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Commit e16b2781 authored by Roland McGrath's avatar Roland McGrath Committed by Linus Torvalds
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ptrace: compat_ptrace_request siginfo 



This adds support for PTRACE_GETSIGINFO and PTRACE_SETSIGINFO in
compat_ptrace_request.  It relies on existing arch definitions for
copy_siginfo_to_user32 and copy_siginfo_from_user32.

On powerpc, this fixes a longstanding regression of 32-bit ptrace
calls on 64-bit kernels vs native calls (64-bit calls or 32-bit
kernels).  This can be seen in a 32-bit call using PTRACE_GETSIGINFO
to examine e.g. siginfo_t.si_addr from a signal that sets it.
(This was broken as of 2.6.24 and, I presume, many or all prior versions.)

Signed-off-by: default avatarRoland McGrath <roland@redhat.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 553a5672

kernel/ptrace.c

+35 −13
Original line number Diff line number Diff line
@@ -323,9 +323,8 @@ static int ptrace_setoptions(struct task_struct *child, long data) 
	return (data & ~PTRACE_O_MASK) ? -EINVAL : 0;

}



static int ptrace_getsiginfo(struct task_struct *child, siginfo_t __user * data)

static int ptrace_getsiginfo(struct task_struct *child, siginfo_t *info)

{

	siginfo_t lastinfo;

	int error = -ESRCH;



	read_lock(&tasklist_lock);
@@ -333,31 +332,25 @@ static int ptrace_getsiginfo(struct task_struct *child, siginfo_t __user * data) 
		error = -EINVAL;

		spin_lock_irq(&child->sighand->siglock);

		if (likely(child->last_siginfo != NULL)) {

			lastinfo = *child->last_siginfo;

			*info = *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)

static int ptrace_setsiginfo(struct task_struct *child, const siginfo_t *info)

{

	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;

			*child->last_siginfo = *info;

			error = 0;

		}

		spin_unlock_irq(&child->sighand->siglock);
@@ -424,6 +417,7 @@ int ptrace_request(struct task_struct *child, long request, 
		   long addr, long data)

{

	int ret = -EIO;

	siginfo_t siginfo;



	switch (request) {

	case PTRACE_PEEKTEXT:
@@ -442,12 +436,22 @@ int ptrace_request(struct task_struct *child, long request, 
	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);

		ret = ptrace_getsiginfo(child, &siginfo);

		if (!ret)

			ret = copy_siginfo_to_user((siginfo_t __user *) data,

						   &siginfo);

		break;



	case PTRACE_SETSIGINFO:

		ret = ptrace_setsiginfo(child, (siginfo_t __user *) data);

		if (copy_from_user(&siginfo, (siginfo_t __user *) data,

				   sizeof siginfo))

			ret = -EFAULT;

		else

			ret = ptrace_setsiginfo(child, &siginfo);

		break;



	case PTRACE_DETACH:	 /* detach a process that was attached. */

		ret = ptrace_detach(child, data);

		break;
@@ -616,6 +620,7 @@ int compat_ptrace_request(struct task_struct *child, compat_long_t request, 
{

	compat_ulong_t __user *datap = compat_ptr(data);

	compat_ulong_t word;

	siginfo_t siginfo;

	int ret;



	switch (request) {
@@ -638,6 +643,23 @@ int compat_ptrace_request(struct task_struct *child, compat_long_t request, 
		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:

		memset(&siginfo, 0, sizeof siginfo);

		if (copy_siginfo_from_user32(

			    &siginfo, (struct compat_siginfo __user *) datap))

			ret = -EFAULT;

		else

			ret = ptrace_setsiginfo(child, &siginfo);

		break;



	default:

		ret = ptrace_request(child, request, addr, data);

	}