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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,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 B14D0C2D0CE for ; Sun, 29 Dec 2019 17:50:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8708D206DB for ; Sun, 29 Dec 2019 17:50:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1577641858; bh=eyMennrsYxgBk8lQdqcO0vm1enPfe43n+1GlBfz2JkQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=C0PY2FJpyr9pBMMIgmlIftozUzwjGdCMvRsXccAZZOefbQfgKRHsE/CuBR/Zh2uXV ZnevY2DajPErrCl3EjiKbu7Us3SvZHb12zOwoYGfdqy28GK1KcpsSBC3pv35sF8E7m +YMIoTWwIHq55doMS0mPY/EuosF86LewzWABUgwo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731992AbfL2Ru5 (ORCPT ); Sun, 29 Dec 2019 12:50:57 -0500 Received: from mail.kernel.org ([198.145.29.99]:35686 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731972AbfL2Ru4 (ORCPT ); Sun, 29 Dec 2019 12:50:56 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 6B88320718; Sun, 29 Dec 2019 17:50:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1577641854; bh=eyMennrsYxgBk8lQdqcO0vm1enPfe43n+1GlBfz2JkQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=I5Hpuk+PoMNhbKTgx+W9ob4TFVa3yn7ILKfw0rZ0XSXDw1CFCQRUhoYD5hLnEmwpd SoehZxbbnalmd7FpkEo96vPWUllGGyK1FW1CGcDx8ntIeNH6mSxArA5YLmrPMgyK37 6b0cZxyk9PQ/aXFbTyczW7WEcz0jAP7tMJBnlTT0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Randy Dunlap , "Peter Zijlstra (Intel)" , Christian Brauner , Josh Poimboeuf , Linus Torvalds , Stephen Rothwell , Thomas Gleixner , cyphar@cyphar.com, keescook@chromium.org, linux@rasmusvillemoes.dk, Ingo Molnar , Sasha Levin Subject: [PATCH 5.4 196/434] ubsan, x86: Annotate and allow __ubsan_handle_shift_out_of_bounds() in uaccess regions Date: Sun, 29 Dec 2019 18:24:09 +0100 Message-Id: <20191229172714.846581295@linuxfoundation.org> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20191229172702.393141737@linuxfoundation.org> References: <20191229172702.393141737@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: Peter Zijlstra [ Upstream commit 9a50dcaf0416a43e1fe411dc61a99c8333c90119 ] The new check_zeroed_user() function uses variable shifts inside of a user_access_begin()/user_access_end() section and that results in GCC emitting __ubsan_handle_shift_out_of_bounds() calls, even though through value range analysis it would be able to see that the UB in question is impossible. Annotate and whitelist this UBSAN function; continued use of user_access_begin()/user_access_end() will undoubtedly result in further uses of function. Reported-by: Randy Dunlap Tested-by: Randy Dunlap Signed-off-by: Peter Zijlstra (Intel) Acked-by: Randy Dunlap Acked-by: Christian Brauner Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Stephen Rothwell Cc: Thomas Gleixner Cc: cyphar@cyphar.com Cc: keescook@chromium.org Cc: linux@rasmusvillemoes.dk Fixes: f5a1a536fa14 ("lib: introduce copy_struct_from_user() helper") Link: https://lkml.kernel.org/r/20191021131149.GA19358@hirez.programming.kicks-ass.net Signed-off-by: Ingo Molnar Signed-off-by: Sasha Levin --- lib/ubsan.c | 5 ++++- tools/objtool/check.c | 1 + 2 files changed, 5 insertions(+), 1 deletion(-) diff --git a/lib/ubsan.c b/lib/ubsan.c index e7d31735950d..0c4681118fcd 100644 --- a/lib/ubsan.c +++ b/lib/ubsan.c @@ -374,9 +374,10 @@ void __ubsan_handle_shift_out_of_bounds(struct shift_out_of_bounds_data *data, struct type_descriptor *lhs_type = data->lhs_type; char rhs_str[VALUE_LENGTH]; char lhs_str[VALUE_LENGTH]; + unsigned long ua_flags = user_access_save(); if (suppress_report(&data->location)) - return; + goto out; ubsan_prologue(&data->location, &flags); @@ -402,6 +403,8 @@ void __ubsan_handle_shift_out_of_bounds(struct shift_out_of_bounds_data *data, lhs_type->type_name); ubsan_epilogue(&flags); +out: + user_access_restore(ua_flags); } EXPORT_SYMBOL(__ubsan_handle_shift_out_of_bounds); diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 044c9a3cb247..f53d3c515cdc 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -481,6 +481,7 @@ static const char *uaccess_safe_builtin[] = { "ubsan_type_mismatch_common", "__ubsan_handle_type_mismatch", "__ubsan_handle_type_mismatch_v1", + "__ubsan_handle_shift_out_of_bounds", /* misc */ "csum_partial_copy_generic", "__memcpy_mcsafe", -- 2.20.1