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[src/trunk]: src/sys Move TRAP_CHLD/TRAP_LWP ptrace information from struct p...
details: https://anonhg.NetBSD.org/src/rev/8e96b24abf7e
branches: trunk
changeset: 454873:8e96b24abf7e
user: kamil <kamil%NetBSD.org@localhost>
date: Mon Sep 30 21:13:33 2019 +0000
description:
Move TRAP_CHLD/TRAP_LWP ptrace information from struct proc to siginfo
Storing struct ptrace_state information inside struct proc was vulnerable
to synchronization bugs, as multiple events emitted in the same time were
overwritting other ones.
Cache the original parent process id in p_oppid. Reusing here p_opptr is
in theory prone to slight race codition.
Change the semantics of PT_GET_PROCESS_STATE, reutning EINVAL for calls
prompting for the value in cases when there wasn't registered an
appropriate event.
Add an alternative approach to check the ptrace_state information, directly
from the siginfo_t value returned from PT_GET_SIGINFO. The original
PT_GET_PROCESS_STATE approach is kept for compat with older NetBSD and
OpenBSD. New code is recommended to keep using PT_GET_PROCESS_STATE.
Add a couple of compile-time asserts for assumptions in the code.
No functional change intended in existing ptrace(2) software.
All ATF ptrace(2) and ATF GDB tests pass.
This change improves reliability of the threading ptrace(2) code.
diffstat:
sys/compat/sys/siginfo.h | 10 ++++++++-
sys/kern/kern_exec.c | 13 +++++------
sys/kern/kern_fork.c | 29 +++++++++----------------
sys/kern/kern_lwp.c | 8 +++---
sys/kern/kern_proc.c | 11 ++-------
sys/kern/kern_sig.c | 14 ++++++++----
sys/kern/sys_lwp.c | 8 +++---
sys/kern/sys_ptrace_common.c | 49 +++++++++++++++++--------------------------
sys/sys/proc.h | 9 +------
sys/sys/siginfo.h | 18 +++++++++++++++-
sys/sys/signalvar.h | 4 +-
11 files changed, 87 insertions(+), 86 deletions(-)
diffs (truncated from 470 to 300 lines):
diff -r 02e0a2475b57 -r 8e96b24abf7e sys/compat/sys/siginfo.h
--- a/sys/compat/sys/siginfo.h Mon Sep 30 21:06:16 2019 +0000
+++ b/sys/compat/sys/siginfo.h Mon Sep 30 21:13:33 2019 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: siginfo.h,v 1.7 2019/06/30 08:49:21 martin Exp $ */
+/* $NetBSD: siginfo.h,v 1.8 2019/09/30 21:13:33 kamil Exp $ */
/*-
* Copyright (c) 2002 The NetBSD Foundation, Inc.
@@ -75,6 +75,14 @@
int _error;
uint64_t _args[8]; /* SYS_MAXSYSARGS */
} _syscall;
+
+ struct {
+ int _pe_report_event;
+ union {
+ pid_t _pe_other_pid;
+ lwpid_t _pe_lwp;
+ } _option;
+ } _ptrace_state;
} _reason;
};
diff -r 02e0a2475b57 -r 8e96b24abf7e sys/kern/kern_exec.c
--- a/sys/kern/kern_exec.c Mon Sep 30 21:06:16 2019 +0000
+++ b/sys/kern/kern_exec.c Mon Sep 30 21:13:33 2019 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: kern_exec.c,v 1.481 2019/09/17 15:19:27 christos Exp $ */
+/* $NetBSD: kern_exec.c,v 1.482 2019/09/30 21:13:33 kamil Exp $ */
/*-
* Copyright (c) 2008 The NetBSD Foundation, Inc.
@@ -59,7 +59,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_exec.c,v 1.481 2019/09/17 15:19:27 christos Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_exec.c,v 1.482 2019/09/30 21:13:33 kamil Exp $");
#include "opt_exec.h"
#include "opt_execfmt.h"
@@ -1339,7 +1339,7 @@
/* posix_spawn(3) reports a single event with implied exec(3) */
if ((p->p_slflag & PSL_TRACED) && !is_spawn) {
mutex_enter(p->p_lock);
- eventswitch(TRAP_EXEC);
+ eventswitch(TRAP_EXEC, 0, 0);
mutex_enter(proc_lock);
}
@@ -2249,7 +2249,7 @@
}
mutex_enter(p->p_lock);
- eventswitch(TRAP_CHLD);
+ eventswitch(TRAP_CHLD, PTRACE_POSIX_SPAWN, p->p_oppid);
}
cpu_return:
@@ -2630,8 +2630,7 @@
if ((p1->p_slflag & (PSL_TRACEPOSIX_SPAWN|PSL_TRACED)) ==
(PSL_TRACEPOSIX_SPAWN|PSL_TRACED)) {
proc_changeparent(p2, p1->p_pptr);
- p1->p_pspid = p2->p_pid;
- p2->p_pspid = p1->p_pid;
+ p2->p_oppid = p1->p_pid;
}
LIST_INSERT_AFTER(p1, p2, p_pglist);
@@ -2685,7 +2684,7 @@
}
mutex_enter(p1->p_lock);
- eventswitch(TRAP_CHLD);
+ eventswitch(TRAP_CHLD, PTRACE_POSIX_SPAWN, pid);
}
return 0;
diff -r 02e0a2475b57 -r 8e96b24abf7e sys/kern/kern_fork.c
--- a/sys/kern/kern_fork.c Mon Sep 30 21:06:16 2019 +0000
+++ b/sys/kern/kern_fork.c Mon Sep 30 21:13:33 2019 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: kern_fork.c,v 1.213 2019/06/13 20:20:18 kamil Exp $ */
+/* $NetBSD: kern_fork.c,v 1.214 2019/09/30 21:13:33 kamil Exp $ */
/*-
* Copyright (c) 1999, 2001, 2004, 2006, 2007, 2008 The NetBSD Foundation, Inc.
@@ -67,7 +67,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_fork.c,v 1.213 2019/06/13 20:20:18 kamil Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_fork.c,v 1.214 2019/09/30 21:13:33 kamil Exp $");
#include "opt_ktrace.h"
#include "opt_dtrace.h"
@@ -252,7 +252,6 @@
int count;
vaddr_t uaddr;
int tnprocs;
- bool trace_fork, trace_vfork;
int error = 0;
p1 = l1->l_proc;
@@ -511,17 +510,9 @@
/*
* Trace fork(2) and vfork(2)-like events on demand in a debugger.
*/
- trace_fork = tracefork(p1, flags);
- trace_vfork = tracevfork(p1, flags);
- if (trace_fork || trace_vfork)
+ if (tracefork(p1, flags) || tracevfork(p1, flags)) {
proc_changeparent(p2, p1->p_pptr);
- if (trace_fork) {
- p1->p_fpid = p2->p_pid;
- p2->p_fpid = p1->p_pid;
- }
- if (trace_vfork) {
- p1->p_vfpid = p2->p_pid;
- p2->p_vfpid = p1->p_pid;
+ p2->p_oppid = p1->p_pid;
}
LIST_INSERT_AFTER(p1, p2, p_pglist);
@@ -605,7 +596,9 @@
*/
if (tracefork(p1, flags) || tracevfork(p1, flags)) {
mutex_enter(p1->p_lock);
- eventswitch(TRAP_CHLD);
+ eventswitch(TRAP_CHLD,
+ tracefork(p1, flags) ? PTRACE_FORK : PTRACE_VFORK,
+ retval[0]);
mutex_enter(proc_lock);
}
@@ -621,8 +614,7 @@
*/
if (tracevforkdone(p1, flags)) {
mutex_enter(p1->p_lock);
- p1->p_vfpid_done = retval[0];
- eventswitch(TRAP_CHLD);
+ eventswitch(TRAP_CHLD, PTRACE_VFORK_DONE, retval[0]);
} else
mutex_exit(proc_lock);
@@ -645,9 +637,10 @@
mutex_exit(proc_lock);
goto my_tracer_is_gone;
}
-
mutex_enter(p->p_lock);
- eventswitch(TRAP_CHLD);
+ eventswitch(TRAP_CHLD,
+ ISSET(p->p_lflag, PL_PPWAIT) ? PTRACE_VFORK : PTRACE_FORK,
+ p->p_oppid);
}
my_tracer_is_gone:
diff -r 02e0a2475b57 -r 8e96b24abf7e sys/kern/kern_lwp.c
--- a/sys/kern/kern_lwp.c Mon Sep 30 21:06:16 2019 +0000
+++ b/sys/kern/kern_lwp.c Mon Sep 30 21:13:33 2019 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: kern_lwp.c,v 1.202 2019/06/04 11:54:03 kamil Exp $ */
+/* $NetBSD: kern_lwp.c,v 1.203 2019/09/30 21:13:33 kamil Exp $ */
/*-
* Copyright (c) 2001, 2006, 2007, 2008, 2009 The NetBSD Foundation, Inc.
@@ -211,7 +211,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_lwp.c,v 1.202 2019/06/04 11:54:03 kamil Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_lwp.c,v 1.203 2019/09/30 21:13:33 kamil Exp $");
#include "opt_ddb.h"
#include "opt_lockdebug.h"
@@ -239,6 +239,7 @@
#include <sys/fstrans.h>
#include <sys/dtrace_bsd.h>
#include <sys/sdt.h>
+#include <sys/ptrace.h>
#include <sys/xcall.h>
#include <sys/uidinfo.h>
#include <sys/sysctl.h>
@@ -1091,8 +1092,7 @@
* about a terminating LWP as it would deadlock.
*/
} else {
- p->p_lwp_exited = l->l_lid;
- eventswitch(TRAP_LWP);
+ eventswitch(TRAP_LWP, PTRACE_LWP_EXIT, l->l_lid);
mutex_enter(proc_lock);
}
}
diff -r 02e0a2475b57 -r 8e96b24abf7e sys/kern/kern_proc.c
--- a/sys/kern/kern_proc.c Mon Sep 30 21:06:16 2019 +0000
+++ b/sys/kern/kern_proc.c Mon Sep 30 21:13:33 2019 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: kern_proc.c,v 1.234 2019/08/02 22:46:44 kamil Exp $ */
+/* $NetBSD: kern_proc.c,v 1.235 2019/09/30 21:13:33 kamil Exp $ */
/*-
* Copyright (c) 1999, 2006, 2007, 2008 The NetBSD Foundation, Inc.
@@ -62,7 +62,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_proc.c,v 1.234 2019/08/02 22:46:44 kamil Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_proc.c,v 1.235 2019/09/30 21:13:33 kamil Exp $");
#ifdef _KERNEL_OPT
#include "opt_kstack.h"
@@ -2263,12 +2263,7 @@
COND_SET_VALUE(p->p_sigpend, psrc->p_sigpend, allowaddr);
COND_SET_VALUE(p->p_lwpctl, psrc->p_lwpctl, allowaddr);
p->p_ppid = psrc->p_ppid;
- p->p_fpid = psrc->p_fpid;
- p->p_vfpid = psrc->p_vfpid;
- p->p_vfpid_done = psrc->p_vfpid_done;
- p->p_lwp_created = psrc->p_lwp_created;
- p->p_lwp_exited = psrc->p_lwp_exited;
- p->p_pspid = psrc->p_pspid;
+ p->p_oppid = psrc->p_oppid;
COND_SET_VALUE(p->p_path, psrc->p_path, allowaddr);
COND_SET_VALUE(p->p_sigctx, psrc->p_sigctx, allowaddr);
p->p_nice = psrc->p_nice;
diff -r 02e0a2475b57 -r 8e96b24abf7e sys/kern/kern_sig.c
--- a/sys/kern/kern_sig.c Mon Sep 30 21:06:16 2019 +0000
+++ b/sys/kern/kern_sig.c Mon Sep 30 21:13:33 2019 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: kern_sig.c,v 1.364 2019/06/21 04:28:12 kamil Exp $ */
+/* $NetBSD: kern_sig.c,v 1.365 2019/09/30 21:13:33 kamil Exp $ */
/*-
* Copyright (c) 2006, 2007, 2008 The NetBSD Foundation, Inc.
@@ -70,7 +70,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_sig.c,v 1.364 2019/06/21 04:28:12 kamil Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_sig.c,v 1.365 2019/09/30 21:13:33 kamil Exp $");
#include "opt_ptrace.h"
#include "opt_dtrace.h"
@@ -1560,7 +1560,7 @@
* an event specific to a traced process only.
*/
void
-eventswitch(int code)
+eventswitch(int code, int pe_report_event, int entity)
{
struct lwp *l = curlwp;
struct proc *p = l->l_proc;
@@ -1605,8 +1605,12 @@
KSI_INIT_TRAP(&ksi);
ksi.ksi_lid = l->l_lid;
- ksi.ksi_info._signo = signo;
- ksi.ksi_info._code = code;
+ ksi.ksi_signo = signo;
+ ksi.ksi_code = code;
+ ksi.ksi_pe_report_event = pe_report_event;
+
+ CTASSERT(sizeof(ksi.ksi_pe_other_pid) == sizeof(ksi.ksi_pe_lwp));
+ ksi.ksi_pe_other_pid = entity;
/* Needed for ktrace */
ps = p->p_sigacts;
diff -r 02e0a2475b57 -r 8e96b24abf7e sys/kern/sys_lwp.c
--- a/sys/kern/sys_lwp.c Mon Sep 30 21:06:16 2019 +0000
+++ b/sys/kern/sys_lwp.c Mon Sep 30 21:13:33 2019 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: sys_lwp.c,v 1.69 2019/07/10 17:52:22 maxv Exp $ */
+/* $NetBSD: sys_lwp.c,v 1.70 2019/09/30 21:13:33 kamil Exp $ */
/*-
* Copyright (c) 2001, 2006, 2007, 2008 The NetBSD Foundation, Inc.
@@ -35,7 +35,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: sys_lwp.c,v 1.69 2019/07/10 17:52:22 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: sys_lwp.c,v 1.70 2019/09/30 21:13:33 kamil Exp $");
#include <sys/param.h>
#include <sys/systm.h>
@@ -45,6 +45,7 @@
#include <sys/syscallargs.h>
#include <sys/kauth.h>
#include <sys/kmem.h>
+#include <sys/ptrace.h>
#include <sys/sleepq.h>
#include <sys/lwpctl.h>
#include <sys/cpu.h>
@@ -91,8 +92,7 @@
}
mutex_enter(p->p_lock);
- p->p_lwp_created = l->l_lid;
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