From patchwork Thu Dec 16 21:53:48 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Wilcox X-Patchwork-Id: 12682827 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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4B5EFC433F5 for ; Thu, 16 Dec 2021 21:56:18 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 757A36B0078; Thu, 16 Dec 2021 16:54:17 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 706B96B007B; Thu, 16 Dec 2021 16:54:17 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5CF616B007D; Thu, 16 Dec 2021 16:54:17 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0119.hostedemail.com [216.40.44.119]) by kanga.kvack.org (Postfix) with ESMTP id 4BBD36B0078 for ; Thu, 16 Dec 2021 16:54:17 -0500 (EST) Received: from smtpin15.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 114A486992 for ; Thu, 16 Dec 2021 21:54:07 +0000 (UTC) X-FDA: 78925010934.15.4C392AC Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf01.hostedemail.com (Postfix) with ESMTP id DCB5A4001A for ; Thu, 16 Dec 2021 21:54:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Transfer-Encoding:MIME-Version: References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To: Content-Type:Content-ID:Content-Description; bh=FxsC6amCuAZFSahXDaieLHiz+Xxu18/zbToomONxAZM=; b=SzQJ4/uELzoWhsgIEpd1ZA6JF5 yz1fVXarmGVFcevbWbo/pU2ZaZS3P1QZQNXTB6U/n0GIdJrHbb45+TcF/YWcscuqIJgSQhY8ylQav 1Ouu1akpTf0aYQBwTyec9gxa0Yj/d/IX0PRvYb9Vw6tq9Gw6dEJZwY7qQecAPkriOLpA1R8rkkf01 /hKGCDYetu7/UaoM6EDKk7sN0AZKJke6DoC2ug6fAZRMdDT48XyhlT2PNKgYjFBtFXQpoivGDomVu O+vp/+bQ/3J2zc5wnrSvPz1bXYHylHfknnGJGkQwfg8tjDWmEtfYqnVl+D+mJMunqxP51fJjSH5JN 22WReiCA==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1mxyhE-00FzY6-MA; Thu, 16 Dec 2021 21:53:52 +0000 From: "Matthew Wilcox (Oracle)" To: Kees Cook Cc: "Matthew Wilcox (Oracle)" , linux-mm@kvack.org, linux-hardening@vger.kernel.org, William Kucharski Subject: [PATCH v4 1/4] mm/usercopy: Check kmap addresses properly Date: Thu, 16 Dec 2021 21:53:48 +0000 Message-Id: <20211216215351.3811471-2-willy@infradead.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20211216215351.3811471-1-willy@infradead.org> References: <20211216215351.3811471-1-willy@infradead.org> MIME-Version: 1.0 X-Rspamd-Queue-Id: DCB5A4001A X-Stat-Signature: zgjpo4j6oc66tmzgztkp46igberb57qx Authentication-Results: imf01.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b="SzQJ4/uE"; dmarc=none; spf=none (imf01.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org X-Rspamd-Server: rspam11 X-HE-Tag: 1639691641-807284 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: If you are copying to an address in the kmap region, you may not copy across a page boundary, no matter what the size of the underlying allocation. You can't kmap() a slab page because slab pages always come from low memory. Signed-off-by: Matthew Wilcox (Oracle) Acked-by: Kees Cook Reviewed-by: William Kucharski --- arch/x86/include/asm/highmem.h | 1 + include/linux/highmem-internal.h | 10 ++++++++++ mm/usercopy.c | 16 ++++++++++------ 3 files changed, 21 insertions(+), 6 deletions(-) diff --git a/arch/x86/include/asm/highmem.h b/arch/x86/include/asm/highmem.h index 032e020853aa..731ee7cc40a5 100644 --- a/arch/x86/include/asm/highmem.h +++ b/arch/x86/include/asm/highmem.h @@ -26,6 +26,7 @@ #include #include #include +#include /* declarations for highmem.c */ extern unsigned long highstart_pfn, highend_pfn; diff --git a/include/linux/highmem-internal.h b/include/linux/highmem-internal.h index 0a0b2b09b1b8..01fb76d101b0 100644 --- a/include/linux/highmem-internal.h +++ b/include/linux/highmem-internal.h @@ -149,6 +149,11 @@ static inline void totalhigh_pages_add(long count) atomic_long_add(count, &_totalhigh_pages); } +static inline bool is_kmap_addr(const void *x) +{ + unsigned long addr = (unsigned long)x; + return addr >= PKMAP_ADDR(0) && addr < PKMAP_ADDR(LAST_PKMAP); +} #else /* CONFIG_HIGHMEM */ static inline struct page *kmap_to_page(void *addr) @@ -234,6 +239,11 @@ static inline void __kunmap_atomic(void *addr) static inline unsigned int nr_free_highpages(void) { return 0; } static inline unsigned long totalhigh_pages(void) { return 0UL; } +static inline bool is_kmap_addr(const void *x) +{ + return false; +} + #endif /* CONFIG_HIGHMEM */ /* diff --git a/mm/usercopy.c b/mm/usercopy.c index b3de3c4eefba..8c039302465f 100644 --- a/mm/usercopy.c +++ b/mm/usercopy.c @@ -228,12 +228,16 @@ static inline void check_heap_object(const void *ptr, unsigned long n, if (!virt_addr_valid(ptr)) return; - /* - * When CONFIG_HIGHMEM=y, kmap_to_page() will give either the - * highmem page or fallback to virt_to_page(). The following - * is effectively a highmem-aware virt_to_head_page(). - */ - page = compound_head(kmap_to_page((void *)ptr)); + 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, + offset_in_page(ptr), n); + return; + } + + page = virt_to_head_page(ptr); if (PageSlab(page)) { /* Check slab allocator for flags and size. */