From mboxrd@z Thu Jan 1 00:00:00 1970 Delivery-date: Wed, 18 Oct 2023 16:33:44 +0200 Received: from metis.whiteo.stw.pengutronix.de ([2a0a:edc0:2:b01:1d::104]) by lore.white.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1qt7cH-00D52A-3G for lore@lore.pengutronix.de; Wed, 18 Oct 2023 16:33:44 +0200 Received: from bombadil.infradead.org ([2607:7c80:54:3::133]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1qt7cF-0004Ny-IV for lore@pengutronix.de; Wed, 18 Oct 2023 16:33:44 +0200 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=/UklYYxKeik6Y2yqQ+Wbl0nlf2+p6Va6qdsAC0Dq7kQ=; b=FjJeri3LUyDrXXxjjnZXxR9VaI NZbJY43r2XBIKiJhqw/6GfV3K1D09PYaHALNZTfboUcHjWNCGMxS4CmVqqGOHtntmM7OCzOm/Zdul i5SRe4R7fWvu9s+hSh+KrtHiyBM3y0Ks+xjHxtvxLq1KShMN9T9IhM+4C9inHXcxfeEhaYL0dIrMx JxE105KU1SbDFGOA5Y6/AANRBlrkypEigqDHiPCdwf3sH175uJb0MiFhItd3U59xe1J8Bua8/sB9F dWCTph6a4vd+HJK8FfXlgu/9tOTvbYtR88U4pCIDIudwE7+sKK3uIx/WMx3t7NMV1Iu6GTYm+sZRE +PUc9x3w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qt7b1-00EuiT-0r; Wed, 18 Oct 2023 14:32:27 +0000 Received: from metis.whiteo.stw.pengutronix.de ([2a0a:edc0:2:b01:1d::104]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qt7ax-00Euhc-2a for barebox@lists.infradead.org; Wed, 18 Oct 2023 14:32:25 +0000 Received: from drehscheibe.grey.stw.pengutronix.de ([2a0a:edc0:0:c01:1d::a2]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1qt7aq-00042Y-L4; Wed, 18 Oct 2023 16:32:16 +0200 Received: from [2a0a:edc0:2:b01:1d::c0] (helo=ptx.whiteo.stw.pengutronix.de) by drehscheibe.grey.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1qt7aq-002Zqt-8j; Wed, 18 Oct 2023 16:32:16 +0200 Received: from mfe by ptx.whiteo.stw.pengutronix.de with local (Exim 4.92) (envelope-from ) id 1qt7aq-00F7Ve-6P; Wed, 18 Oct 2023 16:32:16 +0200 Date: Wed, 18 Oct 2023 16:32:16 +0200 From: Marco Felsch To: Ahmad Fatoum Cc: barebox@lists.infradead.org Message-ID: <20231018143216.oq4k2bqhskurjv5k@pengutronix.de> References: <20231017213608.3494255-1-m.felsch@pengutronix.de> <20231017213608.3494255-5-m.felsch@pengutronix.de> <20231018125341.zdsymavtt7qszclf@pengutronix.de> <139e779b-7c76-699b-d5e2-6ea3fdb69e85@pengutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <139e779b-7c76-699b-d5e2-6ea3fdb69e85@pengutronix.de> User-Agent: NeoMutt/20180716 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20231018_073223_864480_30038BBF X-CRM114-Status: GOOD ( 37.62 ) X-BeenThere: barebox@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "barebox" X-SA-Exim-Connect-IP: 2607:7c80:54:3::133 X-SA-Exim-Mail-From: barebox-bounces+lore=pengutronix.de@lists.infradead.org X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on metis.whiteo.stw.pengutronix.de X-Spam-Level: X-Spam-Status: No, score=-4.9 required=4.0 tests=AWL,BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED,SPF_HELO_NONE,SPF_NONE autolearn=unavailable autolearn_force=no version=3.4.2 Subject: Re: [PATCH 4/4] imx-usb-loader: fix windows usage X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on metis.whiteo.stw.pengutronix.de) On 23-10-18, Ahmad Fatoum wrote: > On 18.10.23 14:53, Marco Felsch wrote: > > On 23-10-18, Ahmad Fatoum wrote: > >> On 17.10.23 23:36, Marco Felsch wrote: > >>> This ports commit 561f0377db5e ("Transfer always specified report 2 > >>> length") from imx_usb_loader[1] to our implementation. > >>> > >>> | commit 561f0377db5e1a36f5ab5e17f97d774f9f1e22ab > >>> | Author: Stefan Agner > >>> | Date: Wed Nov 2 16:51:24 2016 -0700 > >>> | > >>> | Transfer always specified report 2 length > >>> | > >>> | The Windows HIDAPI is very strict when it comes to packet lengths: > >>> | The API always expect the length specified by the device and rejects > >>> | the transfer otherwise. The report size is specified by the HID > >>> | Report Descriptor. The i.MX 6 SoC reports a report 2 size of 1024. > >>> | Currently, imx_usb reads the length from the device specific config > >>> | files and stores it in max_transfer. This change uses max_transfer > >>> | for report 2 when using the HID API. > >>> | > >>> | The boot ROM handles too long transfers just fine. Also NXP's > >>> | sb_loader transfers always complete reports. The change has been > >>> | successfully tested on Linux and Windows. > >>> | > >>> | Given that the device reports the size, it is probably also "the > >>> | right thing to do"... > >>> | > >>> | With that change, we might end up transferring up to 1023 bytes > >>> | more than actually necessary. Make sure that DoIRomDownload does > >>> | not print an error message and returns successfully even if too > >>> | many bytes have been transferred (this now typically happens at the > >>> | end of every file). > >>> | > >>> | In write_dcd use a signed length variable to keep track of remaining > >>> | bytes. Continue transfer loop only if more than 0 bytes are left to > >>> | transfer. Also drop the m_ prefix, m_ is usually used for member > >>> | variables but this is a local variable. > >>> | > >>> | Signed-off-by: Stefan Agner > >>> > >>> [1] https://github.com/boundarydevices/imx_usb_loader/commit/561f0377db5e1a36f5ab5e17f97d774f9f1e22ab > >>> > >>> Signed-off-by: Marco Felsch > >>> --- > >>> scripts/imx/imx-usb-loader.c | 8 ++++++-- > >>> 1 file changed, 6 insertions(+), 2 deletions(-) > >>> > >>> diff --git a/scripts/imx/imx-usb-loader.c b/scripts/imx/imx-usb-loader.c > >>> index 676f077c25..ece4603b2b 100644 > >>> --- a/scripts/imx/imx-usb-loader.c > >>> +++ b/scripts/imx/imx-usb-loader.c > >>> @@ -484,12 +484,16 @@ static int transfer(int report, void *p, unsigned cnt, int *last_trans) > >>> err = libusb_bulk_transfer(usb_dev_handle, > >>> (report < 3) ? 1 : 2 + EP_IN, p, cnt, last_trans, 1000); > >>> } else { > >>> - unsigned char tmp[1028]; > >>> + unsigned char tmp[1028] = { 0 }; > >>> > >>> tmp[0] = (unsigned char)report; > >>> > >>> if (report < 3) { > >>> memcpy(&tmp[1], p, cnt); > >>> + > >>> + if (report == 2) > >>> + cnt = mach_id->max_transfer; > >> > >> Did you verify that this can't result in an out-of-bounds read? > > > > How should that be possible? The tmp-array is always 1028-byte and we > > already do limit cnt to max_transfer if cnt is larger than max_transfer. > > In the case that cnt < mach_id->max_transfer, we increase cnt to > mach_id->max_transfer and pass that to libusb. Are we guaranteed > that libusb won't read out of bounds, i.e. buf + cnt - 1 is always > inside tmp? At the moment it is guaranteed that mach_id->max_transfer is always smaller than 1028. libusb always start to read at &tmp[0] so the last read may transfer useless bytes (0) but we are always within the tmp buffer. So no out-of-bound reads. > >> I'd have expected either an adjustment to tmp's size or a description > >> why a buffer overread can't happen in the commit message. > > > > Sorry but can you elaborate where a buffer overrread can happen? > > You groked the code and wrote the patch, so I hoped you could tell me > "no, buffer overflow can't happen because ...". Please see above. Regards, Marco > > Cheers, > Ahmad > > > > > Regards, > > Marco > > > >>> + > >>> if (mach_id->hid_endpoint) { > >>> int trans; > >>> err = libusb_interrupt_transfer(usb_dev_handle, > >>> @@ -739,7 +743,7 @@ static int send_buf(void *buf, unsigned len) > >>> while (1) { > >>> int now = get_min(cnt, mach_id->max_transfer); > >>> > >>> - if (!now) > >>> + if (now <= 0) > >>> break; > >>> > >>> err = transfer(2, p, now, &now); > >> > >> -- > >> Pengutronix e.K. | | > >> Steuerwalder Str. 21 | http://www.pengutronix.de/ | > >> 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | > >> Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | > >> > >> > > > > -- > Pengutronix e.K. | | > Steuerwalder Str. 21 | http://www.pengutronix.de/ | > 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | > Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | > >