Messages in this thread | | | Date | Fri, 28 Jun 2013 16:52:05 +0200 | From | Oleg Nesterov <> | Subject | Re: [PATCH 3.10-rc7] Fix: kernel/ptrace.c: ptrace_peek_siginfo() missing __put_user() validation |
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On 06/28, Mathieu Desnoyers wrote: > > This __put_user() could be used by unprivileged processes to write into > kernel memory. The issue here is that even if copy_siginfo_to_user() > fails, the error code is not checked before __put_user() is executed. > Luckily, ptrace_peek_siginfo() has been added within the 3.10-rc cycle, > so it has not hit a stable release yet.
Agreed, this looks like 3.10 material.
Acked-by: Oleg Nesterov <oleg@redhat.com>
> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> > CC: Andrey Vagin <avagin@openvz.org> > CC: Roland McGrath <roland@redhat.com> > CC: Oleg Nesterov <oleg@redhat.com> > CC: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> > CC: David Howells <dhowells@redhat.com> > CC: Dave Jones <davej@redhat.com> > CC: Pavel Emelyanov <xemul@parallels.com> > CC: Linus Torvalds <torvalds@linux-foundation.org> > Cc: Pedro Alves <palves@redhat.com> > CC: Andrew Morton <akpm@linux-foundation.org> > CC: Linus Torvalds <torvalds@linux-foundation.org> > --- > kernel/ptrace.c | 20 +++++++++++--------- > 1 file changed, 11 insertions(+), 9 deletions(-) > > Index: linux/kernel/ptrace.c > =================================================================== > --- linux.orig/kernel/ptrace.c > +++ linux/kernel/ptrace.c > @@ -665,20 +665,22 @@ static int ptrace_peek_siginfo(struct ta > if (unlikely(is_compat_task())) { > compat_siginfo_t __user *uinfo = compat_ptr(data); > > - ret = copy_siginfo_to_user32(uinfo, &info); > - ret |= __put_user(info.si_code, &uinfo->si_code); > + if (copy_siginfo_to_user32(uinfo, &info) || > + __put_user(info.si_code, &uinfo->si_code)) { > + ret = -EFAULT; > + break; > + } > + > } else > #endif > { > siginfo_t __user *uinfo = (siginfo_t __user *) data; > > - ret = copy_siginfo_to_user(uinfo, &info); > - ret |= __put_user(info.si_code, &uinfo->si_code); > - } > - > - if (ret) { > - ret = -EFAULT; > - break; > + if (copy_siginfo_to_user(uinfo, &info) || > + __put_user(info.si_code, &uinfo->si_code)) { > + ret = -EFAULT; > + break; > + } > } > > data += sizeof(siginfo_t); > > -- > Mathieu Desnoyers > EfficiOS Inc. > http://www.efficios.com
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