[PATCH 4.19 15/56] netfilter: nft_payload: report ERANGE for too long offset and length

Greg Kroah-Hartman
2022-09-02T12:31:07Z

From: Pablo Neira Ayuso <pablo@netfilter.org>

[ Upstream commit 94254f990c07e9ddf1634e0b727fab821c3b5bf9 ]

Instead of offset and length are truncation to u8, report ERANGE.

Fixes: 96518518cc41 ("netfilter: add nftables")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/netfilter/nft_payload.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/net/netfilter/nft_payload.c b/net/netfilter/nft_payload.c
index fd87216bc0a99..04b9df9e39554 100644
--- a/net/netfilter/nft_payload.c
+++ b/net/netfilter/nft_payload.c
@@ -398,6 +398,7 @@ nft_payload_select_ops(const struct nft_ctx *ctx,
{
enum nft_payload_bases base;
unsigned int offset, len;
+ int err;

if (tb[NFTA_PAYLOAD_BASE] == NULL ||
tb[NFTA_PAYLOAD_OFFSET] == NULL ||
@@ -423,8 +424,13 @@ nft_payload_select_ops(const struct nft_ctx *ctx,
if (tb[NFTA_PAYLOAD_DREG] == NULL)
return ERR_PTR(-EINVAL);

- offset = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_OFFSET]));
- len = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_LEN]));
+ err = nft_parse_u32_check(tb[NFTA_PAYLOAD_OFFSET], U8_MAX, &offset);
+ if (err < 0)
+ return ERR_PTR(err);
+
+ err = nft_parse_u32_check(tb[NFTA_PAYLOAD_LEN], U8_MAX, &len);
+ if (err < 0)
+ return ERR_PTR(err);

if (len <= 4 && is_power_of_2(len) && IS_ALIGNED(offset, len) &&
base != NFT_PAYLOAD_LL_HEADER)
--
2.35.1