[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 <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 = task->mm->dumpable;
	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);

	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;
	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(pid);
	if (child)
		get_task_struct(child);

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

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