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| author | Ian Wilson <iwilson@brocade.com> | 2015-03-12 09:37:58 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-07-03 19:48:08 -0700 |
| commit | 7c6300bb4934b8f9f881b1645c087b2ddba922f9 (patch) | |
| tree | 38fd06af326cfa8f520315a4bf4d1069b71ef2a4 | |
| parent | 59bc21951c78625486741b33eafdacbe57ce688d (diff) | |
| download | lwn-7c6300bb4934b8f9f881b1645c087b2ddba922f9.tar.gz lwn-7c6300bb4934b8f9f881b1645c087b2ddba922f9.zip | |
netfilter: Zero the tuple in nfnl_cthelper_parse_tuple()
commit 78146572b9cd20452da47951812f35b1ad4906be upstream.
nfnl_cthelper_parse_tuple() is called from nfnl_cthelper_new(),
nfnl_cthelper_get() and nfnl_cthelper_del(). In each case they pass
a pointer to an nf_conntrack_tuple data structure local variable:
struct nf_conntrack_tuple tuple;
...
ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
The problem is that this local variable is not initialized, and
nfnl_cthelper_parse_tuple() only initializes two fields: src.l3num and
dst.protonum. This leaves all other fields with undefined values
based on whatever is on the stack:
tuple->src.l3num = ntohs(nla_get_be16(tb[NFCTH_TUPLE_L3PROTONUM]));
tuple->dst.protonum = nla_get_u8(tb[NFCTH_TUPLE_L4PROTONUM]);
The symptom observed was that when the rpc and tns helpers were added
then traffic to port 1536 was being sent to user-space.
Signed-off-by: Ian Wilson <iwilson@brocade.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | net/netfilter/nfnetlink_cthelper.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/net/netfilter/nfnetlink_cthelper.c b/net/netfilter/nfnetlink_cthelper.c index a9da433c8149..3b283edec027 100644 --- a/net/netfilter/nfnetlink_cthelper.c +++ b/net/netfilter/nfnetlink_cthelper.c @@ -74,6 +74,9 @@ nfnl_cthelper_parse_tuple(struct nf_conntrack_tuple *tuple, if (!tb[NFCTH_TUPLE_L3PROTONUM] || !tb[NFCTH_TUPLE_L4PROTONUM]) return -EINVAL; + /* Not all fields are initialized so first zero the tuple */ + memset(tuple, 0, sizeof(struct nf_conntrack_tuple)); + tuple->src.l3num = ntohs(nla_get_be16(tb[NFCTH_TUPLE_L3PROTONUM])); tuple->dst.protonum = nla_get_u8(tb[NFCTH_TUPLE_L4PROTONUM]); |