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![Andrei Vagin](/assets/img/avatar_default.png)
There are a few system calls (pselect, ppoll, etc) which replace a task
sigmask while they are running in a kernel-space
When a task calls one of these syscalls, the kernel saves a current
sigmask in task->saved_sigmask and sets a syscall sigmask.
On syscall-exit-stop, ptrace traps a task before restoring the
saved_sigmask, so PTRACE_GETSIGMASK returns the syscall sigmask and
PTRACE_SETSIGMASK does nothing, because its sigmask is replaced by
saved_sigmask, when the task returns to user-space.
This patch fixes this problem. PTRACE_GETSIGMASK returns saved_sigmask
if it's set. PTRACE_SETSIGMASK drops the TIF_RESTORE_SIGMASK flag.
Link: http://lkml.kernel.org/r/20181120060616.6043-1-avagin@gmail.com
Fixes: 29000caecb
("ptrace: add ability to get/set signal-blocked mask")
Signed-off-by: Andrei Vagin <avagin@gmail.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1308 lines
32 KiB
C
1308 lines
32 KiB
C
/*
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* linux/kernel/ptrace.c
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*
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* (C) Copyright 1999 Linus Torvalds
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*
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* Common interfaces for "ptrace()" which we do not want
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* to continually duplicate across every architecture.
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*/
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#include <linux/capability.h>
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#include <linux/export.h>
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#include <linux/sched.h>
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#include <linux/sched/mm.h>
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#include <linux/sched/coredump.h>
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#include <linux/sched/task.h>
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#include <linux/errno.h>
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#include <linux/mm.h>
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#include <linux/highmem.h>
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#include <linux/pagemap.h>
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#include <linux/ptrace.h>
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#include <linux/security.h>
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#include <linux/signal.h>
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#include <linux/uio.h>
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#include <linux/audit.h>
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#include <linux/pid_namespace.h>
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#include <linux/syscalls.h>
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#include <linux/uaccess.h>
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#include <linux/regset.h>
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#include <linux/hw_breakpoint.h>
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#include <linux/cn_proc.h>
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#include <linux/compat.h>
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#include <linux/sched/signal.h>
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/*
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* Access another process' address space via ptrace.
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* Source/target buffer must be kernel space,
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* Do not walk the page table directly, use get_user_pages
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*/
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int ptrace_access_vm(struct task_struct *tsk, unsigned long addr,
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void *buf, int len, unsigned int gup_flags)
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{
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struct mm_struct *mm;
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int ret;
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mm = get_task_mm(tsk);
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if (!mm)
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return 0;
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if (!tsk->ptrace ||
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(current != tsk->parent) ||
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((get_dumpable(mm) != SUID_DUMP_USER) &&
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!ptracer_capable(tsk, mm->user_ns))) {
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mmput(mm);
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return 0;
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}
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ret = __access_remote_vm(tsk, mm, addr, buf, len, gup_flags);
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mmput(mm);
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return ret;
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}
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void __ptrace_link(struct task_struct *child, struct task_struct *new_parent,
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const struct cred *ptracer_cred)
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{
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BUG_ON(!list_empty(&child->ptrace_entry));
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list_add(&child->ptrace_entry, &new_parent->ptraced);
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child->parent = new_parent;
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child->ptracer_cred = get_cred(ptracer_cred);
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}
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/*
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* ptrace a task: make the debugger its new parent and
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* move it to the ptrace list.
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*
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* Must be called with the tasklist lock write-held.
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*/
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static void ptrace_link(struct task_struct *child, struct task_struct *new_parent)
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{
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rcu_read_lock();
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__ptrace_link(child, new_parent, __task_cred(new_parent));
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rcu_read_unlock();
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}
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/**
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* __ptrace_unlink - unlink ptracee and restore its execution state
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* @child: ptracee to be unlinked
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*
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* Remove @child from the ptrace list, move it back to the original parent,
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* and restore the execution state so that it conforms to the group stop
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* state.
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*
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* Unlinking can happen via two paths - explicit PTRACE_DETACH or ptracer
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* exiting. For PTRACE_DETACH, unless the ptracee has been killed between
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* ptrace_check_attach() and here, it's guaranteed to be in TASK_TRACED.
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* If the ptracer is exiting, the ptracee can be in any state.
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*
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* After detach, the ptracee should be in a state which conforms to the
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* group stop. If the group is stopped or in the process of stopping, the
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* ptracee should be put into TASK_STOPPED; otherwise, it should be woken
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* up from TASK_TRACED.
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*
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* If the ptracee is in TASK_TRACED and needs to be moved to TASK_STOPPED,
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* it goes through TRACED -> RUNNING -> STOPPED transition which is similar
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* to but in the opposite direction of what happens while attaching to a
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* stopped task. However, in this direction, the intermediate RUNNING
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* state is not hidden even from the current ptracer and if it immediately
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* re-attaches and performs a WNOHANG wait(2), it may fail.
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*
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* CONTEXT:
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* write_lock_irq(tasklist_lock)
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*/
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void __ptrace_unlink(struct task_struct *child)
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{
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const struct cred *old_cred;
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BUG_ON(!child->ptrace);
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clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
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child->parent = child->real_parent;
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list_del_init(&child->ptrace_entry);
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old_cred = child->ptracer_cred;
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child->ptracer_cred = NULL;
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put_cred(old_cred);
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spin_lock(&child->sighand->siglock);
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child->ptrace = 0;
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/*
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* Clear all pending traps and TRAPPING. TRAPPING should be
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* cleared regardless of JOBCTL_STOP_PENDING. Do it explicitly.
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*/
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task_clear_jobctl_pending(child, JOBCTL_TRAP_MASK);
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task_clear_jobctl_trapping(child);
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/*
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* Reinstate JOBCTL_STOP_PENDING if group stop is in effect and
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* @child isn't dead.
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*/
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if (!(child->flags & PF_EXITING) &&
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(child->signal->flags & SIGNAL_STOP_STOPPED ||
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child->signal->group_stop_count)) {
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child->jobctl |= JOBCTL_STOP_PENDING;
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/*
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* This is only possible if this thread was cloned by the
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* traced task running in the stopped group, set the signal
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* for the future reports.
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* FIXME: we should change ptrace_init_task() to handle this
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* case.
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*/
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if (!(child->jobctl & JOBCTL_STOP_SIGMASK))
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child->jobctl |= SIGSTOP;
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}
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/*
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* If transition to TASK_STOPPED is pending or in TASK_TRACED, kick
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* @child in the butt. Note that @resume should be used iff @child
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* is in TASK_TRACED; otherwise, we might unduly disrupt
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* TASK_KILLABLE sleeps.
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*/
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if (child->jobctl & JOBCTL_STOP_PENDING || task_is_traced(child))
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ptrace_signal_wake_up(child, true);
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spin_unlock(&child->sighand->siglock);
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}
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/* Ensure that nothing can wake it up, even SIGKILL */
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static bool ptrace_freeze_traced(struct task_struct *task)
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{
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bool ret = false;
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/* Lockless, nobody but us can set this flag */
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if (task->jobctl & JOBCTL_LISTENING)
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return ret;
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spin_lock_irq(&task->sighand->siglock);
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if (task_is_traced(task) && !__fatal_signal_pending(task)) {
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task->state = __TASK_TRACED;
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ret = true;
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}
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spin_unlock_irq(&task->sighand->siglock);
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return ret;
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}
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static void ptrace_unfreeze_traced(struct task_struct *task)
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{
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if (task->state != __TASK_TRACED)
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return;
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WARN_ON(!task->ptrace || task->parent != current);
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/*
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* PTRACE_LISTEN can allow ptrace_trap_notify to wake us up remotely.
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* Recheck state under the lock to close this race.
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*/
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spin_lock_irq(&task->sighand->siglock);
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if (task->state == __TASK_TRACED) {
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if (__fatal_signal_pending(task))
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wake_up_state(task, __TASK_TRACED);
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else
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task->state = TASK_TRACED;
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}
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spin_unlock_irq(&task->sighand->siglock);
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}
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/**
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* ptrace_check_attach - check whether ptracee is ready for ptrace operation
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* @child: ptracee to check for
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* @ignore_state: don't check whether @child is currently %TASK_TRACED
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*
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* Check whether @child is being ptraced by %current and ready for further
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* ptrace operations. If @ignore_state is %false, @child also should be in
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* %TASK_TRACED state and on return the child is guaranteed to be traced
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* and not executing. If @ignore_state is %true, @child can be in any
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* state.
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*
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* CONTEXT:
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* Grabs and releases tasklist_lock and @child->sighand->siglock.
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*
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* RETURNS:
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* 0 on success, -ESRCH if %child is not ready.
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*/
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static int ptrace_check_attach(struct task_struct *child, bool ignore_state)
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{
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int ret = -ESRCH;
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/*
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* We take the read lock around doing both checks to close a
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* possible race where someone else was tracing our child and
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* detached between these two checks. After this locked check,
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* we are sure that this is our traced child and that can only
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* be changed by us so it's not changing right after this.
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*/
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read_lock(&tasklist_lock);
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if (child->ptrace && child->parent == current) {
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WARN_ON(child->state == __TASK_TRACED);
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/*
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* child->sighand can't be NULL, release_task()
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* does ptrace_unlink() before __exit_signal().
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*/
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if (ignore_state || ptrace_freeze_traced(child))
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ret = 0;
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}
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read_unlock(&tasklist_lock);
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if (!ret && !ignore_state) {
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if (!wait_task_inactive(child, __TASK_TRACED)) {
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/*
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* This can only happen if may_ptrace_stop() fails and
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* ptrace_stop() changes ->state back to TASK_RUNNING,
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* so we should not worry about leaking __TASK_TRACED.
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*/
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WARN_ON(child->state == __TASK_TRACED);
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ret = -ESRCH;
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}
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}
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return ret;
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}
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static int ptrace_has_cap(struct user_namespace *ns, unsigned int mode)
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{
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if (mode & PTRACE_MODE_NOAUDIT)
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return has_ns_capability_noaudit(current, ns, CAP_SYS_PTRACE);
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else
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return has_ns_capability(current, ns, CAP_SYS_PTRACE);
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}
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/* Returns 0 on success, -errno on denial. */
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static int __ptrace_may_access(struct task_struct *task, unsigned int mode)
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{
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const struct cred *cred = current_cred(), *tcred;
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struct mm_struct *mm;
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kuid_t caller_uid;
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kgid_t caller_gid;
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if (!(mode & PTRACE_MODE_FSCREDS) == !(mode & PTRACE_MODE_REALCREDS)) {
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WARN(1, "denying ptrace access check without PTRACE_MODE_*CREDS\n");
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return -EPERM;
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}
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/* May we inspect the given task?
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* This check is used both for attaching with ptrace
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* and for allowing access to sensitive information in /proc.
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*
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* ptrace_attach denies several cases that /proc allows
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* because setting up the necessary parent/child relationship
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* or halting the specified task is impossible.
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*/
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/* Don't let security modules deny introspection */
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if (same_thread_group(task, current))
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return 0;
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rcu_read_lock();
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if (mode & PTRACE_MODE_FSCREDS) {
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caller_uid = cred->fsuid;
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caller_gid = cred->fsgid;
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} else {
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/*
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* Using the euid would make more sense here, but something
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* in userland might rely on the old behavior, and this
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* shouldn't be a security problem since
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* PTRACE_MODE_REALCREDS implies that the caller explicitly
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* used a syscall that requests access to another process
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* (and not a filesystem syscall to procfs).
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*/
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caller_uid = cred->uid;
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caller_gid = cred->gid;
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}
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tcred = __task_cred(task);
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if (uid_eq(caller_uid, tcred->euid) &&
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uid_eq(caller_uid, tcred->suid) &&
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uid_eq(caller_uid, tcred->uid) &&
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gid_eq(caller_gid, tcred->egid) &&
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gid_eq(caller_gid, tcred->sgid) &&
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gid_eq(caller_gid, tcred->gid))
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goto ok;
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if (ptrace_has_cap(tcred->user_ns, mode))
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goto ok;
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rcu_read_unlock();
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return -EPERM;
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ok:
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rcu_read_unlock();
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mm = task->mm;
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if (mm &&
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((get_dumpable(mm) != SUID_DUMP_USER) &&
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!ptrace_has_cap(mm->user_ns, mode)))
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return -EPERM;
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return security_ptrace_access_check(task, mode);
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}
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bool ptrace_may_access(struct task_struct *task, unsigned int mode)
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{
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int err;
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task_lock(task);
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err = __ptrace_may_access(task, mode);
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task_unlock(task);
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return !err;
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}
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static int ptrace_attach(struct task_struct *task, long request,
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unsigned long addr,
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unsigned long flags)
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{
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bool seize = (request == PTRACE_SEIZE);
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int retval;
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retval = -EIO;
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if (seize) {
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if (addr != 0)
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goto out;
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if (flags & ~(unsigned long)PTRACE_O_MASK)
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goto out;
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flags = PT_PTRACED | PT_SEIZED | (flags << PT_OPT_FLAG_SHIFT);
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} else {
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flags = PT_PTRACED;
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}
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audit_ptrace(task);
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retval = -EPERM;
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if (unlikely(task->flags & PF_KTHREAD))
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goto out;
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if (same_thread_group(task, current))
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goto out;
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/*
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* Protect exec's credential calculations against our interference;
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* SUID, SGID and LSM creds get determined differently
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* under ptrace.
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*/
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retval = -ERESTARTNOINTR;
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if (mutex_lock_interruptible(&task->signal->cred_guard_mutex))
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goto out;
|
|
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task_lock(task);
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retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH_REALCREDS);
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task_unlock(task);
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if (retval)
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goto unlock_creds;
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write_lock_irq(&tasklist_lock);
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retval = -EPERM;
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if (unlikely(task->exit_state))
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goto unlock_tasklist;
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if (task->ptrace)
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goto unlock_tasklist;
|
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|
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if (seize)
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flags |= PT_SEIZED;
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task->ptrace = flags;
|
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|
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ptrace_link(task, current);
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|
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/* SEIZE doesn't trap tracee on attach */
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if (!seize)
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send_sig_info(SIGSTOP, SEND_SIG_PRIV, task);
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|
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spin_lock(&task->sighand->siglock);
|
|
|
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/*
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* If the task is already STOPPED, set JOBCTL_TRAP_STOP and
|
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* TRAPPING, and kick it so that it transits to TRACED. TRAPPING
|
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* will be cleared if the child completes the transition or any
|
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* event which clears the group stop states happens. We'll wait
|
|
* for the transition to complete before returning from this
|
|
* function.
|
|
*
|
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* This hides STOPPED -> RUNNING -> TRACED transition from the
|
|
* attaching thread but a different thread in the same group can
|
|
* still observe the transient RUNNING state. IOW, if another
|
|
* thread's WNOHANG wait(2) on the stopped tracee races against
|
|
* ATTACH, the wait(2) may fail due to the transient RUNNING.
|
|
*
|
|
* The following task_is_stopped() test is safe as both transitions
|
|
* in and out of STOPPED are protected by siglock.
|
|
*/
|
|
if (task_is_stopped(task) &&
|
|
task_set_jobctl_pending(task, JOBCTL_TRAP_STOP | JOBCTL_TRAPPING))
|
|
signal_wake_up_state(task, __TASK_STOPPED);
|
|
|
|
spin_unlock(&task->sighand->siglock);
|
|
|
|
retval = 0;
|
|
unlock_tasklist:
|
|
write_unlock_irq(&tasklist_lock);
|
|
unlock_creds:
|
|
mutex_unlock(&task->signal->cred_guard_mutex);
|
|
out:
|
|
if (!retval) {
|
|
/*
|
|
* We do not bother to change retval or clear JOBCTL_TRAPPING
|
|
* if wait_on_bit() was interrupted by SIGKILL. The tracer will
|
|
* not return to user-mode, it will exit and clear this bit in
|
|
* __ptrace_unlink() if it wasn't already cleared by the tracee;
|
|
* and until then nobody can ptrace this task.
|
|
*/
|
|
wait_on_bit(&task->jobctl, JOBCTL_TRAPPING_BIT, TASK_KILLABLE);
|
|
proc_ptrace_connector(task, PTRACE_ATTACH);
|
|
}
|
|
|
|
return retval;
|
|
}
|
|
|
|
/**
|
|
* ptrace_traceme -- helper for PTRACE_TRACEME
|
|
*
|
|
* Performs checks and sets PT_PTRACED.
|
|
* Should be used by all ptrace implementations for PTRACE_TRACEME.
|
|
*/
|
|
static int ptrace_traceme(void)
|
|
{
|
|
int ret = -EPERM;
|
|
|
|
write_lock_irq(&tasklist_lock);
|
|
/* Are we already being traced? */
|
|
if (!current->ptrace) {
|
|
ret = security_ptrace_traceme(current->parent);
|
|
/*
|
|
* Check PF_EXITING to ensure ->real_parent has not passed
|
|
* exit_ptrace(). Otherwise we don't report the error but
|
|
* pretend ->real_parent untraces us right after return.
|
|
*/
|
|
if (!ret && !(current->real_parent->flags & PF_EXITING)) {
|
|
current->ptrace = PT_PTRACED;
|
|
ptrace_link(current, current->real_parent);
|
|
}
|
|
}
|
|
write_unlock_irq(&tasklist_lock);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Called with irqs disabled, returns true if childs should reap themselves.
|
|
*/
|
|
static int ignoring_children(struct sighand_struct *sigh)
|
|
{
|
|
int ret;
|
|
spin_lock(&sigh->siglock);
|
|
ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) ||
|
|
(sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT);
|
|
spin_unlock(&sigh->siglock);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Called with tasklist_lock held for writing.
|
|
* Unlink a traced task, and clean it up if it was a traced zombie.
|
|
* Return true if it needs to be reaped with release_task().
|
|
* (We can't call release_task() here because we already hold tasklist_lock.)
|
|
*
|
|
* If it's a zombie, our attachedness prevented normal parent notification
|
|
* or self-reaping. Do notification now if it would have happened earlier.
|
|
* If it should reap itself, return true.
|
|
*
|
|
* If it's our own child, there is no notification to do. But if our normal
|
|
* children self-reap, then this child was prevented by ptrace and we must
|
|
* reap it now, in that case we must also wake up sub-threads sleeping in
|
|
* do_wait().
|
|
*/
|
|
static bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p)
|
|
{
|
|
bool dead;
|
|
|
|
__ptrace_unlink(p);
|
|
|
|
if (p->exit_state != EXIT_ZOMBIE)
|
|
return false;
|
|
|
|
dead = !thread_group_leader(p);
|
|
|
|
if (!dead && thread_group_empty(p)) {
|
|
if (!same_thread_group(p->real_parent, tracer))
|
|
dead = do_notify_parent(p, p->exit_signal);
|
|
else if (ignoring_children(tracer->sighand)) {
|
|
__wake_up_parent(p, tracer);
|
|
dead = true;
|
|
}
|
|
}
|
|
/* Mark it as in the process of being reaped. */
|
|
if (dead)
|
|
p->exit_state = EXIT_DEAD;
|
|
return dead;
|
|
}
|
|
|
|
static int ptrace_detach(struct task_struct *child, unsigned int data)
|
|
{
|
|
if (!valid_signal(data))
|
|
return -EIO;
|
|
|
|
/* Architecture-specific hardware disable .. */
|
|
ptrace_disable(child);
|
|
|
|
write_lock_irq(&tasklist_lock);
|
|
/*
|
|
* We rely on ptrace_freeze_traced(). It can't be killed and
|
|
* untraced by another thread, it can't be a zombie.
|
|
*/
|
|
WARN_ON(!child->ptrace || child->exit_state);
|
|
/*
|
|
* tasklist_lock avoids the race with wait_task_stopped(), see
|
|
* the comment in ptrace_resume().
|
|
*/
|
|
child->exit_code = data;
|
|
__ptrace_detach(current, child);
|
|
write_unlock_irq(&tasklist_lock);
|
|
|
|
proc_ptrace_connector(child, PTRACE_DETACH);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Detach all tasks we were using ptrace on. Called with tasklist held
|
|
* for writing.
|
|
*/
|
|
void exit_ptrace(struct task_struct *tracer, struct list_head *dead)
|
|
{
|
|
struct task_struct *p, *n;
|
|
|
|
list_for_each_entry_safe(p, n, &tracer->ptraced, ptrace_entry) {
|
|
if (unlikely(p->ptrace & PT_EXITKILL))
|
|
send_sig_info(SIGKILL, SEND_SIG_PRIV, p);
|
|
|
|
if (__ptrace_detach(tracer, p))
|
|
list_add(&p->ptrace_entry, dead);
|
|
}
|
|
}
|
|
|
|
int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len)
|
|
{
|
|
int copied = 0;
|
|
|
|
while (len > 0) {
|
|
char buf[128];
|
|
int this_len, retval;
|
|
|
|
this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
|
|
retval = ptrace_access_vm(tsk, src, buf, this_len, FOLL_FORCE);
|
|
|
|
if (!retval) {
|
|
if (copied)
|
|
break;
|
|
return -EIO;
|
|
}
|
|
if (copy_to_user(dst, buf, retval))
|
|
return -EFAULT;
|
|
copied += retval;
|
|
src += retval;
|
|
dst += retval;
|
|
len -= retval;
|
|
}
|
|
return copied;
|
|
}
|
|
|
|
int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len)
|
|
{
|
|
int copied = 0;
|
|
|
|
while (len > 0) {
|
|
char buf[128];
|
|
int this_len, retval;
|
|
|
|
this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
|
|
if (copy_from_user(buf, src, this_len))
|
|
return -EFAULT;
|
|
retval = ptrace_access_vm(tsk, dst, buf, this_len,
|
|
FOLL_FORCE | FOLL_WRITE);
|
|
if (!retval) {
|
|
if (copied)
|
|
break;
|
|
return -EIO;
|
|
}
|
|
copied += retval;
|
|
src += retval;
|
|
dst += retval;
|
|
len -= retval;
|
|
}
|
|
return copied;
|
|
}
|
|
|
|
static int ptrace_setoptions(struct task_struct *child, unsigned long data)
|
|
{
|
|
unsigned flags;
|
|
|
|
if (data & ~(unsigned long)PTRACE_O_MASK)
|
|
return -EINVAL;
|
|
|
|
if (unlikely(data & PTRACE_O_SUSPEND_SECCOMP)) {
|
|
if (!IS_ENABLED(CONFIG_CHECKPOINT_RESTORE) ||
|
|
!IS_ENABLED(CONFIG_SECCOMP))
|
|
return -EINVAL;
|
|
|
|
if (!capable(CAP_SYS_ADMIN))
|
|
return -EPERM;
|
|
|
|
if (seccomp_mode(¤t->seccomp) != SECCOMP_MODE_DISABLED ||
|
|
current->ptrace & PT_SUSPEND_SECCOMP)
|
|
return -EPERM;
|
|
}
|
|
|
|
/* Avoid intermediate state when all opts are cleared */
|
|
flags = child->ptrace;
|
|
flags &= ~(PTRACE_O_MASK << PT_OPT_FLAG_SHIFT);
|
|
flags |= (data << PT_OPT_FLAG_SHIFT);
|
|
child->ptrace = flags;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int ptrace_getsiginfo(struct task_struct *child, kernel_siginfo_t *info)
|
|
{
|
|
unsigned long flags;
|
|
int error = -ESRCH;
|
|
|
|
if (lock_task_sighand(child, &flags)) {
|
|
error = -EINVAL;
|
|
if (likely(child->last_siginfo != NULL)) {
|
|
copy_siginfo(info, child->last_siginfo);
|
|
error = 0;
|
|
}
|
|
unlock_task_sighand(child, &flags);
|
|
}
|
|
return error;
|
|
}
|
|
|
|
static int ptrace_setsiginfo(struct task_struct *child, const kernel_siginfo_t *info)
|
|
{
|
|
unsigned long flags;
|
|
int error = -ESRCH;
|
|
|
|
if (lock_task_sighand(child, &flags)) {
|
|
error = -EINVAL;
|
|
if (likely(child->last_siginfo != NULL)) {
|
|
copy_siginfo(child->last_siginfo, info);
|
|
error = 0;
|
|
}
|
|
unlock_task_sighand(child, &flags);
|
|
}
|
|
return error;
|
|
}
|
|
|
|
static int ptrace_peek_siginfo(struct task_struct *child,
|
|
unsigned long addr,
|
|
unsigned long data)
|
|
{
|
|
struct ptrace_peeksiginfo_args arg;
|
|
struct sigpending *pending;
|
|
struct sigqueue *q;
|
|
int ret, i;
|
|
|
|
ret = copy_from_user(&arg, (void __user *) addr,
|
|
sizeof(struct ptrace_peeksiginfo_args));
|
|
if (ret)
|
|
return -EFAULT;
|
|
|
|
if (arg.flags & ~PTRACE_PEEKSIGINFO_SHARED)
|
|
return -EINVAL; /* unknown flags */
|
|
|
|
if (arg.nr < 0)
|
|
return -EINVAL;
|
|
|
|
if (arg.flags & PTRACE_PEEKSIGINFO_SHARED)
|
|
pending = &child->signal->shared_pending;
|
|
else
|
|
pending = &child->pending;
|
|
|
|
for (i = 0; i < arg.nr; ) {
|
|
kernel_siginfo_t info;
|
|
s32 off = arg.off + i;
|
|
|
|
spin_lock_irq(&child->sighand->siglock);
|
|
list_for_each_entry(q, &pending->list, list) {
|
|
if (!off--) {
|
|
copy_siginfo(&info, &q->info);
|
|
break;
|
|
}
|
|
}
|
|
spin_unlock_irq(&child->sighand->siglock);
|
|
|
|
if (off >= 0) /* beyond the end of the list */
|
|
break;
|
|
|
|
#ifdef CONFIG_COMPAT
|
|
if (unlikely(in_compat_syscall())) {
|
|
compat_siginfo_t __user *uinfo = compat_ptr(data);
|
|
|
|
if (copy_siginfo_to_user32(uinfo, &info)) {
|
|
ret = -EFAULT;
|
|
break;
|
|
}
|
|
|
|
} else
|
|
#endif
|
|
{
|
|
siginfo_t __user *uinfo = (siginfo_t __user *) data;
|
|
|
|
if (copy_siginfo_to_user(uinfo, &info)) {
|
|
ret = -EFAULT;
|
|
break;
|
|
}
|
|
}
|
|
|
|
data += sizeof(siginfo_t);
|
|
i++;
|
|
|
|
if (signal_pending(current))
|
|
break;
|
|
|
|
cond_resched();
|
|
}
|
|
|
|
if (i > 0)
|
|
return i;
|
|
|
|
return ret;
|
|
}
|
|
|
|
#ifdef PTRACE_SINGLESTEP
|
|
#define is_singlestep(request) ((request) == PTRACE_SINGLESTEP)
|
|
#else
|
|
#define is_singlestep(request) 0
|
|
#endif
|
|
|
|
#ifdef PTRACE_SINGLEBLOCK
|
|
#define is_singleblock(request) ((request) == PTRACE_SINGLEBLOCK)
|
|
#else
|
|
#define is_singleblock(request) 0
|
|
#endif
|
|
|
|
#ifdef PTRACE_SYSEMU
|
|
#define is_sysemu_singlestep(request) ((request) == PTRACE_SYSEMU_SINGLESTEP)
|
|
#else
|
|
#define is_sysemu_singlestep(request) 0
|
|
#endif
|
|
|
|
static int ptrace_resume(struct task_struct *child, long request,
|
|
unsigned long data)
|
|
{
|
|
bool need_siglock;
|
|
|
|
if (!valid_signal(data))
|
|
return -EIO;
|
|
|
|
if (request == PTRACE_SYSCALL)
|
|
set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
|
|
else
|
|
clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
|
|
|
|
#ifdef TIF_SYSCALL_EMU
|
|
if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP)
|
|
set_tsk_thread_flag(child, TIF_SYSCALL_EMU);
|
|
else
|
|
clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
|
|
#endif
|
|
|
|
if (is_singleblock(request)) {
|
|
if (unlikely(!arch_has_block_step()))
|
|
return -EIO;
|
|
user_enable_block_step(child);
|
|
} else if (is_singlestep(request) || is_sysemu_singlestep(request)) {
|
|
if (unlikely(!arch_has_single_step()))
|
|
return -EIO;
|
|
user_enable_single_step(child);
|
|
} else {
|
|
user_disable_single_step(child);
|
|
}
|
|
|
|
/*
|
|
* Change ->exit_code and ->state under siglock to avoid the race
|
|
* with wait_task_stopped() in between; a non-zero ->exit_code will
|
|
* wrongly look like another report from tracee.
|
|
*
|
|
* 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
|
|
* 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);
|
|
if (need_siglock)
|
|
spin_lock_irq(&child->sighand->siglock);
|
|
child->exit_code = data;
|
|
wake_up_state(child, __TASK_TRACED);
|
|
if (need_siglock)
|
|
spin_unlock_irq(&child->sighand->siglock);
|
|
|
|
return 0;
|
|
}
|
|
|
|
#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
|
|
|
|
static const struct user_regset *
|
|
find_regset(const struct user_regset_view *view, unsigned int type)
|
|
{
|
|
const struct user_regset *regset;
|
|
int n;
|
|
|
|
for (n = 0; n < view->n; ++n) {
|
|
regset = view->regsets + n;
|
|
if (regset->core_note_type == type)
|
|
return regset;
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
|
|
static int ptrace_regset(struct task_struct *task, int req, unsigned int type,
|
|
struct iovec *kiov)
|
|
{
|
|
const struct user_regset_view *view = task_user_regset_view(task);
|
|
const struct user_regset *regset = find_regset(view, type);
|
|
int regset_no;
|
|
|
|
if (!regset || (kiov->iov_len % regset->size) != 0)
|
|
return -EINVAL;
|
|
|
|
regset_no = regset - view->regsets;
|
|
kiov->iov_len = min(kiov->iov_len,
|
|
(__kernel_size_t) (regset->n * regset->size));
|
|
|
|
if (req == PTRACE_GETREGSET)
|
|
return copy_regset_to_user(task, view, regset_no, 0,
|
|
kiov->iov_len, kiov->iov_base);
|
|
else
|
|
return copy_regset_from_user(task, view, regset_no, 0,
|
|
kiov->iov_len, kiov->iov_base);
|
|
}
|
|
|
|
/*
|
|
* This is declared in linux/regset.h and defined in machine-dependent
|
|
* code. We put the export here, near the primary machine-neutral use,
|
|
* to ensure no machine forgets it.
|
|
*/
|
|
EXPORT_SYMBOL_GPL(task_user_regset_view);
|
|
#endif
|
|
|
|
int ptrace_request(struct task_struct *child, long request,
|
|
unsigned long addr, unsigned long data)
|
|
{
|
|
bool seized = child->ptrace & PT_SEIZED;
|
|
int ret = -EIO;
|
|
kernel_siginfo_t siginfo, *si;
|
|
void __user *datavp = (void __user *) data;
|
|
unsigned long __user *datalp = datavp;
|
|
unsigned long flags;
|
|
|
|
switch (request) {
|
|
case PTRACE_PEEKTEXT:
|
|
case PTRACE_PEEKDATA:
|
|
return generic_ptrace_peekdata(child, addr, data);
|
|
case PTRACE_POKETEXT:
|
|
case PTRACE_POKEDATA:
|
|
return generic_ptrace_pokedata(child, addr, data);
|
|
|
|
#ifdef PTRACE_OLDSETOPTIONS
|
|
case PTRACE_OLDSETOPTIONS:
|
|
#endif
|
|
case PTRACE_SETOPTIONS:
|
|
ret = ptrace_setoptions(child, data);
|
|
break;
|
|
case PTRACE_GETEVENTMSG:
|
|
ret = put_user(child->ptrace_message, datalp);
|
|
break;
|
|
|
|
case PTRACE_PEEKSIGINFO:
|
|
ret = ptrace_peek_siginfo(child, addr, data);
|
|
break;
|
|
|
|
case PTRACE_GETSIGINFO:
|
|
ret = ptrace_getsiginfo(child, &siginfo);
|
|
if (!ret)
|
|
ret = copy_siginfo_to_user(datavp, &siginfo);
|
|
break;
|
|
|
|
case PTRACE_SETSIGINFO:
|
|
ret = copy_siginfo_from_user(&siginfo, datavp);
|
|
if (!ret)
|
|
ret = ptrace_setsiginfo(child, &siginfo);
|
|
break;
|
|
|
|
case PTRACE_GETSIGMASK: {
|
|
sigset_t *mask;
|
|
|
|
if (addr != sizeof(sigset_t)) {
|
|
ret = -EINVAL;
|
|
break;
|
|
}
|
|
|
|
if (test_tsk_restore_sigmask(child))
|
|
mask = &child->saved_sigmask;
|
|
else
|
|
mask = &child->blocked;
|
|
|
|
if (copy_to_user(datavp, mask, sizeof(sigset_t)))
|
|
ret = -EFAULT;
|
|
else
|
|
ret = 0;
|
|
|
|
break;
|
|
}
|
|
|
|
case PTRACE_SETSIGMASK: {
|
|
sigset_t new_set;
|
|
|
|
if (addr != sizeof(sigset_t)) {
|
|
ret = -EINVAL;
|
|
break;
|
|
}
|
|
|
|
if (copy_from_user(&new_set, datavp, sizeof(sigset_t))) {
|
|
ret = -EFAULT;
|
|
break;
|
|
}
|
|
|
|
sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
|
|
|
|
/*
|
|
* Every thread does recalc_sigpending() after resume, so
|
|
* retarget_shared_pending() and recalc_sigpending() are not
|
|
* called here.
|
|
*/
|
|
spin_lock_irq(&child->sighand->siglock);
|
|
child->blocked = new_set;
|
|
spin_unlock_irq(&child->sighand->siglock);
|
|
|
|
clear_tsk_restore_sigmask(child);
|
|
|
|
ret = 0;
|
|
break;
|
|
}
|
|
|
|
case PTRACE_INTERRUPT:
|
|
/*
|
|
* Stop tracee without any side-effect on signal or job
|
|
* control. At least one trap is guaranteed to happen
|
|
* after this request. If @child is already trapped, the
|
|
* current trap is not disturbed and another trap will
|
|
* happen after the current trap is ended with PTRACE_CONT.
|
|
*
|
|
* The actual trap might not be PTRACE_EVENT_STOP trap but
|
|
* the pending condition is cleared regardless.
|
|
*/
|
|
if (unlikely(!seized || !lock_task_sighand(child, &flags)))
|
|
break;
|
|
|
|
/*
|
|
* INTERRUPT doesn't disturb existing trap sans one
|
|
* exception. If ptracer issued LISTEN for the current
|
|
* STOP, this INTERRUPT should clear LISTEN and re-trap
|
|
* tracee into STOP.
|
|
*/
|
|
if (likely(task_set_jobctl_pending(child, JOBCTL_TRAP_STOP)))
|
|
ptrace_signal_wake_up(child, child->jobctl & JOBCTL_LISTENING);
|
|
|
|
unlock_task_sighand(child, &flags);
|
|
ret = 0;
|
|
break;
|
|
|
|
case PTRACE_LISTEN:
|
|
/*
|
|
* Listen for events. Tracee must be in STOP. It's not
|
|
* resumed per-se but is not considered to be in TRACED by
|
|
* wait(2) or ptrace(2). If an async event (e.g. group
|
|
* stop state change) happens, tracee will enter STOP trap
|
|
* again. Alternatively, ptracer can issue INTERRUPT to
|
|
* finish listening and re-trap tracee into STOP.
|
|
*/
|
|
if (unlikely(!seized || !lock_task_sighand(child, &flags)))
|
|
break;
|
|
|
|
si = child->last_siginfo;
|
|
if (likely(si && (si->si_code >> 8) == PTRACE_EVENT_STOP)) {
|
|
child->jobctl |= JOBCTL_LISTENING;
|
|
/*
|
|
* If NOTIFY is set, it means event happened between
|
|
* start of this trap and now. Trigger re-trap.
|
|
*/
|
|
if (child->jobctl & JOBCTL_TRAP_NOTIFY)
|
|
ptrace_signal_wake_up(child, true);
|
|
ret = 0;
|
|
}
|
|
unlock_task_sighand(child, &flags);
|
|
break;
|
|
|
|
case PTRACE_DETACH: /* detach a process that was attached. */
|
|
ret = ptrace_detach(child, data);
|
|
break;
|
|
|
|
#ifdef CONFIG_BINFMT_ELF_FDPIC
|
|
case PTRACE_GETFDPIC: {
|
|
struct mm_struct *mm = get_task_mm(child);
|
|
unsigned long tmp = 0;
|
|
|
|
ret = -ESRCH;
|
|
if (!mm)
|
|
break;
|
|
|
|
switch (addr) {
|
|
case PTRACE_GETFDPIC_EXEC:
|
|
tmp = mm->context.exec_fdpic_loadmap;
|
|
break;
|
|
case PTRACE_GETFDPIC_INTERP:
|
|
tmp = mm->context.interp_fdpic_loadmap;
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
mmput(mm);
|
|
|
|
ret = put_user(tmp, datalp);
|
|
break;
|
|
}
|
|
#endif
|
|
|
|
#ifdef PTRACE_SINGLESTEP
|
|
case PTRACE_SINGLESTEP:
|
|
#endif
|
|
#ifdef PTRACE_SINGLEBLOCK
|
|
case PTRACE_SINGLEBLOCK:
|
|
#endif
|
|
#ifdef PTRACE_SYSEMU
|
|
case PTRACE_SYSEMU:
|
|
case PTRACE_SYSEMU_SINGLESTEP:
|
|
#endif
|
|
case PTRACE_SYSCALL:
|
|
case PTRACE_CONT:
|
|
return ptrace_resume(child, request, data);
|
|
|
|
case PTRACE_KILL:
|
|
if (child->exit_state) /* already dead */
|
|
return 0;
|
|
return ptrace_resume(child, request, SIGKILL);
|
|
|
|
#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
|
|
case PTRACE_GETREGSET:
|
|
case PTRACE_SETREGSET: {
|
|
struct iovec kiov;
|
|
struct iovec __user *uiov = datavp;
|
|
|
|
if (!access_ok(uiov, sizeof(*uiov)))
|
|
return -EFAULT;
|
|
|
|
if (__get_user(kiov.iov_base, &uiov->iov_base) ||
|
|
__get_user(kiov.iov_len, &uiov->iov_len))
|
|
return -EFAULT;
|
|
|
|
ret = ptrace_regset(child, request, addr, &kiov);
|
|
if (!ret)
|
|
ret = __put_user(kiov.iov_len, &uiov->iov_len);
|
|
break;
|
|
}
|
|
#endif
|
|
|
|
case PTRACE_SECCOMP_GET_FILTER:
|
|
ret = seccomp_get_filter(child, addr, datavp);
|
|
break;
|
|
|
|
case PTRACE_SECCOMP_GET_METADATA:
|
|
ret = seccomp_get_metadata(child, addr, datavp);
|
|
break;
|
|
|
|
default:
|
|
break;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
#ifndef arch_ptrace_attach
|
|
#define arch_ptrace_attach(child) do { } while (0)
|
|
#endif
|
|
|
|
SYSCALL_DEFINE4(ptrace, long, request, long, pid, unsigned long, addr,
|
|
unsigned long, data)
|
|
{
|
|
struct task_struct *child;
|
|
long ret;
|
|
|
|
if (request == PTRACE_TRACEME) {
|
|
ret = ptrace_traceme();
|
|
if (!ret)
|
|
arch_ptrace_attach(current);
|
|
goto out;
|
|
}
|
|
|
|
child = find_get_task_by_vpid(pid);
|
|
if (!child) {
|
|
ret = -ESRCH;
|
|
goto out;
|
|
}
|
|
|
|
if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
|
|
ret = ptrace_attach(child, request, addr, data);
|
|
/*
|
|
* Some architectures need to do book-keeping after
|
|
* a ptrace attach.
|
|
*/
|
|
if (!ret)
|
|
arch_ptrace_attach(child);
|
|
goto out_put_task_struct;
|
|
}
|
|
|
|
ret = ptrace_check_attach(child, request == PTRACE_KILL ||
|
|
request == PTRACE_INTERRUPT);
|
|
if (ret < 0)
|
|
goto out_put_task_struct;
|
|
|
|
ret = arch_ptrace(child, request, addr, data);
|
|
if (ret || request != PTRACE_DETACH)
|
|
ptrace_unfreeze_traced(child);
|
|
|
|
out_put_task_struct:
|
|
put_task_struct(child);
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr,
|
|
unsigned long data)
|
|
{
|
|
unsigned long tmp;
|
|
int copied;
|
|
|
|
copied = ptrace_access_vm(tsk, addr, &tmp, sizeof(tmp), FOLL_FORCE);
|
|
if (copied != sizeof(tmp))
|
|
return -EIO;
|
|
return put_user(tmp, (unsigned long __user *)data);
|
|
}
|
|
|
|
int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
|
|
unsigned long data)
|
|
{
|
|
int copied;
|
|
|
|
copied = ptrace_access_vm(tsk, addr, &data, sizeof(data),
|
|
FOLL_FORCE | FOLL_WRITE);
|
|
return (copied == sizeof(data)) ? 0 : -EIO;
|
|
}
|
|
|
|
#if defined CONFIG_COMPAT
|
|
|
|
int compat_ptrace_request(struct task_struct *child, compat_long_t request,
|
|
compat_ulong_t addr, compat_ulong_t data)
|
|
{
|
|
compat_ulong_t __user *datap = compat_ptr(data);
|
|
compat_ulong_t word;
|
|
kernel_siginfo_t siginfo;
|
|
int ret;
|
|
|
|
switch (request) {
|
|
case PTRACE_PEEKTEXT:
|
|
case PTRACE_PEEKDATA:
|
|
ret = ptrace_access_vm(child, addr, &word, sizeof(word),
|
|
FOLL_FORCE);
|
|
if (ret != sizeof(word))
|
|
ret = -EIO;
|
|
else
|
|
ret = put_user(word, datap);
|
|
break;
|
|
|
|
case PTRACE_POKETEXT:
|
|
case PTRACE_POKEDATA:
|
|
ret = ptrace_access_vm(child, addr, &data, sizeof(data),
|
|
FOLL_FORCE | FOLL_WRITE);
|
|
ret = (ret != sizeof(data) ? -EIO : 0);
|
|
break;
|
|
|
|
case PTRACE_GETEVENTMSG:
|
|
ret = put_user((compat_ulong_t) child->ptrace_message, datap);
|
|
break;
|
|
|
|
case PTRACE_GETSIGINFO:
|
|
ret = ptrace_getsiginfo(child, &siginfo);
|
|
if (!ret)
|
|
ret = copy_siginfo_to_user32(
|
|
(struct compat_siginfo __user *) datap,
|
|
&siginfo);
|
|
break;
|
|
|
|
case PTRACE_SETSIGINFO:
|
|
ret = copy_siginfo_from_user32(
|
|
&siginfo, (struct compat_siginfo __user *) datap);
|
|
if (!ret)
|
|
ret = ptrace_setsiginfo(child, &siginfo);
|
|
break;
|
|
#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
|
|
case PTRACE_GETREGSET:
|
|
case PTRACE_SETREGSET:
|
|
{
|
|
struct iovec kiov;
|
|
struct compat_iovec __user *uiov =
|
|
(struct compat_iovec __user *) datap;
|
|
compat_uptr_t ptr;
|
|
compat_size_t len;
|
|
|
|
if (!access_ok(uiov, sizeof(*uiov)))
|
|
return -EFAULT;
|
|
|
|
if (__get_user(ptr, &uiov->iov_base) ||
|
|
__get_user(len, &uiov->iov_len))
|
|
return -EFAULT;
|
|
|
|
kiov.iov_base = compat_ptr(ptr);
|
|
kiov.iov_len = len;
|
|
|
|
ret = ptrace_regset(child, request, addr, &kiov);
|
|
if (!ret)
|
|
ret = __put_user(kiov.iov_len, &uiov->iov_len);
|
|
break;
|
|
}
|
|
#endif
|
|
|
|
default:
|
|
ret = ptrace_request(child, request, addr, data);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
COMPAT_SYSCALL_DEFINE4(ptrace, compat_long_t, request, compat_long_t, pid,
|
|
compat_long_t, addr, compat_long_t, data)
|
|
{
|
|
struct task_struct *child;
|
|
long ret;
|
|
|
|
if (request == PTRACE_TRACEME) {
|
|
ret = ptrace_traceme();
|
|
goto out;
|
|
}
|
|
|
|
child = find_get_task_by_vpid(pid);
|
|
if (!child) {
|
|
ret = -ESRCH;
|
|
goto out;
|
|
}
|
|
|
|
if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
|
|
ret = ptrace_attach(child, request, addr, data);
|
|
/*
|
|
* Some architectures need to do book-keeping after
|
|
* a ptrace attach.
|
|
*/
|
|
if (!ret)
|
|
arch_ptrace_attach(child);
|
|
goto out_put_task_struct;
|
|
}
|
|
|
|
ret = ptrace_check_attach(child, request == PTRACE_KILL ||
|
|
request == PTRACE_INTERRUPT);
|
|
if (!ret) {
|
|
ret = compat_arch_ptrace(child, request, addr, data);
|
|
if (ret || request != PTRACE_DETACH)
|
|
ptrace_unfreeze_traced(child);
|
|
}
|
|
|
|
out_put_task_struct:
|
|
put_task_struct(child);
|
|
out:
|
|
return ret;
|
|
}
|
|
#endif /* CONFIG_COMPAT */
|