ss: fix NULL pointer access when parsing unix sockets with oldformat

When parsing and printing the unix sockets in unix_show(),
if the oldformat is detected, the peer_name member of the sockstat
object is left uninitialized (NULL).
For this reason, if a filter has been specified on the command line,
a strcmp() will crash when trying to access it.

Avoid crash by checking that peer_name is not NULL before
passing it to strcmp().

Cc: Stefano Brivio <sbrivio@redhat.com>
Cc: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Antonio Quartulli <a@unstable.cc>
Reviewed-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>

diff --git a/misc/ss.c b/misc/ss.c
index b35859dc40442778e2480ea043ad650bafaa2957..29a250704c2dd46d3235122dcee5dacc41c3fe0d 100644 (file)
--- a/misc/ss.c
+++ b/misc/ss.c
@@ -3711,7 +3711,10 @@ static int unix_show(struct filter *f)
                        };
 
                        memcpy(st.local.data, &u->name, sizeof(u->name));
-                       if (strcmp(u->peer_name, "*"))
+                       /* when parsing the old format rport is set to 0 and
+                        * therefore peer_name remains NULL
+                        */
+                       if (u->peer_name && strcmp(u->peer_name, "*"))
                                memcpy(st.remote.data, &u->peer_name,
                                       sizeof(u->peer_name));
                        if (run_ssfilter(f->f, &st) == 0) {