Re: [PATCH 5.10 0/6] binder: backports for data leak and UAF

[Carlos Llamas]

On Wed, Nov 30, 2022 at 01:42:23PM +0100, Greg Kroah-Hartman wrote:
> On Wed, Nov 30, 2022 at 03:57:59AM +0000, Carlos Llamas wrote:
> > This series of backports consists of 3 main patches from Todd submitted
> > upstream in [1]. The intention is to avoid untranslated data from the
> > senders to be visible to the target processes. More details of this
> > issue can be found in the same thread.
> > 
> > Furthermore, Todd's patches also fix a use-after-free issue introduced
> > by commit 32e9f56a96d8 ("binder: don't detect sender/target during
> > buffer cleanup"). In which invalid userspace input causes unprocessed
> > objects to be incorrectly released. Any subsequent references to these
> > objects will trigger a UAF as noted by the following KASAN trace:
> > 
> >  [  244.748468] ==================================================================
> >  [  244.750486] BUG: KASAN: use-after-free in binder_ioctl+0xb88/0x32e0
> >  [  244.751276] Read of size 8 at addr ffff67b1865bea58 by task poc/593
> >  [  244.752074] 
> >  [  244.752725] CPU: 0 PID: 593 Comm: poc Not tainted 5.10.156 #1
> >  [  244.753683] Hardware name: linux,dummy-virt (DT)
> >  [  244.754717] Call trace:
> >  [  244.755216]  dump_backtrace+0x0/0x2a0
> >  [  244.755836]  show_stack+0x18/0x2c
> >  [  244.756306]  dump_stack+0xf8/0x164
> >  [  244.756807]  print_address_description.constprop.0+0x9c/0x538
> >  [  244.757590]  kasan_report+0x120/0x200
> >  [  244.758236]  __asan_load8+0xa0/0xc4
> >  [  244.758756]  binder_ioctl+0xb88/0x32e0
> >  [  244.759283]  __arm64_sys_ioctl+0xd4/0x120
> >  [  244.759677]  el0_svc_common.constprop.0+0xac/0x270
> >  [  244.760184]  do_el0_svc+0x38/0xa0
> >  [  244.760540]  el0_svc+0x1c/0x2c
> >  [  244.760898]  el0_sync_handler+0xe8/0x114
> >  [  244.761419]  el0_sync+0x180/0x1c0
> > 
> > This second issue along with the reference to the commit fixing it was
> > first reported by Zi Fan.
> > 
> > The other 3 commits included in this series are simply upstream fixes
> > for the main patches.
> > 
> > I've tested this series applied to 5.10 and 5.4 which fixes the issues
> > above as expected. So please pick these up for 5.10 and 5.4 stable.
> > 
> > [1] https://lore.kernel.org/all/20211130185152.437403-1-tkjos@xxxxxxxxxx/
> > 
> > Thanks,
> > Carlos Llamas
> > 
> > Cc: Zi Fan Tan <zifantan@xxxxxxxxxx>
> > Cc: Todd Kjos <tkjos@xxxxxxxxxx>
> > Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> 
> 
> All now queued up, thanks.
> 
> greg k-h

Thanks Greg. Could you also take this series for 5.4? I've also tested
the fixes for that release.

--
Carlos Llamas