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 A44AF1AF0BB; Tue, 21 Jul 2026 19:30:09 +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=1784662210; cv=none; b=e6XVkH2fAgaD4mQdR7urcC8X3HEStwlFKYrK9UBfQD4fLM8Ez7hUfoICo0JiJ6OWTX8IAfIQmspXqk6xpMheo0DDLdo2+TbOme6zs0wXEPndGW6IyjfQmjtEEMN+X+Jno8bEgCiraIZ+s3d49UJbu2wDf2/U8AVPbFHDgGGH9VQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784662210; c=relaxed/simple; bh=JRnhHWGhr/fbOFtwnbC+YFWPI3UCdmCV1kBmNxJk62s=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=UcLoI8nGGailBTJ4jRkb6zlRMBUvwAuUhwm7izLdJ7MCPPoTjx/pFRuyjEg+XPmdAVRzMcnWKAJDuV28/cT3MrqJU7mSYOuAod/VkwYMtyWp7U/zx2i43nAbQmo0U9nKJv3NJrYHA78xcHq7C2BkKI6ldF70s2xozKjq7S29FQs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=EDCwIT0i; 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="EDCwIT0i" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D2D701F000E9; Tue, 21 Jul 2026 19:30:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784662209; bh=WyMXu4lRBT5NMZQ+NkYp8hqSwI8WhaD82ZGZwNA3Hlk=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=EDCwIT0ibDmTDvCM55kvltnZs4op6MjBFjNyXwziPFkGLw82Flid9GWXVof3xMtWr kXKBPcM0bP5/O42f5OEyZ8kDIcoKo9kRShxD4D0SfCmThJ06RrCj0vPiQVTz8myYEy LHy9qSauBCGaLVJFY5/SS4xGX+90F8HP8UyAusKw= 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 6.12 0357/1276] bpf: Run generic devmap egress prog on private skb Date: Tue, 21 Jul 2026 17:13:20 +0200 Message-ID: <20260721152454.101335603@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152446.065700225@linuxfoundation.org> References: <20260721152446.065700225@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 6.12-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 c19eb814bbfdae..1c64c4cff41ec1 100644 --- a/kernel/bpf/devmap.c +++ b/kernel/bpf/devmap.c @@ -698,6 +698,18 @@ 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