exec: Implement kernel_execve

To allow the kernel not to play games with set_fs to call exec
implement kernel_execve.  The function kernel_execve takes pointers
into kernel memory and copies the values pointed to onto the new
userspace stack.

The calls with arguments from kernel space of do_execve are replaced
with calls to kernel_execve.

The calls do_execve and do_execveat are made static as there are now
no callers outside of exec.

The comments that mention do_execve are updated to refer to
kernel_execve or execve depending on the circumstances.  In addition
to correcting the comments, this makes it easy to grep for do_execve
and verify it is not used.

Inspired-by: https://lkml.kernel.org/r/20200627072704.2447163-1-hch@lst.de
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lkml.kernel.org/r/87wo365ikj.fsf@x220.int.ebiederm.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/security/tomoyo/common.h b/security/tomoyo/common.h
index 050473df5809..85246b9df7ca 100644
--- a/security/tomoyo/common.h
+++ b/security/tomoyo/common.h
@@ -425,7 +425,7 @@ struct tomoyo_request_info {
 	struct tomoyo_obj_info *obj;
 	/*
 	 * For holding parameters specific to execve() request.
-	 * NULL if not dealing do_execve().
+	 * NULL if not dealing execve().
 	 */
 	struct tomoyo_execve *ee;
 	struct tomoyo_domain_info *domain;