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 0036FC43334 for ; Tue, 28 Jun 2022 11:41:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344276AbiF1Ll5 (ORCPT ); Tue, 28 Jun 2022 07:41:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37256 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344267AbiF1Ll4 (ORCPT ); Tue, 28 Jun 2022 07:41:56 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D15FB2E0BE for ; Tue, 28 Jun 2022 04:41:55 -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 6C27861AD2 for ; Tue, 28 Jun 2022 11:41:55 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id EF7D6C3411D; Tue, 28 Jun 2022 11:41:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1656416514; bh=1mnkMgp/rc5QET6ccBgQU57EF5F42ZWZpDSf4eofuWY=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=F2F8329VSF5YilfdUuT4/jS5H59OB6HZgasSX0A1tJrPPNAFUnQncxu8SBEQ1DcbP TsfkF8rOxko9TfVfvSMoAO9hnDqJ+iI3d7/LYN3hE2TWEgcsMMsU8T9XOS/wo0n91i SXC3ey239Zx1mVkrERYDTaFEEMw/BuNk5IOvynfwRa7lNfOLo/AJnIQHH9tDaYOENl D8CHzmaULXhN8sQlIX+Y8hnz1eNytLt4lnUT3/dWYJw/o/pHGyOEcNhBBpkl/6sl1N 2EzwgCMIP/33cJw6+KtZM2rSzhO/dgbGeH2bx79/vNmI4JkNZjxtw5eOI84GgfTXGI 8vKC44fIftPEQ== Message-ID: Subject: Re: [PATCH 23/44] iov_iter_get_pages{,_alloc}(): cap the maxsize with MAX_RW_COUNT From: Jeff Layton To: Al Viro , linux-fsdevel@vger.kernel.org Cc: Linus Torvalds , Jens Axboe , Christoph Hellwig , Matthew Wilcox , David Howells , Dominique Martinet , Christian Brauner Date: Tue, 28 Jun 2022 07:41:52 -0400 In-Reply-To: <20220622041552.737754-23-viro@zeniv.linux.org.uk> References: <20220622041552.737754-1-viro@zeniv.linux.org.uk> <20220622041552.737754-23-viro@zeniv.linux.org.uk> Content-Type: text/plain; charset="ISO-8859-15" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.44.2 (3.44.2-1.fc36) MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Wed, 2022-06-22 at 05:15 +0100, Al Viro wrote: > All callers can and should handle iov_iter_get_pages() returning > fewer pages than requested. All in-kernel ones do. And it makes > the arithmetical overflow analysis much simpler... >=20 > Signed-off-by: Al Viro > --- > lib/iov_iter.c | 4 ++++ > 1 file changed, 4 insertions(+) >=20 > diff --git a/lib/iov_iter.c b/lib/iov_iter.c > index 30f4158382d6..c3fb7853dbe8 100644 > --- a/lib/iov_iter.c > +++ b/lib/iov_iter.c > @@ -1367,6 +1367,8 @@ ssize_t iov_iter_get_pages(struct iov_iter *i, > maxsize =3D i->count; > if (!maxsize) > return 0; > + if (maxsize > MAX_RW_COUNT) > + maxsize =3D MAX_RW_COUNT; > =20 > if (likely(user_backed_iter(i))) { > unsigned int gup_flags =3D 0; > @@ -1485,6 +1487,8 @@ ssize_t iov_iter_get_pages_alloc(struct iov_iter *i= , > maxsize =3D i->count; > if (!maxsize) > return 0; > + if (maxsize > MAX_RW_COUNT) > + maxsize =3D MAX_RW_COUNT; > =20 > if (likely(user_backed_iter(i))) { > unsigned int gup_flags =3D 0; Reviewed-by: Jeff Layton