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 A6AB444AB61; Tue, 21 Jul 2026 21:26:03 +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=1784669164; cv=none; b=fZAsUHltDhRV2RfgjHl65mk8MVB2zC3AMvCxUWCEbCb+BmKQZGkxo8Q+Gc5NY/QcPsszzrnB1+CSpyjHBgs2iw610ka1N/cVAWulg7gtpKZcZXRpPsCQKz7V4YFNGOTj0AX9keXCvT1oPWnzErUjRsRNXhcH0xHxmADTGEiX848= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784669164; c=relaxed/simple; bh=iQ3dbV/ZdQ3/idtPfmrD6PNTbYDyrXxlKqO7IylsMQ0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=iM28oca/TmXaQBEkqb9RzbbNmgk8JnMjcyfawczHdTom/X+RBErxsSj5dsLCd9xNhRNE7TiKp14NEufpgkI+Sya3zqoN3W8nTyxyhwxN4isFVUmRAvDgsjaigeOnk+GzSuVu3uXYAYWeSpda0F0GMshENMY4djuOTXNa5nSsGbk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=lKec7rR8; 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="lKec7rR8" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1CFE11F000E9; Tue, 21 Jul 2026 21:26:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784669163; bh=QXK5ltXD6M9UN1Sol73KD379/2fKQbUe7nOD1VLElYY=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=lKec7rR8/fq895wMo1x9ejSZnBDIY1RTXqMZnAPVOO9dEe0qvGHumyDj/2KIXQo95 rWuaZB6xx/x5aGebk478OtBbNsENZSoiX7ONxV2OFFEk5Yyf1pIovFiSs3AuS2d0fB y+pdAfIgCKoZfxu4KDIu9jCHpvns9nX1x6Piu4Yw= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jiayuan Chen , Jakub Kicinski , =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= , Sun Jian , Alexei Starovoitov , Sasha Levin Subject: [PATCH 6.1 0451/1067] bpf: Run generic devmap egress prog on private skb Date: Tue, 21 Jul 2026 17:17:32 +0200 Message-ID: <20260721152434.706914998@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152424.521567757@linuxfoundation.org> References: <20260721152424.521567757@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-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Sun Jian [ Upstream commit 6001896f00984d317fb75160ba05c4a885fbe2a0 ] Generic XDP devmap multi redirect uses skb_clone() for intermediate destinations and sends the last destination with the original skb. This can leave multiple destinations sharing the same packet data. This becomes visible after generic devmap egress-program support was added: a devmap egress program may mutate packet data, and another destination sharing the same data can observe that mutation. Native XDP broadcast redirect does not have this issue because xdpf_clone() copies the frame data for each destination. Generic XDP should provide the same per-destination isolation before running a devmap egress program. Fix this by making cloned skbs private before running the generic devmap egress program. Use skb_copy() instead of skb_unshare() so allocation failure does not consume the skb and the existing caller error paths keep their ownership semantics. Fixes: 2ea5eabaf04a ("bpf: devmap: Implement devmap prog execution for generic XDP") Suggested-by: Jiayuan Chen Suggested-by: Jakub Kicinski Reviewed-by: Toke Høiland-Jørgensen Signed-off-by: Sun Jian Link: https://lore.kernel.org/r/20260612114032.244616-2-sun.jian.kdev@gmail.com Signed-off-by: Alexei Starovoitov Signed-off-by: Sasha Levin --- kernel/bpf/devmap.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c index fac0773fe9a0c4..f4e28ad6c920dd 100644 --- a/kernel/bpf/devmap.c +++ b/kernel/bpf/devmap.c @@ -681,6 +681,18 @@ int dev_map_generic_redirect(struct bpf_dtab_netdev *dst, struct sk_buff *skb, if (unlikely(err)) return err; + if (dst->xdp_prog && skb_cloned(skb)) { + struct sk_buff *nskb; + + nskb = skb_copy(skb, GFP_ATOMIC); + if (!nskb) + return -ENOMEM; + + nskb->mac_len = skb->mac_len; + consume_skb(skb); + skb = nskb; + } + /* Redirect has already succeeded semantically at this point, so we just * return 0 even if packet is dropped. Helper below takes care of * freeing skb. -- 2.53.0