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  1. 10 7月, 2023 1 次提交
  3. 08 3月, 2023 28 次提交
  5. 18 10月, 2022 1 次提交
  7. 15 4月, 2022 3 次提交
  9. 04 11月, 2020 1 次提交
    • T
      binder: fix UAF when releasing todo list · 3c7fa538
      由 Todd Kjos 提交于 
      stable inclusion
from linux-4.19.153
commit 35cc2facc2a5ff52b9aa03f2dc81dcb000d97da3
CVE: CVE-2020-0423

--------------------------------

commit f3277cbf 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: NTodd 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: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>
Reviewed-by: NJason Yan <yanaijie@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>
      3c7fa538
  11. 27 12月, 2019 4 次提交
  13. 06 12月, 2018 1 次提交
    • T
      binder: fix race that allows malicious free of live buffer · 553927d6
      由 Todd Kjos 提交于 
      commit 7bada55ab50697861eee6bb7d60b41e68a961a9c upstream.

Malicious code can attempt to free buffers using the BC_FREE_BUFFER
ioctl to binder. There are protections against a user freeing a buffer
while in use by the kernel, however there was a window where
BC_FREE_BUFFER could be used to free a recently allocated buffer that
was not completely initialized. This resulted in a use-after-free
detected by KASAN with a malicious test program.

This window is closed by setting the buffer's allow_user_free attribute
to 0 when the buffer is allocated or when the user has previously freed
it instead of waiting for the caller to set it. The problem was that
when the struct buffer was recycled, allow_user_free was stale and set
to 1 allowing a free to go through.
Signed-off-by: NTodd Kjos <tkjos@google.com>
Acked-by: NArve Hjønnevåg <arve@android.com>
Cc: stable <stable@vger.kernel.org> # 4.14
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      553927d6
  15. 08 8月, 2018 1 次提交