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 F0A95C433EF for ; Tue, 10 May 2022 13:19:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242981AbiEJNXm (ORCPT ); Tue, 10 May 2022 09:23:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45946 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243520AbiEJNWB (ORCPT ); Tue, 10 May 2022 09:22:01 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0313C506E4; Tue, 10 May 2022 06:16:14 -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 42261615F8; Tue, 10 May 2022 13:15:42 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4BD67C385C2; Tue, 10 May 2022 13:15:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1652188541; bh=vCU5qEkJjk+EcRlpBM/zbmu5Bbw3XDvJpwb9pfhgSjI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NxpuoeBF3jEtDmU3kw6/vNyMKo5EzZ2cgF8NRLgOwXRitcKb3cSx5NqcwSn/YpXMv r97PBBrBbG8AsCdyBCO87qnwARxPRein+zIjuUJERKq4t2XbsawVkXn/Cnss4m42+7 1ntebiqDE+752Wf6DAMSGGkADxsWWIhfGV2uX7WI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mikulas Patocka , Linus Torvalds , Sasha Levin Subject: [PATCH 4.14 42/78] x86: __memcpy_flushcache: fix wrong alignment if size > 2^32 Date: Tue, 10 May 2022 15:07:28 +0200 Message-Id: <20220510130733.780119348@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220510130732.522479698@linuxfoundation.org> References: <20220510130732.522479698@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: Mikulas Patocka [ Upstream commit a6823e4e360fe975bd3da4ab156df7c74c8b07f3 ] The first "if" condition in __memcpy_flushcache is supposed to align the "dest" variable to 8 bytes and copy data up to this alignment. However, this condition may misbehave if "size" is greater than 4GiB. The statement min_t(unsigned, size, ALIGN(dest, 8) - dest); casts both arguments to unsigned int and selects the smaller one. However, the cast truncates high bits in "size" and it results in misbehavior. For example: suppose that size == 0x100000001, dest == 0x200000002 min_t(unsigned, size, ALIGN(dest, 8) - dest) == min_t(0x1, 0xe) == 0x1; ... dest += 0x1; so we copy just one byte "and" dest remains unaligned. This patch fixes the bug by replacing unsigned with size_t. Signed-off-by: Mikulas Patocka Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- arch/x86/lib/usercopy_64.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/lib/usercopy_64.c b/arch/x86/lib/usercopy_64.c index 2c3b4bcbe8f2..0650b440b389 100644 --- a/arch/x86/lib/usercopy_64.c +++ b/arch/x86/lib/usercopy_64.c @@ -140,7 +140,7 @@ void memcpy_flushcache(void *_dst, const void *_src, size_t size) /* cache copy and flush to align dest */ if (!IS_ALIGNED(dest, 8)) { - unsigned len = min_t(unsigned, size, ALIGN(dest, 8) - dest); + size_t len = min_t(size_t, size, ALIGN(dest, 8) - dest); memcpy((void *) dest, (void *) source, len); clean_cache_range((void *) dest, len); -- 2.35.1