/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_PTRACE_H
#define _LINUX_PTRACE_H
#include <linux/compiler.h> /* For unlikely. */
#include <linux/sched.h> /* For struct task_struct. */
#include <linux/sched/signal.h> /* For send_sig(), same_thread_group(), etc. */
#include <linux/err.h> /* for IS_ERR_VALUE */
#include <linux/bug.h> /* For BUG_ON. */
#include <linux/pid_namespace.h> /* For task_active_pid_ns. */
#include <uapi/linux/ptrace.h>
#include <linux/seccomp.h>
/* Add sp to seccomp_data, as seccomp is user API, we don't want to modify it */
struct syscall_info {
__u64 sp;
struct seccomp_data data;
};
extern int ptrace_access_vm(struct task_struct *tsk, unsigned long addr,
void *buf, int len, unsigned int gup_flags);
/*
* Ptrace flags
*
* The owner ship rules for task->ptrace which holds the ptrace
* flags is simple. When a task is running it owns it's task->ptrace
* flags. When the a task is stopped the ptracer owns task->ptrace.
*/
#define PT_SEIZED 0x00010000 /* SEIZE used, enable new behavior */
#define PT_PTRACED 0x00000001
#define PT_OPT_FLAG_SHIFT 3
/* PT_TRACE_* event enable flags */
#define PT_EVENT_FLAG(event) (1 << (PT_OPT_FLAG_SHIFT + (event)))
#define PT_TRACESYSGOOD PT_EVENT_FLAG(0)
#define PT_TRACE_FORK PT_EVENT_FLAG(PTRACE_EVENT_FORK)
#define PT_TRACE_VFORK PT_EVENT_FLAG(PTRACE_EVENT_VFORK)
#define PT_TRACE_CLONE PT_EVENT_FLAG(PTRACE_EVENT_CLONE)
#define PT_TRACE_EXEC PT_EVENT_FLAG(PTRACE_EVENT_EXEC)
#define PT_TRACE_VFORK_DONE PT_EVENT_FLAG(PTRACE_EVENT_VFORK_DONE)
#define PT_TRACE_EXIT PT_EVENT_FLAG(PTRACE_EVENT_EXIT)
#define PT_TRACE_SECCOMP PT_EVENT_FLAG(PTRACE_EVENT_SECCOMP)
#define PT_EXITKILL (PTRACE_O_EXITKILL << PT_OPT_FLAG_SHIFT)
#define PT_SUSPEND_SECCOMP (PTRACE_O_SUSPEND_SECCOMP << PT_OPT_FLAG_SHIFT)
extern long arch_ptrace(struct task_struct *child, long request,
unsigned long addr, unsigned long data);
extern int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len);
extern int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len);
extern void ptrace_disable(struct task_struct *);
extern int ptrace_request(struct task_struct *child, long request,
unsigned long addr, unsigned long data);
extern int 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);
extern void __ptrace_unlink(struct task_struct *child);
extern void exit_ptrace(struct task_struct *tracer, struct list_head *dead);
#define PTRACE_MODE_READ 0x01
#define PTRACE_MODE_ATTACH 0x02
#define PTRACE_MODE_NOAUDIT 0x04
#define PTRACE_MODE_FSCREDS 0x08
#define PTRACE_MODE_REALCREDS 0x10
/* shorthands for READ/ATTACH and FSCREDS/REALCREDS combinations */
#define PTRACE_MODE_READ_FSCREDS (PTRACE_MODE_READ | PTRACE_MODE_FSCREDS)
#define PTRACE_MODE_READ_REALCREDS (PTRACE_MODE_READ | PTRACE_MODE_REALCREDS)
#define PTRACE_MODE_ATTACH_FSCREDS (PTRACE_MODE_ATTACH | PTRACE_MODE_FSCREDS)
#define PTRACE_MODE_ATTACH_REALCREDS (PTRACE_MODE_ATTACH | PTRACE_MODE_REALCREDS)
/**
* ptrace_may_access - check whether the caller is permitted to access
* a target task.
* @task: target task
* @mode: selects type of access and caller credentials
*
* Returns true on success, false on denial.
*
* One of the flags PTRACE_MODE_FSCREDS and PTRACE_MODE_REALCREDS must
* be set in @mode to specify whether the access was requested through
* a filesystem syscall (should use effective capabilities and fsuid
* of the caller) or through an explicit syscall such as
* process_vm_writev or ptrace (and should use the real credentials).
*/
extern bool ptrace_may_access(struct task_struct *task, unsigned int mode);
static inline int ptrace_reparented(struct task_struct *child)
{
return !same_thread_group(child->real_parent, child->parent);
}
static inline void ptrace_unlink(struct task_struct *child)
{
if (unlikely(child->ptrace))
__ptrace_unlink(child);
}
int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr,
unsigned long data);
int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
unsigned long data);
/**
* ptrace_parent - return the task that is tracing the given task
* @task: task to consider
*
* Returns %NULL if no one is tracing @task, or the &struct task_struct
* pointer to its tracer.
*
* Must called under rcu_read_lock(). The pointer returned might be kept
* live only by RCU. During exec, this may be called with task_lock() held
* on @task, still held from when check_unsafe_exec() was called.
*/
static inline struct task_struct *ptrace_parent(struct task_struct *task)
{
if (unlikely(task->ptrace))
return rcu_dereference(task->parent);
return NULL;
}
/**
* ptrace_event_enabled - test whether a ptrace event is enabled
* @task: ptracee of interest
* @event: %PTRACE_EVENT_* to test
*
* Test whether @event is enabled for ptracee @task.
*
* Returns %true if @event is enabled, %false otherwise.
*/
static inline bool ptrace_event_enabled(struct task_struct *task, int event)
{
return task->ptrace & PT_EVENT_FLAG(event);
}
/**
* ptrace_event - possibly stop for a ptrace event notification
* @event: %PTRACE_EVENT_* value to report
* @message: value for %PTRACE_GETEVENTMSG to return
*
* Check whether @event is enabled and, if so, report @event and @message
* to the ptrace parent.
*
* Called without locks.
*/
static inline void ptrace_event(int event, unsigned long message)
{
if (unlikely(ptrace_event_enabled(current, event))) {
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)
send_sig(SIGTRAP, current, 0);
}
}
/**
* ptrace_event_pid - possibly stop for a ptrace event notification
* @event: %PTRACE_EVENT_* value to report
* @pid: process identifier for %PTRACE_GETEVENTMSG to return
*
* Check whether @event is enabled and, if so, report @event and @pid
* to the ptrace parent. @pid is reported as the pid_t seen from the
* ptrace parent's pid namespace.
*
* Called without locks.
*/
static inline void ptrace_event_pid(int event, struct pid *pid)
{
/*
* FIXME: There's a potential race if a ptracer in a different pid
* namespace than parent attaches between computing message below and
* when we acquire tasklist_lock in ptrace_stop(). If this happens,
* the ptracer will get a bogus pid from PTRACE_GETEVENTMSG.
*/
unsigned long message = 0;
struct pid_namespace *ns;
rcu_read_lock();
ns = task_active_pid_ns(rcu_dereference(current->parent));
if (ns)
message = pid_nr_ns(pid, ns);
rcu_read_unlock();
ptrace_event(event, message);
}
/**
* ptrace_init_task - initialize ptrace state for a new child
* @child: new child task
* @ptrace: true if child should be ptrace'd by parent's tracer
*
* This is called immediately after adding @child to its parent's children
* list. @ptrace is false in the normal case, and true to ptrace @child.
*
* Called with current's siglock and write_lock_irq(&tasklist_lock) held.
*/
static inline void ptrace_init_task(struct task_struct *child, bool ptrace)
{
INIT_LIST_HEAD(&child->ptrace_entry);
INIT_LIST_HEAD(&child->ptraced);
child->jobctl = 0;
child->ptrace = 0;
child->parent = child->real_parent;
if (unlikely(ptrace) && current->ptrace) {
child->ptrace = current->ptrace;
__ptrace_link(child, current->parent, current->ptracer_cred);
if (child->ptrace & PT_SEIZED)
task_set_jobctl_pending(child, JOBCTL_TRAP_STOP);
else
sigaddset(&child->pending.signal, SIGSTOP);
}
else
child->ptracer_cred = NULL;
}
/**
* ptrace_release_task - final ptrace-related cleanup of a zombie being reaped
* @task: task in %EXIT_DEAD state
*
* Called with write_lock(&tasklist_lock) held.
*/
static inline void ptrace_release_task(struct task_struct *task)
{
BUG_ON(!list_empty(&task->ptraced));
ptrace_unlink(task);
BUG_ON(!list_empty(&task->ptrace_entry));
}
#ifndef force_successful_syscall_return
/*
* System call handlers that, upon successful completion, need to return a
* negative value should call force_successful_syscall_return() right before
* returning. On architectures where the syscall convention provides for a
* separate error flag (e.g., alpha, ia64, ppc{,64}, sparc{,64}, possibly
* others), this macro can be used to ensure that the error flag will not get
* set. On architectures which do not support a separate error flag, the macro
* is a no-op and the spurious error condition needs to be filtered out by some
* other means (e.g., in user-level, by passing an extra argument to the
* syscall handler, or something along those lines).
*/
#define force_successful_syscall_return() do { } while (0)
#endif
#ifndef is_syscall_success
/*
* On most systems we can tell if a syscall is a success based on if the retval
* is an error value. On some systems like ia64 and powerpc they have different
* indicators of success/failure and must define their own.
*/
#define is_syscall_success(regs) (!IS_ERR_VALUE((unsigned long)(regs_return_value(regs))))
#endif
/*
* <asm/ptrace.h> should define the following things inside #ifdef __KERNEL__.
*
* These do-nothing inlines are used when the arch does not
* implement single-step. The kerneldoc comments are here
* to document the interface for all arch definitions.
*/
#ifndef arch_has_single_step
/**
* arch_has_single_step - does this CPU support user-mode single-step?
*
* If this is defined, then there must be function declarations or
* inlines for user_enable_single_step() and user_disable_single_step().
* arch_has_single_step() should evaluate to nonzero iff the machine
* supports instruction single-step for user mode.
* It can be a constant or it can test a CPU feature bit.
*/
#define arch_has_single_step() (0)
/**
* user_enable_single_step - single-step in user-mode task
* @task: either current or a task stopped in %TASK_TRACED
*
* This can only be called when arch_has_single_step() has returned nonzero.
* Set @task so that when it returns to user mode, it will trap after the
* next single instruction executes. If arch_has_block_step() is defined,
* this must clear the effects of user_enable_block_step() too.
*/
static inline void user_enable_single_step(struct task_struct *task)
{
BUG(); /* This can never be called. */
}
/**
* user_disable_single_step - cancel user-mode single-step
* @task: either current or a task stopped in %TASK_TRACED
*
* Clear @task of the effects of user_enable_single_step() and
* user_enable_block_step(). This can be called whether or not either
* of those was ever called on @task, and even if arch_has_single_step()
* returned zero.
*/
static inline void user_disable_single_step(struct task_struct *task)
{
}
#else
extern void user_enable_single_step(struct task_struct *);
extern void user_disable_single_step(struct task_struct *);
#endif /* arch_has_single_step */
#ifndef arch_has_block_step
/**
* arch_has_block_step - does this CPU support user-mode block-step?
*
* If this is defined, then there must be a function declaration or inline
* for user_enable_block_step(), and arch_has_single_step() must be defined
* too. arch_has_block_step() should evaluate to nonzero iff the machine
* supports step-until-branch for user mode. It can be a constant or it
* can test a CPU feature bit.
*/
#define arch_has_block_step() (0)
/**
* user_enable_block_step - step until branch in user-mode task
* @task: either current or a task stopped in %TASK_TRACED
*
* This can only be called when arch_has_block_step() has returned nonzero,
* and will never be called when single-instruction stepping is being used.
* Set @task so that when it returns to user mode, it will trap after the
* next branch or trap taken.
*/
static inline void user_enable_block_step(struct task_struct *task)
{
BUG(); /* This can never be called. */
}
#else
extern void user_enable_block_step(struct task_struct *);
#endif /* arch_has_block_step */
#ifdef ARCH_HAS_USER_SINGLE_STEP_REPORT
extern void user_single_step_report(struct pt_regs *regs);
#else
static inline void user_single_step_report(struct pt_regs *regs)
{
kernel_siginfo_t info;
clear_siginfo(&info);
info.si_signo = SIGTRAP;
info.si_errno = 0;
info.si_code = SI_USER;
info.si_pid = 0;
info.si_uid = 0;
force_sig_info(&info);
}
#endif
#ifndef arch_ptrace_stop_needed
/**
* arch_ptrace_stop_needed - Decide whether arch_ptrace_stop() should be called
*
* This is called with the siglock held, to decide whether or not it's
* necessary to release the siglock and call arch_ptrace_stop(). It can be
* defined to a constant if arch_ptrace_stop() is never required, or always
* is. On machines where this makes sense, it should be defined to a quick
* test to optimize out calling arch_ptrace_stop() when it would be
* superfluous. For example, if the thread has not been back to user mode
* since the last stop, the thread state might indicate that nothing needs
* to be done.
*
* This is guaranteed to be invoked once before a task stops for ptrace and
* may include arch-specific operations necessary prior to a ptrace stop.
*/
#define arch_ptrace_stop_needed() (0)
#endif
#ifndef arch_ptrace_stop
/**
* arch_ptrace_stop - Do machine-specific work before stopping for ptrace
*
* This is called with no locks held when arch_ptrace_stop_needed() has
* just returned nonzero. It is allowed to block, e.g. for user memory
* access. The arch can have machine-specific work to be done before
* ptrace stops. On ia64, register backing store gets written back to user
* memory here. Since this can be costly (requires dropping the siglock),
* we only do it when the arch requires it for this particular stop, as
* indicated by arch_ptrace_stop_needed().
*/
#define arch_ptrace_stop() do { } while (0)
#endif
#ifndef current_pt_regs
#define current_pt_regs() task_pt_regs(current)
#endif
#ifndef current_user_stack_pointer
#define current_user_stack_pointer() user_stack_pointer(current_pt_regs())
#endif
extern int task_current_syscall(struct task_struct *target, struct syscall_info *info);
extern void sigaction_compat_abi(struct k_sigaction *act, struct k_sigaction *oact);
/*
* ptrace report for syscall entry and exit looks identical.
*/
static inline int ptrace_report_syscall(unsigned long message)
{
int ptrace = current->ptrace;
int signr;
if (!(ptrace & PT_PTRACED))
return 0;
signr = ptrace_notify(SIGTRAP | ((ptrace & PT_TRACESYSGOOD) ? 0x80 : 0),
message);
/*
* this isn't the same as continuing with a signal, but it will do
* for normal use. strace only continues with a signal if the
* stopping signal is not SIGTRAP. -brl
*/
if (signr)
send_sig(signr, current, 1);
return fatal_signal_pending(current);
}
/**
* ptrace_report_syscall_entry - task is about to attempt a system call
* @regs: user register state of current task
*
* This will be called if %SYSCALL_WORK_SYSCALL_TRACE or
* %SYSCALL_WORK_SYSCALL_EMU have been set, when the current task has just
* entered the kernel for a system call. Full user register state is
* available here. Changing the values in @regs can affect the system
* call number and arguments to be tried. It is safe to block here,
* preventing the system call from beginning.
*
* Returns zero normally, or nonzero if the calling arch code should abort
* the system call. That must prevent normal entry so no system call is
* made. If @task ever returns to user mode after this, its register state
* is unspecified, but should be something harmless like an %ENOSYS error
* return. It should preserve enough information so that syscall_rollback()
* can work (see asm-generic/syscall.h).
*
* Called without locks, just after entering kernel mode.
*/
static inline __must_check int ptrace_report_syscall_entry(
struct pt_regs *regs)
{
return ptrace_report_syscall(PTRACE_EVENTMSG_SYSCALL_ENTRY);
}
/**
* ptrace_report_syscall_exit - task has just finished a system call
* @regs: user register state of current task
* @step: nonzero if simulating single-step or block-step
*
* This will be called if %SYSCALL_WORK_SYSCALL_TRACE has been set, when
* the current task has just finished an attempted system call. Full
* user register state is available here. It is safe to block here,
* preventing signals from being processed.
*
* If @step is nonzero, this report is also in lieu of the normal
* trap that would follow the system call instruction because
* user_enable_block_step() or user_enable_single_step() was used.
* In this case, %SYSCALL_WORK_SYSCALL_TRACE might not be set.
*
* Called without locks, just before checking for pending signals.
*/
static inline void ptrace_report_syscall_exit(struct pt_regs *regs, int step)
{
if (step)
user_single_step_report(regs);
else
ptrace_report_syscall(PTRACE_EVENTMSG_SYSCALL_EXIT);
}
#endif
