From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D995BC433F5 for ; Mon, 27 Sep 2021 17:03:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B586B60F3A for ; Mon, 27 Sep 2021 17:03:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235809AbhI0RFa (ORCPT ); Mon, 27 Sep 2021 13:05:30 -0400 Received: from mail.kernel.org ([198.145.29.99]:44148 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235779AbhI0RF0 (ORCPT ); Mon, 27 Sep 2021 13:05:26 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 32FC960F3A; Mon, 27 Sep 2021 17:03:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1632762228; bh=eMrAGugYg/5rQWoFUzfyk4o2zjkOsj8fpBoskmh4PV4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TNJhuOoZfId0U/cGznHIeaV741Hbf3Y/G93xthrgxOToQZRpPQ9ywqrKRhyx8G+Zz 2FKRbdNc4oULjVIk7/C8DU0Q1L1F0xb7+TTdbRhhvJ6eSTxIj3n8jlRSRtIvqMvjM0 gbgF08N2mRHv+EO6TvK2n2wITGMdmI8veNe2suQw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Martijn Coenen , Christian Brauner , Todd Kjos Subject: [PATCH 5.4 11/68] binder: make sure fd closes complete Date: Mon, 27 Sep 2021 19:02:07 +0200 Message-Id: <20210927170220.324232120@linuxfoundation.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20210927170219.901812470@linuxfoundation.org> References: <20210927170219.901812470@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Todd Kjos commit 5fdb55c1ac9585eb23bb2541d5819224429e103d upstream. During BC_FREE_BUFFER processing, the BINDER_TYPE_FDA object cleanup may close 1 or more fds. The close operations are completed using the task work mechanism -- which means the thread needs to return to userspace or the file object may never be dereferenced -- which can lead to hung processes. Force the binder thread back to userspace if an fd is closed during BC_FREE_BUFFER handling. Fixes: 80cd795630d6 ("binder: fix use-after-free due to ksys_close() during fdget()") Cc: stable Reviewed-by: Martijn Coenen Acked-by: Christian Brauner Signed-off-by: Todd Kjos Link: https://lore.kernel.org/r/20210830195146.587206-1-tkjos@google.com Signed-off-by: Greg Kroah-Hartman --- drivers/android/binder.c | 23 +++++++++++++++++------ 1 file changed, 17 insertions(+), 6 deletions(-) --- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -2239,6 +2239,7 @@ static void binder_deferred_fd_close(int } static void binder_transaction_buffer_release(struct binder_proc *proc, + struct binder_thread *thread, struct binder_buffer *buffer, binder_size_t failed_at, bool is_failure) @@ -2398,8 +2399,16 @@ static void binder_transaction_buffer_re &proc->alloc, &fd, buffer, offset, sizeof(fd)); WARN_ON(err); - if (!err) + if (!err) { binder_deferred_fd_close(fd); + /* + * Need to make sure the thread goes + * back to userspace to complete the + * deferred close + */ + if (thread) + thread->looper_need_return = true; + } } } break; default: @@ -3469,7 +3478,7 @@ err_bad_parent: err_copy_data_failed: binder_free_txn_fixups(t); trace_binder_transaction_failed_buffer_release(t->buffer); - binder_transaction_buffer_release(target_proc, t->buffer, + binder_transaction_buffer_release(target_proc, NULL, t->buffer, buffer_offset, true); if (target_node) binder_dec_node_tmpref(target_node); @@ -3546,7 +3555,9 @@ err_invalid_target_handle: * Cleanup buffer and free it. */ static void -binder_free_buf(struct binder_proc *proc, struct binder_buffer *buffer) +binder_free_buf(struct binder_proc *proc, + struct binder_thread *thread, + struct binder_buffer *buffer) { binder_inner_proc_lock(proc); if (buffer->transaction) { @@ -3574,7 +3585,7 @@ binder_free_buf(struct binder_proc *proc binder_node_inner_unlock(buf_node); } trace_binder_transaction_buffer_release(buffer); - binder_transaction_buffer_release(proc, buffer, 0, false); + binder_transaction_buffer_release(proc, thread, buffer, 0, false); binder_alloc_free_buf(&proc->alloc, buffer); } @@ -3775,7 +3786,7 @@ static int binder_thread_write(struct bi proc->pid, thread->pid, (u64)data_ptr, buffer->debug_id, buffer->transaction ? "active" : "finished"); - binder_free_buf(proc, buffer); + binder_free_buf(proc, thread, buffer); break; } @@ -4463,7 +4474,7 @@ retry: buffer->transaction = NULL; binder_cleanup_transaction(t, "fd fixups failed", BR_FAILED_REPLY); - binder_free_buf(proc, buffer); + binder_free_buf(proc, thread, buffer); binder_debug(BINDER_DEBUG_FAILED_TRANSACTION, "%d:%d %stransaction %d fd fixups failed %d/%d, line %d\n", proc->pid, thread->pid,