From patchwork Wed Jan 24 19:12:45 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pablo Neira Ayuso X-Patchwork-Id: 13529592 X-Patchwork-Delegate: kuba@kernel.org Received: from mail.netfilter.org (mail.netfilter.org [217.70.188.207]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 0B33812FF86; Wed, 24 Jan 2024 19:12:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.70.188.207 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706123578; cv=none; b=U/nSSZn08+sYyDybssK0pmjANUO3krcOY7Go8WsL44tjrOhX5vlA4bmmOwjltw5bGVamtyZmweEwP4VLQX6JV6qlFuGuRMJFU0x4PiVNeUu0KaQjwXxfugrwtNKPRW+0ch/qijeww6Xp8lCMpjK4Qv9zKAOKfL6YCY/JKKCNhyk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706123578; c=relaxed/simple; bh=q90eiDpNR7uw27jH2PMKt2VlFOUOFLn+A0N0UFQBn0g=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=TkBC8kKMaBqJF4wGi+24b+BsJUbvEWbzG1pry3BtVDnLk9annDYJ9KmasyiBEs0+nG3s3b7xEFgweXoIcNfavSZ2jEm55ETXjCyZpAgHeuFPQlz9kvwl+rkbSMugjdRvItmpBvjcEE5CKDsNe48S1tEtrwG3ujNnZwZQAh5/0vo= 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; arc=none smtp.client-ip=217.70.188.207 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 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 Subject: [PATCH net 3/6] netfilter: nft_limit: reject configurations that cause integer overflow Date: Wed, 24 Jan 2024 20:12:45 +0100 Message-Id: <20240124191248.75463-4-pablo@netfilter.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20240124191248.75463-1-pablo@netfilter.org> References: <20240124191248.75463-1-pablo@netfilter.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: kuba@kernel.org From: Florian Westphal Reject bogus configs where internal token counter wraps around. This only occurs with very very large requests, such as 17gbyte/s. Its better to reject this rather than having incorrect ratelimit. Fixes: d2168e849ebf ("netfilter: nft_limit: add per-byte limiting") Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nft_limit.c | 23 ++++++++++++++++------- 1 file changed, 16 insertions(+), 7 deletions(-) diff --git a/net/netfilter/nft_limit.c b/net/netfilter/nft_limit.c index 79039afde34e..cefa25e0dbb0 100644 --- a/net/netfilter/nft_limit.c +++ b/net/netfilter/nft_limit.c @@ -58,17 +58,19 @@ static inline bool nft_limit_eval(struct nft_limit_priv *priv, u64 cost) static int nft_limit_init(struct nft_limit_priv *priv, const struct nlattr * const tb[], bool pkts) { + u64 unit, tokens, rate_with_burst; bool invert = false; - u64 unit, tokens; if (tb[NFTA_LIMIT_RATE] == NULL || tb[NFTA_LIMIT_UNIT] == NULL) return -EINVAL; priv->rate = be64_to_cpu(nla_get_be64(tb[NFTA_LIMIT_RATE])); + if (priv->rate == 0) + return -EINVAL; + unit = be64_to_cpu(nla_get_be64(tb[NFTA_LIMIT_UNIT])); - priv->nsecs = unit * NSEC_PER_SEC; - if (priv->rate == 0 || priv->nsecs < unit) + if (check_mul_overflow(unit, NSEC_PER_SEC, &priv->nsecs)) return -EOVERFLOW; if (tb[NFTA_LIMIT_BURST]) @@ -77,18 +79,25 @@ static int nft_limit_init(struct nft_limit_priv *priv, if (pkts && priv->burst == 0) priv->burst = NFT_LIMIT_PKT_BURST_DEFAULT; - if (priv->rate + priv->burst < priv->rate) + if (check_add_overflow(priv->rate, priv->burst, &rate_with_burst)) return -EOVERFLOW; if (pkts) { - tokens = div64_u64(priv->nsecs, priv->rate) * priv->burst; + u64 tmp = div64_u64(priv->nsecs, priv->rate); + + if (check_mul_overflow(tmp, priv->burst, &tokens)) + return -EOVERFLOW; } else { + u64 tmp; + /* The token bucket size limits the number of tokens can be * accumulated. tokens_max specifies the bucket size. * tokens_max = unit * (rate + burst) / rate. */ - tokens = div64_u64(priv->nsecs * (priv->rate + priv->burst), - priv->rate); + if (check_mul_overflow(priv->nsecs, rate_with_burst, &tmp)) + return -EOVERFLOW; + + tokens = div64_u64(tmp, priv->rate); } if (tb[NFTA_LIMIT_FLAGS]) {