Merge git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf

Pablo Neira Ayuso says:

====================
Netfilter fixes for net

The following patchset contains Netfilter fixes for net:

1) Harden set element field checks to avoid out-of-bound memory access,
   this patch also fixes the type of issue described in 7e6bc1f6cabc
   ("netfilter: nf_tables: stricter validation of element data") in a
   broader way.

2) Patches to restrict the chain, set, and rule id lookup in the
   transaction to the corresponding top-level table, patches from
   Thadeu Lima de Souza Cascardo.

3) Fix incorrect comment in ip6t_LOG.h

4) nft_data_init() performs upfront validation of the expected data.
   struct nft_data_desc is used to describe the expected data to be
   received from userspace. The .size field represents the maximum size
   that can be stored, for bound checks. Then, .len is an input/output field
   which stores the expected length as input (this is optional, to restrict
   the checks), as output it stores the real length received from userspace
   (if it was not specified as input). This patch comes in response to
   7e6bc1f6cabc ("netfilter: nf_tables: stricter validation of element data")
   to address this type of issue in a more generic way by avoid opencoded
   data validation. Next patch requires this as a dependency.

5) Disallow jump to implicit chain from set element, this configuration
   is invalid. Only allow jump to chain via immediate expression is
   supported at this stage.

6) Fix possible null-pointer derefence in the error path of table updates,
   if memory allocation of the transaction fails. From Florian Westphal.

* git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf:
  netfilter: nf_tables: fix null deref due to zeroed list head
  netfilter: nf_tables: disallow jump to implicit chain from set element
  netfilter: nf_tables: upfront validation of data via nft_data_init()
  netfilter: ip6t_LOG: Fix a typo in a comment
  netfilter: nf_tables: do not allow RULE_ID to refer to another chain
  netfilter: nf_tables: do not allow CHAIN_ID to refer to another table
  netfilter: nf_tables: do not allow SET_ID to refer to another table
  netfilter: nf_tables: validate variable length element extension
====================

Link: https://lore.kernel.org/r/20220809220532.130240-1-pablo@netfilter.org/
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 19 insertions, 3 deletions

diff --git a/net/netfilter/nft_immediate.c b/net/netfilter/nft_immediate.c
index b80f7b507349..5f28b21abc7d 100644
--- a/net/netfilter/nft_immediate.c
+++ b/net/netfilter/nft_immediate.c
@@ -29,20 +29,36 @@ static const struct nla_policy nft_immediate_policy[NFTA_IMMEDIATE_MAX + 1] = {
 	[NFTA_IMMEDIATE_DATA]	= { .type = NLA_NESTED },
 };
 
+static enum nft_data_types nft_reg_to_type(const struct nlattr *nla)
+{
+	enum nft_data_types type;
+	u8 reg;
+
+	reg = ntohl(nla_get_be32(nla));
+	if (reg == NFT_REG_VERDICT)
+		type = NFT_DATA_VERDICT;
+	else
+		type = NFT_DATA_VALUE;
+
+	return type;
+}
+
 static int nft_immediate_init(const struct nft_ctx *ctx,
 			      const struct nft_expr *expr,
 			      const struct nlattr * const tb[])
 {
 	struct nft_immediate_expr *priv = nft_expr_priv(expr);
-	struct nft_data_desc desc;
+	struct nft_data_desc desc = {
+		.size	= sizeof(priv->data),
+	};
 	int err;
 
 	if (tb[NFTA_IMMEDIATE_DREG] == NULL ||
 	    tb[NFTA_IMMEDIATE_DATA] == NULL)
 		return -EINVAL;
 
-	err = nft_data_init(ctx, &priv->data, sizeof(priv->data), &desc,
-			    tb[NFTA_IMMEDIATE_DATA]);
+	desc.type = nft_reg_to_type(tb[NFTA_IMMEDIATE_DREG]);
+	err = nft_data_init(ctx, &priv->data, &desc, tb[NFTA_IMMEDIATE_DATA]);
 	if (err < 0)
 		return err;