Author: kib
Date: Sun Jan 14 09:29:06 2018
New Revision: 327959
URL: https://svnweb.freebsd.org/changeset/base/327959
Log:
MFC r327816, r327834:
Update comment explaining the check, to reality.
Modified:
stable/11/sys/amd64/amd64/support.S
stable/11/sys/i386/i386/support.s
Directory Properties:
stable/11/ (props changed)
Modified: stable/11/sys/amd64/amd64/support.S
==============================================================================
--- stable/11/sys/amd64/amd64/support.S Sun Jan 14 06:03:40 2018
(r327958)
+++ stable/11/sys/amd64/amd64/support.S Sun Jan 14 09:29:06 2018
(r327959)
@@ -225,12 +225,11 @@ ENTRY(copyout)
jz done_copyout
/*
- * Check explicitly for non-user addresses. If 486 write protection
- * is being used, this check is essential because we are in kernel
- * mode so the h/w does not provide any protection against writing
- * kernel addresses.
+ * Check explicitly for non-user addresses. This check is essential
+ * because it prevents usermode from writing into the kernel. We do
+ * not verify anywhere else that the user did not specify a rogue
+ * address.
*/
-
/*
* First, prevent address wrapping.
*/
Modified: stable/11/sys/i386/i386/support.s
==============================================================================
--- stable/11/sys/i386/i386/support.s Sun Jan 14 06:03:40 2018
(r327958)
+++ stable/11/sys/i386/i386/support.s Sun Jan 14 09:29:06 2018
(r327959)
@@ -284,12 +284,11 @@ ENTRY(copyout)
jz done_copyout
/*
- * Check explicitly for non-user addresses. If 486 write protection
- * is being used, this check is essential because we are in kernel
- * mode so the h/w does not provide any protection against writing
- * kernel addresses.
+ * Check explicitly for non-user addresses. This check is essential
+ * because it prevents usermode from writing into the kernel. We do
+ * not verify anywhere else that the user did not specify a rogue
+ * address.
*/
-
/*
* First, prevent address wrapping.
*/
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