Fix a bug affecting secure-delete mode introduced by (6768). (CVS 6773)

FossilOrigin-Name: a433ca821c134caeac0fa16416eb95c647416b95

manifest

@@ -1,5 +1,5 @@
-C Fix\sfor\s#3918.\sAlso,\sfix\sthe\sTRACE\smacros\sin\sbalance_nonroot().\s(CVS\s6772)
-D 2009-06-17T11:13:28
+C Fix\sa\sbug\saffecting\ssecure-delete\smode\sintroduced\sby\s(6768).\s(CVS\s6773)
+D 2009-06-17T11:49:53
 F Makefile.arm-wince-mingw32ce-gcc fcd5e9cd67fe88836360bb4f9ef4cb7f8e2fb5a0
 F Makefile.in 8b8fb7823264331210cddf103831816c286ba446
 F Makefile.linux-gcc d53183f4aa6a9192d249731c90dbdffbd2c68654
@@ -106,7 +106,7 @@ F src/auth.c 98db07c2088455797678eb1031f42d4d94d18a71
 F src/backup.c ff50af53184a5fd7bdee4d620b5dabef74717c79
 F src/bitvec.c 0ef0651714728055d43de7a4cdd95e703fac0119
 F src/btmutex.c 9b899c0d8df3bd68f527b0afe03088321b696d3c
-F src/btree.c 371458438e6436e02b50796edb124a8d0e51299f
+F src/btree.c 9225e0726c5837425dab4f5888ea427f8fa69854
 F src/btree.h f70b694e8c163227369a66863b01fbff9009f323
 F src/btreeInt.h df64030d632f8c8ac217ed52e8b6b3eacacb33a5
 F src/build.c 75b57e3f4de1b34d4e1e49d350dc87febff48ba0
@@ -735,7 +735,7 @@ F tool/speedtest2.tcl ee2149167303ba8e95af97873c575c3e0fab58ff
 F tool/speedtest8.c 2902c46588c40b55661e471d7a86e4dd71a18224
 F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e
 F tool/vdbe-compress.tcl 672f81d693a03f80f5ae60bfefacd8a349e76746
-P 18f2076ac21dd0ab343a79461837f5591f9d4d87
-R e09f9b7c30f5fb6a040ae5f6d3595072
+P 368e44ec2e648b04f3b817f82586ccd864e60c89
+R 444656ca6a3315a23012c708051029b1
 U danielk1977
-Z fa0237a4a1ebff673136562f4d6dd1cb
+Z d87ec3d960f446a07cb36cccdf89b502

manifest.uuid

@@ -1 +1 @@
-368e44ec2e648b04f3b817f82586ccd864e60c89
+a433ca821c134caeac0fa16416eb95c647416b95

src/btree.c

@@ -9,7 +9,7 @@
 **    May you share freely, never taking more than you give.
 **
 *************************************************************************
-** $Id: btree.c,v 1.631 2009/06/17 11:13:28 danielk1977 Exp $
+** $Id: btree.c,v 1.632 2009/06/17 11:49:53 danielk1977 Exp $
 **
 ** This file implements a external (disk-based) database using BTrees.
 ** See the header comment on "btreeInt.h" for additional information.
@@ -5423,6 +5423,10 @@ static int balance_nonroot(
   assert( pParent->nOverflow==0 || pParent->nOverflow==1 );
   assert( pParent->nOverflow==0 || pParent->aOvfl[0].idx==iParentIdx );
 
+  if( !aOvflSpace ){
+    return SQLITE_NOMEM;
+  }
+
   /* Find the sibling pages to balance. Also locate the cells in pParent 
   ** that divide the siblings. An attempt is made to find NN siblings on 
   ** either side of pPage. More siblings are taken from one side, however, 
@@ -5478,7 +5482,17 @@ static int balance_nonroot(
       ** This is safe because dropping a cell only overwrites the first
       ** four bytes of it, and this function does not need the first
       ** four bytes of the divider cell. So the pointer is safe to use
-      ** later on.  */
+      ** later on.  
+      **
+      ** Unless SQLite is compiled in secure-delete mode. In this case,
+      ** the dropCell() routine will overwrite the entire cell with zeroes.
+      ** In this case, temporarily copy the cell into the aOvflSpace[]
+      ** buffer. It will be copied out again as soon as the aSpace[] buffer
+      ** is allocated.  */
+#ifdef SQLITE_SECURE_DELETE
+      memcpy(&aOvflSpace[apDiv[i]-pParent->aData], apDiv[i], szNew[i]);
+      apDiv[i] = &aOvflSpace[apDiv[i]-pParent->aData];
+#endif
       dropCell(pParent, i+nxDiv-pParent->nOverflow, szNew[i]);
     }
   }
@@ -5497,7 +5511,7 @@ static int balance_nonroot(
      + pBt->pageSize                               /* aSpace1 */
      + k*nOld;                                     /* Page copies (apCopy) */
   apCell = sqlite3ScratchMalloc( szScratch ); 
-  if( apCell==0 || aOvflSpace==0 ){
+  if( apCell==0 ){
     rc = SQLITE_NOMEM;
     goto balance_cleanup;
   }