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=-3.8 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 autolearn=no 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 5508DC32750 for ; Tue, 13 Aug 2019 22:37:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 184722084D for ; Tue, 13 Aug 2019 22:37:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1565735860; bh=lrOZASxu/z0pdhBkfBWynYYBnN9chRPR1Jd4/Y5Nq0I=; h=Date:From:To:Subject:List-ID:From; b=frF0nNUImA7zXuFGVcEr1MRya+ddChDHIw7hTA8tqsk9rb8bVj2wxTW61MPfas50Z DaGCMYLOQ5cqtzLoYgT9KZLErRi4SmvLxKzB9/4NhxVHpmH9MFZgDknu+Kbx0wfVNI flI+KjzH0sEKCcF1Q7cAvRUxRlXSJfCVFLJMzPwU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727350AbfHMWhj (ORCPT ); Tue, 13 Aug 2019 18:37:39 -0400 Received: from mail.kernel.org ([198.145.29.99]:49242 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726698AbfHMWhj (ORCPT ); Tue, 13 Aug 2019 18:37:39 -0400 Received: from akpm3.svl.corp.google.com (unknown [104.133.8.65]) (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 538B120840; Tue, 13 Aug 2019 22:37:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1565735858; bh=lrOZASxu/z0pdhBkfBWynYYBnN9chRPR1Jd4/Y5Nq0I=; h=Date:From:To:Subject:From; b=fr3c7e9XCyrxG4ubpzNyrlL6Eu86lnJG5M2K0W65HGZTMpDSriAIGdBulpBWDiljL Wmcd5UTHHNw7BV3c8PoKZ6kLBGBCqx9kGFZKErUm2k21VQODvoAF9ZdOxhxN0cwaD+ IjRWDGrYEP3EoeyENIQ9tYiAN2PfER7eRZ9DPH5o= Date: Tue, 13 Aug 2019 15:37:37 -0700 From: akpm@linux-foundation.org To: william.kucharski@oracle.com, tsoni@codeaurora.org, stable@vger.kernel.org, psodagud@codeaurora.org, keescook@chromium.org, gregkh@linuxfoundation.org, isaacm@codeaurora.org, akpm@linux-foundation.org, mm-commits@vger.kernel.org, torvalds@linux-foundation.org Subject: [patch 11/18] mm/usercopy: use memory range to be accessed for wraparound check Message-ID: <20190813223737.DHDZP%akpm@linux-foundation.org> User-Agent: s-nail v14.9.10 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: "Isaac J. Manjarres" Subject: mm/usercopy: use memory range to be accessed for wraparound check 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 --- mm/usercopy.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/mm/usercopy.c~mm-usercopy-use-memory-range-to-be-accessed-for-wraparound-check +++ a/mm/usercopy.c @@ -147,7 +147,7 @@ static inline void check_bogus_address(c bool to_user) { /* Reject if object wraps past end of memory. */ - if (ptr + n < ptr) + if (ptr + (n - 1) < ptr) usercopy_abort("wrapped address", NULL, to_user, 0, ptr + n); /* Reject if NULL or ZERO-allocation. */ _