netfilter: nft_payload: report ERANGE for too long offset and length

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>

diff --git a/net/netfilter/nft_payload.c b/net/netfilter/nft_payload.c
index 2e7ac007cb30fe6c02429034d102b4f2d6df9ceb..4fee67abfe2c57c7215a3406127179cd3be71ff7 100644 (file)
--- a/net/netfilter/nft_payload.c
+++ b/net/netfilter/nft_payload.c
@@ -833,6 +833,7 @@ 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 ||
@@ -859,8 +860,13 @@ 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 && base != NFT_PAYLOAD_INNER_HEADER)