[PATCH AUTOSEL 4.19 23/73] netfilter: nft_compat: ebtables 'nat' table is normal chain type

Sasha Levin
2018-11-14T22:22:17Z

From: Florian Westphal <fw@strlen.de>

[ Upstream commit e4844c9c62a0fe47980d6c3d4b7a096a5d755925 ]

Unlike ip(6)tables, the ebtables nat table has no special properties.
This bug causes 'ebtables -A' to fail when using a target such as
'snat' (ebt_snat target sets ".table = "nat"'). Targets that have
no table restrictions work fine.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/netfilter/nft_compat.c | 21 ++++++++++++---------
1 file changed, 12 insertions(+), 9 deletions(-)

diff --git a/net/netfilter/nft_compat.c b/net/netfilter/nft_compat.c
index 32535eea51b2..ad2fe6a7e47d 100644
--- a/net/netfilter/nft_compat.c
+++ b/net/netfilter/nft_compat.c
@@ -54,9 +54,11 @@ static bool nft_xt_put(struct nft_xt *xt)
return false;
}

-static int nft_compat_chain_validate_dependency(const char *tablename,
- const struct nft_chain *chain)
+static int nft_compat_chain_validate_dependency(const struct nft_ctx *ctx,
+ const char *tablename)
{
+ enum nft_chain_types type = NFT_CHAIN_T_DEFAULT;
+ const struct nft_chain *chain = ctx->chain;
const struct nft_base_chain *basechain;

if (!tablename ||
@@ -64,9 +66,12 @@ static int nft_compat_chain_validate_dependency(const char *tablename,
return 0;

basechain = nft_base_chain(chain);
- if (strcmp(tablename, "nat") == 0 &&
- basechain->type->type != NFT_CHAIN_T_NAT)
- return -EINVAL;
+ if (strcmp(tablename, "nat") == 0) {
+ if (ctx->family != NFPROTO_BRIDGE)
+ type = NFT_CHAIN_T_NAT;
+ if (basechain->type->type != type)
+ return -EINVAL;
+ }

return 0;
}
@@ -323,8 +328,7 @@ static int nft_target_validate(const struct nft_ctx *ctx,
if (target->hooks && !(hook_mask & target->hooks))
return -EINVAL;

- ret = nft_compat_chain_validate_dependency(target->table,
- ctx->chain);
+ ret = nft_compat_chain_validate_dependency(ctx, target->table);
if (ret < 0)
return ret;
}
@@ -570,8 +574,7 @@ static int nft_match_validate(const struct nft_ctx *ctx,
if (match->hooks && !(hook_mask & match->hooks))
return -EINVAL;

- ret = nft_compat_chain_validate_dependency(match->table,
- ctx->chain);
+ ret = nft_compat_chain_validate_dependency(ctx, match->table);
if (ret < 0)
return ret;
}
--
2.17.1