netfilter: fix wrong arithmetics regarding NFT_REJECT_ICMPX_MAX
NFT_REJECT_ICMPX_MAX should be __NFT_REJECT_ICMPX_MAX - 1.
nft_reject_icmp_code() and nft_reject_icmpv6_code() are called from the
packet path, so BUG_ON in case we try to access an unknown abstracted
ICMP code. This should not happen since we already validate this from
nft_reject_{inet,bridge}_init().
Fixes: 51b0a5d ("netfilter: nft_reject: introduce icmp code abstraction for inet and bridge")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h
index c26df67..f31fe7b 100644
--- a/include/uapi/linux/netfilter/nf_tables.h
+++ b/include/uapi/linux/netfilter/nf_tables.h
@@ -774,7 +774,7 @@
NFT_REJECT_ICMPX_ADMIN_PROHIBITED,
__NFT_REJECT_ICMPX_MAX
};
-#define NFT_REJECT_ICMPX_MAX (__NFT_REJECT_ICMPX_MAX + 1)
+#define NFT_REJECT_ICMPX_MAX (__NFT_REJECT_ICMPX_MAX - 1)
/**
* enum nft_reject_attributes - nf_tables reject expression netlink attributes
diff --git a/net/netfilter/nft_reject.c b/net/netfilter/nft_reject.c
index ec8a456..57d3e1a 100644
--- a/net/netfilter/nft_reject.c
+++ b/net/netfilter/nft_reject.c
@@ -72,7 +72,7 @@
}
EXPORT_SYMBOL_GPL(nft_reject_dump);
-static u8 icmp_code_v4[NFT_REJECT_ICMPX_MAX] = {
+static u8 icmp_code_v4[NFT_REJECT_ICMPX_MAX + 1] = {
[NFT_REJECT_ICMPX_NO_ROUTE] = ICMP_NET_UNREACH,
[NFT_REJECT_ICMPX_PORT_UNREACH] = ICMP_PORT_UNREACH,
[NFT_REJECT_ICMPX_HOST_UNREACH] = ICMP_HOST_UNREACH,
@@ -81,8 +81,7 @@
int nft_reject_icmp_code(u8 code)
{
- if (code > NFT_REJECT_ICMPX_MAX)
- return -EINVAL;
+ BUG_ON(code > NFT_REJECT_ICMPX_MAX);
return icmp_code_v4[code];
}
@@ -90,7 +89,7 @@
EXPORT_SYMBOL_GPL(nft_reject_icmp_code);
-static u8 icmp_code_v6[NFT_REJECT_ICMPX_MAX] = {
+static u8 icmp_code_v6[NFT_REJECT_ICMPX_MAX + 1] = {
[NFT_REJECT_ICMPX_NO_ROUTE] = ICMPV6_NOROUTE,
[NFT_REJECT_ICMPX_PORT_UNREACH] = ICMPV6_PORT_UNREACH,
[NFT_REJECT_ICMPX_HOST_UNREACH] = ICMPV6_ADDR_UNREACH,
@@ -99,8 +98,7 @@
int nft_reject_icmpv6_code(u8 code)
{
- if (code > NFT_REJECT_ICMPX_MAX)
- return -EINVAL;
+ BUG_ON(code > NFT_REJECT_ICMPX_MAX);
return icmp_code_v6[code];
}