Messages in this thread | | | Date | Wed, 30 Nov 2022 03:57:59 +0000 | Subject | [PATCH 5.10 0/6] binder: backports for data leak and UAF | From | Carlos Llamas <> |
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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@google.com/
Thanks, Carlos Llamas
Cc: Zi Fan Tan <zifantan@google.com> Cc: Todd Kjos <tkjos@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Alessandro Astone (2): binder: Address corner cases in deferred copy and fixup binder: Gracefully handle BINDER_TYPE_FDA objects with num_fds=0
Arnd Bergmann (1): binder: fix pointer cast warning
Todd Kjos (3): binder: avoid potential data leakage when copying txn binder: read pre-translated fds from sender buffer binder: defer copies of pre-patched txn data
drivers/android/binder.c | 437 ++++++++++++++++++++++++++++++++++----- 1 file changed, 383 insertions(+), 54 deletions(-)
-- 2.38.1.584.g0f3c55d4c2-goog
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