From a76e62b50dc0fb869a5371448395700eb3d31bd3 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Fri, 6 Jul 2018 20:06:05 +0200 Subject: [PATCH] netfilter: nft_compat: explicitly reject ERROR and standard target [ Upstream commit 21d5e078192d244df3d6049f9464fff2f72cfd68 ] iptables-nft never requests these, but make this explicitly illegal. If it were quested, kernel could oops as ->eval is NULL, furthermore, the builtin targets have no owning module so its possible to rmmod eb/ip/ip6_tables module even if they would be loaded. Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- net/netfilter/nft_compat.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/net/netfilter/nft_compat.c b/net/netfilter/nft_compat.c index 3bd637eadc42..6da1cec1494a 100644 --- a/net/netfilter/nft_compat.c +++ b/net/netfilter/nft_compat.c @@ -825,10 +825,18 @@ nft_target_select_ops(const struct nft_ctx *ctx, rev = ntohl(nla_get_be32(tb[NFTA_TARGET_REV])); family = ctx->afi->family; + if (strcmp(tg_name, XT_ERROR_TARGET) == 0 || + strcmp(tg_name, XT_STANDARD_TARGET) == 0 || + strcmp(tg_name, "standard") == 0) + return ERR_PTR(-EINVAL); + /* Re-use the existing target if it's already loaded. */ list_for_each_entry(nft_target, &nft_target_list, head) { struct xt_target *target = nft_target->ops.data; + if (!target->target) + continue; + if (nft_target_cmp(target, tg_name, rev, family)) return &nft_target->ops; } @@ -837,6 +845,11 @@ nft_target_select_ops(const struct nft_ctx *ctx, if (IS_ERR(target)) return ERR_PTR(-ENOENT); + if (!target->target) { + err = -EINVAL; + goto err; + } + if (target->targetsize > nla_len(tb[NFTA_TARGET_INFO])) { err = -EINVAL; goto err; -- 2.20.1