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authorFlorian Westphal <fw@strlen.de>2024-01-19 13:11:32 +0100
committerPablo Neira Ayuso <pablo@netfilter.org>2024-01-24 20:01:16 +0100
commitc9d9eb9c53d37cdebbad56b91e40baf42d5a97aa (patch)
tree589e2e69c942f3c4110682995a8748ffddf46171 /net
parentnetfilter: nft_chain_filter: handle NETDEV_UNREGISTER for inet/ingress basechain (diff)
downloadlinux-c9d9eb9c53d37cdebbad56b91e40baf42d5a97aa.tar.xz
linux-c9d9eb9c53d37cdebbad56b91e40baf42d5a97aa.zip
netfilter: nft_limit: reject configurations that cause integer overflow
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 <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net')
-rw-r--r--net/netfilter/nft_limit.c23
1 files 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]) {