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=1793364726; b=bH2frVEC1f9Yc8OilBPE6sz8PskBieA50E17fSR/o7/7Wr6EHGv0lVcCxcWYuPtUvHB0 4yNtQgx3uHYm0rdfcytdM/86M5xKnMLE6Z0OLpkLj+cIgefIt5/vY99XZI/Q9RS/PHo25 Q9iCZipL+7c+NsTW92HoEcqeoDor+XTfrTc3wclaUTC/LYomFMYwiD+rOiQqmGkySc/Yl V3UGIBj8CcyPXlLdBFAoyaiiXIOqaL7ahZtl33fIcEDwo/NWdJlD73gUZtSaNlLbDXqp3 qAjbi/AJJXWbqclzGnRjUtyMy+2vyqnvx4LmhGY2QlD1eC0CsrfZGFZY2FwiSEQ7XpQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793364726; h=Received:DKIM-Signature:Subject:To:Cc:From:Date:Message-ID: MIME-Version:Content-Type:Content-Transfer-Encoding; bh=ZDmDK3RLnnlinRdVBsJh/crxoJhyTr+GBTnbouTyepQ=; b=Huy4u9ewwqch0GgHjJnNIQw38jH31qJs2GbtSJyjW4+mNYXglzUxqUtXH0oByXZaQ1qH dx65jUmB23h9eKn64VL/5h8/m7J3F8BcSi76oJ8WdkF7xO/6+2uUFZVq8HM25peWwDx/1 Mzs5PUZIkp1dO7SgV4ewdmSR4QLu4LjnUcnaFjBZdxYd0NMZ/Ij2PJFmAf0ig8JQyW7jz u6+azDNPG85DxIlC+DuWSop1qhqThrLtmVXfAf1kU6lHjGJj2RukaV3jXNkGH3kK6Jeaj MSjLTSidh7b1gNzAARAomEyMNMSlUclAxf9R5hTv2bbrt/Fqyl8K4OeM0Wae+dIiFsg== 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=elZMnkEP; 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 3DEB1606A31F for ; Fri, 30 Oct 2026 12:52:06 +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=elZMnkEP Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8FCD71F00A1A; Fri, 30 Oct 2026 12:52:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793364726; bh=ZDmDK3RLnnlinRdVBsJh/crxoJhyTr+GBTnbouTyepQ=; h=Subject:To:Cc:From:Date; b=elZMnkEPZT98KTOO7cwPG90PJBvB8JDRD+fuj2RaeyxExIaYkfMPHbh6/KK5oageB WMkV7f/nS4dKBBBNe654jDD4seVT6miCGsgYPJCF0xedwh9K2zyoZdWPYJ9Fjs8xDL Fzi+xYKFuKg7hJPTCiZ/D9+/r+5LcMYClvb5SY64= Subject: FAILED: patch "[PATCH] net: skbuff: propagate shared-frag marker in skb_zerocopy()" failed to apply to 6.18-stable tree To: pointerliu@126.com,edumazet@kernel.org,kuba@kernel.org Cc: From: Date: Fri, 30 Oct 2026 13:51:55 +0100 Message-ID: <2026103055-chastise-denial-90ef@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 6.18-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-6.18.y git checkout FETCH_HEAD git cherry-pick -x 79dc34beb1fdb3da79753e51e15c68591a2561fe # git commit -s git send-email --to '' --in-reply-to '2026103055-chastise-denial-90ef@gregkh' --subject-prefix 'PATCH 6.18.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;