kernel-wide: fix missing validations on __get/__put/__copy_to/__copy_from_user()
I found the following pattern that leads in to interesting findings:
grep -r "ret.*|=.*__put_user" *
grep -r "ret.*|=.*__get_user" *
grep -r "ret.*|=.*__copy" *
The __put_user() calls in compat_ioctl.c, ptrace compat, signal compat,
since those appear in compat code, we could probably expect the kernel
addresses not to be reachable in the lower 32-bit range, so I think they
might not be exploitable.
For the "__get_user" cases, I don't think those are exploitable: the worse
that can happen is that the kernel will copy kernel memory into in-kernel
buffers, and will fail immediately afterward.
The alpha csum_partial_copy_from_user() seems to be missing the
access_ok() check entirely. The fix is inspired from x86. This could
lead to information leak on alpha. I also noticed that many architectures
map csum_partial_copy_from_user() to csum_partial_copy_generic(), but I
wonder if the latter is performing the access checks on every
architectures.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/sparc/kernel/sys_sparc32.c b/arch/sparc/kernel/sys_sparc32.c
index 3d0ddbc..7136885 100644
--- a/arch/sparc/kernel/sys_sparc32.c
+++ b/arch/sparc/kernel/sys_sparc32.c
@@ -169,10 +169,10 @@
new_ka.ka_restorer = restorer;
ret = get_user(u_handler, &act->sa_handler);
new_ka.sa.sa_handler = compat_ptr(u_handler);
- ret |= __copy_from_user(&set32, &act->sa_mask, sizeof(compat_sigset_t));
+ ret |= copy_from_user(&set32, &act->sa_mask, sizeof(compat_sigset_t));
sigset_from_compat(&new_ka.sa.sa_mask, &set32);
- ret |= __get_user(new_ka.sa.sa_flags, &act->sa_flags);
- ret |= __get_user(u_restorer, &act->sa_restorer);
+ ret |= get_user(new_ka.sa.sa_flags, &act->sa_flags);
+ ret |= get_user(u_restorer, &act->sa_restorer);
new_ka.sa.sa_restorer = compat_ptr(u_restorer);
if (ret)
return -EFAULT;
@@ -183,9 +183,9 @@
if (!ret && oact) {
sigset_to_compat(&set32, &old_ka.sa.sa_mask);
ret = put_user(ptr_to_compat(old_ka.sa.sa_handler), &oact->sa_handler);
- ret |= __copy_to_user(&oact->sa_mask, &set32, sizeof(compat_sigset_t));
- ret |= __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
- ret |= __put_user(ptr_to_compat(old_ka.sa.sa_restorer), &oact->sa_restorer);
+ ret |= copy_to_user(&oact->sa_mask, &set32, sizeof(compat_sigset_t));
+ ret |= put_user(old_ka.sa.sa_flags, &oact->sa_flags);
+ ret |= put_user(ptr_to_compat(old_ka.sa.sa_restorer), &oact->sa_restorer);
if (ret)
ret = -EFAULT;
}
