From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793364746; b=nLVjAJ0MTHYJK/IlxXw8PEkb3NVvV/c4dcZ3yp6WMoPM9rAho8IvtDgPsaRHT4MS7gIC 9paWdaonlxHqbaFQP6mHEoQBxtX9FG2xHdAz9f9EYtv6ZGa4af1uPzuLpQxx5sa4Wz0uk QRMRW6RWosOOfJwT2vGFaQLfUDhyoKEsyoRCKaqG29/8gbm0WFEWm/upxU3Ga9KWkAAXT JA7ndA8zXDmVxYv9EncwIDZ7zapjFkDvzNPrxslzL8WqYv4yihfLdmszKuPy5UhePYeZZ 7YzTjQbk0m2gPUNKuiqgTtRZbFruqh5b4zrs11Fy6jXO/RzHYFHvn3sjkoIqTNFEP/g== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793364746; h=Received:DKIM-Signature:Subject:To:Cc:From:Date:Message-ID: MIME-Version:Content-Type:Content-Transfer-Encoding; bh=Q9KXP6ajcFvTDueWoylr3kKEJjLSP+y3MQvGqdsX29M=; b=zj2D8tzLfl5MsIf/4ooE4qHR208OyWvp6cQSaN4BYyjwmqYIyUro9Y8UM627JZ8nfhFO +5Qm55GEwlA4OTasUuvE91ouXIyPbkz1Utps5Db/Ipoi/u90SaCBE74ane6cCnaJXGy3+ jmJ9ceo2qdi6fneUG66oRLdy2ZZKd5CJBNyUBqSl53Q3RKUHxNHCiGhOtWyQMSA1qiFbK RNCEOPBI5PAlVp+IwUqFa5g4I/hmmXePFmC6+h3SPaK0hjvNCfGWTYyMee0Ss8YkjhFRh qM158CVs5UM6FgOv279Gtj1AZ7YRImeXNziJLZepHARsoSMBpYjGemsc1GffKc5mowg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=Jlvq0cXX; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 30057606A326 for ; Fri, 30 Oct 2026 12:52:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=Jlvq0cXX Received: by smtp.kernel.org (Postfix) with ESMTPSA id 48D0B1F00A16; Fri, 30 Oct 2026 12:52:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793364740; bh=Q9KXP6ajcFvTDueWoylr3kKEJjLSP+y3MQvGqdsX29M=; h=Subject:To:Cc:From:Date; b=Jlvq0cXXs2bYxsGEC2MN9N6yeZuUB0ERlZudzuiVh7kDQ7pXsXLqaJXAHYDDDCElQ RkfDaaSL8s3BDlD5zN0fTg5hTladPPa0ZzsAIbtBx0RCS7ndrv2j2yRU+Tqp+ogTr5 /YEGCPzYmmxFozEG3kqFRz1oKmAjBOmzr+VK1G6c= Subject: FAILED: patch "[PATCH] net: skbuff: propagate shared-frag marker in skb_zerocopy()" failed to apply to 5.15-stable tree To: pointerliu@126.com,edumazet@kernel.org,kuba@kernel.org Cc: From: Date: Fri, 30 Oct 2026 13:51:57 +0100 Message-ID: <2026103057-flight-cider-b6ae@gregkh> X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x 79dc34beb1fdb3da79753e51e15c68591a2561fe # git commit -s git send-email --to '' --in-reply-to '2026103057-flight-cider-b6ae@gregkh' --subject-prefix 'PATCH 5.15.y' 'HEAD^..' Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 79dc34beb1fdb3da79753e51e15c68591a2561fe Mon Sep 17 00:00:00 2001 From: Zizhen Liu Date: Thu, 22 Oct 2026 18:42:17 +0800 Subject: [PATCH] net: skbuff: propagate shared-frag marker in skb_zerocopy() skb_zerocopy() moves frag descriptors from @from into @to and takes a reference on each frag, but it does not copy skb_shinfo(from)->flags into skb_shinfo(to)->flags. A destination skb holding the same page-cache backed frags as the source therefore reports skb_has_shared_frag() as false. That breaks the invariant relied on by later in-place writers. ESP input checks skb_has_shared_frag() before deciding whether an uncloned nonlinear skb can skip skb_cow_data(); with the marker lost, an skb that skb_zerocopy() built for nfnetlink_queue or for an openvswitch upcall is decrypted in place, letting an unprivileged user write into the page cache of a root-owned read-only file. Propagate SKBFL_SHARED_FRAG when frag descriptors are copied, as done for the other frag-transfer helpers. Fixes: af2806f8f90a ("net: Export skb_zerocopy() to zerocopy from one skb to another") Fixes: f4c50a4034e6 ("xfrm: esp: avoid in-place decrypt on shared skb frags") Cc: stable@kernel.org Signed-off-by: Zizhen Liu Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20261022104217.1852191-1-pointerliu@126.com Signed-off-by: Jakub Kicinski diff --git a/net/core/skbuff.c b/net/core/skbuff.c index eb9fcc4b1fd1..6a7c02b7653a 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -3966,6 +3966,8 @@ skb_zerocopy(struct sk_buff *to, struct sk_buff *from, int len, int hlen) } skb_shinfo(to)->nr_frags = j; + skb_shinfo(to)->flags |= skb_shinfo(from)->flags & SKBFL_SHARED_FRAG; + if (i > 0 && from->unreadable) to->unreadable = 1;