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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5C9A5C7618A for ; Mon, 20 Mar 2023 13:08:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231278AbjCTNIi (ORCPT ); Mon, 20 Mar 2023 09:08:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58308 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231455AbjCTNIh (ORCPT ); Mon, 20 Mar 2023 09:08:37 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A8A981D90B for ; Mon, 20 Mar 2023 06:08:36 -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 35164614DE for ; Mon, 20 Mar 2023 13:08:36 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9D1E2C433EF; Mon, 20 Mar 2023 13:08:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1679317715; bh=JgqXBeuo9mNExK8qnTz5gcWTcoLVjSxDpWYG/0SpQWo=; h=From:To:Cc:Subject:Date:From; b=BtMHbKKY6Mik2BHwxXhbm8p7PQVGcSdV6mE6vJ8e0cgJyNKFiB45FyMadaUvhv146 iw9NCWaJVgDpWd+UYaABeBTyVPS2oB4AACJbOv1FGzPBGfeqr5Bg1O3uixjqClwKsg cTSVncI7kN4ZZUdAdNb6IohX/CuQIrpG4OXItriRs0bF1XRcQUWQg3cmoSj/i3NBjm oPns1foxIZQBRkAWR2xUQdVfBc8K8xtYdpC796KsdzGRrP7MuJYXu9xJ8kozsttcUm HGImv0+bsxc1RE9bacjXbirMWeWkb8XM1LYNZC57epftWL2blfkMNpSeo418N17DaJ jYVgl0uNzE6iQ== From: Lee Jones To: lee@kernel.org Cc: stable@vger.kernel.org, Jiri Kosina , Greg Kroah-Hartman Subject: [PATCH v4.19.y 1/2] HID: core: Provide new max_buffer_size attribute to over-ride the default Date: Mon, 20 Mar 2023 13:08:23 +0000 Message-Id: <20230320130824.2771361-1-lee@kernel.org> X-Mailer: git-send-email 2.40.0.rc1.284.g88254d51c5-goog MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org commit b1a37ed00d7908a991c1d0f18a8cba3c2aa99bdc upstream. Presently, when a report is processed, its proposed size, provided by the user of the API (as Report Size * Report Count) is compared against the subsystem default HID_MAX_BUFFER_SIZE (16k). However, some low-level HID drivers allocate a reduced amount of memory to their buffers (e.g. UHID only allocates UHID_DATA_MAX (4k) buffers), rending this check inadequate in some cases. In these circumstances, if the received report ends up being smaller than the proposed report size, the remainder of the buffer is zeroed. That is, the space between sizeof(csize) (size of the current report) and the rsize (size proposed i.e. Report Size * Report Count), which can be handled up to HID_MAX_BUFFER_SIZE (16k). Meaning that memset() shoots straight past the end of the buffer boundary and starts zeroing out in-use values, often resulting in calamity. This patch introduces a new variable into 'struct hid_ll_driver' where individual low-level drivers can over-ride the default maximum value of HID_MAX_BUFFER_SIZE (16k) with something more sympathetic to the interface. Signed-off-by: Lee Jones Signed-off-by: Jiri Kosina Signed-off-by: Greg Kroah-Hartman [Lee: Backported to v4.19.y] Signed-off-by: Lee Jones --- drivers/hid/hid-core.c | 18 +++++++++++++----- include/linux/hid.h | 3 +++ 2 files changed, 16 insertions(+), 5 deletions(-) diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c index 8cc79d0d11fb2..c8d687f795caa 100644 --- a/drivers/hid/hid-core.c +++ b/drivers/hid/hid-core.c @@ -258,6 +258,7 @@ static int hid_add_field(struct hid_parser *parser, unsigned report_type, unsign { struct hid_report *report; struct hid_field *field; + unsigned int max_buffer_size = HID_MAX_BUFFER_SIZE; unsigned int usages; unsigned int offset; unsigned int i; @@ -288,8 +289,11 @@ static int hid_add_field(struct hid_parser *parser, unsigned report_type, unsign offset = report->size; report->size += parser->global.report_size * parser->global.report_count; + if (parser->device->ll_driver->max_buffer_size) + max_buffer_size = parser->device->ll_driver->max_buffer_size; + /* Total size check: Allow for possible report index byte */ - if (report->size > (HID_MAX_BUFFER_SIZE - 1) << 3) { + if (report->size > (max_buffer_size - 1) << 3) { hid_err(parser->device, "report is too long\n"); return -1; } @@ -1567,6 +1571,7 @@ int hid_report_raw_event(struct hid_device *hid, int type, u8 *data, u32 size, struct hid_report_enum *report_enum = hid->report_enum + type; struct hid_report *report; struct hid_driver *hdrv; + int max_buffer_size = HID_MAX_BUFFER_SIZE; unsigned int a; u32 rsize, csize = size; u8 *cdata = data; @@ -1583,10 +1588,13 @@ int hid_report_raw_event(struct hid_device *hid, int type, u8 *data, u32 size, rsize = hid_compute_report_size(report); - if (report_enum->numbered && rsize >= HID_MAX_BUFFER_SIZE) - rsize = HID_MAX_BUFFER_SIZE - 1; - else if (rsize > HID_MAX_BUFFER_SIZE) - rsize = HID_MAX_BUFFER_SIZE; + if (hid->ll_driver->max_buffer_size) + max_buffer_size = hid->ll_driver->max_buffer_size; + + if (report_enum->numbered && rsize >= max_buffer_size) + rsize = max_buffer_size - 1; + else if (rsize > max_buffer_size) + rsize = max_buffer_size; if (csize < rsize) { dbg_hid("report %d is too short, (%d < %d)\n", report->id, diff --git a/include/linux/hid.h b/include/linux/hid.h index c51ebce2197e0..79c6c3b4e0044 100644 --- a/include/linux/hid.h +++ b/include/linux/hid.h @@ -799,6 +799,7 @@ struct hid_driver { * @raw_request: send raw report request to device (e.g. feature report) * @output_report: send output report to device * @idle: send idle request to device + * @max_buffer_size: over-ride maximum data buffer size (default: HID_MAX_BUFFER_SIZE) */ struct hid_ll_driver { int (*start)(struct hid_device *hdev); @@ -823,6 +824,8 @@ struct hid_ll_driver { int (*output_report) (struct hid_device *hdev, __u8 *buf, size_t len); int (*idle)(struct hid_device *hdev, int report, int idle, int reqtype); + + unsigned int max_buffer_size; }; extern struct hid_ll_driver i2c_hid_ll_driver; -- 2.40.0.rc1.284.g88254d51c5-goog