From: Jann Horn jannh@google.com
[ Upstream commit e8b8ae7ce32e17a5c29f0289e9e2a39c7dcaa1b8 ]
While binder transactions with the same binder_proc as sender and recipient are forbidden, transactions with the same task_struct as sender and recipient are possible (even though currently there is a weird check in binder_transaction() that rejects them in the target==0 case). Therefore, task_struct identities can't be used to distinguish whether the caller is running in the context of the sender or the recipient.
Since I see no easy way to make this WARN_ON() useful and correct, let's just remove it.
Fixes: 44d8047f1d87 ("binder: use standard functions to allocate fds") Reported-by: syzbot+e113a0b970b7b3f394ba@syzkaller.appspotmail.com Acked-by: Christian Brauner christian.brauner@ubuntu.com Acked-by: Todd Kjos tkjos@google.com Signed-off-by: Jann Horn jannh@google.com Link: https://lore.kernel.org/r/20200806165359.2381483-1-jannh@google.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/android/binder.c | 2 -- 1 file changed, 2 deletions(-)
diff --git a/drivers/android/binder.c b/drivers/android/binder.c index af85d37aef680..adab46ca5dff7 100644 --- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -2324,8 +2324,6 @@ static void binder_transaction_buffer_release(struct binder_proc *proc, * file is done when the transaction is torn * down. */ - WARN_ON(failed_at && - proc->tsk == current->group_leader); } break; case BINDER_TYPE_PTR: /*