From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BC348C433EF for ; Tue, 5 Oct 2021 21:44:10 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 6FB1C61163 for ; Tue, 5 Oct 2021 21:44:10 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 6FB1C61163 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id ED3A16B0071; Tue, 5 Oct 2021 17:44:09 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id E8334900002; Tue, 5 Oct 2021 17:44:09 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D4B8D6B0074; Tue, 5 Oct 2021 17:44:09 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0254.hostedemail.com [216.40.44.254]) by kanga.kvack.org (Postfix) with ESMTP id C4F8A6B0071 for ; Tue, 5 Oct 2021 17:44:09 -0400 (EDT) Received: from smtpin38.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 847FC3209C for ; Tue, 5 Oct 2021 21:44:09 +0000 (UTC) X-FDA: 78663712218.38.9318070 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf26.hostedemail.com (Postfix) with ESMTP id 3D34520061F5 for ; Tue, 5 Oct 2021 21:44:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=S/z5lzUmzIzMefjNTXKVthCH9yQdMwjFhwmMowYOCJY=; b=IiwjgVYCWaygv9zNE0yjEj9drG KjhL5Jygxj2yEz1eCjJqJOyOg2OlF4IJxNBixRIDbCPZm3q7EFEkon8BGFwCmi+a7OiLzGmPJd/ca MNebbiLteKrLqEF+M+aAqmBcjnrMhDcr3DbvTRwlzzlsWLTjGVuFO/1BMwC1j134rg3vy6HCh6YBe 0mYqe7UcqLP3OMf/JHqsssFVy6ARhdTJVMdxdkRu/3iFOP3iGAFxqfF19Whv7zLzX8VtCcwMGrjHl gEQgdUWxFmqsH7GliZH8SQ/7w3b6wvpaBoUtujyFV2FsKig1j9hlhDIp7/7iZsQIohfeCNZKsoFAm XRzKc3cQ==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1mXsDR-000Ie5-VB; Tue, 05 Oct 2021 21:43:32 +0000 Date: Tue, 5 Oct 2021 22:43:13 +0100 From: Matthew Wilcox To: Kees Cook Cc: linux-mm@kvack.org, Thomas Gleixner Subject: Re: [PATCH 1/3] mm/usercopy: Check kmap addresses properly Message-ID: References: <20211004224224.4137992-1-willy@infradead.org> <20211004224224.4137992-2-willy@infradead.org> <202110051422.3E52FBDE18@keescook> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <202110051422.3E52FBDE18@keescook> X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 3D34520061F5 X-Stat-Signature: hmr849p4e5medeef4d3fykq9n3rzu5a7 Authentication-Results: imf26.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=IiwjgVYC; dmarc=none; spf=none (imf26.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org X-HE-Tag: 1633470248-41876 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, Oct 05, 2021 at 02:23:09PM -0700, Kees Cook wrote: > > + if (is_kmap_addr(ptr)) { > > + unsigned long page_end = (unsigned long)ptr | (PAGE_SIZE - 1); > > + > > + if ((unsigned long)ptr + n - 1 > page_end) > > + usercopy_abort("kmap", NULL, to_user, 0, n); > > It's likely not worth getting an offset here, but "0" above could be > something like "ptr - PKMAP_ADDR(0)". Mmm. page_offset(ptr) should do the trick, no? > Either way: > > Acked-by: Kees Cook > > Thanks! > > -Kees > > > + return; > > + } > > + > > + page = virt_to_head_page(ptr); > > > > if (PageSlab(page)) { > > /* Check slab allocator for flags and size. */ > > -- > > 2.32.0 > > > > -- > Kees Cook