--- linux-2.4.20-oM3-orig/mm/mmap.c	Wed Mar 31 12:41:23 2004
+++ linux-2.4.20-oM3-mod/mm/mmap.c	Wed May 12 17:05:08 2004
@@ -17,6 +17,7 @@
 #include <linux/file.h>
 #include <linux/fs.h>
 #include <linux/personality.h>
+#include <linux/mount.h>
 
 #include <asm/uaccess.h>
 #include <asm/pgalloc.h>
@@ -558,8 +559,15 @@
 	int registration_result = 0;
 #endif /* CONFIG_MOSIX */
 
-	if (file && (!file->f_op || !file->f_op->mmap))
-		return -ENODEV;
+	if (file) {
+		if (!file->f_op || !file->f_op->mmap)
+			return -ENODEV;
+
+	if ((len = PAGE_ALIGN(len)) == 0)
+		if ((prot & PROT_EXEC) && (file->f_vfsmnt) && (file->f_vfsmnt->mnt_flags & MNT_NOEXEC))
+			return -EPERM;
+	}
+
 #ifdef CONFIG_MOSIX_FS
 	if(file && file_is_mfs(file))
 		return(mmap_read_instead(file, addr, len, prot, flags, pgoff));
@@ -571,12 +579,11 @@
 	if (!len)
 		return addr;
 
-	if (len > TASK_SIZE)
-		return -EINVAL;
-
-	/* This cannot be zero now */
 	len = PAGE_ALIGN(len);
 
+	if (len > TASK_SIZE || len == 0)
+ 		return -EINVAL;
+
 	/* offset overflow? */
 	if ((pgoff + (len >> PAGE_SHIFT)) < pgoff)
 		return -EINVAL;
@@ -1250,6 +1257,8 @@
 		break;
 	}
 no_mmaps:
+	if (last < first)
+		return;
 	/*
 	 * If the PGD bits are not consecutive in the virtual address, the
 	 * old method of shifting the VA >> by PGDIR_SHIFT doesn't work.
@@ -1398,6 +1407,9 @@
 	len = PAGE_ALIGN(len);
 	if (!len)
 		return addr;
+
+	if ((addr + len) > TASK_SIZE || (addr + len) < addr)
+		return -EINVAL;
 
 #ifdef CONFIG_MOSIX
 	if(current->mosix.dflags & DDEPUTY)