[PATCH iproute2 v2 2/2] ss: fix vsock port filter

[Luigi Leonardi <leonardi@redhat.com>]

parse_hostcond() initializes aafilter.port to -1L (0xFFFFFFFFFFFFFFFF)
as a sentinel for "no port filter". When parsing a vsock port it called
get_u32() via a cast:

    get_u32((__u32 *)&a.port, port, 0)

get_u32() only writes 4 bytes, leaving the upper 32 bits of the 8-byte
long set from the -1 initialization. For example, for port 27354 this
produces 0xFFFFFFFF00006ADA, which never compares equal to sockstat.lport and
causes all vsock port filters to silently match nothing.

Fix by parsing into a temporary __u32 and assigning it to a.port, which
zero-extends the value correctly. When the user specifies '*' the if
block is skipped entirely and the -1 sentinel is preserved.

Fixes: 012cb515 ("ss: change aafilter port from int to long (inode support)")
Suggested-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Luigi Leonardi <leonardi@redhat.com>
---
 misc/ss.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/misc/ss.c b/misc/ss.c
index ff1a88de..a3570715 100644
--- a/misc/ss.c
+++ b/misc/ss.c
@@ -2322,9 +2322,13 @@ 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))
-			return NULL;
+		if (port && strcmp(port, "*")) {
+			__u32 vport;
+
+			if (get_u32(&vport, port, 0))
+				return NULL;
+			a.port = vport;
+		}
 
 		if (!is_port && addr[0] && strcmp(addr, "*")) {
 			a.addr.bitlen = 32;

-- 
2.55.0