Fix the VFSes so that there is no 32-bit integer overflow in the

xShmMap method if the WAL file size exceeds about 25 terabytes, or
if the header is corrupted to make SQLite think that the WAL file size
is that big.
[bugs:/info/2026-05-21T03:53:03Z|Bug 2026-05-21T03:53:03Z].

FossilOrigin-Name: 9ac4a33a2932d353c4871fd8e09c10addf827f1fc3fc9380037d738cf2cd0353

manifest

@@ -1,5 +1,5 @@
-C Fix\sa\sbuffer\soverread\sin\sthe\ssession\smodule\sthat\scould\soccur\swhen\sprocessing\sa\scorrupt\schangeset.
-D 2026-05-21T14:58:36.935
+C Fix\sthe\sVFSes\sso\sthat\sthere\sis\sno\s32-bit\sinteger\soverflow\sin\sthe\nxShmMap\smethod\sif\sthe\sWAL\sfile\ssize\sexceeds\sabout\s25\sterabytes,\sor\nif\sthe\sheader\sis\scorrupted\sto\smake\sSQLite\sthink\sthat\sthe\sWAL\sfile\ssize\nis\sthat\sbig.\n[bugs:/info/2026-05-21T03:53:03Z|Bug\s2026-05-21T03:53:03Z].
+D 2026-05-21T15:14:35.420
 F .fossil-settings/binary-glob 61195414528fb3ea9693577e1980230d78a1f8b0a54c78cf1b9b24d0a409ed6a x
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
@@ -721,8 +721,8 @@ F src/os.h 1ff5ae51d339d0e30d8a9d814f4b8f8e448169304d83a7ed9db66a65732f3e63
 F src/os_common.h 6c0eb8dd40ef3e12fe585a13e709710267a258e2c8dd1c40b1948a1d14582e06
 F src/os_kv.c e7d96727db5b67e39d590a68cc61c86daf4c093c36c011a09ebfb521182ec28d
 F src/os_setup.h 8efc64eda6a6c2f221387eefc2e7e45fd5a3d5c8337a7a83519ba4fbd2957ae2
-F src/os_unix.c a07dce662f6c4e18098f6faa9f7ec7cf311f56ee9151bed2aad4dcd55852c9e2
-F src/os_win.c beae6892a5301541b932e8ada4c34dc871d96d4d98a28051382f32138501b1b9
+F src/os_unix.c 83759942d1ea8d59daed50901c123016f845fada74caf3496b8a2537c9a08838
+F src/os_win.c 8df4b34ec6a08616a7ac33164999524ef773fa359d39ae9ae0e7e1ae4f167440
 F src/os_win.h c06ccc3a090cf54202ea58981c298817f3309d4c9e4d52ad0a02927346493721
 F src/pager.c fbec9063ea139dfa5d94ce540671752b89f8e8dc38f8a1f614bab1aa04a2dd40
 F src/pager.h 6137149346e6c8a3ddc1eeb40aee46381e9bc8b0fcc6dda8a1efde993c2275b8
@@ -2205,8 +2205,8 @@ F tool/warnings-clang.sh bbf6a1e685e534c92ec2bfba5b1745f34fb6f0bc2a362850723a9ee
 F tool/warnings.sh a554d13f6e5cf3760f041b87939e3d616ec6961859c3245e8ef701d1eafc2ca2
 F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
 F tool/winmain.c 00c8fb88e365c9017db14c73d3c78af62194d9644feaf60e220ab0f411f3604c
-P 035f1d2f284a081e6aef01cc773a3784458ec8e6297f3fbf4063670a9e65278c
-R 1e2b795dd24a1dc54fabb62c538c6eaa
-U dan
-Z e2539ec2b0b2717cf345cab8558dd8c0
+P 869a51ae84dfaaf824c872e4b3024f35eea7fa67bb584759a2d42ebf8404ef6e
+R 9253aad57f0e0c2cd700de54d1f4d82b
+U drh
+Z 444f216a004346dc782c26e43224aa07
 # Remove this line to create a well-formed Fossil manifest.

manifest.uuid

@@ -1 +1 @@
-869a51ae84dfaaf824c872e4b3024f35eea7fa67bb584759a2d42ebf8404ef6e
+9ac4a33a2932d353c4871fd8e09c10addf827f1fc3fc9380037d738cf2cd0353

src/os_unix.c

@@ -5140,9 +5140,9 @@ static int unixShmMap(
   nReqRegion = ((iRegion+nShmPerMap) / nShmPerMap) * nShmPerMap;
 
   if( pShmNode->nRegion<nReqRegion ){
-    char **apNew;                      /* New apRegion[] array */
-    int nByte = nReqRegion*szRegion;   /* Minimum required file size */
-    struct stat sStat;                 /* Used by fstat() */
+    char **apNew;                         /* New apRegion[] array */
+    i64 nByte = nReqRegion*(i64)szRegion; /* Minimum required file size */
+    struct stat sStat;                    /* Used by fstat() */
 
     pShmNode->szRegion = szRegion;
 
@@ -5173,7 +5173,7 @@ static int unixShmMap(
         */
         else{
           static const int pgsz = 4096;
-          int iPg;
+          i64 iPg;
 
           /* Write to the last byte of each newly allocated or extended page */
           assert( (nByte % pgsz)==0 );
@@ -5199,8 +5199,8 @@ static int unixShmMap(
     }
     pShmNode->apRegion = apNew;
     while( pShmNode->nRegion<nReqRegion ){
-      int nMap = szRegion*nShmPerMap;
-      int i;
+      i64 nMap = (i64)szRegion*(i64)nShmPerMap;
+      i64 i;
       void *pMem;
       if( pShmNode->hShm>=0 ){
         pMem = osMmap(0, nMap,

src/os_win.c

@@ -3599,7 +3599,7 @@ static int winShmMap(
   if( pShmNode->nRegion<=iRegion ){
     HANDLE hShared = pShmNode->hSharedShm;
     struct ShmRegion *apNew;           /* New aRegion[] array */
-    int nByte = (iRegion+1)*szRegion;  /* Minimum required file size */
+    i64 nByte = ((i64)iRegion+1)*(i64)szRegion;  /* Minimum file size */
     sqlite3_int64 sz;                  /* Current size of wal-index file */
 
     pShmNode->szRegion = szRegion;
@@ -3630,7 +3630,7 @@ static int winShmMap(
 
     /* Map the requested memory region into this processes address space. */
     apNew = (struct ShmRegion*)sqlite3_realloc64(
-        pShmNode->aRegion, (iRegion+1)*sizeof(apNew[0])
+        pShmNode->aRegion, ((i64)iRegion+1)*sizeof(apNew[0])
     );
     if( !apNew ){
       rc = SQLITE_IOERR_NOMEM_BKPT;
@@ -3652,19 +3652,19 @@ static int winShmMap(
 #else
       hMap = osCreateFileMappingW(hShared, NULL, protect, 0, nByte, NULL);
 #endif
-      OSTRACE(("SHM-MAP-CREATE pid=%lu, region=%d, size=%d, rc=%s\n",
+      OSTRACE(("SHM-MAP-CREATE pid=%lu, region=%d, size=%lld, rc=%s\n",
                osGetCurrentProcessId(), pShmNode->nRegion, nByte,
                hMap ? "ok" : "failed"));
       if( hMap ){
-        int iOffset = pShmNode->nRegion*szRegion;
+        i64 iOffset = pShmNode->nRegion*szRegion;
         int iOffsetShift = iOffset % winSysInfo.dwAllocationGranularity;
 #ifdef SQLITE_UWP
         pMap = osMapViewOfFileFromApp(hMap, flags,
-            iOffset - iOffsetShift, szRegion + iOffsetShift
+            iOffset - iOffsetShift, (i64)szRegion + iOffsetShift
         );
 #else
         pMap = osMapViewOfFile(hMap, flags,
-            0, iOffset - iOffsetShift, szRegion + iOffsetShift
+            0, iOffset - iOffsetShift, (i64)szRegion + iOffsetShift
         );
 #endif
         OSTRACE(("SHM-MAP-MAP pid=%lu, region=%d, offset=%d, size=%d, rc=%s\n",
@@ -3687,7 +3687,7 @@ static int winShmMap(
 
 shmpage_out:
   if( pShmNode->nRegion>iRegion ){
-    int iOffset = iRegion*szRegion;
+    i64 iOffset = (i64)iRegion*(i64)szRegion;
     int iOffsetShift = iOffset % winSysInfo.dwAllocationGranularity;
     char *p = (char *)pShmNode->aRegion[iRegion].pMap;
     *pp = (void *)&p[iOffsetShift];