Todd Kjos 401d4d79a8 binder: fix UAF when releasing todo list ... commit f3277cbfba upstream. When releasing a thread todo list when tearing down a binder_proc, the following race was possible which could result in a use-after-free: 1. Thread 1: enter binder_release_work from binder_thread_release 2. Thread 2: binder_update_ref_for_handle() -> binder_dec_node_ilocked() 3. Thread 2: dec nodeA --> 0 (will free node) 4. Thread 1: ACQ inner_proc_lock 5. Thread 2: block on inner_proc_lock 6. Thread 1: dequeue work (BINDER_WORK_NODE, part of nodeA) 7. Thread 1: REL inner_proc_lock 8. Thread 2: ACQ inner_proc_lock 9. Thread 2: todo list cleanup, but work was already dequeued 10. Thread 2: free node 11. Thread 2: REL inner_proc_lock 12. Thread 1: deref w->type (UAF) The problem was that for a BINDER_WORK_NODE, the binder_work element must not be accessed after releasing the inner_proc_lock while processing the todo list elements since another thread might be handling a deref on the node containing the binder_work element leading to the node being freed. Signed-off-by: Todd Kjos <tkjos@google.com> Link: https://lore.kernel.org/r/20201009232455.4054810-1-tkjos@google.com Cc: <stable@vger.kernel.org> # 4.14, 4.19, 5.4, 5.8 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2020-10-29 09:57:25 +01:00
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Kconfig	binder: add functions to copy to/from binder buffers	2019-02-12 10:43:57 +01:00
Makefile	treewide: Add SPDX license identifier - Makefile/Kconfig	2019-05-21 10:50:46 +02:00
binder.c	binder: fix UAF when releasing todo list	2020-10-29 09:57:25 +01:00
binder_alloc.c	binder: Don't use mmput() from shrinker function.	2020-07-29 10:18:41 +02:00
binder_alloc.h	binder: return errors from buffer copy functions	2019-07-01 08:42:47 +02:00
binder_alloc_selftest.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 282	2019-06-05 17:36:37 +02:00
binder_internal.h	binder: prevent UAF for binderfs devices II	2020-03-12 13:00:17 +01:00
binder_trace.h	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 282	2019-06-05 17:36:37 +02:00
binderfs.c	binderfs: use refcount for binder control devices too	2020-03-25 08:25:50 +01:00