--- linux-2.4.22/mm/mmap.c	Fri Jun 13 16:51:39 2003
+++ linux-2.4.26/mm/mmap.c	Wed Feb 18 14:36:32 2004
@@ -14,6 +14,7 @@
 #include <linux/file.h>
 #include <linux/fs.h>
 #include <linux/personality.h>
+#include <linux/mount.h>
 
 #include <asm/uaccess.h>
 #include <asm/pgalloc.h>
@@ -69,7 +70,7 @@
 	    return 1;
 
 	/* The page cache contains buffer pages these days.. */
-	free = atomic_read(&page_cache_size);
+	free = page_cache_size;
 	free += nr_free_pages();
 	free += nr_swap_pages;
 
@@ -400,8 +401,13 @@
 	int error;
 	rb_node_t ** rb_link, * rb_parent;
 
-	if (file && (!file->f_op || !file->f_op->mmap))
-		return -ENODEV;
+	if (file) {
+		if (!file->f_op || !file->f_op->mmap)
+			return -ENODEV;
+
+		if ((prot & PROT_EXEC) && (file->f_vfsmnt->mnt_flags & MNT_NOEXEC))
+			return -EPERM;
+	}
 
 	if (!len)
 		return addr;
@@ -1041,6 +1047,9 @@
 	if (!len)
 		return addr;
 
+	if ((addr + len) > TASK_SIZE || (addr + len) < addr)
+		return -EINVAL;
+
 	/*
 	 * mlock MCL_FUTURE?
 	 */