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 89BE22E54D3 for ; Thu, 23 Jul 2026 14:18:49 +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=1784816330; cv=none; b=SUK6iZGpd9BqIjiKhY4r4Us1KbJk5ClKfdSJOkBGZ99S9FU8STY/pAqHe4uEB8Myi8m8xbYeAhctlD6MOZc+aIsvtZ0PgOLs89fUXPY4kf4zEA4w9LZToknBnTsxz+/XzLgoRhHT4mYVMROZwkHMzNSEEQbLJ6aOUCGzT4kHPSo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784816330; c=relaxed/simple; bh=FflLKKUeF2IJAmHm9dpRD4wRW3OPH965950QZnG84Q8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=CvdXyZV7YQs5n96o770WEI8v+kOeatE0CAFFYotj4+Vl1jv8pcGcnAwPU7nSrb7Yt3vjg1DBLTO4a0Cnj90qHHX3FVR6l8+lipEly3InAhj5VTPX8cnP4nCQd0kg/apYb17g/X3WU+Ye7pKqEvWp2smzd4j7aAiBK/NOejQJ+9Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 Received: by smtp.kernel.org (Postfix) with ESMTPSA id B2A5B1F00A3A; Thu, 23 Jul 2026 14:18:48 +0000 (UTC) From: Sasha Levin To: stable@vger.kernel.org Cc: Theodor Arsenij Larionov-Trichkine , Florian Westphal , Sasha Levin Subject: [PATCH 6.18.y 2/2] netfilter: nft_fib: reject fib expression on the netdev egress hook Date: Thu, 23 Jul 2026 10:18:35 -0400 Message-ID: <20260723141835.3216078-2-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260723141835.3216078-1-sashal@kernel.org> References: <2026072053-enlarging-dispersal-0c87@gregkh> <20260723141835.3216078-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Theodor Arsenij Larionov-Trichkine [ Upstream commit d07955dd34ecae17d35d8c7d0a273a3fba653a8c ] A fib expression in a netdev egress base chain dereferences nft_in(pkt), NULL on the transmit path, causing a NULL pointer dereference at eval. nft_fib_validate() masks the hook with NF_INET_* values, but netdev hook numbers are a separate enum that aliases them (NF_NETDEV_EGRESS == NF_INET_LOCAL_IN), so an egress chain passes validation and then faults. Add nft_fib_netdev_validate() that limits each result/flag to the netdev hook where the device it reads exists: the input-device cases (OIF, OIFNAME, ADDRTYPE with F_IIF) to ingress, the output-device case (ADDRTYPE with F_OIF) to egress, ADDRTYPE with no device flag to both. Also restrict nft_fib_validate() to NFPROTO_IPV4/IPV6/INET so its NF_INET_* masks are not applied to another family's hooks. Fixes: 42df6e1d221d ("netfilter: Introduce egress hook") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/netfilter-devel/ajxsjcDOnwllMfoR@strlen.de/ Signed-off-by: Theodor Arsenij Larionov-Trichkine Signed-off-by: Florian Westphal Signed-off-by: Sasha Levin --- net/netfilter/nft_fib.c | 9 +++++++++ net/netfilter/nft_fib_netdev.c | 29 ++++++++++++++++++++++++++++- 2 files changed, 37 insertions(+), 1 deletion(-) diff --git a/net/netfilter/nft_fib.c b/net/netfilter/nft_fib.c index cf76733d9c0e36..7b2a0a031c4b4f 100644 --- a/net/netfilter/nft_fib.c +++ b/net/netfilter/nft_fib.c @@ -31,6 +31,15 @@ int nft_fib_validate(const struct nft_ctx *ctx, const struct nft_expr *expr) const struct nft_fib *priv = nft_expr_priv(expr); unsigned int hooks; + switch (ctx->family) { + case NFPROTO_IPV4: + case NFPROTO_IPV6: + case NFPROTO_INET: + break; + default: + return -EOPNOTSUPP; + } + switch (priv->result) { case NFT_FIB_RESULT_OIF: case NFT_FIB_RESULT_OIFNAME: diff --git a/net/netfilter/nft_fib_netdev.c b/net/netfilter/nft_fib_netdev.c index 3f3478abd84546..5774a754402780 100644 --- a/net/netfilter/nft_fib_netdev.c +++ b/net/netfilter/nft_fib_netdev.c @@ -50,6 +50,33 @@ static void nft_fib_netdev_eval(const struct nft_expr *expr, regs->verdict.code = NFT_BREAK; } +static int nft_fib_netdev_validate(const struct nft_ctx *ctx, + const struct nft_expr *expr) +{ + const struct nft_fib *priv = nft_expr_priv(expr); + unsigned int hooks; + + switch (priv->result) { + case NFT_FIB_RESULT_OIF: + case NFT_FIB_RESULT_OIFNAME: + hooks = (1 << NF_NETDEV_INGRESS); + break; + case NFT_FIB_RESULT_ADDRTYPE: + if (priv->flags & NFTA_FIB_F_IIF) + hooks = (1 << NF_NETDEV_INGRESS); + else if (priv->flags & NFTA_FIB_F_OIF) + hooks = (1 << NF_NETDEV_EGRESS); + else + hooks = (1 << NF_NETDEV_INGRESS) | + (1 << NF_NETDEV_EGRESS); + break; + default: + return -EINVAL; + } + + return nft_chain_validate_hooks(ctx->chain, hooks); +} + static struct nft_expr_type nft_fib_netdev_type; static const struct nft_expr_ops nft_fib_netdev_ops = { .type = &nft_fib_netdev_type, @@ -57,7 +84,7 @@ static const struct nft_expr_ops nft_fib_netdev_ops = { .eval = nft_fib_netdev_eval, .init = nft_fib_init, .dump = nft_fib_dump, - .validate = nft_fib_validate, + .validate = nft_fib_netdev_validate, }; static struct nft_expr_type nft_fib_netdev_type __read_mostly = { -- 2.53.0