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 <[email protected]> > Signed-off-by: Mathieu Desnoyers <[email protected]> > CC: Andrey Vagin <[email protected]> > CC: Roland McGrath <[email protected]> > CC: Oleg Nesterov <[email protected]> > CC: "Paul E. McKenney" <[email protected]> > CC: David Howells <[email protected]> > CC: Dave Jones <[email protected]> > CC: Pavel Emelyanov <[email protected]> > CC: Linus Torvalds <[email protected]> > Cc: Pedro Alves <[email protected]> > CC: Andrew Morton <[email protected]> > CC: Linus Torvalds <[email protected]> > --- > 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
