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 E48B4C761AF for ; Fri, 31 Mar 2023 16:12:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233230AbjCaQMd (ORCPT ); Fri, 31 Mar 2023 12:12:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34640 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232133AbjCaQLo (ORCPT ); Fri, 31 Mar 2023 12:11:44 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 44DB422905 for ; Fri, 31 Mar 2023 09:10:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1680279012; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=t1cUbUkat/Gf1dtGRXqhXt4i30LjR64ymk07qbS2yB8=; b=U8/ij63IJG+hIXIidPzaXoV0AGIHIKKrw8MVFvfSY5D3aEyVVfjT9jVhoH/vRlirL+HEeo KhsqsmfaLTrnZlOxoSCXEgzDezJKwSx6SG8+0fgibZWdgykehK7toohpaEXgLZqnT390iB QTpVlTZX4vVQ0Pke15HQITXwvxn0wBg= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-488-2g961z0wNy-7npZvx0P1sg-1; Fri, 31 Mar 2023 12:10:10 -0400 X-MC-Unique: 2g961z0wNy-7npZvx0P1sg-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id C8816185A78B; Fri, 31 Mar 2023 16:10:06 +0000 (UTC) Received: from warthog.procyon.org.uk (unknown [10.33.36.18]) by smtp.corp.redhat.com (Postfix) with ESMTP id CD6FD1121314; Fri, 31 Mar 2023 16:10:04 +0000 (UTC) From: David Howells To: Matthew Wilcox , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni Cc: David Howells , Al Viro , Christoph Hellwig , Jens Axboe , Jeff Layton , Christian Brauner , Chuck Lever III , Linus Torvalds , netdev@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Willem de Bruijn Subject: [PATCH v3 16/55] ip, udp: Make sendmsg(MSG_SPLICE_PAGES) copy unspliceable data Date: Fri, 31 Mar 2023 17:08:35 +0100 Message-Id: <20230331160914.1608208-17-dhowells@redhat.com> In-Reply-To: <20230331160914.1608208-1-dhowells@redhat.com> References: <20230331160914.1608208-1-dhowells@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.1 on 10.11.54.3 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org If sendmsg() with MSG_SPLICE_PAGES encounters a page that shouldn't be spliced - a slab page, for instance, or one with a zero count - make __ip_append_data() copy it. Signed-off-by: David Howells cc: Willem de Bruijn cc: "David S. Miller" cc: Eric Dumazet cc: Jakub Kicinski cc: Paolo Abeni cc: Jens Axboe cc: Matthew Wilcox cc: netdev@vger.kernel.org --- net/ipv4/ip_output.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c index e2eaba817c1f..41a954ac9e1a 100644 --- a/net/ipv4/ip_output.c +++ b/net/ipv4/ip_output.c @@ -1004,13 +1004,32 @@ static int __ip_splice_pages(struct sock *sk, struct sk_buff *skb, struct page *page = NULL, **pages = &page; ssize_t copy = *pcopy; size_t off; + bool put = false; int err; copy = iov_iter_extract_pages(&msg->msg_iter, &pages, copy, 1, 0, &off); if (copy <= 0) return copy ?: -EIO; + if (!sendpage_ok(page)) { + const void *p = kmap_local_page(page); + void *q; + + q = page_frag_memdup(NULL, p + off, copy, + sk->sk_allocation, ULONG_MAX); + kunmap_local(p); + if (!q) { + iov_iter_revert(&msg->msg_iter, copy); + return -ENOMEM; + } + page = virt_to_page(q); + off = offset_in_page(q); + put = true; + } + err = skb_append_pagefrags(skb, page, off, copy); + if (put) + put_page(page); if (err < 0) { iov_iter_revert(&msg->msg_iter, copy); return err;