From mboxrd@z Thu Jan 1 00:00:00 1970 Delivery-date: Wed, 18 Oct 2023 15:08:43 +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 1qt6I0-00D1Fu-B8 for lore@lore.pengutronix.de; Wed, 18 Oct 2023 15:08:43 +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 1qt6Hz-00038I-3h for lore@pengutronix.de; Wed, 18 Oct 2023 15:08:43 +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:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=SfHinWfiMuZo2/8rSw4W43fmbAqB/+h2DGO7HfvjxV8=; b=Uj74l7Y4FxK7s6Rv36iDbOXclQ v0PrgQBEIypsBza2Mz6V6c31oGCq6gJffWMjfkP9I3IzHtjEOJUAozQRaG34JlTCjBGPykBuo6fmj MivDPJO9QgGKofdVGlvoSESVb3TDOGIDXQJysJHNzW60IFdkqVODrW7ekVQk3JXRIOgY+4PGImP3R GbcGGTA2lv585hrJje5EpQRYFx2Nxwh1PRLJ1OXYDf/9qa1iljMrnoxsblO1O2nbBp19cZrDO7cFu t2SCvwP1le99/9yB4MC/vcPYxgWyw1XsC4ZDFMEGcgkglXUx0+4QU5R5r6B9bVIQuNvwipbmlmZHo 48VqCguw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qt6Gx-00EjyB-0u; Wed, 18 Oct 2023 13:07:39 +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 1qt6Gt-00Ejx9-2F for barebox@lists.infradead.org; Wed, 18 Oct 2023 13:07:37 +0000 Received: from ptz.office.stw.pengutronix.de ([2a0a:edc0:0:900:1d::77] helo=[127.0.0.1]) by metis.whiteo.stw.pengutronix.de with esmtp (Exim 4.92) (envelope-from ) id 1qt6Gs-0002ul-Cs; Wed, 18 Oct 2023 15:07:34 +0200 Message-ID: <139e779b-7c76-699b-d5e2-6ea3fdb69e85@pengutronix.de> Date: Wed, 18 Oct 2023 15:07:34 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.13.0 Content-Language: en-US To: Marco Felsch Cc: barebox@lists.infradead.org References: <20231017213608.3494255-1-m.felsch@pengutronix.de> <20231017213608.3494255-5-m.felsch@pengutronix.de> <20231018125341.zdsymavtt7qszclf@pengutronix.de> From: Ahmad Fatoum In-Reply-To: <20231018125341.zdsymavtt7qszclf@pengutronix.de> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20231018_060735_736613_E660DA63 X-CRM114-Status: GOOD ( 28.27 ) 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=-6.6 required=4.0 tests=AWL,BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,NICE_REPLY_A,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 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? > >> 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 ...". 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 |