From: Pablo Neira Ayuso <pablo@netfilter.org>
To: netfilter-devel@vger.kernel.org
Cc: davem@davemloft.net, netdev@vger.kernel.org
Subject: [PATCH 01/11] netfilter: nf_tables: fix oops during rule dump
Date: Thu, 23 May 2019 23:35:37 +0200 [thread overview]
Message-ID: <20190523213547.15523-2-pablo@netfilter.org> (raw)
In-Reply-To: <20190523213547.15523-1-pablo@netfilter.org>
From: Florian Westphal <fw@strlen.de>
We can oops in nf_tables_fill_rule_info().
Its not possible to fetch previous element in rcu-protected lists
when deletions are not prevented somehow: list_del_rcu poisons
the ->prev pointer value.
Before rcu-conversion this was safe as dump operations did hold
nfnetlink mutex.
Pass previous rule as argument, obtained by keeping a pointer to
the previous rule during traversal.
Fixes: d9adf22a291883 ("netfilter: nf_tables: use call_rcu in netlink dumps")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
net/netfilter/nf_tables_api.c | 20 +++++++++++---------
1 file changed, 11 insertions(+), 9 deletions(-)
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 28241e82fd15..4b5159936034 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -2270,13 +2270,13 @@ static int nf_tables_fill_rule_info(struct sk_buff *skb, struct net *net,
u32 flags, int family,
const struct nft_table *table,
const struct nft_chain *chain,
- const struct nft_rule *rule)
+ const struct nft_rule *rule,
+ const struct nft_rule *prule)
{
struct nlmsghdr *nlh;
struct nfgenmsg *nfmsg;
const struct nft_expr *expr, *next;
struct nlattr *list;
- const struct nft_rule *prule;
u16 type = nfnl_msg_type(NFNL_SUBSYS_NFTABLES, event);
nlh = nlmsg_put(skb, portid, seq, type, sizeof(struct nfgenmsg), flags);
@@ -2296,8 +2296,7 @@ static int nf_tables_fill_rule_info(struct sk_buff *skb, struct net *net,
NFTA_RULE_PAD))
goto nla_put_failure;
- if ((event != NFT_MSG_DELRULE) && (rule->list.prev != &chain->rules)) {
- prule = list_prev_entry(rule, list);
+ if (event != NFT_MSG_DELRULE && prule) {
if (nla_put_be64(skb, NFTA_RULE_POSITION,
cpu_to_be64(prule->handle),
NFTA_RULE_PAD))
@@ -2344,7 +2343,7 @@ static void nf_tables_rule_notify(const struct nft_ctx *ctx,
err = nf_tables_fill_rule_info(skb, ctx->net, ctx->portid, ctx->seq,
event, 0, ctx->family, ctx->table,
- ctx->chain, rule);
+ ctx->chain, rule, NULL);
if (err < 0) {
kfree_skb(skb);
goto err;
@@ -2369,12 +2368,13 @@ static int __nf_tables_dump_rules(struct sk_buff *skb,
const struct nft_chain *chain)
{
struct net *net = sock_net(skb->sk);
+ const struct nft_rule *rule, *prule;
unsigned int s_idx = cb->args[0];
- const struct nft_rule *rule;
+ prule = NULL;
list_for_each_entry_rcu(rule, &chain->rules, list) {
if (!nft_is_active(net, rule))
- goto cont;
+ goto cont_skip;
if (*idx < s_idx)
goto cont;
if (*idx > s_idx) {
@@ -2386,11 +2386,13 @@ static int __nf_tables_dump_rules(struct sk_buff *skb,
NFT_MSG_NEWRULE,
NLM_F_MULTI | NLM_F_APPEND,
table->family,
- table, chain, rule) < 0)
+ table, chain, rule, prule) < 0)
return 1;
nl_dump_check_consistent(cb, nlmsg_hdr(skb));
cont:
+ prule = rule;
+cont_skip:
(*idx)++;
}
return 0;
@@ -2546,7 +2548,7 @@ static int nf_tables_getrule(struct net *net, struct sock *nlsk,
err = nf_tables_fill_rule_info(skb2, net, NETLINK_CB(skb).portid,
nlh->nlmsg_seq, NFT_MSG_NEWRULE, 0,
- family, table, chain, rule);
+ family, table, chain, rule, NULL);
if (err < 0)
goto err;
--
2.11.0
next prev parent reply other threads:[~2019-05-23 21:36 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-23 21:35 [PATCH 00/11] Netfilter/IPVS fixes for net Pablo Neira Ayuso
2019-05-23 21:35 ` Pablo Neira Ayuso [this message]
2019-05-23 21:35 ` [PATCH 02/11] netfilter: nf_queue: fix reinject verdict handling Pablo Neira Ayuso
2019-05-23 21:35 ` [PATCH 03/11] netfilter: nft_fib: Fix existence check support Pablo Neira Ayuso
2019-05-23 21:35 ` [PATCH 04/11] ipvs: Fix use-after-free in ip_vs_in Pablo Neira Ayuso
2019-05-23 21:35 ` [PATCH 05/11] selftests: netfilter: missing error check when setting up veth interface Pablo Neira Ayuso
2019-05-23 21:35 ` [PATCH 06/11] netfilter: nat: fix udp checksum corruption Pablo Neira Ayuso
2019-05-23 21:35 ` [PATCH 07/11] netfilter: nf_flow_table: ignore DF bit setting Pablo Neira Ayuso
2019-05-23 21:35 ` [PATCH 08/11] netfilter: nft_flow_offload: set liberal tracking mode for tcp Pablo Neira Ayuso
2019-05-23 21:35 ` [PATCH 09/11] netfilter: nft_flow_offload: don't offload when sequence numbers need adjustment Pablo Neira Ayuso
2019-05-23 21:35 ` [PATCH 10/11] netfilter: nft_flow_offload: IPCB is only valid for ipv4 family Pablo Neira Ayuso
2019-05-23 21:35 ` [PATCH 11/11] selftests: netfilter: add flowtable test script Pablo Neira Ayuso
2019-05-23 21:45 ` [PATCH 00/11] Netfilter/IPVS fixes for net David Miller
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