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authorEric W. Biederman <ebiederm@xmission.com>2022-01-27 12:15:32 -0600
committerEric W. Biederman <ebiederm@xmission.com>2022-03-18 09:44:19 -0500
commit336d4b814bf078fa698488632c19beca47308896 (patch)
tree9e757560447836890ef250488bfc899e55da1423 /include/linux/ptrace.h
parent355f841a3f8ca980c9682937a5257d3a1f6fc09d (diff)
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ptrace: Move setting/clearing ptrace_message into ptrace_stop
Today ptrace_message is easy to overlook as it not a core part of ptrace_stop. It has been overlooked so much that there are places that set ptrace_message and don't clear it, and places that never set it. So if you get an unlucky sequence of events the ptracer may be able to read a ptrace_message that does not apply to the current ptrace stop. Move setting of ptrace_message into ptrace_stop so that it always gets set before the stop, and always gets cleared after the stop. This prevents non-sense from being reported to userspace and makes ptrace_message more visible in the ptrace helper functions so that kernel developers can see it. Link: https://lkml.kernel.org/r/87bky67qfv.fsf_-_@email.froward.int.ebiederm.org Acked-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Diffstat (limited to 'include/linux/ptrace.h')
-rw-r--r--include/linux/ptrace.h9
1 files changed, 3 insertions, 6 deletions
diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h
index 5310f43e4762..3e6b46e2b7be 100644
--- a/include/linux/ptrace.h
+++ b/include/linux/ptrace.h
@@ -60,7 +60,7 @@ extern int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned
extern void ptrace_disable(struct task_struct *);
extern int ptrace_request(struct task_struct *child, long request,
unsigned long addr, unsigned long data);
-extern void ptrace_notify(int exit_code);
+extern void ptrace_notify(int exit_code, unsigned long message);
extern void __ptrace_link(struct task_struct *child,
struct task_struct *new_parent,
const struct cred *ptracer_cred);
@@ -155,8 +155,7 @@ static inline bool ptrace_event_enabled(struct task_struct *task, int event)
static inline void ptrace_event(int event, unsigned long message)
{
if (unlikely(ptrace_event_enabled(current, event))) {
- current->ptrace_message = message;
- ptrace_notify((event << 8) | SIGTRAP);
+ ptrace_notify((event << 8) | SIGTRAP, message);
} else if (event == PTRACE_EVENT_EXEC) {
/* legacy EXEC report via SIGTRAP */
if ((current->ptrace & (PT_PTRACED|PT_SEIZED)) == PT_PTRACED)
@@ -424,8 +423,7 @@ static inline int ptrace_report_syscall(unsigned long message)
if (!(ptrace & PT_PTRACED))
return 0;
- current->ptrace_message = message;
- ptrace_notify(SIGTRAP | ((ptrace & PT_TRACESYSGOOD) ? 0x80 : 0));
+ ptrace_notify(SIGTRAP | ((ptrace & PT_TRACESYSGOOD) ? 0x80 : 0), message);
/*
* this isn't the same as continuing with a signal, but it will do
@@ -437,7 +435,6 @@ static inline int ptrace_report_syscall(unsigned long message)
current->exit_code = 0;
}
- current->ptrace_message = 0;
return fatal_signal_pending(current);
}