("NULL\n");
 406         break;
 407       }
 408       case SQLITE_INTEGER: {
 409         printf("(integer) %lld\n", sqlite3_column_int64(pStmt, i));
 410         break;
 411       }
 412       case SQLITE_FLOAT: {
 413         printf("(float) %f\n", sqlite3_column_double(pStmt, i));
 414         break;
 415       }
 416       case SQLITE_TEXT: {
 417         switch( sqlite3_value_encoding(sqlite3_column_value(pStmt,i)) ){
 418           case SQLITE_UTF8: {
 419             printf("(utf8) x'");
 420             n = sqlite3_column_bytes(pStmt, i);
 421             data = sqlite3_column_blob(pStmt, i);
 422             printHex(data, n, 35);
 423             printf("'\n");
 424             break;
 425           }
 426           case SQLITE_UTF16BE: {
 427             printf("(utf16be) x'");
 428             n = sqlite3_column_bytes16(pStmt, i);
 429             data = sqlite3_column_blob(pStmt, i);
 430             printHex(data, n, 35);
 431             printf("'\n");
 432             break;
 433           }
 434           case SQLITE_UTF16LE: {
 435             printf("(utf16le) x'");
 436             n = sqlite3_column_bytes16(pStmt, i);
 437             data = sqlite3_column_blob(pStmt, i);
 438             printHex(data, n, 35);
 439             printf("'\n");
 440             break;
 441           }
 442           default: {
 443             printf("Illegal return from sqlite3_value_encoding(): %d\n",
 444                 sqlite3_value_encoding(sqlite3_column_value(pStmt,i)));
 445             abort();
 446           }
 447         }
 448         break;
 449       }
 450       case SQLITE_BLOB: {
 451         n = sqlite3_column_bytes(pStmt, i);
 452         data = sqlite3_column_blob(pStmt, i);
 453         printf("(blob %d bytes) x'", n);
 454         printHex(data, n, 35);
 455         printf("'\n");
 456         break;
 457       }
 458     }
 459   }
 460 }
 461
 462 /*
 463 ** Report a failure of the invariant:  The current output row of pOrig
 464 ** does not appear in any row of the output from pTest.
 465 */
 466 static void reportInvariantFailed(
 467   sqlite3_stmt *pOrig,   /* The original query */
 468   sqlite3_stmt *pTest,   /* The alternative test query with a missing row */
 469   int iRow               /* Row number in pOrig */
 470 ){
 471   int iTestRow = 0;
 472   printf("Invariant check failed on row %d.\n", iRow);
 473   printf("Original query --------------------------------------------------\n");
 474   printf("%s\n", sqlite3_expanded_sql(pOrig));
 475   printf("Alternative query -----------------------------------------------\n");
 476   printf("%s\n", sqlite3_expanded_sql(pTest));
 477   printf("Result row that is missing from the alternative -----------------\n");
 478   printRow(pOrig, iRow);
 479   printf("Complete results from the alternative query ---------------------\n");
 480   sqlite3_reset(pTest);
 481   while( sqlite3_step(pTest)==SQLITE_ROW ){
 482     iTestRow++;
 483     printRow(pTest, iTestRow);
 484   }
 485   sqlite3_finalize(pTest);
 486   abort();
 487 }