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SubjectRe: [PATCH] binder: prevent transactions to context manager from its own process.
On Mon, Jul 15, 2019 at 12:18 PM Hridya Valsaraju <hridya@google.com> wrote:
>
> Currently, a transaction to context manager from its own process
> is prevented by checking if its binder_proc struct is the same as
> that of the sender. However, this would not catch cases where the
> process opens the binder device again and uses the new fd to send
> a transaction to the context manager.
>
> Reported-by: syzbot+8b3c354d33c4ac78bfad@syzkaller.appspotmail.com
> Signed-off-by: Hridya Valsaraju <hridya@google.com>

Acked-by: Todd Kjos <tkjos@google.com>

> ---
> drivers/android/binder.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/android/binder.c b/drivers/android/binder.c
> index e4d25ebec5be..89b9cedae088 100644
> --- a/drivers/android/binder.c
> +++ b/drivers/android/binder.c
> @@ -3138,7 +3138,7 @@ static void binder_transaction(struct binder_proc *proc,
> else
> return_error = BR_DEAD_REPLY;
> mutex_unlock(&context->context_mgr_node_lock);
> - if (target_node && target_proc == proc) {
> + if (target_node && target_proc->pid == proc->pid) {
> binder_user_error("%d:%d got transaction to context manager from process owning it\n",
> proc->pid, thread->pid);
> return_error = BR_FAILED_REPLY;
> --
> 2.22.0.510.g264f2c817a-goog
>

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