From: Pablo Neira Ayuso <pablo@netfilter.org>
To: netfilter-devel@vger.kernel.org
Cc: davem@davemloft.net, netdev@vger.kernel.org
Subject: [PATCH 3/9] netfilter: helper: Add the rcu lock when call __nf_conntrack_helper_find
Date: Fri, 14 Apr 2017 02:26:45 +0200 [thread overview]
Message-ID: <1492129611-29336-4-git-send-email-pablo@netfilter.org> (raw)
In-Reply-To: <1492129611-29336-1-git-send-email-pablo@netfilter.org>
From: Gao Feng <fgao@ikuai8.com>
When invoke __nf_conntrack_helper_find, it needs the rcu lock to
protect the helper module which would not be unloaded.
Now there are two caller nf_conntrack_helper_try_module_get and
ctnetlink_create_expect which don't hold rcu lock. And the other
callers left like ctnetlink_change_helper, ctnetlink_create_conntrack,
and ctnetlink_glue_attach_expect, they already hold the rcu lock
or spin_lock_bh.
Remove the rcu lock in functions nf_ct_helper_expectfn_find_by_name
and nf_ct_helper_expectfn_find_by_symbol. Because they return one pointer
which needs rcu lock, so their caller should hold the rcu lock, not in
these two functions.
Signed-off-by: Gao Feng <fgao@ikuai8.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
net/netfilter/nf_conntrack_helper.c | 17 ++++++++++++-----
net/netfilter/nf_conntrack_netlink.c | 10 ++++++++--
2 files changed, 20 insertions(+), 7 deletions(-)
diff --git a/net/netfilter/nf_conntrack_helper.c b/net/netfilter/nf_conntrack_helper.c
index 6dc44d9b4190..4eeb3418366a 100644
--- a/net/netfilter/nf_conntrack_helper.c
+++ b/net/netfilter/nf_conntrack_helper.c
@@ -158,16 +158,25 @@ nf_conntrack_helper_try_module_get(const char *name, u16 l3num, u8 protonum)
{
struct nf_conntrack_helper *h;
+ rcu_read_lock();
+
h = __nf_conntrack_helper_find(name, l3num, protonum);
#ifdef CONFIG_MODULES
if (h == NULL) {
- if (request_module("nfct-helper-%s", name) == 0)
+ rcu_read_unlock();
+ if (request_module("nfct-helper-%s", name) == 0) {
+ rcu_read_lock();
h = __nf_conntrack_helper_find(name, l3num, protonum);
+ } else {
+ return h;
+ }
}
#endif
if (h != NULL && !try_module_get(h->me))
h = NULL;
+ rcu_read_unlock();
+
return h;
}
EXPORT_SYMBOL_GPL(nf_conntrack_helper_try_module_get);
@@ -311,38 +320,36 @@ void nf_ct_helper_expectfn_unregister(struct nf_ct_helper_expectfn *n)
}
EXPORT_SYMBOL_GPL(nf_ct_helper_expectfn_unregister);
+/* Caller should hold the rcu lock */
struct nf_ct_helper_expectfn *
nf_ct_helper_expectfn_find_by_name(const char *name)
{
struct nf_ct_helper_expectfn *cur;
bool found = false;
- rcu_read_lock();
list_for_each_entry_rcu(cur, &nf_ct_helper_expectfn_list, head) {
if (!strcmp(cur->name, name)) {
found = true;
break;
}
}
- rcu_read_unlock();
return found ? cur : NULL;
}
EXPORT_SYMBOL_GPL(nf_ct_helper_expectfn_find_by_name);
+/* Caller should hold the rcu lock */
struct nf_ct_helper_expectfn *
nf_ct_helper_expectfn_find_by_symbol(const void *symbol)
{
struct nf_ct_helper_expectfn *cur;
bool found = false;
- rcu_read_lock();
list_for_each_entry_rcu(cur, &nf_ct_helper_expectfn_list, head) {
if (cur->expectfn == symbol) {
found = true;
break;
}
}
- rcu_read_unlock();
return found ? cur : NULL;
}
EXPORT_SYMBOL_GPL(nf_ct_helper_expectfn_find_by_symbol);
diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index 59ee27deb9a0..06d28ac663df 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -3133,23 +3133,27 @@ ctnetlink_create_expect(struct net *net,
return -ENOENT;
ct = nf_ct_tuplehash_to_ctrack(h);
+ rcu_read_lock();
if (cda[CTA_EXPECT_HELP_NAME]) {
const char *helpname = nla_data(cda[CTA_EXPECT_HELP_NAME]);
helper = __nf_conntrack_helper_find(helpname, u3,
nf_ct_protonum(ct));
if (helper == NULL) {
+ rcu_read_unlock();
#ifdef CONFIG_MODULES
if (request_module("nfct-helper-%s", helpname) < 0) {
err = -EOPNOTSUPP;
goto err_ct;
}
+ rcu_read_lock();
helper = __nf_conntrack_helper_find(helpname, u3,
nf_ct_protonum(ct));
if (helper) {
err = -EAGAIN;
- goto err_ct;
+ goto err_rcu;
}
+ rcu_read_unlock();
#endif
err = -EOPNOTSUPP;
goto err_ct;
@@ -3159,11 +3163,13 @@ ctnetlink_create_expect(struct net *net,
exp = ctnetlink_alloc_expect(cda, ct, helper, &tuple, &mask);
if (IS_ERR(exp)) {
err = PTR_ERR(exp);
- goto err_ct;
+ goto err_rcu;
}
err = nf_ct_expect_related_report(exp, portid, report);
nf_ct_expect_put(exp);
+err_rcu:
+ rcu_read_unlock();
err_ct:
nf_ct_put(ct);
return err;
--
2.1.4
next prev parent reply other threads:[~2017-04-14 0:27 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-14 0:26 [PATCH 0/9] Netfilter fixes for net Pablo Neira Ayuso
2017-04-14 0:26 ` [PATCH 1/9] netfilter: xt_TCPMSS: add more sanity tests on tcph->doff Pablo Neira Ayuso
2017-04-14 0:26 ` [PATCH 2/9] netfilter: ctnetlink: using bit to represent the ct event Pablo Neira Ayuso
2017-04-14 0:26 ` Pablo Neira Ayuso [this message]
2017-04-14 0:26 ` [PATCH 4/9] netfilter: ctnetlink: make it safer when checking the ct helper name Pablo Neira Ayuso
2017-04-14 0:26 ` [PATCH 5/9] netfilter: make it safer during the inet6_dev->addr_list traversal Pablo Neira Ayuso
2017-04-14 0:26 ` [PATCH 6/9] netfilter: ctnetlink: skip dumping expect when nfct_help(ct) is NULL Pablo Neira Ayuso
2017-04-14 0:26 ` [PATCH 7/9] netfilter: nf_ct_expect: use proper RCU list traversal/update APIs Pablo Neira Ayuso
2017-04-14 0:26 ` [PATCH 8/9] netfilter: nft_hash: do not dump the auto generated seed Pablo Neira Ayuso
2017-04-14 0:26 ` [PATCH 9/9] netfilter: ipt_CLUSTERIP: Fix wrong conntrack netns refcnt usage Pablo Neira Ayuso
2017-04-14 14:59 ` [PATCH 0/9] Netfilter fixes for net David Miller
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