diff options
| author | Liping Zhang <zlpnobody@gmail.com> | 2017-05-07 22:01:56 +0800 |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2017-05-15 12:42:29 +0200 |
| commit | 9338d7b4418e9996a7642867d8f6b482a6040ed6 (patch) | |
| tree | 5bf37ab11070434ed04c1bcfe12194925bfffd25 /include | |
| parent | d91fc59cd77c719f33eda65c194ad8f95a055190 (diff) | |
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 <zlpnobody@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/net/netfilter/nf_conntrack_helper.h | 2 |
1 files changed, 2 insertions, 0 deletions
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 <linux/refcount.h> #include <net/netfilter/nf_conntrack.h> #include <net/netfilter/nf_conntrack_extend.h> #include <net/netfilter/nf_conntrack_expect.h> @@ -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; |