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ptrace: Always take siglock in ptrace_resume 

Make code analysis simpler and future changes easier by
always taking siglock in ptrace_resume.

Tested-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Link: https://lkml.kernel.org/r/20220505182645.497868-11-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
This commit is contained in:
Eric W. Biederman 2022-04-29 10:50:17 -05:00
parent 2500ad1c7f
commit 5b4197cb28
1 changed files with 2 additions and 11 deletions
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13
kernel/ptrace.c
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@ -837,8 +837,6 @@ static long ptrace_get_rseq_configuration(struct task_struct *task,
static int ptrace_resume(struct task_struct *child, long request, static int ptrace_resume(struct task_struct *child, long request,
unsigned long data) unsigned long data)
{ {
bool need_siglock;
if (!valid_signal(data)) if (!valid_signal(data))
return -EIO; return -EIO;
@ -874,18 +872,11 @@ static int ptrace_resume(struct task_struct *child, long request,
* Note that we need siglock even if ->exit_code == data and/or this * Note that we need siglock even if ->exit_code == data and/or this
* status was not reported yet, the new status must not be cleared by * status was not reported yet, the new status must not be cleared by
* wait_task_stopped() after resume. * wait_task_stopped() after resume.
*
* If data == 0 we do not care if wait_task_stopped() reports the old
* status and clears the code too; this can't race with the tracee, it
* takes siglock after resume.
*/ */
need_siglock = data && !thread_group_empty(current); spin_lock_irq(&child->sighand->siglock);
if (need_siglock)
spin_lock_irq(&child->sighand->siglock);
child->exit_code = data; child->exit_code = data;
wake_up_state(child, __TASK_TRACED); wake_up_state(child, __TASK_TRACED);
if (need_siglock) spin_unlock_irq(&child->sighand->siglock);
spin_unlock_irq(&child->sighand->siglock);
return 0; return 0;
} }