netfilter: nft_compat: reject unused compat flag

[ Upstream commit 292781c3c5485ce33bd22b2ef1b2bed709b4d672 ]

Flag (1 << 0) is ignored is set, never used, reject it it with EINVAL
instead.

Fixes: 0ca743a55991 ("netfilter: nf_tables: add compatibility layer for x_tables")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h
index ca30232..117c6a9 100644 (file)
--- a/include/uapi/linux/netfilter/nf_tables.h
+++ b/include/uapi/linux/netfilter/nf_tables.h
@@ -285,9 +285,11 @@ enum nft_rule_attributes {
 /**
  * enum nft_rule_compat_flags - nf_tables rule compat flags
  *
+ * @NFT_RULE_COMPAT_F_UNUSED: unused
  * @NFT_RULE_COMPAT_F_INV: invert the check result
  */
 enum nft_rule_compat_flags {
+       NFT_RULE_COMPAT_F_UNUSED = (1 << 0),
        NFT_RULE_COMPAT_F_INV   = (1 << 1),
        NFT_RULE_COMPAT_F_MASK  = NFT_RULE_COMPAT_F_INV,
 };

diff --git a/net/netfilter/nft_compat.c b/net/netfilter/nft_compat.c
index 001b684..ed71d5e 100644 (file)
--- a/net/netfilter/nft_compat.c
+++ b/net/netfilter/nft_compat.c
@@ -212,7 +212,8 @@ static int nft_parse_compat(const struct nlattr *attr, u16 *proto, bool *inv)
                return -EINVAL;
 
        flags = ntohl(nla_get_be32(tb[NFTA_RULE_COMPAT_FLAGS]));
-       if (flags & ~NFT_RULE_COMPAT_F_MASK)
+       if (flags & NFT_RULE_COMPAT_F_UNUSED ||
+           flags & ~NFT_RULE_COMPAT_F_MASK)
                return -EINVAL;
        if (flags & NFT_RULE_COMPAT_F_INV)
                *inv = true;