[src/trunk]: src/sys/arch/amd64/amd64 Do not dereference user pointer in ptra...

[kamil <kamil%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/273c3f9ab400
branches:  trunk
changeset: 458660:273c3f9ab400
user:      kamil <kamil%NetBSD.org@localhost>
date:      Tue Aug 06 01:34:29 2019 +0000

description:
Do not dereference user pointer in ptrace_machdep_dorequest()/amd64

Always use copyin(9) for reading user memory.

This fixes SMAP crash on some amd64 machines.

Reported by <msaitoh>

diffstat:

 sys/arch/amd64/amd64/process_machdep.c |  25 ++++++++++++++++---------
 1 files changed, 16 insertions(+), 9 deletions(-)

diffs (47 lines):

diff -r 0700a8135074 -r 273c3f9ab400 sys/arch/amd64/amd64/process_machdep.c
--- a/sys/arch/amd64/amd64/process_machdep.c    Tue Aug 06 00:19:57 2019 +0000
+++ b/sys/arch/amd64/amd64/process_machdep.c    Tue Aug 06 01:34:29 2019 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: process_machdep.c,v 1.43 2019/07/24 16:36:47 bouyer Exp $      */
+/*     $NetBSD: process_machdep.c,v 1.44 2019/08/06 01:34:29 kamil Exp $       */
 
 /*
  * Copyright (c) 1998, 2000 The NetBSD Foundation, Inc.
@@ -74,7 +74,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: process_machdep.c,v 1.43 2019/07/24 16:36:47 bouyer Exp $");
+__KERNEL_RCSID(0, "$NetBSD: process_machdep.c,v 1.44 2019/08/06 01:34:29 kamil Exp $");
 
 #include "opt_xen.h"
 #include <sys/param.h>
@@ -327,14 +327,21 @@
                if (!process_machdep_validxstate(lt->l_proc))
                        return EINVAL;
                if (__predict_false(l->l_proc->p_flag & PK_32)) {
-                       struct netbsd32_iovec *user_iov = addr;
-                       iov.iov_base = NETBSD32PTR64(user_iov->iov_base);
-                       iov.iov_len = user_iov->iov_len;
+                       struct netbsd32_iovec user_iov;
+                       if ((error = copyin(addr, &user_iov, sizeof(user_iov)))
+                           != 0)
+                               return error;
+
+                       iov.iov_base = NETBSD32PTR64(user_iov.iov_base);
+                       iov.iov_len = user_iov.iov_len;
                } else {
-                       struct iovec *user_iov;
-                       user_iov = (struct iovec*)addr;
-                       iov.iov_base = user_iov->iov_base;
-                       iov.iov_len = user_iov->iov_len;
+                       struct iovec user_iov;
+                       if ((error = copyin(addr, &user_iov, sizeof(user_iov)))
+                           != 0)
+                               return error;
+
+                       iov.iov_base = user_iov.iov_base;
+                       iov.iov_len = user_iov.iov_len;
                }
 
                error = proc_vmspace_getref(l->l_proc, &vm);