diff options
author | Gao Feng <fgao@ikuai8.com> | 2017-03-29 19:11:27 +0800 |
---|---|---|
committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2017-04-08 23:52:15 +0200 |
commit | 8b5995d0633b04f9a0d321a7cc77e386440730cf (patch) | |
tree | d495422d1ce9a6b03ba312921d2b4b9ad90779d8 /net/netfilter/nf_conntrack_helper.c | |
parent | 97aae0df1de4d7dd80905fb067e28b032a132995 (diff) | |
download | linux-8b5995d0633b04f9a0d321a7cc77e386440730cf.tar.bz2 |
netfilter: helper: Add the rcu lock when call __nf_conntrack_helper_find
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>
Diffstat (limited to 'net/netfilter/nf_conntrack_helper.c')
-rw-r--r-- | net/netfilter/nf_conntrack_helper.c | 17 |
1 files changed, 12 insertions, 5 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); |