Avoid casting a value larger than 2^31 to a (size_t) on systems where it

 is a 32-bit type.

FossilOrigin-Name: 46c3085dcad6372ac20eff499e17fe11680fdf4adb9186bf8b12221a5047e485

1 files changed, 7 insertions, 0 deletions

diff --git a/src/os_unix.c b/src/os_unix.c
index 157be3c3a..99a06279f 100644
--- a/src/os_unix.c
+++ b/src/os_unix.c
@@ -3858,6 +3858,13 @@ static int unixFileControl(sqlite3_file *id, int op, void *pArg){
       if( newLimit>sqlite3GlobalConfig.mxMmap ){
         newLimit = sqlite3GlobalConfig.mxMmap;
       }
+
+      /* The value of newLimit may be eventually cast to (size_t) and passed
+      ** to mmap(). Restrict its value to 2GB if (size_t) is a 32-bit type. */
+      if( sizeof(size_t)<8 ){
+        newLimit = (newLimit & 0x7FFFFFFF);
+      }
+
       *(i64*)pArg = pFile->mmapSizeMax;
       if( newLimit>=0 && newLimit!=pFile->mmapSizeMax && pFile->nFetchOut==0 ){
         pFile->mmapSizeMax = newLimit;