Add a NEVER() on an always-false conditional in pager.c.

Make sure the text of the master journal file is zero-terminated before
trying to process it - to prevent a buffer overrun in strlen(). (CVS 6937)

FossilOrigin-Name: cc9430e334fe98e1c35d408f81a2d8953377cda6

manifest

@@ -1,5 +1,5 @@
-C Remove\sthe\s"proc\szeroblob"\simplementation\sfrom\sincrvacuum2.test.\sIt\sis\sno\slonger\srequired\sas\sof\s(6906)\sand,\sas\s#3988\spoints\sout,\sunreliable.\s(CVS\s6936)
-D 2009-07-25T13:42:50
+C Add\sa\sNEVER()\son\san\salways-false\sconditional\sin\spager.c.\nMake\ssure\sthe\stext\sof\sthe\smaster\sjournal\sfile\sis\szero-terminated\sbefore\ntrying\sto\sprocess\sit\s-\sto\sprevent\sa\sbuffer\soverrun\sin\sstrlen().\s(CVS\s6937)
+D 2009-07-25T14:18:57
 F Makefile.arm-wince-mingw32ce-gcc fcd5e9cd67fe88836360bb4f9ef4cb7f8e2fb5a0
 F Makefile.in df9359da7a726ccb67a45db905c5447d5c00c6ef
 F Makefile.linux-gcc d53183f4aa6a9192d249731c90dbdffbd2c68654
@@ -147,7 +147,7 @@ F src/os_common.h 8c61457df58f1a4bd5f5adc3e90e01b37bf7afbc
 F src/os_os2.c bed77dc26e3a95ce4a204936b9a1ca6fe612fcc5
 F src/os_unix.c cdb2a08b9ce4aa13b3f7b91d4dd60fb48be9f56a
 F src/os_win.c 725c38a524d168ce280446ad8761d731bc516405
-F src/pager.c 2ccb1152741996d3f6125232f14dfcf654bdd29f
+F src/pager.c 23c9823d72b0213d7cbf3ca6e5aeb9735b467d5d
 F src/pager.h 11852d044c86cf5a9d6e34171fb0c4fcf1f6265f
 F src/parse.y bcd46d43fbd23a22b8c020a3eb1806b794794ed5
 F src/pcache.c c92ffd4f3e1279b3766854c6d18b5bf4aac0d1fa
@@ -738,7 +738,7 @@ F tool/speedtest2.tcl ee2149167303ba8e95af97873c575c3e0fab58ff
 F tool/speedtest8.c 2902c46588c40b55661e471d7a86e4dd71a18224
 F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e
 F tool/vdbe-compress.tcl 672f81d693a03f80f5ae60bfefacd8a349e76746
-P 64c7afc704e95e13fb3315be402525d277a0d8d8
-R 20f40ca3310104ddabf364141e8ccf5e
-U danielk1977
-Z 017be7b24b2900b43c5f14b11b4aa4e2
+P 03153831635342a744ee42f14cb041499cdece2a
+R 4106cc756a07d0d168a7b40655b87b37
+U drh
+Z 8238038a139f353098e7137beba5542a

manifest.uuid

@@ -1 +1 @@
-03153831635342a744ee42f14cb041499cdece2a
+cc9430e334fe98e1c35d408f81a2d8953377cda6

src/pager.c

@@ -18,7 +18,7 @@
 ** file simultaneously, or one process from reading the database while
 ** another is writing.
 **
-** @(#) $Id: pager.c,v 1.621 2009/07/25 11:40:08 danielk1977 Exp $
+** @(#) $Id: pager.c,v 1.622 2009/07/25 14:18:57 drh Exp $
 */
 #ifndef SQLITE_OMIT_DISKIO
 #include "sqliteInt.h"
@@ -1728,14 +1728,15 @@ static int pager_delmaster(Pager *pPager, const char *zMaster){
     /* Load the entire master journal file into space obtained from
     ** sqlite3_malloc() and pointed to by zMasterJournal. 
     */
-    zMasterJournal = (char *)sqlite3Malloc((int)nMasterJournal + nMasterPtr);
+    zMasterJournal = sqlite3Malloc((int)nMasterJournal + nMasterPtr + 1);
     if( !zMasterJournal ){
       rc = SQLITE_NOMEM;
       goto delmaster_out;
     }
-    zMasterPtr = &zMasterJournal[nMasterJournal];
+    zMasterPtr = &zMasterJournal[nMasterJournal+1];
     rc = sqlite3OsRead(pMaster, zMasterJournal, (int)nMasterJournal, 0);
     if( rc!=SQLITE_OK ) goto delmaster_out;
+    zMasterJournal[nMasterJournal] = 0;
 
     zJournal = zMasterJournal;
     while( (zJournal-zMasterJournal)<nMasterJournal ){
@@ -3110,8 +3111,9 @@ static int pagerStress(void *p, PgHdr *pPg){
   ** be restored to its current value when the "ROLLBACK TO sp" is 
   ** executed.
   */
-  if( rc==SQLITE_OK && pPg->pgno>pPager->dbSize && subjRequiresPage(pPg) ){
-assert(0);
+  if( NEVER(
+      rc==SQLITE_OK && pPg->pgno>pPager->dbSize && subjRequiresPage(pPg)
+  ) ){
     rc = subjournalPage(pPg);
   }