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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B8517CCA495 for ; Tue, 7 Jun 2022 22:27:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1350860AbiFGW1W (ORCPT ); Tue, 7 Jun 2022 18:27:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50582 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1384234AbiFGWZX (ORCPT ); Tue, 7 Jun 2022 18:25:23 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 98242270F0E; Tue, 7 Jun 2022 12:23:12 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 1D7B360BA3; Tue, 7 Jun 2022 19:23:12 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 28369C385A2; Tue, 7 Jun 2022 19:23:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1654629791; bh=bNxTvQwfvlCQhLBV5XP5eB24HHOeNW7RiIDKe2u+9rk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=koisK5YpfCZ+3r1SpMzmuJQltY9DE+gIk8rHBWkOlPojeKrMJG5NXQsNqlwqk0qhG PSNdPg04qWLT1H+tQRH/O6jdvovGurjtL320CztkU6XBdyMF8LYLH6dw2DaOHPcp25 tJuEbkTFhFHpV/zE9umjoEbFLn3NR1WTJDtXd5Oo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Vincent Whitchurch , Richard Weinberger Subject: [PATCH 5.18 819/879] um: Fix out-of-bounds read in LDT setup Date: Tue, 7 Jun 2022 19:05:37 +0200 Message-Id: <20220607165026.625812779@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220607165002.659942637@linuxfoundation.org> References: <20220607165002.659942637@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Vincent Whitchurch commit 2a4a62a14be1947fa945c5c11ebf67326381a568 upstream. syscall_stub_data() expects the data_count parameter to be the number of longs, not bytes. ================================================================== BUG: KASAN: stack-out-of-bounds in syscall_stub_data+0x70/0xe0 Read of size 128 at addr 000000006411f6f0 by task swapper/1 CPU: 0 PID: 1 Comm: swapper Not tainted 5.18.0+ #18 Call Trace: show_stack.cold+0x166/0x2a7 __dump_stack+0x3a/0x43 dump_stack_lvl+0x1f/0x27 print_report.cold+0xdb/0xf81 kasan_report+0x119/0x1f0 kasan_check_range+0x3a3/0x440 memcpy+0x52/0x140 syscall_stub_data+0x70/0xe0 write_ldt_entry+0xac/0x190 init_new_ldt+0x515/0x960 init_new_context+0x2c4/0x4d0 mm_init.constprop.0+0x5ed/0x760 mm_alloc+0x118/0x170 0x60033f48 do_one_initcall+0x1d7/0x860 0x60003e7b kernel_init+0x6e/0x3d4 new_thread_handler+0x1e7/0x2c0 The buggy address belongs to stack of task swapper/1 and is located at offset 64 in frame: init_new_ldt+0x0/0x960 This frame has 2 objects: [32, 40) 'addr' [64, 80) 'desc' ================================================================== Fixes: 858259cf7d1c443c83 ("uml: maintain own LDT entries") Signed-off-by: Vincent Whitchurch Cc: stable@vger.kernel.org Signed-off-by: Richard Weinberger Signed-off-by: Greg Kroah-Hartman --- arch/x86/um/ldt.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- a/arch/x86/um/ldt.c +++ b/arch/x86/um/ldt.c @@ -23,9 +23,11 @@ static long write_ldt_entry(struct mm_id { long res; void *stub_addr; + + BUILD_BUG_ON(sizeof(*desc) % sizeof(long)); + res = syscall_stub_data(mm_idp, (unsigned long *)desc, - (sizeof(*desc) + sizeof(long) - 1) & - ~(sizeof(long) - 1), + sizeof(*desc) / sizeof(long), addr, &stub_addr); if (!res) { unsigned long args[] = { func,