Module Name: src
Committed By: maxv
Date: Sat Mar 18 13:39:23 UTC 2017
Modified Files:
src/sys/arch/amd64/amd64: trap.c
src/sys/arch/i386/i386: trap.c
Log Message:
Mmh, allow iret to be handled when an #SS fault (T_STKFLT) happens. Even
if the sdm is far from being clear, it appears that iret can trigger an #SS
fault if %ss points to a writable but non-present segment; in which case
the kernel would panic, thinking the fault was internal to it.
In particular, userland can create a broken segment in the ldt with
USER_LDT, update its %ss with setcontext and trigger the panic. I don't
think amd64 is affected since USER_LDT does not exist there, and the
changes on tf_ss seem correct - but I'm still adding T_STKFLT for safety.
To generate a diff of this commit:
cvs rdiff -u -r1.93 -r1.94 src/sys/arch/amd64/amd64/trap.c
cvs rdiff -u -r1.286 -r1.287 src/sys/arch/i386/i386/trap.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/arch/amd64/amd64/trap.c
diff -u src/sys/arch/amd64/amd64/trap.c:1.93 src/sys/arch/amd64/amd64/trap.c:1.94
--- src/sys/arch/amd64/amd64/trap.c:1.93 Thu Mar 9 00:16:07 2017
+++ src/sys/arch/amd64/amd64/trap.c Sat Mar 18 13:39:23 2017
@@ -1,4 +1,4 @@
-/* $NetBSD: trap.c,v 1.93 2017/03/09 00:16:07 chs Exp $ */
+/* $NetBSD: trap.c,v 1.94 2017/03/18 13:39:23 maxv Exp $ */
/*-
* Copyright (c) 1998, 2000 The NetBSD Foundation, Inc.
@@ -68,7 +68,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: trap.c,v 1.93 2017/03/09 00:16:07 chs Exp $");
+__KERNEL_RCSID(0, "$NetBSD: trap.c,v 1.94 2017/03/18 13:39:23 maxv Exp $");
#include "opt_ddb.h"
#include "opt_kgdb.h"
@@ -301,6 +301,7 @@ trap(struct trapframe *frame)
case T_PROTFLT:
case T_SEGNPFLT:
case T_ALIGNFLT:
+ case T_STKFLT:
case T_TSSFLT:
if (p == NULL)
goto we_re_toast;
Index: src/sys/arch/i386/i386/trap.c
diff -u src/sys/arch/i386/i386/trap.c:1.286 src/sys/arch/i386/i386/trap.c:1.287
--- src/sys/arch/i386/i386/trap.c:1.286 Tue Mar 14 07:02:53 2017
+++ src/sys/arch/i386/i386/trap.c Sat Mar 18 13:39:23 2017
@@ -1,5 +1,5 @@
-/* $NetBSD: trap.c,v 1.286 2017/03/14 07:02:53 ozaki-r Exp $ */
+/* $NetBSD: trap.c,v 1.287 2017/03/18 13:39:23 maxv Exp $ */
/*-
* Copyright (c) 1998, 2000, 2005, 2006, 2007, 2008 The NetBSD Foundation, Inc.
@@ -69,7 +69,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: trap.c,v 1.286 2017/03/14 07:02:53 ozaki-r Exp $");
+__KERNEL_RCSID(0, "$NetBSD: trap.c,v 1.287 2017/03/18 13:39:23 maxv Exp $");
#include "opt_ddb.h"
#include "opt_kgdb.h"
@@ -328,6 +328,7 @@ trap(struct trapframe *frame)
case T_PROTFLT:
case T_SEGNPFLT:
case T_ALIGNFLT:
+ case T_STKFLT:
case T_TSSFLT:
if (p == NULL)
goto we_re_toast;
