From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ed1-f49.google.com (mail-ed1-f49.google.com [209.85.208.49]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 49C5128504B for ; Fri, 3 Oct 2025 12:03:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.208.49 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759493035; cv=none; b=n/h7bF5bYzYVQ8ThZ+1ahYxHOft9sDNOHT+xwXw4qtw8ogtouyPv9FFsB9qdluC94FEqsKy1zGaop5OywEfoBisB7nlfLrKUL7Uftf2q+2VkhYep7dgw5Oe9ZC2/+iShJNCzNizNDALiXxn6pzfQ3+zML7OBDTsJ4GhBH1e+s8M= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759493035; c=relaxed/simple; bh=TKJ68FQzM4OxoqzPD1unNLoApkMeRnB7fJR+0WinljE=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=OK6CbTSO5S+bweuY99zrg71PeQ/iN/VDKPgfJPcccJta+ElQKZa95TRN/Qwl0xB1/+LXCngxtgMdOjW3Ns3OEBu5adLnWeLl4vvn087X1jgVbZoUwyBCW9pMrlS5pkrLluk2ASGIkTNShOPRHaPJ7Mrz/9cRHl5D0iIWKbE2Bv8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=cloudflare.com; spf=pass smtp.mailfrom=cloudflare.com; dkim=pass (2048-bit key) header.d=cloudflare.com header.i=@cloudflare.com header.b=A6ic5k8z; arc=none smtp.client-ip=209.85.208.49 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=cloudflare.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=cloudflare.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=cloudflare.com header.i=@cloudflare.com header.b="A6ic5k8z" Received: by mail-ed1-f49.google.com with SMTP id 4fb4d7f45d1cf-6349e3578adso3968571a12.1 for ; Fri, 03 Oct 2025 05:03:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cloudflare.com; s=google09082023; t=1759493031; x=1760097831; darn=vger.kernel.org; h=mime-version:message-id:date:references:in-reply-to:subject:cc:to :from:from:to:cc:subject:date:message-id:reply-to; bh=7EUW43HWolyI7T5LSzYWxB/vbzNla21nNsPp9mz+OZo=; b=A6ic5k8z7XJBy13VqJMYMttQy54y34Q46MyX++5vj0WvkgXfhwKNVU/EBdnJpMH2t7 SEiYkp8wdNSI6Cp+0sZJpCczgSXv1aKZJCPWiJHk2w/9tcNWXoJ0X2BW3jOe3xEWCCQc ne6TExW7IzmCaQusiTOrbDJZd+7K1v2fRh9roXUPG2i/y6xay9qZ7y4h+yD1XdS047Ox Jj1nXOC6Jmopx7aoSYpV3nkZxMja5Yrwva1/WByxdLaQRpPb9dwjo21JxCg3RdgRg8Wx LmrANYRVOR/vtABl5tKy7XxmQ5lT0+Bs1kenJ6vdBAmsvVs7r6yraoK1Gm6ocDH6/51F 98Bw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1759493031; x=1760097831; h=mime-version:message-id:date:references:in-reply-to:subject:cc:to :from:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=7EUW43HWolyI7T5LSzYWxB/vbzNla21nNsPp9mz+OZo=; b=j+7Jlw5qDqyVdYxwqmVmJjX2TDceda7y+e6uz4iSFrB71ixng3KwzYH0fWX+Vc04Fc yMSAJQJJd5EF4C+6yM6n0I2QXN+yu6agpM3AnMayY5Kdejg0zWvdxKPaknXLnkq99gg0 /+/GLtDP3YhLfImjKpFhJRz9ja2575tITgH/kLtWQPGhTGBaIenUcjjF8kEwwKZZhvgW /IzaosOqDuUKYtisb+6wXEzAP9D+3BPM51fwwkQfRNIsyOh5c19oJrBfP/VlN0LbYmpv rE3tIzfMXKbPUs3dEcMPTvJKldMQz0GGqf0fKlX+S9GBB3lUd9jMBuPWoXY5aris+kXC Z88A== X-Gm-Message-State: AOJu0YzbXBTjRgOFgT0iTy6jtO7lqqgBf2JdKtrhuZ6JZoPxAO+QmU61 G6QWZcE4I0Ct1iT6bfcvmf4BYfcJ/yDPpVcbAT0hYTpYAVcvygcnkZC4k7FEE2bOIOk= X-Gm-Gg: ASbGncvWCnYKxgVNg3ZqtsfBdReEYQKVcU4RmoabJrzq5QDdrw7ql9QJwrhDGvFcn0o HbYtCvgWiq9ei2y8RrOJc8mkIE74mMh44gem4Fkom0Hf/PjqezahpXRD4nzaPgztar9LX7gnGDx /7DHML3d6GkCzRUnJogSFiy613GNG6NUfq8i5CagXfZERwfsgbky6WOaaYZ96RotwYa1guyKS0n mXGeoijtOCoXsO1uSVHEGg2HKuBmZYPgL7QpKJUGADgfgIn00QdLg+T+hj49ak+bXLCl0yxSmCZ qqW4zDiWWLA4cdqmp8y4XK+YZvAJ8evzzsMb2PR+c44xPd1ENfHh+A0PveGvTJ61EdGe7sOu568 UEfNXVexJ2kp99HuG6lyBxArzo0cDUhhZ1CeU4dCjtJxmMpQ8 X-Google-Smtp-Source: AGHT+IHgY7YMNMn1KWKsL3AP2dmLTqwcNzT1KzlBF2R4fZUXm4QNPcsYDW6TGFHfq2FabuVmsQODEQ== X-Received: by 2002:a05:6402:2793:b0:62f:ce89:606f with SMTP id 4fb4d7f45d1cf-63934900286mr2753027a12.12.1759493031527; Fri, 03 Oct 2025 05:03:51 -0700 (PDT) Received: from cloudflare.com ([2a09:bac5:5063:2dc::49:214]) by smtp.gmail.com with ESMTPSA id 4fb4d7f45d1cf-6378811ef5esm3893480a12.43.2025.10.03.05.03.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 03 Oct 2025 05:03:50 -0700 (PDT) From: Jakub Sitnicki To: bpf@vger.kernel.org Cc: netdev@vger.kernel.org, kernel-team@cloudflare.com Subject: Re: [PATCH RFC bpf-next 5/9] bpf: Make bpf_skb_vlan_push helper metadata-safe In-Reply-To: <20250929-skb-meta-rx-path-v1-5-de700a7ab1cb@cloudflare.com> (Jakub Sitnicki's message of "Mon, 29 Sep 2025 16:09:10 +0200") References: <20250929-skb-meta-rx-path-v1-0-de700a7ab1cb@cloudflare.com> <20250929-skb-meta-rx-path-v1-5-de700a7ab1cb@cloudflare.com> Date: Fri, 03 Oct 2025 14:03:48 +0200 Message-ID: <87cy742nvf.fsf@cloudflare.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain On Mon, Sep 29, 2025 at 04:09 PM +02, Jakub Sitnicki wrote: > Use the metadata-aware helper to move packet bytes after skb_push(), > ensuring metadata remains valid after calling the BPF helper. > > Also, take care to reserve sufficient headroom for metadata to fit. > > Signed-off-by: Jakub Sitnicki > --- > include/linux/if_vlan.h | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/include/linux/if_vlan.h b/include/linux/if_vlan.h > index 4ecc2509b0d4..b0e1f57d51aa 100644 > --- a/include/linux/if_vlan.h > +++ b/include/linux/if_vlan.h > @@ -355,16 +355,17 @@ static inline int __vlan_insert_inner_tag(struct sk_buff *skb, > __be16 vlan_proto, u16 vlan_tci, > unsigned int mac_len) > { > + const u8 meta_len = mac_len > ETH_HLEN ? skb_metadata_len(skb) : 0; This is a typo. Should be: + const u8 meta_len = mac_len > ETH_TLEN ? skb_metadata_len(skb) : 0; ^^^^^^^^ > struct vlan_ethhdr *veth; > > - if (skb_cow_head(skb, VLAN_HLEN) < 0) > + if (skb_cow_head(skb, meta_len + VLAN_HLEN) < 0) > return -ENOMEM; > > skb_push(skb, VLAN_HLEN); > > /* Move the mac header sans proto to the beginning of the new header. */ > if (likely(mac_len > ETH_TLEN)) > - memmove(skb->data, skb->data + VLAN_HLEN, mac_len - ETH_TLEN); > + skb_postpush_data_move(skb, VLAN_HLEN, mac_len - ETH_TLEN); > if (skb_mac_header_was_set(skb)) > skb->mac_header -= VLAN_HLEN;