From aaf2bb422c25859fad0a66fb722bc47866004ab8 Mon Sep 17 00:00:00 2001 From: Laura Garcia Liebana Date: Tue, 9 Aug 2016 20:46:16 +0200 Subject: [PATCH] netfilter: nft_exthdr: Add size check on u8 nft_exthdr attributes commit 4da449ae1df9cfeb167e78f250b250eff64bc65e upstream. 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 Signed-off-by: Pablo Neira Ayuso [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings --- 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 55c939f5371fa..c04e91c5c78ea 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, { struct nft_exthdr *priv = nft_expr_priv(expr); int err; + 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; if (priv->len == 0 || priv->len > FIELD_SIZEOF(struct nft_data, data)) return -EINVAL; -- 2.47.3