From mboxrd@z Thu Jan 1 00:00:00 1970 Delivery-date: Tue, 07 Dec 2021 10:16:55 +0100 Received: from metis.ext.pengutronix.de ([2001:67c:670:201:290:27ff:fe1d:cc33]) by lore.white.stw.pengutronix.de with esmtp (Exim 4.92) (envelope-from ) id 1muWal-0008Mb-51 for lore@lore.pengutronix.de; Tue, 07 Dec 2021 10:16:55 +0100 Received: from bombadil.infradead.org ([2607:7c80:54:e::133]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1muWak-0002x0-1B for lore@pengutronix.de; Tue, 07 Dec 2021 10:16:54 +0100 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:From:In-Reply-To:MIME-Version: References:Message-ID:Subject:Cc:To:Date:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=qNXIIbl5hxpYZsXb3PvpfNys3w0EfAeFBzotVE5R1Ag=; b=MYFEv4yWsVHE94Ho7VytaRthfN DpPF8BVgFs+zXiLNymtgVZwI/lon3VUrO58p15e6wuv/C4FMbRrwvmsTIRYJqMMoh74FwO/RpSvkl k1+XLReK6IrzHw6JTlKKm02k1NRqf4+s4BvXxKRXaEj735sty6E6tcNWM8hJ+Vq/C8UuKmgSbUuU7 BINPejLTNM/uWRZ6q2cpq+UOKO4m+0hAEZWqqcTk/yWlcYg5fGwUgkP8G//hB7Ope1e0nlbQwHsKy jDkBtyGxfSUmCIDAlkAif4TR6zmIA6Dl5XxXp+poOpRNMqdTutJVd2k5284KJA1zk4UtBUwkiJZBG tIngUenQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1muWZK-007lEC-7m; Tue, 07 Dec 2021 09:15:26 +0000 Received: from metis.ext.pengutronix.de ([2001:67c:670:201:290:27ff:fe1d:cc33]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1muWX5-007kPy-D5 for barebox@lists.infradead.org; Tue, 07 Dec 2021 09:13:08 +0000 Received: from ptx.hi.pengutronix.de ([2001:67c:670:100:1d::c0]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1muWX3-0002BE-UW; Tue, 07 Dec 2021 10:13:05 +0100 Received: from sha by ptx.hi.pengutronix.de with local (Exim 4.92) (envelope-from ) id 1muWX3-0003ng-Ij; Tue, 07 Dec 2021 10:13:05 +0100 Date: Tue, 7 Dec 2021 10:13:05 +0100 To: Ahmad Fatoum Cc: barebox@lists.infradead.org Message-ID: <20211207091305.GL28260@pengutronix.de> References: <20211129071454.2014315-1-ahmad@a3f.at> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20211129071454.2014315-1-ahmad@a3f.at> X-Sent-From: Pengutronix Hildesheim X-URL: http://www.pengutronix.de/ X-IRC: #ptxdist @freenode X-Accept-Language: de,en X-Accept-Content-Type: text/plain X-Uptime: 10:12:51 up 292 days, 12:36, 143 users, load average: 0.14, 0.23, 0.22 User-Agent: Mutt/1.10.1 (2018-07-13) From: Sascha Hauer X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20211207_011307_502250_C9AB6F80 X-CRM114-Status: GOOD ( 25.14 ) 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: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "barebox" X-SA-Exim-Connect-IP: 2607:7c80:54:e::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.ext.pengutronix.de X-Spam-Level: X-Spam-Status: No, score=-4.8 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 master] fs: /dev/mem: handle copy at offset 0 correctly X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on metis.ext.pengutronix.de) On Mon, Nov 29, 2021 at 08:14:54AM +0100, Ahmad Fatoum wrote: > Despite that /dev/mem has a size of 0, the check preventing > out-of-bounds access works for /dev/mem as well, because of unsigned > wrap around. Corner case is when offset is zero. There will be no wrap > around and > > count = min(count, 0 - 0) = 0 > > Leading to unexpected behavior with e.g. > > memcmp -s /dev/mem 0 > > on systems without MMU. Fix this. > > Signed-off-by: Ahmad Fatoum > --- > fs/devfs-core.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) Applied, thanks Sascha > > diff --git a/fs/devfs-core.c b/fs/devfs-core.c > index 3715e543e632..2d016e0e4861 100644 > --- a/fs/devfs-core.c > +++ b/fs/devfs-core.c > @@ -573,7 +573,10 @@ ssize_t mem_copy(struct device_d *dev, void *dst, const void *src, > if (!dev || dev->num_resources < 1) > return -1; > > - count = size = min(count, resource_size(&dev->resource[0]) - offset); > + if (resource_size(&dev->resource[0]) > 0 || offset != 0) > + count = min(count, resource_size(&dev->resource[0]) - offset); > + > + size = count; > > /* no rwsize specification given. Do whatever memcpy likes best */ > if (!rwsize) { > -- > 2.33.0 > > > _______________________________________________ > barebox mailing list > barebox@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/barebox > -- 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 | _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox