Module Name: src
Committed By: jmcneill
Date: Wed Aug 31 22:58:39 UTC 2011
Modified Files:
src/sys/kern: kern_subr.c sys_process.c
src/sys/sys: proc.h ptrace.h
Log Message:
PR# kern/45312: ptrace: PT_SETREGS can't alter system calls
Add a new PT_SYSCALLEMU request that cancels the current syscall, for
use with PT_SYSCALL.
To generate a diff of this commit:
cvs rdiff -u -r1.209 -r1.210 src/sys/kern/kern_subr.c
cvs rdiff -u -r1.159 -r1.160 src/sys/kern/sys_process.c
cvs rdiff -u -r1.308 -r1.309 src/sys/sys/proc.h
cvs rdiff -u -r1.42 -r1.43 src/sys/sys/ptrace.h
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/kern/kern_subr.c
diff -u src/sys/kern/kern_subr.c:1.209 src/sys/kern/kern_subr.c:1.210
--- src/sys/kern/kern_subr.c:1.209 Wed Jul 27 14:35:34 2011
+++ src/sys/kern/kern_subr.c Wed Aug 31 22:58:39 2011
@@ -1,4 +1,4 @@
-/* $NetBSD: kern_subr.c,v 1.209 2011/07/27 14:35:34 uebayasi Exp $ */
+/* $NetBSD: kern_subr.c,v 1.210 2011/08/31 22:58:39 jmcneill Exp $ */
/*-
* Copyright (c) 1997, 1998, 1999, 2002, 2007, 2008 The NetBSD Foundation, Inc.
@@ -79,7 +79,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_subr.c,v 1.209 2011/07/27 14:35:34 uebayasi Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_subr.c,v 1.210 2011/08/31 22:58:39 jmcneill Exp $");
#include "opt_ddb.h"
#include "opt_md.h"
@@ -686,6 +686,8 @@
int
trace_enter(register_t code, const register_t *args, int narg)
{
+ int error = 0;
+
#ifdef SYSCALL_DEBUG
scdebug_call(code, args);
#endif /* SYSCALL_DEBUG */
@@ -694,10 +696,16 @@
#ifdef PTRACE
if ((curlwp->l_proc->p_slflag & (PSL_SYSCALL|PSL_TRACED)) ==
- (PSL_SYSCALL|PSL_TRACED))
+ (PSL_SYSCALL|PSL_TRACED)) {
process_stoptrace();
+ if (curlwp->l_proc->p_slflag & PSL_SYSCALLEMU) {
+ /* tracer will emulate syscall for us */
+ error = EJUSTRETURN;
+ CLR(curlwp->l_proc->p_slflag, PSL_SYSCALLEMU);
+ }
+ }
#endif
- return 0;
+ return error;
}
/*
Index: src/sys/kern/sys_process.c
diff -u src/sys/kern/sys_process.c:1.159 src/sys/kern/sys_process.c:1.160
--- src/sys/kern/sys_process.c:1.159 Tue Aug 30 22:45:55 2011
+++ src/sys/kern/sys_process.c Wed Aug 31 22:58:39 2011
@@ -1,4 +1,4 @@
-/* $NetBSD: sys_process.c,v 1.159 2011/08/30 22:45:55 christos Exp $ */
+/* $NetBSD: sys_process.c,v 1.160 2011/08/31 22:58:39 jmcneill Exp $ */
/*-
* Copyright (c) 2008, 2009 The NetBSD Foundation, Inc.
@@ -118,7 +118,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: sys_process.c,v 1.159 2011/08/30 22:45:55 christos Exp $");
+__KERNEL_RCSID(0, "$NetBSD: sys_process.c,v 1.160 2011/08/31 22:58:39 jmcneill Exp $");
#include "opt_ptrace.h"
#include "opt_ktrace.h"
@@ -195,6 +195,7 @@
case PT_DETACH:
case PT_LWPINFO:
case PT_SYSCALL:
+ case PT_SYSCALLEMU:
case PT_DUMPCORE:
result = KAUTH_RESULT_ALLOW;
break;
@@ -370,6 +371,7 @@
case PT_DETACH:
case PT_LWPINFO:
case PT_SYSCALL:
+ case PT_SYSCALLEMU:
case PT_DUMPCORE:
#ifdef PT_STEP
case PT_STEP:
@@ -453,6 +455,7 @@
case PT_DETACH:
case PT_KILL:
case PT_SYSCALL:
+ case PT_SYSCALLEMU:
case PT_ATTACH:
case PT_TRACE_ME:
pheld = 1;
@@ -714,6 +717,14 @@
}
break;
+ case PT_SYSCALLEMU:
+ if (!ISSET(t->p_slflag, PSL_SYSCALL) || t->p_stat != SSTOP) {
+ error = EINVAL;
+ break;
+ }
+ SET(t->p_slflag, PSL_SYSCALLEMU);
+ break;
+
case PT_KILL:
/* just send the process a KILL signal. */
signo = SIGKILL;
Index: src/sys/sys/proc.h
diff -u src/sys/sys/proc.h:1.308 src/sys/sys/proc.h:1.309
--- src/sys/sys/proc.h:1.308 Wed Jul 27 13:20:07 2011
+++ src/sys/sys/proc.h Wed Aug 31 22:58:39 2011
@@ -1,4 +1,4 @@
-/* $NetBSD: proc.h,v 1.308 2011/07/27 13:20:07 uebayasi Exp $ */
+/* $NetBSD: proc.h,v 1.309 2011/08/31 22:58:39 jmcneill Exp $ */
/*-
* Copyright (c) 2006, 2007, 2008 The NetBSD Foundation, Inc.
@@ -378,6 +378,7 @@
#define PSL_FSTRACE 0x00010000 /* Debugger process being traced by procfs */
#define PSL_CHTRACED 0x00400000 /* Child has been traced & reparented */
#define PSL_SYSCALL 0x04000000 /* process has PT_SYSCALL enabled */
+#define PSL_SYSCALLEMU 0x08000000 /* cancel in-progress syscall */
/*
* Kept in p_stflag and protected by p_stmutex.
Index: src/sys/sys/ptrace.h
diff -u src/sys/sys/ptrace.h:1.42 src/sys/sys/ptrace.h:1.43
--- src/sys/sys/ptrace.h:1.42 Mon Dec 14 00:48:35 2009
+++ src/sys/sys/ptrace.h Wed Aug 31 22:58:39 2011
@@ -1,4 +1,4 @@
-/* $NetBSD: ptrace.h,v 1.42 2009/12/14 00:48:35 matt Exp $ */
+/* $NetBSD: ptrace.h,v 1.43 2011/08/31 22:58:39 jmcneill Exp $ */
/*-
* Copyright (c) 1984, 1993
@@ -47,6 +47,7 @@
#define PT_DUMPCORE 12 /* make the child generate a core dump */
#define PT_LWPINFO 13 /* get info about the LWP */
#define PT_SYSCALL 14 /* stop on syscall entry/exit */
+#define PT_SYSCALLEMU 15 /* cancel syscall, tracer will emulate it */
#define PT_FIRSTMACH 32 /* for machine-specific requests */
#include <machine/ptrace.h> /* machine-specific requests, if any */
