netfilter: nf_tables: validate maximum value of u32 netlink attributes
Fetch value and validate u32 netlink attribute. This validation is
usually required when the u32 netlink attributes are being stored in a
field whose size is smaller.
This patch revisits 4da449ae1df9 ("netfilter: nft_exthdr: Add size check
on u8 nft_exthdr attributes").
Fixes: 96518518cc41 ("netfilter: add nftables")
Suggested-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Laura Garcia Liebana <nevola@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
diff --git a/net/netfilter/nft_byteorder.c b/net/netfilter/nft_byteorder.c
index b78c28b..ee63d98 100644
--- a/net/netfilter/nft_byteorder.c
+++ b/net/netfilter/nft_byteorder.c
@@ -99,6 +99,7 @@
const struct nlattr * const tb[])
{
struct nft_byteorder *priv = nft_expr_priv(expr);
+ u32 size, len;
int err;
if (tb[NFTA_BYTEORDER_SREG] == NULL ||
@@ -117,7 +118,12 @@
return -EINVAL;
}
- priv->size = ntohl(nla_get_be32(tb[NFTA_BYTEORDER_SIZE]));
+ err = nft_parse_u32_check(tb[NFTA_BYTEORDER_SIZE], U8_MAX, &size);
+ if (err < 0)
+ return err;
+
+ priv->size = size;
+
switch (priv->size) {
case 2:
case 4:
@@ -128,7 +134,12 @@
}
priv->sreg = nft_parse_register(tb[NFTA_BYTEORDER_SREG]);
- priv->len = ntohl(nla_get_be32(tb[NFTA_BYTEORDER_LEN]));
+ err = nft_parse_u32_check(tb[NFTA_BYTEORDER_LEN], U8_MAX, &len);
+ if (err < 0)
+ return err;
+
+ priv->len = len;
+
err = nft_validate_register_load(priv->sreg, priv->len);
if (err < 0)
return err;