Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754424AbaKXQHq (ORCPT ); Mon, 24 Nov 2014 11:07:46 -0500 Received: from mail-qg0-f52.google.com ([209.85.192.52]:64406 "EHLO mail-qg0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753951AbaKXQHn (ORCPT ); Mon, 24 Nov 2014 11:07:43 -0500 MIME-Version: 1.0 In-Reply-To: <1416415597-21235-1-git-send-email-borneo.antonio@gmail.com> References: <1416149064-25655-1-git-send-email-borneo.antonio@gmail.com> <1416415597-21235-1-git-send-email-borneo.antonio@gmail.com> Date: Mon, 24 Nov 2014 11:07:42 -0500 Message-ID: Subject: Re: [PATCH V2] HID: i2c-hid: fix race condition reading reports From: Benjamin Tissoires To: Antonio Borneo Cc: Jiri Kosina , linux-input , Benjamin Tissoires , "linux-kernel@vger.kernel.org" , Jean-Baptiste Maneyrol Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Nov 19, 2014 at 11:46 AM, Antonio Borneo wrote: > From: Jean-Baptiste Maneyrol > > 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 > Cc: stable@vger.kernel.org > --- > V1 -> V2 > rename the synchronous buffer as rawbuf (instead of the > asynchronous one) Sorry for the lag and thanks for resubmitting. This one is reviewed-by: Benjamin Tissoires Cheers, Benjamin > > 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 933bf10..c66e6ac 100644 > --- a/drivers/hid/i2c-hid/i2c-hid.c > +++ b/drivers/hid/i2c-hid/i2c-hid.c > @@ -137,6 +137,7 @@ 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 */ > > @@ -504,9 +505,11 @@ 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; > @@ -522,10 +525,11 @@ 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; > } > @@ -552,12 +556,12 @@ 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; > @@ -566,7 +570,7 @@ 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; > } > -- > 2.1.3 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-input" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/