[RFC PATCH v3 3/3] ptrace: add PTRACE_EVENT_SECCOMP support to PTRACE_GET_SYSCALL_INFO

From: Elvira Khabirova
Date: Sat Nov 24 2018 - 20:09:44 EST


Extend PTRACE_GET_SYSCALL_INFO to support PTRACE_EVENT_SECCOMP stops.
The information returned is the same as for syscall-enter-stops.

Signed-off-by: Elvira Khabirova <lineprinter@xxxxxxxxxxxx>
Signed-off-by: Dmitry V. Levin <ldv@xxxxxxxxxxxx>
---
include/linux/ptrace.h | 1 +
include/linux/sched.h | 1 +
include/linux/tracehook.h | 1 +
kernel/ptrace.c | 7 +++++--
4 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h
index 6c2ffed907f5..a993d0fde865 100644
--- a/include/linux/ptrace.h
+++ b/include/linux/ptrace.h
@@ -166,6 +166,7 @@ static inline void ptrace_event(int event, unsigned long message)
{
if (unlikely(ptrace_event_enabled(current, event))) {
current->ptrace_message = message;
+ current->ptrace_event = event;
ptrace_notify((event << 8) | SIGTRAP);
} else if (event == PTRACE_EVENT_EXEC) {
/* legacy EXEC report via SIGTRAP */
diff --git a/include/linux/sched.h b/include/linux/sched.h
index a51c13c2b1a0..86215fb654d6 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -964,6 +964,7 @@ struct task_struct {

/* Ptrace state: */
unsigned long ptrace_message;
+ int ptrace_event;
kernel_siginfo_t *last_siginfo;

struct task_io_accounting ioac;
diff --git a/include/linux/tracehook.h b/include/linux/tracehook.h
index 633a83fe7051..5d2e5aa07a5c 100644
--- a/include/linux/tracehook.h
+++ b/include/linux/tracehook.h
@@ -66,6 +66,7 @@ static inline int ptrace_report_syscall(struct pt_regs *regs,
return 0;

current->ptrace_message = message;
+ current->ptrace_event = 0;
ptrace_notify(SIGTRAP | ((ptrace & PT_TRACESYSGOOD) ? 0x80 : 0));

/*
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 92c47cd5ad84..74a37e74c7f1 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -904,7 +904,9 @@ static int ptrace_get_syscall(struct task_struct *child,
unsigned long actual_size;
unsigned long write_size;

- if (child->ptrace_message == PTRACE_EVENTMSG_SYSCALL_ENTRY) {
+ if ((child->ptrace_event == 0 &&
+ child->ptrace_message == PTRACE_EVENTMSG_SYSCALL_ENTRY) ||
+ child->ptrace_event == PTRACE_EVENT_SECCOMP) {
int i;

info.op = PTRACE_SYSCALL_INFO_ENTRY;
@@ -917,7 +919,8 @@ static int ptrace_get_syscall(struct task_struct *child,
for (i = 0; i < ARRAY_SIZE(args); i++)
info.entry.args[i] = args[i];
actual_size = offsetofend(struct ptrace_syscall_info, entry);
- } else if (child->ptrace_message == PTRACE_EVENTMSG_SYSCALL_EXIT) {
+ } else if (child->ptrace_event == 0 &&
+ child->ptrace_message == PTRACE_EVENTMSG_SYSCALL_EXIT) {
info.op = PTRACE_SYSCALL_INFO_EXIT;
info.arch = syscall_get_arch(child);
info.exit.rval = syscall_get_error(child, regs);
--
2.19.1