From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E47D03A16AC; Fri, 4 Sep 2026 05:21:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788499263; cv=none; b=K2OS+wV5EutumQRjW17DpH3uoiRAsjwiNXxCj9ObkQgp3NC73XMeG4AeAliOB9Z9XBVe5Pbsmk7HzdSej6Mb/nqYx38bLoFOTR0BjVPQ4/2GMrcv29d6TxMANFVcj/UR/QX6ptkVLUu6VF2dSQUZEXyJB2M4tAi9rxPrEd9uxuc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788499263; c=relaxed/simple; bh=klS8g1qmxyaYg62tL3DCSVHVdwQeONbTkmFbFEMk2a0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=MCncVDZS/pdW0P5Q6Wqlka2CBbMtSp/JpmXtsVdG1lPqhhXPqybqduI/Ud20O6uBYh5KkIM2B2mPF4YxLnftQpHeTpLE52CaJZeeogCki/Qd6Ccirt6kDgnJZAE/12ppJngpEgIJ4awmJQbpJ5Hzu9xryp3dXqqS+Kao/6gc40c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Ekv78/BB; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="Ekv78/BB" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 46B591F00A3D; Fri, 4 Sep 2026 05:21:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788499261; bh=xeOPoHtxVURP7TsXZTlDnTuSS0sSNA75bZAHj8vx78Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Ekv78/BBrV+DN3mK+csg7iGMPH0w7InRJmi+ZnMPUB214eOUvQ6+tZ1i3N8PdIOzV oB5KsdvTRBH4N71SO1FwNSThkMK3nNC0Jub1q7Tqyk7N9Qbo+0fwiES3CyHJmAUXzJ kBSSYu3CSUAc2lUn7bACa5iB08NSQ/i3X2IAwuVk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Vega , Zhiling Zou , Ido Schimmel , Paolo Abeni Subject: [PATCH 7.2 353/713] ip: orphan prefetched skbs before multicast forwarding Date: Fri, 4 Sep 2026 06:55:21 +0200 Message-ID: <20260904045811.742526230@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260904045803.810145556@linuxfoundation.org> References: <20260904045803.810145556@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Zhiling Zou commit e36ce6e78fe3fc3c071a26750783b7ba081ce10d upstream. IPv4 and IPv6 input preserve an skb->sk association installed by bpf_sk_assign() so that local delivery can use the selected socket under RCU. Both address families can also prefetch a socket in UDP early demux. In both paths (BPF and UDP early demux) a reference is not guaranteed to be held on the socket. When a multicast packet is not locally deliverable, IPv6 hands the original skb to ip6_mr_input(). IPv4's ip_mr_input() similarly keeps the original skb when local delivery is not needed. Either path can put the skb on an unresolved multicast route queue or forward it after the receive-side RCU section ends. After the prefetched socket is destroyed, a later skb free invokes sock_pfree() and dereferences the stale skb->sk. Orphan the skb before each non-local multicast forwarding path. Local delivery retains the original skb; the existing skb_clone() calls provide multicast forwarding with a socket-free clone. Fixes: cf7fbe660f2d ("bpf: Add socket assign support") Fixes: 08842c43d016 ("udp: no longer touch sk->sk_refcnt in early demux") Cc: stable@vger.kernel.org Reported-by: Vega Signed-off-by: Zhiling Zou Reported-by: Vega Signed-off-by: Zhiling Zou Reviewed-by: Ido Schimmel Link: https://patch.msgid.link/0c52eb3d7532aaf8bccf37e0f7c922143c639735.1786552223.git.zhilinz@nebusec.ai Signed-off-by: Paolo Abeni Signed-off-by: Greg Kroah-Hartman --- net/ipv4/ipmr.c | 3 +++ net/ipv6/ip6_input.c | 1 + 2 files changed, 4 insertions(+) --- a/net/ipv4/ipmr.c +++ b/net/ipv4/ipmr.c @@ -2213,6 +2213,9 @@ int ip_mr_input(struct sk_buff *skb) if (IPCB(skb)->flags & IPSKB_FORWARDED) goto dont_forward; + if (!local) + skb_orphan(skb); + mrt = ipmr_rt_fib_lookup(net, skb); if (IS_ERR(mrt)) { kfree_skb(skb); --- a/net/ipv6/ip6_input.c +++ b/net/ipv6/ip6_input.c @@ -622,6 +622,7 @@ int ip6_mc_input(struct sk_buff *skb) if (deliver) { skb2 = skb_clone(skb, GFP_ATOMIC); } else { + skb_orphan(skb); skb2 = skb; skb = NULL; }