From mboxrd@z Thu Jan 1 00:00:00 1970 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752764AbeADKoH (ORCPT + 1 other); Thu, 4 Jan 2018 05:44:07 -0500 Received: from mail-qt0-f193.google.com ([209.85.216.193]:36297 "EHLO mail-qt0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752727AbeADKoF (ORCPT ); Thu, 4 Jan 2018 05:44:05 -0500 X-Google-Smtp-Source: ACJfBosk/4X2yWt3hcFCODsJJ85sMMk5YkN+IFt3YqG+EKpCT4P9mLxeV1r/leYPijlqVU22eXx7iuDzh1Ub83x5iek= MIME-Version: 1.0 In-Reply-To: <20180102173006.506-1-aaron.ma@canonical.com> References: <20180102173006.506-1-aaron.ma@canonical.com> From: Benjamin Tissoires Date: Thu, 4 Jan 2018 11:44:04 +0100 Message-ID: Subject: Re: [PATCH 1/2] HID: core: i2c-hid: fix size check and type usage To: Aaron Ma Cc: lkml , linux-input@vger.kernel.org, Jiri Kosina Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: Hi Aaron, There are quite some changes I'd like to see in this patch. See below. On Tue, Jan 2, 2018 at 6:30 PM, Aaron Ma wrote: > When convert char array with signed int, if the inbuf[x] is negative then > upper bits will be set to 1. Fix this by using u8 instead of char. > > ret_size has to be at least 3, hid_input_report use it after minus 2 bytes. > > size should be more than 0 to keep memset safe. > > Cc: stable@vger.kernel.org > Signed-off-by: Aaron Ma > --- > drivers/hid/hid-core.c | 4 ++-- > drivers/hid/i2c-hid/i2c-hid.c | 10 +++++----- I'd like to have this patch at least split in 2. One for hid-core, one for i2c-hid. Both files are not targeting the same issue, so it would make sense to not have them in the same patch. > 2 files changed, 7 insertions(+), 7 deletions(-) > > diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c > index 0c3f608131cf..992547771d96 100644 > --- a/drivers/hid/hid-core.c > +++ b/drivers/hid/hid-core.c > @@ -1506,7 +1506,7 @@ int hid_report_raw_event(struct hid_device *hid, int type, u8 *data, int size, > if (rsize > HID_MAX_BUFFER_SIZE) > rsize = HID_MAX_BUFFER_SIZE; > > - if (csize < rsize) { > + if ((csize < rsize) && (csize > 0)) { I would think a call to this function with a csize <= 0 is a reason to fail. And actually, I think an other thing we shouold do is changing the prototype to have an unsigned int for size instead of a simple int. Tracking the impact of such change might involve a bigger patch than a simple check here, but we should be able to at least have the compiler complaining if some driver starts using negative values. > dbg_hid("report %d is too short, (%d < %d)\n", report->id, > csize, rsize); > memset(cdata + csize, 0, rsize - csize); > @@ -1566,7 +1566,7 @@ int hid_input_report(struct hid_device *hid, int type, u8 *data, int size, int i > report_enum = hid->report_enum + type; > hdrv = hid->driver; > > - if (!size) { > + if (size <= 0) { This should also be solved by changing the prototype of the function. > dbg_hid("empty report\n"); > ret = -1; > goto unlock; > diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c > index e054ee43c1e2..09404ffdb08b 100644 > --- a/drivers/hid/i2c-hid/i2c-hid.c > +++ b/drivers/hid/i2c-hid/i2c-hid.c > @@ -144,10 +144,10 @@ struct i2c_hid { > * register of the 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 */ > + u8 *inbuf; /* Input buffer */ > + u8 *rawbuf; /* Raw Input buffer */ > + u8 *cmdbuf; /* Command buffer */ > + u8 *argsbuf; /* Command arguments buffer */ > > unsigned long flags; /* device flags */ > unsigned long quirks; /* Various quirks */ > @@ -473,7 +473,7 @@ static void i2c_hid_get_input(struct i2c_hid *ihid) > > ret_size = ihid->inbuf[0] | ihid->inbuf[1] << 8; > > - if (!ret_size) { > + if (ret_size <= 2) { Please do a separate case, after this one. RESET is acked by a size of 0, a size of 1 or 2 is a bug that needs to be fixed from the HW point of view. Cheers, Benjamin > /* host or device initiated RESET completed */ > if (test_and_clear_bit(I2C_HID_RESET_PENDING, &ihid->flags)) > wake_up(&ihid->wait); > -- > 2.14.3 >