Fix a buffer overread during compilation of CREATE VIRTUAL TABLE statements that featured an explicit database name but no virtual table arguments. For example, "CREATE VIRTUAL TABLE main.ft USING fts4".

FossilOrigin-Name: f095cde579e7417306e11b5c1d2dd90b6bb547d5

manifest

@@ -1,5 +1,5 @@
-C More\stest\scases\sfor\sthe\sbalancer.
-D 2014-11-27T04:23:19.652
+C Fix\sa\sbuffer\soverread\sduring\scompilation\sof\sCREATE\sVIRTUAL\sTABLE\sstatements\sthat\sfeatured\san\sexplicit\sdatabase\sname\sbut\sno\svirtual\stable\sarguments.\sFor\sexample,\s"CREATE\sVIRTUAL\sTABLE\smain.ft\sUSING\sfts4".
+D 2014-11-27T11:36:36.295
 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
 F Makefile.in a226317fdf3f4c895fb3cfedc355b4d0868ce1fb
 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@ -238,7 +238,7 @@ F src/sqliteLimit.h 164b0e6749d31e0daa1a4589a169d31c0dec7b3d
 F src/status.c 81712116e826b0089bb221b018929536b2b5406f
 F src/table.c f142bba7903e93ca8d113a5b8877a108ad1a27dc
 F src/tclsqlite.c 0a874655dd39a9875e39c5d3c464db662171d228
-F src/test1.c 6b0469b8e06c77b1de1d3e4a3834cf26edea9cc7
+F src/test1.c a0bce4f47da65b76c80e5f8bf9a5ef174603866a
 F src/test2.c 98049e51a17dc62606a99a9eb95ee477f9996712
 F src/test3.c 1c0e5d6f080b8e33c1ce8b3078e7013fdbcd560c
 F src/test4.c 9b32d22f5f150abe23c1830e2057c4037c45b3df
@@ -300,7 +300,7 @@ F src/vdbeblob.c 4af4bfb71f6df7778397b4a0ebc1879793276778
 F src/vdbemem.c 31d8eabb0cd78bfeab4e5124c7363c3e9e54db9f
 F src/vdbesort.c 42c166f7ca78cb643c7f4e4bdfa83c59d363d1a6
 F src/vdbetrace.c 7e4222955e07dd707a2f360c0eb73452be1cb010
-F src/vtab.c 2a30791bbd7926b589401bd09c3abb33de563793
+F src/vtab.c c08ec66f45919eaa726bf88aa53eb08379d607f9
 F src/wal.c 486e644b3b8aa5ad066f625bc428aa8ff7001405
 F src/wal.h df01efe09c5cb8c8e391ff1715cca294f89668a4
 F src/walker.c c253b95b4ee44b21c406e2a1052636c31ea27804
@@ -1091,7 +1091,7 @@ F test/vacuum4.test d3f8ecff345f166911568f397d2432c16d2867d9
 F test/varint.test ab7b110089a08b9926ed7390e7e97bdefeb74102
 F test/veryquick.test 57ab846bacf7b90cf4e9a672721ea5c5b669b661
 F test/view.test f311691d696a5cc27e3c1b875cec1b0866b4ccd9
-F test/vtab1.test b631d147b198cfd7903ab5fed028eb2a3d321dc6
+F test/vtab1.test 1cef14310144718812351a61c5cfb4ba8494a171
 F test/vtab2.test 7bcffc050da5c68f4f312e49e443063e2d391c0d
 F test/vtab3.test b45f47d20f225ccc9c28dc915d92740c2dee311e
 F test/vtab4.test 942f8b8280b3ea8a41dae20e7822d065ca1cb275
@@ -1223,7 +1223,7 @@ F tool/vdbe_profile.tcl 67746953071a9f8f2f668b73fe899074e2c6d8c1
 F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
 F tool/warnings.sh 0abfd78ceb09b7f7c27c688c8e3fe93268a13b32
 F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
-P f242394e079dd185aad90f2aee902a5edf27e150
-R dee46347027ae53917346a5c99ff404e
-U drh
-Z 45538c84f085c10577fd84190398d06f
+P 358ea818f7ea5aa55bafaf4057e9fc7a5fd77c11
+R a4b8cae126976a974aa80f7f44ce5b7f
+U dan
+Z 67582253c41fc622f4b8d67b4605ed6a

manifest.uuid

@@ -1 +1 @@
-358ea818f7ea5aa55bafaf4057e9fc7a5fd77c11
+f095cde579e7417306e11b5c1d2dd90b6bb547d5

src/test1.c

@@ -3638,6 +3638,7 @@ static int test_prepare_v2(
 ){
   sqlite3 *db;
   const char *zSql;
+  char *zCopy = 0;                /* malloc() copy of zSql */
   int bytes;
   const char *zTail = 0;
   sqlite3_stmt *pStmt = 0;
@@ -3653,7 +3654,21 @@ static int test_prepare_v2(
   zSql = Tcl_GetString(objv[2]);
   if( Tcl_GetIntFromObj(interp, objv[3], &bytes) ) return TCL_ERROR;
 
-  rc = sqlite3_prepare_v2(db, zSql, bytes, &pStmt, objc>=5 ? &zTail : 0);
+  /* Instead of using zSql directly, make a copy into a buffer obtained
+  ** directly from malloc(). The idea is to make it easier for valgrind
+  ** to spot buffer overreads.  */
+  if( bytes>=0 ){
+    zCopy = malloc(bytes);
+    memcpy(zCopy, zSql, bytes);
+  }else{
+    int n = strlen(zSql) + 1;
+    zCopy = malloc(n);
+    memcpy(zCopy, zSql, n);
+  }
+  rc = sqlite3_prepare_v2(db, zCopy, bytes, &pStmt, objc>=5 ? &zTail : 0);
+  free(zCopy);
+  zTail = &zSql[(zTail - zCopy)];
+
   assert(rc==SQLITE_OK || pStmt==0);
   Tcl_ResetResult(interp);
   if( sqlite3TestErrCode(interp, db, rc) ) return TCL_ERROR;

src/vtab.c

@@ -332,7 +332,12 @@ void sqlite3VtabBeginParse(
   addModuleArgument(db, pTable, sqlite3NameFromToken(db, pModuleName));
   addModuleArgument(db, pTable, 0);
   addModuleArgument(db, pTable, sqlite3DbStrDup(db, pTable->zName));
-  pParse->sNameToken.n = (int)(&pModuleName->z[pModuleName->n] - pName1->z);
+  assert( (pParse->sNameToken.z==pName2->z && pName2->z!=0)
+       || (pParse->sNameToken.z==pName1->z && pName2->z==0)
+  );
+  pParse->sNameToken.n = (int)(
+      &pModuleName->z[pModuleName->n] - pParse->sNameToken.z
+  );
 
 #ifndef SQLITE_OMIT_AUTHORIZATION
   /* Creating a virtual table invokes the authorization callback twice.

test/vtab1.test

@@ -1395,4 +1395,46 @@ do_execsql_test 21.3 {
   SELECT * FROM t9v WHERE a=b;
 } {2 2 2}
 
+#-------------------------------------------------------------------------
+# At one point executing a CREATE VIRTUAL TABLE statement that specified 
+# a database name but no virtual table arguments was causing an internal
+# buffer overread. Valgrind would report errors while running the following 
+# tests. Specifically:
+#
+#   CREATE VIRTUAL TABLE t1 USING fts4;          -- Ok - no db name.
+#   CREATE VIRTUAL TABLE main.t1 USING fts4(x);  -- Ok - has vtab arguments.
+#   CREATE VIRTUAL TABLE main.t1 USING fts4;     -- Had the problem. 
+#
+ifcapable fts3 {
+  forcedelete test.db2
+  set nm [string repeat abcdefghij 100]
+  do_execsql_test 22.1 {
+    ATTACH 'test.db2' AS $nm
+  }
+  
+  execsql "SELECT * FROM sqlite_master"
+  do_execsql_test 22.2 "CREATE VIRTUAL TABLE ${nm}.t1 USING fts4"
+  
+  do_test 22.3.1 {
+    set sql "CREATE VIRTUAL TABLE ${nm}.t2 USING fts4"
+    set stmt [sqlite3_prepare_v2 db $sql -1 dummy]
+    sqlite3_step $stmt
+  } {SQLITE_DONE}
+  
+  do_test 22.3.2 {
+    sqlite3_finalize $stmt
+  } {SQLITE_OK}
+  
+  do_test 22.4.1 {
+    set sql "CREATE VIRTUAL TABLE ${nm}.t3 USING fts4"
+    set n [string length $sql]
+    set stmt [sqlite3_prepare db "${sql}xyz" $n dummy]
+    sqlite3_step $stmt
+  } {SQLITE_DONE}
+  
+  do_test 22.4.2 {
+    sqlite3_finalize $stmt
+  } {SQLITE_OK}
+}
+
 finish_test