From 43814e60dcd38a7e721d1b4ea6d9d9571ffa9f3b Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Fri, 27 May 2022 09:56:18 +0200 Subject: [PATCH] netfilter: nf_tables: sanitize nft_set_desc_concat_parse() Add several sanity checks for nft_set_desc_concat_parse(): - validate desc->field_count not larger than desc->field_len array. - field length cannot be larger than desc->field_len (ie. U8_MAX) - total length of the concatenation cannot be larger than register array. Joint work with Florian Westphal. Fixes: c1894f2477ec ("netfilter: nf_tables: Support for sets with multiple ranged fields") Reported-by: Reviewed-by: Stefano Brivio Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_tables_api.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-) diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index f4f1d0a2da43c..dcefb5f36b3af 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -4246,6 +4246,9 @@ static int nft_set_desc_concat_parse(const struct nlattr *attr, u32 len; int err; + if (desc->field_count >= ARRAY_SIZE(desc->field_len)) + return -E2BIG; + err = nla_parse_nested_deprecated(tb, NFTA_SET_FIELD_MAX, attr, nft_concat_policy, NULL); if (err < 0) @@ -4255,9 +4258,8 @@ static int nft_set_desc_concat_parse(const struct nlattr *attr, return -EINVAL; len = ntohl(nla_get_be32(tb[NFTA_SET_FIELD_LEN])); - - if (len * BITS_PER_BYTE / 32 > NFT_REG32_COUNT) - return -E2BIG; + if (!len || len > U8_MAX) + return -EINVAL; desc->field_len[desc->field_count++] = len; @@ -4268,7 +4270,8 @@ static int nft_set_desc_concat(struct nft_set_desc *desc, const struct nlattr *nla) { struct nlattr *attr; - int rem, err; + u32 num_regs = 0; + int rem, err, i; nla_for_each_nested(attr, nla, rem) { if (nla_type(attr) != NFTA_LIST_ELEM) @@ -4279,6 +4282,12 @@ static int nft_set_desc_concat(struct nft_set_desc *desc, return err; } + for (i = 0; i < desc->field_count; i++) + num_regs += DIV_ROUND_UP(desc->field_len[i], sizeof(u32)); + + if (num_regs > NFT_REG32_COUNT) + return -E2BIG; + return 0; } -- 2.39.5