From patchwork Wed May 4 16:44:30 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 569741 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6960FC433F5 for ; Wed, 4 May 2022 17:07:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1356116AbiEDRLN (ORCPT ); Wed, 4 May 2022 13:11:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38974 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1356813AbiEDRJo (ORCPT ); Wed, 4 May 2022 13:09:44 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 76B5E21806; Wed, 4 May 2022 09:55:46 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id F2431616B8; Wed, 4 May 2022 16:55:45 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4CD14C385A5; Wed, 4 May 2022 16:55:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1651683345; bh=xh0CIvo5OSsNTrwskNOMVvGcZpqhPK91MF32l7lHP9c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Bh7xyKWd/U3EpowSL3G69W9YRgcz7vMc2uwuDrLhNeTyCcSNaSDyMIkkp3b730aSs 9Grs0aNPVUNyVNIo5DYqEoT0IvCavv3cF9B7YZFNa04U8mM8rEZ+32I1PeBAgm3cIJ JKNTQyee01NtcINznbyN94xson2pYgCjgT8+reEM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Todd Kjos , stable , Alessandro Astone Subject: [PATCH 5.17 032/225] binder: Gracefully handle BINDER_TYPE_FDA objects with num_fds=0 Date: Wed, 4 May 2022 18:44:30 +0200 Message-Id: <20220504153113.119453489@linuxfoundation.org> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220504153110.096069935@linuxfoundation.org> References: <20220504153110.096069935@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Alessandro Astone commit ef38de9217a04c9077629a24652689d8fdb4c6c6 upstream. Some android userspace is sending BINDER_TYPE_FDA objects with num_fds=0. Like the previous patch, this is reproducible when playing a video. Before commit 09184ae9b575 BINDER_TYPE_FDA objects with num_fds=0 were 'correctly handled', as in no fixup was performed. After commit 09184ae9b575 we aggregate fixup and skip regions in binder_ptr_fixup structs and distinguish between the two by using the skip_size field: if it's 0, then it's a fixup, otherwise skip. When processing BINDER_TYPE_FDA objects with num_fds=0 we add a skip region of skip_size=0, and this causes issues because now binder_do_deferred_txn_copies will think this was a fixup region. To address that, return early from binder_translate_fd_array to avoid adding an empty skip region. Fixes: 09184ae9b575 ("binder: defer copies of pre-patched txn data") Acked-by: Todd Kjos Cc: stable Signed-off-by: Alessandro Astone Link: https://lore.kernel.org/r/20220415120015.52684-1-ales.astone@gmail.com Signed-off-by: Greg Kroah-Hartman --- drivers/android/binder.c | 3 +++ 1 file changed, 3 insertions(+) --- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -2486,6 +2486,9 @@ static int binder_translate_fd_array(str struct binder_proc *proc = thread->proc; int ret; + if (fda->num_fds == 0) + return 0; + fd_buf_size = sizeof(u32) * fda->num_fds; if (fda->num_fds >= SIZE_MAX / sizeof(u32)) { binder_user_error("%d:%d got transaction with invalid number of fds (%lld)\n",