From 4da449ae1df9cfeb167e78f250b250eff64bc65e Mon Sep 17 00:00:00 2001
From: Laura Garcia Liebana <nevola@gmail.com>
Date: Tue, 9 Aug 2016 20:46:16 +0200
Subject: [PATCH] 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>
---
net/netfilter/nft_exthdr.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/net/netfilter/nft_exthdr.c b/net/netfilter/nft_exthdr.c
index ba7aed13e174..82c264e40278 100644
--- a/net/netfilter/nft_exthdr.c
+++ b/net/netfilter/nft_exthdr.c
@@ -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,
--
2.50.1