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[2620:137:e000::1:20]) by mx.google.com with ESMTP id c2-20020aa79522000000b0062dbafd7a3esi1027283pfp.100.2023.04.06.02.46.16; Thu, 06 Apr 2023 02:46:29 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b=DZdnQbDH; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236608AbjDFJpC (ORCPT + 99 others); Thu, 6 Apr 2023 05:45:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52324 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236552AbjDFJod (ORCPT ); Thu, 6 Apr 2023 05:44:33 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 857637ED3 for ; Thu, 6 Apr 2023 02:43:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1680774198; 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=srNjm2pDsZ7bySZjGb738UmToW4CeRBJkACWB8iZ9Oo=; b=DZdnQbDHDZ81cV3GhHqMZlnKie25s2NMBQs3kLLHGpntZDouCk3BU4VEXjkZW5v3JB2LAn sJ4D1MM1WU9M114yF1GpVFcc7BJSAHehrYAyx2AOXVDKvLiWm0RSNzX52apbf6zOSnQrDM GpO13ziw0LCMvQvNGZ0uRZJsBTyvFfg= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-237-DOKvdq12P_Wm-Yg8pakj4Q-1; Thu, 06 Apr 2023 05:43:11 -0400 X-MC-Unique: DOKvdq12P_Wm-Yg8pakj4Q-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id B992E38601AC; Thu, 6 Apr 2023 09:43:10 +0000 (UTC) Received: from warthog.procyon.org.uk (unknown [10.33.36.18]) by smtp.corp.redhat.com (Postfix) with ESMTP id A7FC6492C14; Thu, 6 Apr 2023 09:43:08 +0000 (UTC) From: David Howells To: netdev@vger.kernel.org Cc: David Howells , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Willem de Bruijn , Matthew Wilcox , Al Viro , Christoph Hellwig , Jens Axboe , Jeff Layton , Christian Brauner , Chuck Lever III , Linus Torvalds , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, David Ahern Subject: [PATCH net-next v5 06/19] tcp: Make sendmsg(MSG_SPLICE_PAGES) copy unspliceable data Date: Thu, 6 Apr 2023 10:42:32 +0100 Message-Id: <20230406094245.3633290-7-dhowells@redhat.com> In-Reply-To: <20230406094245.3633290-1-dhowells@redhat.com> References: <20230406094245.3633290-1-dhowells@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.9 X-Spam-Status: No, score=-0.2 required=5.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H2,SPF_HELO_NONE,SPF_NONE autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1762419686981169978?= X-GMAIL-MSGID: =?utf-8?q?1762419686981169978?= 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 tcp_sendmsg() copy it. Signed-off-by: David Howells cc: Eric Dumazet cc: "David S. Miller" cc: David Ahern cc: Jakub Kicinski cc: Paolo Abeni cc: Jens Axboe cc: Matthew Wilcox cc: netdev@vger.kernel.org --- net/ipv4/tcp.c | 28 +++++++++++++++++++++++++--- 1 file changed, 25 insertions(+), 3 deletions(-) diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 510bacc7ce7b..238a8ad6527c 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -1418,10 +1418,10 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size) goto do_error; copy = err; } else if (zc == 2) { - /* Splice in data. */ + /* Splice in data if we can; copy if we can't. */ struct page *page = NULL, **pages = &page; size_t off = 0, part; - bool can_coalesce; + bool can_coalesce, put = false; int i = skb_shinfo(skb)->nr_frags; copy = iov_iter_extract_pages(&msg->msg_iter, &pages, @@ -1448,12 +1448,34 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size) goto wait_for_space; copy = part; + 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); + err = copy ?: -ENOMEM; + goto do_error; + } + page = virt_to_page(q); + off = offset_in_page(q); + put = true; + can_coalesce = false; + } + if (can_coalesce) { skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy); } else { - get_page(page); + if (!put) + get_page(page); + put = false; skb_fill_page_desc_noacc(skb, i, page, off, copy); } + if (put) + put_page(page); page = NULL; if (!(flags & MSG_NO_SHARED_FRAGS))