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ptrace: compat_ptrace_request siginfo

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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: Roland McGrath <roland@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Roland McGrath 2008-04-20 13:10:12 -07:00 committed by Linus Torvalds
parent 553a56726b
commit e16b278164
1 changed files with 35 additions and 13 deletions
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48
kernel/ptrace.c
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@ -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);
}