From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.netfilter.org (mail.netfilter.org [217.70.190.124]) (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 56F4733DEFC; Fri, 1 May 2026 12:22:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.70.190.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777638166; cv=none; b=QTD+Q/xYDEPvmPijZ2FTeobdptXnnID0aZaRPH2MWYMHO/CjsFB1mEhbqWLUTjuxblOkTVN0EO29lQ2KBzo7FuzvsRyFaM0Yr2/CBeyHUJ5lCrhhwJsTiZvEz7DNZcD73pPQQMYGuqjdPLJww20UYHLKIqVs5WgwuLgCjPCq7WY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777638166; c=relaxed/simple; bh=bhiKm6M74xm031cVP6+ToqroBKbknE/Nv2ppBGtPndA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Kt7z9KdyiGy1fpoWH7oGTjBc42m/hbAYCO3uBtY/iLRGDdaT/QHKi2ECjoHOLK+7SrEPyCJjvBgpLY2tCm4CHpKbLDydT5PY+/4FNkoU4PI7qGH9YhQMdUbFTjLn87rnu+YpnO0rdk5tp32VuDH3MJgGcHdW9tfRvoGrd7vg29Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=netfilter.org; spf=pass smtp.mailfrom=netfilter.org; dkim=pass (2048-bit key) header.d=netfilter.org header.i=@netfilter.org header.b=vivOYYYa; arc=none smtp.client-ip=217.70.190.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=netfilter.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=netfilter.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=netfilter.org header.i=@netfilter.org header.b="vivOYYYa" Received: from localhost.localdomain (mail-agni [217.70.190.124]) by mail.netfilter.org (Postfix) with ESMTPSA id 3D5676017E; Fri, 1 May 2026 14:22:43 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=netfilter.org; s=2025; t=1777638163; bh=6Fbmlx9W1FFkks5H2o6ltT3KOGrIEtVpn4vAhzuEI7w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=vivOYYYanONMjDcIg2O57jlbHZMIwc0P6aMSgijIqgHSXNeJzl2K6f8Pis28adh6g 91rbsdS/S80gcMoy5UJQKfhNnzdIbKKtRqfBh9rDsuNmpJ4T47ZLxUXoaPb3WzeF5c VcOZawwygriGeeqS0ASWAYRJ7GdQQKbzLHdOK57q32kPK4s4ZYDsDU85alhASSDMVo 8c2UzhpLaaImJuGrERP2JNyG2YpmjyOJoqZZnwGfIwcWig7wgHB3ZWqZ2IU1AJqJ1M tIT8CloORRceSbwuXlwvW6jj0nfjYkgN8K88ZCLyYIt+mXiNk1k8r9UsU3kuu2vGp8 mdzwHwIzI0gpA== From: Pablo Neira Ayuso To: netfilter-devel@vger.kernel.org Cc: davem@davemloft.net, netdev@vger.kernel.org, kuba@kernel.org, pabeni@redhat.com, edumazet@google.com, fw@strlen.de, horms@kernel.org Subject: [PATCH net 01/14] netfilter: replace skb_try_make_writable() by skb_ensure_writable() Date: Fri, 1 May 2026 14:22:24 +0200 Message-ID: <20260501122237.296262-2-pablo@netfilter.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260501122237.296262-1-pablo@netfilter.org> References: <20260501122237.296262-1-pablo@netfilter.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit skb_try_make_writable() only works on clones and uncloned packets might have their network header in paged fragments. nft_fwd needs to work for the ingress and egress hooks, but the egress hook where skb->data points to the mac header, use skb_network_offset() to include the mac header. The flowtable is fine since it already uses the transport offset. Fixes: d32de98ea70f ("netfilter: nft_fwd_netdev: allow to forward packets via neighbour layer") Fixes: 7d2086871762 ("netfilter: nf_flow_table: move ipv4 offload hook code to nf_flow_table") Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_flow_table_ip.c | 4 ++-- net/netfilter/nft_fwd_netdev.c | 5 +++-- 2 files changed, 5 insertions(+), 4 deletions(-) diff --git a/net/netfilter/nf_flow_table_ip.c b/net/netfilter/nf_flow_table_ip.c index fd56d663cb5b..dbd7644fdbeb 100644 --- a/net/netfilter/nf_flow_table_ip.c +++ b/net/netfilter/nf_flow_table_ip.c @@ -524,7 +524,7 @@ static int nf_flow_offload_forward(struct nf_flowtable_ctx *ctx, return 0; } - if (skb_try_make_writable(skb, thoff + ctx->hdrsize)) + if (skb_ensure_writable(skb, thoff + ctx->hdrsize)) return -1; flow_offload_refresh(flow_table, flow, false); @@ -1037,7 +1037,7 @@ static int nf_flow_offload_ipv6_forward(struct nf_flowtable_ctx *ctx, return 0; } - if (skb_try_make_writable(skb, thoff + ctx->hdrsize)) + if (skb_ensure_writable(skb, thoff + ctx->hdrsize)) return -1; flow_offload_refresh(flow_table, flow, false); diff --git a/net/netfilter/nft_fwd_netdev.c b/net/netfilter/nft_fwd_netdev.c index 4bce36c3a6a0..2cc809303ce8 100644 --- a/net/netfilter/nft_fwd_netdev.c +++ b/net/netfilter/nft_fwd_netdev.c @@ -100,6 +100,7 @@ static void nft_fwd_neigh_eval(const struct nft_expr *expr, int oif = regs->data[priv->sreg_dev]; unsigned int verdict = NF_STOLEN; struct sk_buff *skb = pkt->skb; + int nhoff = skb_network_offset(skb); struct net_device *dev; int neigh_table; @@ -111,7 +112,7 @@ static void nft_fwd_neigh_eval(const struct nft_expr *expr, verdict = NFT_BREAK; goto out; } - if (skb_try_make_writable(skb, sizeof(*iph))) { + if (skb_ensure_writable(skb, nhoff + sizeof(*iph))) { verdict = NF_DROP; goto out; } @@ -132,7 +133,7 @@ static void nft_fwd_neigh_eval(const struct nft_expr *expr, verdict = NFT_BREAK; goto out; } - if (skb_try_make_writable(skb, sizeof(*ip6h))) { + if (skb_ensure_writable(skb, nhoff + sizeof(*ip6h))) { verdict = NF_DROP; goto out; } -- 2.47.3