Re: [PATCH iproute2] ss: fix vsock port filter

[Stephen Hemminger <stephen@networkplumber.org>]

On Wed, 22 Apr 2026 10:03:49 +0200
Stefano Garzarella <sgarzare@redhat.com> wrote:

> On Wed, 22 Apr 2026 at 01:38, Stephen Hemminger <stephen@networkplumber.org> wrote:
> >
> > On Tue, 21 Apr 2026 14:35:12 +0200
> > Luigi Leonardi <leonardi@redhat.com> wrote:
> >  
> > > parse_hostcond() uses get_u32() to parse the vsock port into the
> > > aafilter.port field, which is a long. On 64-bit systems, get_u32()
> > > only writes the lower 32 bits, leaving the upper 32 bits set from
> > > the -1 initialization. This causes the port comparison
> > > "a->port != s->rport" in run_ssfilter() to always fail, since the
> > > corrupted long value never matches the int rport.
> > >
> > > Fix by using get_long() instead, consistent with how AF_PACKET and
> > > AF_NETLINK handle the same field.
> > >
> > > Fixes: c759116a0b2b ("ss: add AF_VSOCK support")
> > > Signed-off-by: Luigi Leonardi <leonardi@redhat.com>
> > > ---
> > >  misc/ss.c | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/misc/ss.c b/misc/ss.c
> > > index 14e9f27a..6e3321ac 100644
> > > --- a/misc/ss.c
> > > +++ b/misc/ss.c
> > > @@ -2323,7 +2323,7 @@ void *parse_hostcond(char *addr, bool is_port)
> > >               port = find_port(addr, is_port);
> > >
> > >               if (port && strcmp(port, "*") &&
> > > -                 get_u32((__u32 *)&a.port, port, 0))
> > > +                 get_long(&a.port, port, 0))
> > >                       return NULL;  
> >
> > If you use get_long() then the code could get negative values.
> > Actually have port in ss as signed value seems like a mistake in original design.
> >
> > The port in unix domain socket is inode number.
> > Originally it was int, but got changed to long back in 6.6
> >
> > The port in ss cache is int.  
> 
> Yeah, as I mentioned I think the issue was introduced by commit
> 012cb515 ("ss: change aafilter port from int to long (inode support)").

What about this which avoids the cast but keeps the same semantics.

diff --git a/misc/ss.c b/misc/ss.c
index 14e9f27a..e830e146 100644
--- a/misc/ss.c
+++ b/misc/ss.c
@@ -2317,14 +2317,16 @@ void *parse_hostcond(char *addr, bool is_port)
 
 	if (fam == AF_VSOCK) {
 		__u32 cid = ~(__u32)0;
+		__u32 vport = 0;
 
 		a.addr.family = AF_VSOCK;
 
 		port = find_port(addr, is_port);
-
-		if (port && strcmp(port, "*") &&
-		    get_u32((__u32 *)&a.port, port, 0))
-			return NULL;
+		if (port && strcmp(port, "*")) {
+			if (get_u32(&vport, port, 0))
+				return NULL;
+		}
+		a.port = vport;
 
 		if (!is_port && addr[0] && strcmp(addr, "*")) {
 			a.addr.bitlen = 32;