From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 67E366FA1 for ; Wed, 30 Nov 2022 18:31:03 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DB992C433D7; Wed, 30 Nov 2022 18:31:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1669833063; bh=N5gmWKMS3/Mr565LXbrAXmMZDEEfshujGKGnOtyNpD8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=MFS+EoBMIBGK/RyMxaT+roNqZhcPWaGNPyVIbAU3oC0j41YEKZl5ripR3XQjfyFKt 7jO+r17LVV/g9D6k5iX+FOPPfPs3DaQQd2dhNL4MXn8yEH2ewA0yOAAypaYbp/6UYj g7RiwrgOid9atXY9db+lDXYFFlZdlWDXy2LWeTrg= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Todd Kjos , stable , Alessandro Astone , Carlos Llamas Subject: [PATCH 5.10 130/162] binder: Gracefully handle BINDER_TYPE_FDA objects with num_fds=0 Date: Wed, 30 Nov 2022 19:23:31 +0100 Message-Id: <20221130180532.014265851@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221130180528.466039523@linuxfoundation.org> References: <20221130180528.466039523@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Signed-off-by: Carlos Llamas 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 @@ -2891,6 +2891,9 @@ 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",