Hello,
On Fri, 18 Sep 2026, Julian Anastasov wrote:
> On Thu, 17 Sep 2026, Zihan Xi wrote:
>
> > ip_vs_ftp_out() creates a wildcard data connection from the
> > server-advertised passive port. If that port is one of the configured FTP
> > control ports, ip_vs_conn_new() binds the FTP helper to the new connection
> > again. A subsequent wildcard lookup can then extend a controlled-connection
> > chain.
> >
> > Reject zero and configured control ports before creating passive
> > connections. For active mode, reject a zero client port and a data port
> > derived from a configured control port.
> >
> > Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> > Cc: [email protected]
> > Reported-by: Vega <[email protected]>
> > Assisted-by: LLM
> > Co-developed-by: Luxing Yin <[email protected]>
> > Signed-off-by: Luxing Yin <[email protected]>
> > Signed-off-by: Zihan Xi <[email protected]>
>
> Patch looks good to me for the nf tree, thanks!
>
> Signed-off-by: Julian Anastasov <[email protected]>
Patch is ok but needs to be resent with
the other patch:
pw-bot: changes-requested
> > changes in v2:
> > - Reject the data port derived from a configured control port in
> > ip_vs_ftp_in() to cover the active-mode bypass.
> > - v1 Link:
> > https://lore.kernel.org/all/[email protected]/
> >
> > net/netfilter/ipvs/ip_vs_ftp.c | 18 ++++++++++++++++++
> > 1 file changed, 18 insertions(+)
> >
> > diff --git a/net/netfilter/ipvs/ip_vs_ftp.c b/net/netfilter/ipvs/ip_vs_ftp.c
> > index 9e3e005a82635..4822a1a75212d 100644
> > --- a/net/netfilter/ipvs/ip_vs_ftp.c
> > +++ b/net/netfilter/ipvs/ip_vs_ftp.c
> > @@ -62,6 +62,17 @@ static unsigned short ports[IP_VS_APP_MAX_PORTS] = {21,
> > 0};
> > module_param_array(ports, ushort, &ports_count, 0444);
> > MODULE_PARM_DESC(ports, "Ports to monitor for FTP control commands");
> >
> > +static bool is_control_port(u16 port)
> > +{
> > + unsigned int i;
> > +
> > + for (i = 0; i < ports_count; i++) {
> > + if (ports[i] == port)
> > + return true;
> > + }
> > + return false;
> > +}
> > +
> >
> > static char *ip_vs_ftp_data_ptr(struct sk_buff *skb, struct ip_vs_iphdr
> > *ipvsh)
> > {
> > @@ -319,6 +330,10 @@ static int ip_vs_ftp_out(struct ip_vs_app *app, struct
> > ip_vs_conn *cp,
> > return 1;
> > }
> >
> > + /* Do not redirect data to control ports */
> > + if (!port || is_control_port(ntohs(port)))
> > + return 0;
> > +
> > /* Now update or create a connection entry for it */
> > {
> > struct ip_vs_conn_param p;
> > @@ -529,6 +544,9 @@ static int ip_vs_ftp_in(struct ip_vs_app *app, struct
> > ip_vs_conn *cp,
> > return 1;
> > }
> >
> > + if (!port || is_control_port(ntohs(cp->vport) - 1))
> > + return 0;
> > +
> > /* Passive mode off */
> > cp->app_data = (void *) IP_VS_FTP_ACTIVE;
> >
> > --
> > 2.43.0
Regards
--
Julian Anastasov <[email protected]>
