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 A429715C8A for ; Mon, 5 Dec 2022 19:41:34 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 267C5C433C1; Mon, 5 Dec 2022 19:41:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1670269294; bh=BQNdWReGvAkUwVullySob+6qwTixLw9cbIcBpGqJwBE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FekrII2T1qRajSeUBsjoYU/HPfQjt3cRvQ3NyOjyp+Y4AaCAat8umAmHAYKukvYtf 0w4on1TgAEPyWgExzPNQV02e5AjGxfZfVUWlYWjt7bQIWbOdhjI2rX+LGbZwMsFZPz lfpNooS9eqGwOVGjG4wEKJkUhj0VRQguIQjmgsyo= 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 5.4 074/153] binder: Gracefully handle BINDER_TYPE_FDA objects with num_fds=0 Date: Mon, 5 Dec 2022 20:09:58 +0100 Message-Id: <20221205190810.843870132@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221205190808.733996403@linuxfoundation.org> References: <20221205190808.733996403@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 @@ -2894,6 +2894,9 @@ 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",