From: "Dmitry V. Levin" <ldv@altlinux.org>
To: Oleg Nesterov <oleg@redhat.com>, Andy Lutomirski <luto@kernel.org>
Cc: Elvira Khabirova <lineprinter@altlinux.org>,
Eugene Syromyatnikov <esyr@redhat.com>,
Steven Rostedt <rostedt@goodmis.org>,
Ingo Molnar <mingo@redhat.com>, Kees Cook <keescook@chromium.org>,
Jann Horn <jannh@google.com>,
Michael Ellerman <mpe@ellerman.id.au>,
linux-api@vger.kernel.org, linux-kernel@vger.kernel.org,
strace-devel@lists.strace.io
Subject: [PATCH v4 1/2] ptrace: save the type of syscall-stop in ptrace_message
Date: Wed, 28 Nov 2018 16:06:01 +0300 [thread overview]
Message-ID: <20181128130601.GC28206@altlinux.org> (raw)
In-Reply-To: <20181128130439.GB28206@altlinux.org>
From: Elvira Khabirova <lineprinter@altlinux.org>
Define two constants, PTRACE_EVENTMSG_SYSCALL_ENTRY and
PTRACE_EVENTMSG_SYSCALL_EXIT, and place them in ptrace_message
for the duration of syscall-stops.
This way ptracers can distinguish syscall-enter-stops
from syscall-exit-stops using PTRACE_GETEVENTMSG request.
Signed-off-by: Elvira Khabirova <lineprinter@altlinux.org>
Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
---
include/linux/tracehook.h | 9 ++++++---
include/uapi/linux/ptrace.h | 10 ++++++++++
2 files changed, 16 insertions(+), 3 deletions(-)
diff --git a/include/linux/tracehook.h b/include/linux/tracehook.h
index 40b0b4c1bf7b..633a83fe7051 100644
--- a/include/linux/tracehook.h
+++ b/include/linux/tracehook.h
@@ -57,13 +57,15 @@ struct linux_binprm;
/*
* ptrace report for syscall entry and exit looks identical.
*/
-static inline int ptrace_report_syscall(struct pt_regs *regs)
+static inline int ptrace_report_syscall(struct pt_regs *regs,
+ unsigned long message)
{
int ptrace = current->ptrace;
if (!(ptrace & PT_PTRACED))
return 0;
+ current->ptrace_message = message;
ptrace_notify(SIGTRAP | ((ptrace & PT_TRACESYSGOOD) ? 0x80 : 0));
/*
@@ -76,6 +78,7 @@ static inline int ptrace_report_syscall(struct pt_regs *regs)
current->exit_code = 0;
}
+ current->ptrace_message = 0;
return fatal_signal_pending(current);
}
@@ -101,7 +104,7 @@ static inline int ptrace_report_syscall(struct pt_regs *regs)
static inline __must_check int tracehook_report_syscall_entry(
struct pt_regs *regs)
{
- return ptrace_report_syscall(regs);
+ return ptrace_report_syscall(regs, PTRACE_EVENTMSG_SYSCALL_ENTRY);
}
/**
@@ -126,7 +129,7 @@ static inline void tracehook_report_syscall_exit(struct pt_regs *regs, int step)
if (step)
user_single_step_report(regs);
else
- ptrace_report_syscall(regs);
+ ptrace_report_syscall(regs, PTRACE_EVENTMSG_SYSCALL_EXIT);
}
/**
diff --git a/include/uapi/linux/ptrace.h b/include/uapi/linux/ptrace.h
index d5a1b8a492b9..cb138902d042 100644
--- a/include/uapi/linux/ptrace.h
+++ b/include/uapi/linux/ptrace.h
@@ -104,6 +104,16 @@ struct seccomp_metadata {
#define PTRACE_O_MASK (\
0x000000ff | PTRACE_O_EXITKILL | PTRACE_O_SUSPEND_SECCOMP)
+/*
+ * These values are stored in task->ptrace_message by tracehook_report_syscall_*
+ * to describe current syscall-stop.
+ *
+ * Values for these constants are chosen so that they do not appear
+ * in task->ptrace_message by other means.
+ */
+#define PTRACE_EVENTMSG_SYSCALL_ENTRY 0x80000000U
+#define PTRACE_EVENTMSG_SYSCALL_EXIT 0x90000000U
+
#include <asm/ptrace.h>
--
ldv
next prev parent reply other threads:[~2018-11-28 13:06 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-28 13:04 [PATCH v4 0/2] ptrace: add PTRACE_GET_SYSCALL_INFO request Dmitry V. Levin
2018-11-28 13:06 ` Dmitry V. Levin [this message]
2018-11-28 13:49 ` [PATCH v4 1/2] ptrace: save the type of syscall-stop in ptrace_message Oleg Nesterov
2018-11-28 14:05 ` Dmitry V. Levin
2018-11-28 14:20 ` Oleg Nesterov
2018-11-28 15:23 ` Dmitry V. Levin
2018-11-28 22:11 ` Dmitry V. Levin
2018-11-28 23:17 ` Andy Lutomirski
2018-11-29 10:34 ` Dmitry V. Levin
2018-11-29 15:03 ` Oleg Nesterov
2018-11-29 14:47 ` Oleg Nesterov
2018-11-29 21:10 ` Dmitry V. Levin
2018-11-30 11:29 ` Oleg Nesterov
2018-11-30 22:53 ` Dmitry V. Levin
2018-11-28 13:07 ` [PATCH v4 2/2] ptrace: add PTRACE_GET_SYSCALL_INFO request Dmitry V. Levin
2018-11-28 14:10 ` Oleg Nesterov
2018-11-28 14:29 ` Oleg Nesterov
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