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 DDA993B2D1D; Tue, 21 Jul 2026 20:36:04 +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=1784666167; cv=none; b=Eun0ete08A3bucuflPSqrj0/wXYJ0xh7E5FGHL5OjRbPaL9x2r4qJQ9qWdmnHSRg4S0nPieeedVtDHgHTen1BSHB/TGvjvM+Ka85Gv79b2YSTHEBfj6z/cwI+BF8F1yAiVCN64c6zqgbKoRNYNxS9dndNrBf1gKlSSndliCavLU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784666167; c=relaxed/simple; bh=qF6ZobCe8e8YK4r8YQIN9Zhh2UzlM3AQFEBTm4soK3g=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=kUxDb2/LoXA2ZRAUnofv85BuViD/HplAtAlDKW/Vi/2YRVVtC9t7q16Hz4w4TamISqrm7KMka90RfhvYa8+GI4k+ikDc9GQ7NEtEFMvBprRVDzIVSpjZBm97MvDhZyKl+Nee/ojyG5yP6vng7sPq0RAHykxQFv1dyX6YDlRQ29c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=MGhF3ASq; 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="MGhF3ASq" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D8B6D1F00A3A; Tue, 21 Jul 2026 20:36:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784666164; bh=odX3u8uJlfhuM6x2JMPbXz3VWNdytXDbjxiaAuKs8eU=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=MGhF3ASq0ct0jsuV97QH53SfPE3EBCZXbiBOI767gZokGc1p0bm/W84teN29VjN1S T+1AsXjBlMo8FUxp84XnCHDErd58c7AIDnQS13sWSEid+LRdoi9KcKY2KTGhzFwkLO EIh2zexn4BRHJ647vfJGzQvl4HACY+/WZ9IyM1SE= 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 6.6 0579/1266] bpf: Run generic devmap egress prog on private skb Date: Tue, 21 Jul 2026 17:16:56 +0200 Message-ID: <20260721152454.823701043@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152441.786066624@linuxfoundation.org> References: <20260721152441.786066624@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 6.6-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 3f710d5af55d4b..8ce3b152dcd5b9 100644 --- a/kernel/bpf/devmap.c +++ b/kernel/bpf/devmap.c @@ -687,6 +687,18 @@ 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