netfilter: nft_exthdr: Add size check on u8 nft_exthdr attributes

Fix the direct assignment of offset and length attributes included in
nft_exthdr structure from u32 data to u8.

Signed-off-by: Laura Garcia Liebana <nevola@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Laura Garcia Liebana 2016-08-09 20:46:16 +02:00 committed by Pablo Neira Ayuso
parent aa0c2c68ab
commit 4da449ae1d

View File

@ -59,6 +59,7 @@ static int nft_exthdr_init(const struct nft_ctx *ctx,
const struct nlattr * const tb[])
{
struct nft_exthdr *priv = nft_expr_priv(expr);
u32 offset, len;
if (tb[NFTA_EXTHDR_DREG] == NULL ||
tb[NFTA_EXTHDR_TYPE] == NULL ||
@ -66,9 +67,15 @@ static int nft_exthdr_init(const struct nft_ctx *ctx,
tb[NFTA_EXTHDR_LEN] == NULL)
return -EINVAL;
offset = ntohl(nla_get_be32(tb[NFTA_EXTHDR_OFFSET]));
len = ntohl(nla_get_be32(tb[NFTA_EXTHDR_LEN]));
if (offset > U8_MAX || len > U8_MAX)
return -ERANGE;
priv->type = nla_get_u8(tb[NFTA_EXTHDR_TYPE]);
priv->offset = ntohl(nla_get_be32(tb[NFTA_EXTHDR_OFFSET]));
priv->len = ntohl(nla_get_be32(tb[NFTA_EXTHDR_LEN]));
priv->offset = offset;
priv->len = len;
priv->dreg = nft_parse_register(tb[NFTA_EXTHDR_DREG]);
return nft_validate_register_store(ctx, priv->dreg, NULL,