From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760983AbbA2JhT (ORCPT ); Thu, 29 Jan 2015 04:37:19 -0500 Received: from ip4-83-240-67-251.cust.nbox.cz ([83.240.67.251]:44856 "EHLO ip4-83-240-18-248.cust.nbox.cz" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1760041AbbA2JF7 (ORCPT ); Thu, 29 Jan 2015 04:05:59 -0500 From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Jean-Baptiste Maneyrol , Antonio Borneo , Jiri Kosina , Jiri Slaby Subject: [PATCH 3.12 020/176] HID: i2c-hid: fix race condition reading reports Date: Wed, 28 Jan 2015 15:27:30 +0100 Message-Id: <5927cd034b1a289e1c73018fc908403c0ce15658.1422455352.git.jslaby@suse.cz> X-Mailer: git-send-email 2.2.2 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jean-Baptiste Maneyrol 3.12-stable review patch. If anyone has any objections, please let me know. =============== commit 6296f4a8eb86f9abcc370fb7a1a116b8441c17fd upstream. Current driver uses a common buffer for reading reports either synchronously in i2c_hid_get_raw_report() and asynchronously in the interrupt handler. There is race condition if an interrupt arrives immediately after the report is received in i2c_hid_get_raw_report(); the common buffer is modified by the interrupt handler with the new report and then i2c_hid_get_raw_report() proceed using wrong data. Fix it by using a separate buffers for synchronous reports. Signed-off-by: Jean-Baptiste Maneyrol [Antonio Borneo: cleanup, rebase to v3.17, submit mainline] Signed-off-by: Antonio Borneo Reviewed-by: Benjamin Tissoires Signed-off-by: Jiri Kosina Signed-off-by: Jiri Slaby --- drivers/hid/i2c-hid/i2c-hid.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c index c1336193b04b..ffa9c9e13741 100644 --- a/drivers/hid/i2c-hid/i2c-hid.c +++ b/drivers/hid/i2c-hid/i2c-hid.c @@ -136,6 +136,7 @@ struct i2c_hid { * descriptor. */ unsigned int bufsize; /* i2c buffer size */ char *inbuf; /* Input buffer */ + char *rawbuf; /* Raw Input buffer */ char *cmdbuf; /* Command buffer */ char *argsbuf; /* Command arguments buffer */ @@ -486,9 +487,11 @@ static void i2c_hid_find_max_report(struct hid_device *hid, unsigned int type, static void i2c_hid_free_buffers(struct i2c_hid *ihid) { kfree(ihid->inbuf); + kfree(ihid->rawbuf); kfree(ihid->argsbuf); kfree(ihid->cmdbuf); ihid->inbuf = NULL; + ihid->rawbuf = NULL; ihid->cmdbuf = NULL; ihid->argsbuf = NULL; ihid->bufsize = 0; @@ -504,10 +507,11 @@ static int i2c_hid_alloc_buffers(struct i2c_hid *ihid, size_t report_size) report_size; /* report */ ihid->inbuf = kzalloc(report_size, GFP_KERNEL); + ihid->rawbuf = kzalloc(report_size, GFP_KERNEL); ihid->argsbuf = kzalloc(args_len, GFP_KERNEL); ihid->cmdbuf = kzalloc(sizeof(union command) + args_len, GFP_KERNEL); - if (!ihid->inbuf || !ihid->argsbuf || !ihid->cmdbuf) { + if (!ihid->inbuf || !ihid->rawbuf || !ihid->argsbuf || !ihid->cmdbuf) { i2c_hid_free_buffers(ihid); return -ENOMEM; } @@ -534,12 +538,12 @@ static int i2c_hid_get_raw_report(struct hid_device *hid, ret = i2c_hid_get_report(client, report_type == HID_FEATURE_REPORT ? 0x03 : 0x01, - report_number, ihid->inbuf, ask_count); + report_number, ihid->rawbuf, ask_count); if (ret < 0) return ret; - ret_count = ihid->inbuf[0] | (ihid->inbuf[1] << 8); + ret_count = ihid->rawbuf[0] | (ihid->rawbuf[1] << 8); if (ret_count <= 2) return 0; @@ -548,7 +552,7 @@ static int i2c_hid_get_raw_report(struct hid_device *hid, /* The query buffer contains the size, dropping it in the reply */ count = min(count, ret_count - 2); - memcpy(buf, ihid->inbuf + 2, count); + memcpy(buf, ihid->rawbuf + 2, count); return count; } -- 2.2.2