diff options
| -rw-r--r-- | sys/amd64/amd64/support.S | 9 | ||||
| -rw-r--r-- | sys/i386/i386/support.s | 9 |
2 files changed, 8 insertions, 10 deletions
diff --git a/sys/amd64/amd64/support.S b/sys/amd64/amd64/support.S index 041f5f1..efa023e 100644 --- a/sys/amd64/amd64/support.S +++ b/sys/amd64/amd64/support.S @@ -226,12 +226,11 @@ 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. */ diff --git a/sys/i386/i386/support.s b/sys/i386/i386/support.s index feffc15..e18abbf 100644 --- a/sys/i386/i386/support.s +++ b/sys/i386/i386/support.s @@ -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. */ |
