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 X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 85F27C3A5A1 for ; Thu, 22 Aug 2019 17:40:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5EA4720870 for ; Thu, 22 Aug 2019 17:40:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1566495607; bh=Zn66wKxlgl4PKInOyortwhBLQxo9D77ZuDpoSaETRPw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Y2h1s8NoUkDS/H9rpgQI5HdtuPUIMsgERXPFJYTDnkyenqYKSkMThPA5yfzJ5Wi8w dQBR2M+rcKPEbMbZNKCzxHal5xmWoljzMGO4bNUv+Arf9tfdrw291m91eQSbF1XUXa hBwaTZe0WFbnUALlQM5V6561DdnWreefsFUTzge8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2392855AbfHVRkG (ORCPT ); Thu, 22 Aug 2019 13:40:06 -0400 Received: from mail.kernel.org ([198.145.29.99]:45266 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2404096AbfHVRYJ (ORCPT ); Thu, 22 Aug 2019 13:24:09 -0400 Received: from localhost (wsip-184-188-36-2.sd.sd.cox.net [184.188.36.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id D952F23406; Thu, 22 Aug 2019 17:24:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1566494649; bh=Zn66wKxlgl4PKInOyortwhBLQxo9D77ZuDpoSaETRPw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=vk44Ph0u+uwua+bXqdrg/2RRgYrKN6kLR7ep4dCpWqD0Rvd6QW62ZAiMkqaDdrsI/ HxgZUr/E8c2wWiR7xK8U7F7yfcvmw90tChRPVYJA7Dcvh1mHpOvAubX4TSRwfI/dyJ egeAKDdKV+clZIKrcUlp5DeFxTziK7XUbUzPZjqA= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Prasad Sodagudi , "Isaac J. Manjarres" , William Kucharski , Kees Cook , Trilok Soni , Andrew Morton , Linus Torvalds Subject: [PATCH 4.9 043/103] mm/usercopy: use memory range to be accessed for wraparound check Date: Thu, 22 Aug 2019 10:18:31 -0700 Message-Id: <20190822171730.551985628@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20190822171728.445189830@linuxfoundation.org> References: <20190822171728.445189830@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Isaac J. Manjarres commit 951531691c4bcaa59f56a316e018bc2ff1ddf855 upstream. Currently, when checking to see if accessing n bytes starting at address "ptr" will cause a wraparound in the memory addresses, the check in check_bogus_address() adds an extra byte, which is incorrect, as the range of addresses that will be accessed is [ptr, ptr + (n - 1)]. This can lead to incorrectly detecting a wraparound in the memory address, when trying to read 4 KB from memory that is mapped to the the last possible page in the virtual address space, when in fact, accessing that range of memory would not cause a wraparound to occur. Use the memory range that will actually be accessed when considering if accessing a certain amount of bytes will cause the memory address to wrap around. Link: http://lkml.kernel.org/r/1564509253-23287-1-git-send-email-isaacm@codeaurora.org Fixes: f5509cc18daa ("mm: Hardened usercopy") Signed-off-by: Prasad Sodagudi Signed-off-by: Isaac J. Manjarres Co-developed-by: Prasad Sodagudi Reviewed-by: William Kucharski Acked-by: Kees Cook Cc: Greg Kroah-Hartman Cc: Trilok Soni Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds [kees: backport to v4.9] Signed-off-by: Kees Cook Signed-off-by: Greg Kroah-Hartman --- mm/usercopy.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/mm/usercopy.c +++ b/mm/usercopy.c @@ -124,7 +124,7 @@ static inline const char *check_kernel_t static inline const char *check_bogus_address(const void *ptr, unsigned long n) { /* Reject if object wraps past end of memory. */ - if ((unsigned long)ptr + n < (unsigned long)ptr) + if ((unsigned long)ptr + (n - 1) < (unsigned long)ptr) return ""; /* Reject if NULL or ZERO-allocation. */