Re: [PATCH] ipvs: avoid oops in nf_ct_seqadj_set when called from ip_vs_ftp helper

	Hello,

On Fri, 13 Dec 2013, Jesper Dangaard Brouer wrote:

The IPVS FTP helper ip_vs_ftp can trigger an OOPS in nf_ct_seqadj_set,
after commit 41d73ec053d2 (netfilter: nf_conntrack: make sequence
number adjustments usuable without NAT).

We can avoid the oops in nf_ct_seqadj_set() by in ip_vs_ftp_out()
instead of calling nf_nat_mangle_tcp_packet() we simply call
__nf_nat_mangle_tcp_packet() with a "false" last parameter, which
indicate not invoking the seqadj code.

After this fix, I've tested that FTP over IPVS, with module ip_vs_ftp
loaded, works for both passive and active FTP.

	There is still a problem when RIP and VIP differ in
text length because now ack_seq sent to RIP is not
adjusted after receiving the the 227 Entering Passive Mode
reply. I tried also to set *diff, ack_seq was corrected
but the result was bad checksum.

Fixes: 41d73ec053d2 (netfilter: nf_conntrack: make sequence number adjustments usuable without NAT)
Signed-off-by: Jesper Dangaard Brouer <redacted>

---
I'm uncertain if this is the correct fix.  Perhaps the ip_vs_ftp
helper need to allocate/init the seqadj extension instead?

	Agreed, lets try nfct_seqadj_ext_add() + nf_ct_seqadj_init()
if nfct_seqadj(ct) is NULL.

Regards

--
Julian Anastasov [off-list ref]