[GitHub/mt8127/android_kernel_alcatel_ttab.git] / kernel / ptrace.c

/*
 * linux/kernel/ptrace.c
 *
 * (C) Copyright 1999 Linus Torvalds
 *
 * Common interfaces for "ptrace()" which we do not want
 * to continually duplicate across every architecture.
 */

#include <linux/capability.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/mm.h>
#include <linux/highmem.h>
#include <linux/pagemap.h>
#include <linux/smp_lock.h>
#include <linux/ptrace.h>
#include <linux/security.h>
#include <linux/signal.h>
#include <linux/audit.h>
#include <linux/pid_namespace.h>

#include <asm/pgtable.h>
#include <asm/uaccess.h>

/*
 * ptrace a task: make the debugger its new parent and
 * move it to the ptrace list.
 *
 * Must be called with the tasklist lock write-held.
 */
void __ptrace_link(struct task_struct *child, struct task_struct *new_parent)
{
	BUG_ON(!list_empty(&child->ptrace_list));
	if (child->parent == new_parent)
		return;
	list_add(&child->ptrace_list, &child->parent->ptrace_children);
	remove_parent(child);
	child->parent = new_parent;
	add_parent(child);
}
 
/*
 * Turn a tracing stop into a normal stop now, since with no tracer there
 * would be no way to wake it up with SIGCONT or SIGKILL.  If there was a
 * signal sent that would resume the child, but didn't because it was in
 * TASK_TRACED, resume it now.
 * Requires that irqs be disabled.
 */
void ptrace_untrace(struct task_struct *child)
{
	spin_lock(&child->sighand->siglock);
	if (child->state == TASK_TRACED) {
		if (child->signal->flags & SIGNAL_STOP_STOPPED) {
			child->state = TASK_STOPPED;
		} else {
			signal_wake_up(child, 1);
		}
	}
	spin_unlock(&child->sighand->siglock);
}

/*
 * unptrace a task: move it back to its original parent and
 * remove it from the ptrace list.
 *
 * Must be called with the tasklist lock write-held.
 */
void __ptrace_unlink(struct task_struct *child)
{
	BUG_ON(!child->ptrace);

	child->ptrace = 0;
	if (!list_empty(&child->ptrace_list)) {
		list_del_init(&child->ptrace_list);
		remove_parent(child);
		child->parent = child->real_parent;
		add_parent(child);
	}

	if (child->state == TASK_TRACED)
		ptrace_untrace(child);
}

/*
 * Check that we have indeed attached to the thing..
 */
int ptrace_check_attach(struct task_struct *child, int kill)
{
	int ret = -ESRCH;

	/*
	 * We take the read lock around doing both checks to close a
	 * possible race where someone else was tracing our child and
	 * detached between these two checks.  After this locked check,
	 * we are sure that this is our traced child and that can only
	 * be changed by us so it's not changing right after this.
	 */
	read_lock(&tasklist_lock);
	if ((child->ptrace & PT_PTRACED) && child->parent == current &&
	    (!(child->ptrace & PT_ATTACHED) || child->real_parent != current)
	    && child->signal != NULL) {
		ret = 0;
		spin_lock_irq(&child->sighand->siglock);
		if (child->state == TASK_STOPPED) {
			child->state = TASK_TRACED;
		} else if (child->state != TASK_TRACED && !kill) {
			ret = -ESRCH;
		}
		spin_unlock_irq(&child->sighand->siglock);
	}
	read_unlock(&tasklist_lock);

	if (!ret && !kill) {
		wait_task_inactive(child);
	}

	/* All systems go.. */
	return ret;
}

static int may_attach(struct task_struct *task)
{
	/* May we inspect the given task?
	 * This check is used both for attaching with ptrace
	 * and for allowing access to sensitive information in /proc.
	 *
	 * ptrace_attach denies several cases that /proc allows
	 * because setting up the necessary parent/child relationship
	 * or halting the specified task is impossible.
	 */
	int dumpable = 0;
	/* Don't let security modules deny introspection */
	if (task == current)
		return 0;
	if (((current->uid != task->euid) ||
	     (current->uid != task->suid) ||
	     (current->uid != task->uid) ||
	     (current->gid != task->egid) ||
	     (current->gid != task->sgid) ||
	     (current->gid != task->gid)) && !capable(CAP_SYS_PTRACE))
		return -EPERM;
	smp_rmb();
	if (task->mm)
		dumpable = get_dumpable(task->mm);
	if (!dumpable && !capable(CAP_SYS_PTRACE))
		return -EPERM;

	return security_ptrace(current, task);
}

int ptrace_may_attach(struct task_struct *task)
{
	int err;
	task_lock(task);
	err = may_attach(task);
	task_unlock(task);
	return !err;
}

int ptrace_attach(struct task_struct *task)
{
	int retval;
	unsigned long flags;

	audit_ptrace(task);

	retval = -EPERM;
	if (task->pid <= 1)
		goto out;
	if (task->tgid == current->tgid)
		goto out;

repeat:
	/*
	 * Nasty, nasty.
	 *
	 * We want to hold both the task-lock and the
	 * tasklist_lock for writing at the same time.
	 * But that's against the rules (tasklist_lock
	 * is taken for reading by interrupts on other
	 * cpu's that may have task_lock).
	 */
	task_lock(task);
	if (!write_trylock_irqsave(&tasklist_lock, flags)) {
		task_unlock(task);
		do {
			cpu_relax();
		} while (!write_can_lock(&tasklist_lock));
		goto repeat;
	}

	if (!task->mm)
		goto bad;
	/* the same process cannot be attached many times */
	if (task->ptrace & PT_PTRACED)
		goto bad;
	retval = may_attach(task);
	if (retval)
		goto bad;

	/* Go */
	task->ptrace |= PT_PTRACED | ((task->real_parent != current)
				      ? PT_ATTACHED : 0);
	if (capable(CAP_SYS_PTRACE))
		task->ptrace |= PT_PTRACE_CAP;

	__ptrace_link(task, current);

	force_sig_specific(SIGSTOP, task);

bad:
	write_unlock_irqrestore(&tasklist_lock, flags);
	task_unlock(task);
out:
	return retval;
}

static inline void __ptrace_detach(struct task_struct *child, unsigned int data)
{
	child->exit_code = data;
	/* .. re-parent .. */
	__ptrace_unlink(child);
	/* .. and wake it up. */
	if (child->exit_state != EXIT_ZOMBIE)
		wake_up_process(child);
}

int ptrace_detach(struct task_struct *child, unsigned int data)
{
	if (!valid_signal(data))
		return -EIO;

	/* Architecture-specific hardware disable .. */
	ptrace_disable(child);
	clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);

	write_lock_irq(&tasklist_lock);
	/* protect against de_thread()->release_task() */
	if (child->ptrace)
		__ptrace_detach(child, data);
	write_unlock_irq(&tasklist_lock);

	return 0;
}

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 = access_process_vm(tsk, src, buf, this_len, 0);
		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 = access_process_vm(tsk, dst, buf, this_len, 1);
		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, long data)
{
	child->ptrace &= ~PT_TRACE_MASK;

	if (data & PTRACE_O_TRACESYSGOOD)
		child->ptrace |= PT_TRACESYSGOOD;

	if (data & PTRACE_O_TRACEFORK)
		child->ptrace |= PT_TRACE_FORK;

	if (data & PTRACE_O_TRACEVFORK)
		child->ptrace |= PT_TRACE_VFORK;

	if (data & PTRACE_O_TRACECLONE)
		child->ptrace |= PT_TRACE_CLONE;

	if (data & PTRACE_O_TRACEEXEC)
		child->ptrace |= PT_TRACE_EXEC;

	if (data & PTRACE_O_TRACEVFORKDONE)
		child->ptrace |= PT_TRACE_VFORK_DONE;

	if (data & PTRACE_O_TRACEEXIT)
		child->ptrace |= PT_TRACE_EXIT;

	return (data & ~PTRACE_O_MASK) ? -EINVAL : 0;
}

static int ptrace_getsiginfo(struct task_struct *child, siginfo_t __user * data)
{
	siginfo_t lastinfo;
	int error = -ESRCH;

	read_lock(&tasklist_lock);
	if (likely(child->sighand != NULL)) {
		error = -EINVAL;
		spin_lock_irq(&child->sighand->siglock);
		if (likely(child->last_siginfo != NULL)) {
			lastinfo = *child->last_siginfo;
			error = 0;
		}
		spin_unlock_irq(&child->sighand->siglock);
	}
	read_unlock(&tasklist_lock);
	if (!error)
		return copy_siginfo_to_user(data, &lastinfo);
	return error;
}

static int ptrace_setsiginfo(struct task_struct *child, siginfo_t __user * data)
{
	siginfo_t newinfo;
	int error = -ESRCH;

	if (copy_from_user(&newinfo, data, sizeof (siginfo_t)))
		return -EFAULT;

	read_lock(&tasklist_lock);
	if (likely(child->sighand != NULL)) {
		error = -EINVAL;
		spin_lock_irq(&child->sighand->siglock);
		if (likely(child->last_siginfo != NULL)) {
			*child->last_siginfo = newinfo;
			error = 0;
		}
		spin_unlock_irq(&child->sighand->siglock);
	}
	read_unlock(&tasklist_lock);
	return error;
}

int ptrace_request(struct task_struct *child, long request,
		   long addr, long data)
{
	int ret = -EIO;

	switch (request) {
#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, (unsigned long __user *) data);
		break;
	case PTRACE_GETSIGINFO:
		ret = ptrace_getsiginfo(child, (siginfo_t __user *) data);
		break;
	case PTRACE_SETSIGINFO:
		ret = ptrace_setsiginfo(child, (siginfo_t __user *) data);
		break;
	case PTRACE_DETACH:	 /* detach a process that was attached. */
		ret = ptrace_detach(child, data);
		break;
	default:
		break;
	}

	return ret;
}

/**
 * ptrace_traceme  --  helper for PTRACE_TRACEME
 *
 * Performs checks and sets PT_PTRACED.
 * Should be used by all ptrace implementations for PTRACE_TRACEME.
 */
int ptrace_traceme(void)
{
	int ret = -EPERM;

	/*
	 * Are we already being traced?
	 */
	task_lock(current);
	if (!(current->ptrace & PT_PTRACED)) {
		ret = security_ptrace(current->parent, current);
		/*
		 * Set the ptrace bit in the process ptrace flags.
		 */
		if (!ret)
			current->ptrace |= PT_PTRACED;
	}
	task_unlock(current);
	return ret;
}

/**
 * ptrace_get_task_struct  --  grab a task struct reference for ptrace
 * @pid:       process id to grab a task_struct reference of
 *
 * This function is a helper for ptrace implementations.  It checks
 * permissions and then grabs a task struct for use of the actual
 * ptrace implementation.
 *
 * Returns the task_struct for @pid or an ERR_PTR() on failure.
 */
struct task_struct *ptrace_get_task_struct(pid_t pid)
{
	struct task_struct *child;

	/*
	 * Tracing init is not allowed.
	 */
	if (pid == 1)
		return ERR_PTR(-EPERM);

	read_lock(&tasklist_lock);
	child = find_task_by_pid_ns(pid,
			current->nsproxy->pid_ns);
	if (child)
		get_task_struct(child);

	read_unlock(&tasklist_lock);
	if (!child)
		return ERR_PTR(-ESRCH);
	return child;
}

#ifndef arch_ptrace_attach
#define arch_ptrace_attach(child)	do { } while (0)
#endif

#ifndef __ARCH_SYS_PTRACE
asmlinkage long sys_ptrace(long request, long pid, long addr, long data)
{
	struct task_struct *child;
	long ret;

	/*
	 * This lock_kernel fixes a subtle race with suid exec
	 */
	lock_kernel();
	if (request == PTRACE_TRACEME) {
		ret = ptrace_traceme();
		goto out;
	}

	child = ptrace_get_task_struct(pid);
	if (IS_ERR(child)) {
		ret = PTR_ERR(child);
		goto out;
	}

	if (request == PTRACE_ATTACH) {
		ret = ptrace_attach(child);
		/*
		 * 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);
	if (ret < 0)
		goto out_put_task_struct;

	ret = arch_ptrace(child, request, addr, data);
	if (ret < 0)
		goto out_put_task_struct;

 out_put_task_struct:
	put_task_struct(child);
 out:
	unlock_kernel();
	return ret;
}
#endif /* __ARCH_SYS_PTRACE */

int generic_ptrace_peekdata(struct task_struct *tsk, long addr, long data)
{
	unsigned long tmp;
	int copied;

	copied = access_process_vm(tsk, addr, &tmp, sizeof(tmp), 0);
	if (copied != sizeof(tmp))
		return -EIO;
	return put_user(tmp, (unsigned long __user *)data);
}

int generic_ptrace_pokedata(struct task_struct *tsk, long addr, long data)
{
	int copied;

	copied = access_process_vm(tsk, addr, &data, sizeof(data), 1);
	return (copied == sizeof(data)) ? 0 : -EIO;
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/kernel/ptrace.c
	3	*
	4	* (C) Copyright 1999 Linus Torvalds
	5	*
	6	* Common interfaces for "ptrace()" which we do not want
	7	* to continually duplicate across every architecture.
	8	*/
	9
c59ede7b	10	#include <linux/capability.h>
1da177e4 LT	11	#include <linux/module.h>
	12	#include <linux/sched.h>
	13	#include <linux/errno.h>
	14	#include <linux/mm.h>
	15	#include <linux/highmem.h>
	16	#include <linux/pagemap.h>
	17	#include <linux/smp_lock.h>
	18	#include <linux/ptrace.h>
	19	#include <linux/security.h>
7ed20e1a	20	#include <linux/signal.h>
a5cb013d	21	#include <linux/audit.h>
b488893a	22	#include <linux/pid_namespace.h>
1da177e4 LT	23
	24	#include <asm/pgtable.h>
	25	#include <asm/uaccess.h>
	26
	27	/*
	28	* ptrace a task: make the debugger its new parent and
	29	* move it to the ptrace list.
	30	*
	31	* Must be called with the tasklist lock write-held.
	32	*/
36c8b586	33	void __ptrace_link(struct task_struct child, struct task_struct new_parent)
1da177e4	34	{
524223ca	35	BUG_ON(!list_empty(&child->ptrace_list));
1da177e4 LT	36	if (child->parent == new_parent)
	37	return;
	38	list_add(&child->ptrace_list, &child->parent->ptrace_children);
9b678ece	39	remove_parent(child);
1da177e4	40	child->parent = new_parent;
9b678ece	41	add_parent(child);
1da177e4 LT	42	}
	43
	44	/*
	45	* Turn a tracing stop into a normal stop now, since with no tracer there
	46	* would be no way to wake it up with SIGCONT or SIGKILL. If there was a
	47	* signal sent that would resume the child, but didn't because it was in
	48	* TASK_TRACED, resume it now.
	49	* Requires that irqs be disabled.
	50	*/
36c8b586	51	void ptrace_untrace(struct task_struct *child)
1da177e4 LT	52	{
	53	spin_lock(&child->sighand->siglock);
	54	if (child->state == TASK_TRACED) {
	55	if (child->signal->flags & SIGNAL_STOP_STOPPED) {
	56	child->state = TASK_STOPPED;
	57	} else {
	58	signal_wake_up(child, 1);
	59	}
	60	}
	61	spin_unlock(&child->sighand->siglock);
	62	}
	63
	64	/*
	65	* unptrace a task: move it back to its original parent and
	66	* remove it from the ptrace list.
	67	*
	68	* Must be called with the tasklist lock write-held.
	69	*/
36c8b586	70	void __ptrace_unlink(struct task_struct *child)
1da177e4	71	{
5ecfbae0 ON	72	BUG_ON(!child->ptrace);
5ecfbae0 ON	73
1da177e4 LT	74	child->ptrace = 0;
	75	if (!list_empty(&child->ptrace_list)) {
	76	list_del_init(&child->ptrace_list);
9b678ece	77	remove_parent(child);
1da177e4	78	child->parent = child->real_parent;
9b678ece	79	add_parent(child);
1da177e4 LT	80	}
1da177e4 LT	81
e57a5059 RM	82	if (child->state == TASK_TRACED)
e57a5059 RM	83	ptrace_untrace(child);
1da177e4 LT	84	}
	85
	86	/*
	87	* Check that we have indeed attached to the thing..
	88	*/
	89	int ptrace_check_attach(struct task_struct *child, int kill)
	90	{
	91	int ret = -ESRCH;
	92
	93	/*
	94	* We take the read lock around doing both checks to close a
	95	* possible race where someone else was tracing our child and
	96	* detached between these two checks. After this locked check,
	97	* we are sure that this is our traced child and that can only
	98	* be changed by us so it's not changing right after this.
	99	*/
	100	read_lock(&tasklist_lock);
	101	if ((child->ptrace & PT_PTRACED) && child->parent == current &&
	102	(!(child->ptrace & PT_ATTACHED) \|\| child->real_parent != current)
	103	&& child->signal != NULL) {
	104	ret = 0;
	105	spin_lock_irq(&child->sighand->siglock);
	106	if (child->state == TASK_STOPPED) {
	107	child->state = TASK_TRACED;
	108	} else if (child->state != TASK_TRACED && !kill) {
	109	ret = -ESRCH;
	110	}
	111	spin_unlock_irq(&child->sighand->siglock);
	112	}
	113	read_unlock(&tasklist_lock);
	114
	115	if (!ret && !kill) {
	116	wait_task_inactive(child);
	117	}
	118
	119	/* All systems go.. */
	120	return ret;
	121	}
	122
ab8d11be MS	123	static int may_attach(struct task_struct *task)
ab8d11be MS	124	{
df26c40e EB	125	/* May we inspect the given task?
	126	* This check is used both for attaching with ptrace
	127	* and for allowing access to sensitive information in /proc.
	128	*
	129	* ptrace_attach denies several cases that /proc allows
	130	* because setting up the necessary parent/child relationship
	131	* or halting the specified task is impossible.
	132	*/
	133	int dumpable = 0;
	134	/* Don't let security modules deny introspection */
	135	if (task == current)
	136	return 0;
ab8d11be MS	137	if (((current->uid != task->euid) \|\|
	138	(current->uid != task->suid) \|\|
	139	(current->uid != task->uid) \|\|
	140	(current->gid != task->egid) \|\|
	141	(current->gid != task->sgid) \|\|
	142	(current->gid != task->gid)) && !capable(CAP_SYS_PTRACE))
	143	return -EPERM;
	144	smp_rmb();
df26c40e	145	if (task->mm)
6c5d5238	146	dumpable = get_dumpable(task->mm);
df26c40e	147	if (!dumpable && !capable(CAP_SYS_PTRACE))
ab8d11be MS	148	return -EPERM;
	149
	150	return security_ptrace(current, task);
	151	}
	152
	153	int ptrace_may_attach(struct task_struct *task)
	154	{
	155	int err;
	156	task_lock(task);
	157	err = may_attach(task);
	158	task_unlock(task);
	159	return !err;
	160	}
	161
1da177e4 LT	162	int ptrace_attach(struct task_struct *task)
	163	{
	164	int retval;
6175ecfe	165	unsigned long flags;
f5b40e36	166
a5cb013d AV	167	audit_ptrace(task);
a5cb013d AV	168
1da177e4 LT	169	retval = -EPERM;
1da177e4 LT	170	if (task->pid <= 1)
f5b40e36	171	goto out;
28d838cc	172	if (task->tgid == current->tgid)
f5b40e36 LT	173	goto out;
f5b40e36 LT	174
f358166a LT	175	repeat:
	176	/*
	177	* Nasty, nasty.
	178	*
	179	* We want to hold both the task-lock and the
	180	* tasklist_lock for writing at the same time.
	181	* But that's against the rules (tasklist_lock
	182	* is taken for reading by interrupts on other
	183	* cpu's that may have task_lock).
	184	*/
f5b40e36	185	task_lock(task);
6175ecfe	186	if (!write_trylock_irqsave(&tasklist_lock, flags)) {
f358166a LT	187	task_unlock(task);
	188	do {
	189	cpu_relax();
	190	} while (!write_can_lock(&tasklist_lock));
	191	goto repeat;
	192	}
f5b40e36	193
df26c40e EB	194	if (!task->mm)
df26c40e EB	195	goto bad;
1da177e4 LT	196	/* the same process cannot be attached many times */
	197	if (task->ptrace & PT_PTRACED)
	198	goto bad;
ab8d11be	199	retval = may_attach(task);
1da177e4 LT	200	if (retval)
	201	goto bad;
	202
	203	/* Go */
	204	task->ptrace \|= PT_PTRACED \| ((task->real_parent != current)
	205	? PT_ATTACHED : 0);
	206	if (capable(CAP_SYS_PTRACE))
	207	task->ptrace \|= PT_PTRACE_CAP;
1da177e4	208
1da177e4	209	__ptrace_link(task, current);
1da177e4 LT	210
1da177e4 LT	211	force_sig_specific(SIGSTOP, task);
1da177e4 LT	212
1da177e4 LT	213	bad:
6175ecfe	214	write_unlock_irqrestore(&tasklist_lock, flags);
1da177e4	215	task_unlock(task);
f5b40e36	216	out:
1da177e4 LT	217	return retval;
	218	}
	219
d5f70c00	220	static inline void __ptrace_detach(struct task_struct *child, unsigned int data)
5ecfbae0 ON	221	{
	222	child->exit_code = data;
	223	/* .. re-parent .. */
	224	__ptrace_unlink(child);
	225	/* .. and wake it up. */
	226	if (child->exit_state != EXIT_ZOMBIE)
	227	wake_up_process(child);
	228	}
	229
1da177e4 LT	230	int ptrace_detach(struct task_struct *child, unsigned int data)
1da177e4 LT	231	{
7ed20e1a	232	if (!valid_signal(data))
5ecfbae0	233	return -EIO;
1da177e4 LT	234
	235	/* Architecture-specific hardware disable .. */
	236	ptrace_disable(child);
7d941432	237	clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
1da177e4	238
1da177e4	239	write_lock_irq(&tasklist_lock);
d5f70c00	240	/* protect against de_thread()->release_task() */
5ecfbae0 ON	241	if (child->ptrace)
5ecfbae0 ON	242	__ptrace_detach(child, data);
1da177e4 LT	243	write_unlock_irq(&tasklist_lock);
	244
	245	return 0;
	246	}
	247
1da177e4 LT	248	int ptrace_readdata(struct task_struct tsk, unsigned long src, char __user dst, int len)
	249	{
	250	int copied = 0;
	251
	252	while (len > 0) {
	253	char buf[128];
	254	int this_len, retval;
	255
	256	this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
	257	retval = access_process_vm(tsk, src, buf, this_len, 0);
	258	if (!retval) {
	259	if (copied)
	260	break;
	261	return -EIO;
	262	}
	263	if (copy_to_user(dst, buf, retval))
	264	return -EFAULT;
	265	copied += retval;
	266	src += retval;
	267	dst += retval;
	268	len -= retval;
	269	}
	270	return copied;
	271	}
	272
	273	int ptrace_writedata(struct task_struct tsk, char __user src, unsigned long dst, int len)
	274	{
	275	int copied = 0;
	276
	277	while (len > 0) {
	278	char buf[128];
	279	int this_len, retval;
	280
	281	this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
	282	if (copy_from_user(buf, src, this_len))
	283	return -EFAULT;
	284	retval = access_process_vm(tsk, dst, buf, this_len, 1);
	285	if (!retval) {
	286	if (copied)
	287	break;
	288	return -EIO;
	289	}
	290	copied += retval;
	291	src += retval;
	292	dst += retval;
	293	len -= retval;
	294	}
	295	return copied;
	296	}
	297
	298	static int ptrace_setoptions(struct task_struct *child, long data)
	299	{
	300	child->ptrace &= ~PT_TRACE_MASK;
	301
	302	if (data & PTRACE_O_TRACESYSGOOD)
	303	child->ptrace \|= PT_TRACESYSGOOD;
	304
	305	if (data & PTRACE_O_TRACEFORK)
	306	child->ptrace \|= PT_TRACE_FORK;
	307
	308	if (data & PTRACE_O_TRACEVFORK)
	309	child->ptrace \|= PT_TRACE_VFORK;
	310
	311	if (data & PTRACE_O_TRACECLONE)
312	child->ptrace \|= PT_TRACE_CLONE;
313
314	if (data & PTRACE_O_TRACEEXEC)
315	child->ptrace \|= PT_TRACE_EXEC;
316
317	if (data & PTRACE_O_TRACEVFORKDONE)
318	child->ptrace \|= PT_TRACE_VFORK_DONE;
319
320	if (data & PTRACE_O_TRACEEXIT)
321	child->ptrace \|= PT_TRACE_EXIT;
322
323	return (data & ~PTRACE_O_MASK) ? -EINVAL : 0;
324	}
325
326	static int ptrace_getsiginfo(struct task_struct child, siginfo_t __user data)
327	{
328	siginfo_t lastinfo;
329	int error = -ESRCH;
330
331	read_lock(&tasklist_lock);
332	if (likely(child->sighand != NULL)) {
333	error = -EINVAL;
334	spin_lock_irq(&child->sighand->siglock);
335	if (likely(child->last_siginfo != NULL)) {
336	lastinfo = *child->last_siginfo;
337	error = 0;
338	}
339	spin_unlock_irq(&child->sighand->siglock);
340	}
341	read_unlock(&tasklist_lock);
342	if (!error)
343	return copy_siginfo_to_user(data, &lastinfo);
344	return error;
345	}
346
347	static int ptrace_setsiginfo(struct task_struct child, siginfo_t __user data)
348	{
349	siginfo_t newinfo;
350	int error = -ESRCH;
351
352	if (copy_from_user(&newinfo, data, sizeof (siginfo_t)))
353	return -EFAULT;
354
355	read_lock(&tasklist_lock);
356	if (likely(child->sighand != NULL)) {
357	error = -EINVAL;
358	spin_lock_irq(&child->sighand->siglock);
359	if (likely(child->last_siginfo != NULL)) {
360	*child->last_siginfo = newinfo;
361	error = 0;
362	}
363	spin_unlock_irq(&child->sighand->siglock);
364	}
365	read_unlock(&tasklist_lock);
366	return error;
367	}
368
369	int ptrace_request(struct task_struct *child, long request,
370	long addr, long data)
371	{
372	int ret = -EIO;
373
374	switch (request) {
375	#ifdef PTRACE_OLDSETOPTIONS
376	case PTRACE_OLDSETOPTIONS:
377	#endif
378	case PTRACE_SETOPTIONS:
379	ret = ptrace_setoptions(child, data);
380	break;
381	case PTRACE_GETEVENTMSG:
382	ret = put_user(child->ptrace_message, (unsigned long __user *) data);
383	break;
384	case PTRACE_GETSIGINFO:
385	ret = ptrace_getsiginfo(child, (siginfo_t __user *) data);
386	break;
387	case PTRACE_SETSIGINFO:
388	ret = ptrace_setsiginfo(child, (siginfo_t __user *) data);
389	break;
1bcf5482 AD	390	case PTRACE_DETACH: /* detach a process that was attached. */
	391	ret = ptrace_detach(child, data);
	392	break;
1da177e4 LT	393	default:
	394	break;
	395	}
	396
	397	return ret;
	398	}
481bed45	399
6b9c7ed8 CH	400	/**
	401	* ptrace_traceme -- helper for PTRACE_TRACEME
	402	*
	403	* Performs checks and sets PT_PTRACED.
	404	* Should be used by all ptrace implementations for PTRACE_TRACEME.
	405	*/
	406	int ptrace_traceme(void)
481bed45	407	{
f5b40e36	408	int ret = -EPERM;
481bed45 CH	409
481bed45 CH	410	/*
6b9c7ed8 CH	411	* Are we already being traced?
6b9c7ed8 CH	412	*/
f5b40e36 LT	413	task_lock(current);
	414	if (!(current->ptrace & PT_PTRACED)) {
	415	ret = security_ptrace(current->parent, current);
	416	/*
	417	* Set the ptrace bit in the process ptrace flags.
	418	*/
	419	if (!ret)
	420	current->ptrace \|= PT_PTRACED;
	421	}
	422	task_unlock(current);
	423	return ret;
6b9c7ed8	424	}
481bed45	425
6b9c7ed8 CH	426	/**
	427	* ptrace_get_task_struct -- grab a task struct reference for ptrace
	428	* @pid: process id to grab a task_struct reference of
	429	*
	430	* This function is a helper for ptrace implementations. It checks
	431	* permissions and then grabs a task struct for use of the actual
	432	* ptrace implementation.
	433	*
	434	* Returns the task_struct for @pid or an ERR_PTR() on failure.
	435	*/
	436	struct task_struct *ptrace_get_task_struct(pid_t pid)
	437	{
	438	struct task_struct *child;
481bed45 CH	439
481bed45 CH	440	/*
6b9c7ed8	441	* Tracing init is not allowed.
481bed45 CH	442	*/
481bed45 CH	443	if (pid == 1)
6b9c7ed8	444	return ERR_PTR(-EPERM);
481bed45	445
481bed45	446	read_lock(&tasklist_lock);
b488893a PE	447	child = find_task_by_pid_ns(pid,
b488893a PE	448	current->nsproxy->pid_ns);
481bed45 CH	449	if (child)
481bed45 CH	450	get_task_struct(child);
f400e198	451
481bed45 CH	452	read_unlock(&tasklist_lock);
481bed45 CH	453	if (!child)
6b9c7ed8 CH	454	return ERR_PTR(-ESRCH);
6b9c7ed8 CH	455	return child;
481bed45 CH	456	}
481bed45 CH	457
0ac15559 CH	458	#ifndef arch_ptrace_attach
	459	#define arch_ptrace_attach(child) do { } while (0)
	460	#endif
	461
6b9c7ed8	462	#ifndef __ARCH_SYS_PTRACE
481bed45 CH	463	asmlinkage long sys_ptrace(long request, long pid, long addr, long data)
	464	{
	465	struct task_struct *child;
	466	long ret;
	467
	468	/*
	469	* This lock_kernel fixes a subtle race with suid exec
	470	*/
	471	lock_kernel();
6b9c7ed8 CH	472	if (request == PTRACE_TRACEME) {
6b9c7ed8 CH	473	ret = ptrace_traceme();
481bed45	474	goto out;
6b9c7ed8 CH	475	}
	476
	477	child = ptrace_get_task_struct(pid);
	478	if (IS_ERR(child)) {
	479	ret = PTR_ERR(child);
	480	goto out;
	481	}
481bed45 CH	482
	483	if (request == PTRACE_ATTACH) {
	484	ret = ptrace_attach(child);
0ac15559 CH	485	/*
	486	* Some architectures need to do book-keeping after
	487	* a ptrace attach.
	488	*/
	489	if (!ret)
	490	arch_ptrace_attach(child);
005f18df	491	goto out_put_task_struct;
481bed45 CH	492	}
	493
	494	ret = ptrace_check_attach(child, request == PTRACE_KILL);
	495	if (ret < 0)
	496	goto out_put_task_struct;
	497
	498	ret = arch_ptrace(child, request, addr, data);
	499	if (ret < 0)
	500	goto out_put_task_struct;
	501
	502	out_put_task_struct:
	503	put_task_struct(child);
	504	out:
	505	unlock_kernel();
	506	return ret;
	507	}
	508	#endif /* __ARCH_SYS_PTRACE */
76647323 AD	509
	510	int generic_ptrace_peekdata(struct task_struct *tsk, long addr, long data)
	511	{
	512	unsigned long tmp;
	513	int copied;
	514
	515	copied = access_process_vm(tsk, addr, &tmp, sizeof(tmp), 0);
	516	if (copied != sizeof(tmp))
	517	return -EIO;
	518	return put_user(tmp, (unsigned long __user *)data);
	519	}
f284ce72 AD	520
	521	int generic_ptrace_pokedata(struct task_struct *tsk, long addr, long data)
	522	{
	523	int copied;
	524
	525	copied = access_process_vm(tsk, addr, &data, sizeof(data), 1);
	526	return (copied == sizeof(data)) ? 0 : -EIO;
	527	}