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=-20.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=unavailable 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 63F98C6499A for ; Mon, 19 Jul 2021 17:22:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4CB5761181 for ; Mon, 19 Jul 2021 17:22:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1355970AbhGSQkV (ORCPT ); Mon, 19 Jul 2021 12:40:21 -0400 Received: from mail.kernel.org ([198.145.29.99]:41938 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1348742AbhGSPZE (ORCPT ); Mon, 19 Jul 2021 11:25:04 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 040FF600EF; Mon, 19 Jul 2021 16:05:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1626710742; bh=zcdR+7Ixce2wcvSTjoQub02GaLVwOc/g7cAn+ekALic=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=xvW6ZKKrFCjv3SRruuGTIOR1tuK83lx3ZyL6M3LAAxeL9G9pWya3lC6/XjsACB+eY B8PIP5rAt4K4JgR/JV9eZ8Mngqw5er/5G5zzr8/8yThLYCc8ZtwHAvbi30Vbs4QgC4 1e1DVaQxlFjoTjd0lKjrXJJmuKiNUEc733vDAHMU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Al Viro , Sasha Levin Subject: [PATCH 5.13 090/351] iov_iter_advance(): use consistent semantics for move past the end Date: Mon, 19 Jul 2021 16:50:36 +0200 Message-Id: <20210719144947.471372587@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210719144944.537151528@linuxfoundation.org> References: <20210719144944.537151528@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: linux-kernel@vger.kernel.org From: Al Viro [ Upstream commit 3b3fc051cd2cba42bf736fa62780857d251a1236 ] asking to advance by more than we have left in the iov_iter should move to the very end; it should *not* leave negative i->count and it should not spew into syslog, etc. - it's a legitimate operation. Signed-off-by: Al Viro Signed-off-by: Sasha Levin --- lib/iov_iter.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/lib/iov_iter.c b/lib/iov_iter.c index 9eb7c31688cc..459c33c26bea 100644 --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -1117,8 +1117,6 @@ static inline void pipe_truncate(struct iov_iter *i) static void pipe_advance(struct iov_iter *i, size_t size) { struct pipe_inode_info *pipe = i->pipe; - if (unlikely(i->count < size)) - size = i->count; if (size) { struct pipe_buffer *buf; unsigned int p_mask = pipe->ring_size - 1; @@ -1159,6 +1157,8 @@ static void iov_iter_bvec_advance(struct iov_iter *i, size_t size) void iov_iter_advance(struct iov_iter *i, size_t size) { + if (unlikely(i->count < size)) + size = i->count; if (unlikely(iov_iter_is_pipe(i))) { pipe_advance(i, size); return; @@ -1168,7 +1168,6 @@ void iov_iter_advance(struct iov_iter *i, size_t size) return; } if (unlikely(iov_iter_is_xarray(i))) { - size = min(size, i->count); i->iov_offset += size; i->count -= size; return; -- 2.30.2