From d91fc59cd77c719f33eda65c194ad8f95a055190 Mon Sep 17 00:00:00 2001 From: Liping Zhang Date: Sun, 7 May 2017 22:01:55 +0800 Subject: netfilter: introduce nf_conntrack_helper_put helper function And convert module_put invocation to nf_conntrack_helper_put, this is prepared for the followup patch, which will add a refcnt for cthelper, so we can reject the deleting request when cthelper is in use. Signed-off-by: Liping Zhang Signed-off-by: Pablo Neira Ayuso --- include/net/netfilter/nf_conntrack_helper.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/net') diff --git a/include/net/netfilter/nf_conntrack_helper.h b/include/net/netfilter/nf_conntrack_helper.h index e04fa7691e5d..c1c12411103a 100644 --- a/include/net/netfilter/nf_conntrack_helper.h +++ b/include/net/netfilter/nf_conntrack_helper.h @@ -79,6 +79,8 @@ struct nf_conntrack_helper *__nf_conntrack_helper_find(const char *name, struct nf_conntrack_helper *nf_conntrack_helper_try_module_get(const char *name, u16 l3num, u8 protonum); +void nf_conntrack_helper_put(struct nf_conntrack_helper *helper); + void nf_ct_helper_init(struct nf_conntrack_helper *helper, u16 l3num, u16 protonum, const char *name, u16 default_port, u16 spec_port, u32 id, -- cgit v1.2.3 From 9338d7b4418e9996a7642867d8f6b482a6040ed6 Mon Sep 17 00:00:00 2001 From: Liping Zhang Date: Sun, 7 May 2017 22:01:56 +0800 Subject: netfilter: nfnl_cthelper: reject del request if helper obj is in use We can still delete the ct helper even if it is in use, this will cause a use-after-free error. In more detail, I mean: # nfct helper add ssdp inet udp # iptables -t raw -A OUTPUT -p udp -j CT --helper ssdp # nfct helper delete ssdp //--> oops, succeed! BUG: unable to handle kernel paging request at 000026ca IP: 0x26ca [...] Call Trace: ? ipv4_helper+0x62/0x80 [nf_conntrack_ipv4] nf_hook_slow+0x21/0xb0 ip_output+0xe9/0x100 ? ip_fragment.constprop.54+0xc0/0xc0 ip_local_out+0x33/0x40 ip_send_skb+0x16/0x80 udp_send_skb+0x84/0x240 udp_sendmsg+0x35d/0xa50 So add reference count to fix this issue, if ct helper is used by others, reject the delete request. Apply this patch: # nfct helper delete ssdp nfct v1.4.3: netlink error: Device or resource busy Signed-off-by: Liping Zhang Signed-off-by: Pablo Neira Ayuso --- include/net/netfilter/nf_conntrack_helper.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/net') diff --git a/include/net/netfilter/nf_conntrack_helper.h b/include/net/netfilter/nf_conntrack_helper.h index c1c12411103a..c519bb5b5bb8 100644 --- a/include/net/netfilter/nf_conntrack_helper.h +++ b/include/net/netfilter/nf_conntrack_helper.h @@ -9,6 +9,7 @@ #ifndef _NF_CONNTRACK_HELPER_H #define _NF_CONNTRACK_HELPER_H +#include #include #include #include @@ -26,6 +27,7 @@ struct nf_conntrack_helper { struct hlist_node hnode; /* Internal use. */ char name[NF_CT_HELPER_NAME_LEN]; /* name of the module */ + refcount_t refcnt; struct module *me; /* pointer to self */ const struct nf_conntrack_expect_policy *expect_policy; -- cgit v1.2.3 From 591054469b3eef34bc097c30fae8ededddf8d796 Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Mon, 15 May 2017 11:17:34 +0100 Subject: netfilter: nf_tables: revisit chain/object refcounting from elements Andreas reports that the following incremental update using our commit protocol doesn't work. # nft -f incremental-update.nft delete element ip filter client_to_any { 10.180.86.22 : goto CIn_1 } delete chain ip filter CIn_1 ... Error: Could not process rule: Device or resource busy The existing code is not well-integrated into the commit phase protocol, since element deletions do not result in refcount decrement from the preparation phase. This results in bogus EBUSY errors like the one above. Two new functions come with this patch: * nft_set_elem_activate() function is used from the abort path, to restore the set element refcounting on objects that occurred from the preparation phase. * nft_set_elem_deactivate() that is called from nft_del_setelem() to decrement set element refcounting on objects from the preparation phase in the commit protocol. The nft_data_uninit() has been renamed to nft_data_release() since this function does not uninitialize any data store in the data register, instead just releases the references to objects. Moreover, a new function nft_data_hold() has been introduced to be used from nft_set_elem_activate(). Reported-by: Andreas Schultz Signed-off-by: Pablo Neira Ayuso --- include/net/netfilter/nf_tables.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/net') diff --git a/include/net/netfilter/nf_tables.h b/include/net/netfilter/nf_tables.h index 028faec8fc27..8a8bab8d7b15 100644 --- a/include/net/netfilter/nf_tables.h +++ b/include/net/netfilter/nf_tables.h @@ -176,7 +176,7 @@ struct nft_data_desc { int nft_data_init(const struct nft_ctx *ctx, struct nft_data *data, unsigned int size, struct nft_data_desc *desc, const struct nlattr *nla); -void nft_data_uninit(const struct nft_data *data, enum nft_data_types type); +void nft_data_release(const struct nft_data *data, enum nft_data_types type); int nft_data_dump(struct sk_buff *skb, int attr, const struct nft_data *data, enum nft_data_types type, unsigned int len); -- cgit v1.2.3