rtnl: Make sure that we only accept netlink messages from kernel

diff --git a/src/rtnl.c b/src/rtnl.c
index 3cd6c4b..e53f5e8 100644 (file)
--- a/src/rtnl.c
+++ b/src/rtnl.c
@@ -1368,10 +1368,11 @@ static void rtnl_message(void *buf, size_t len)
                if (!NLMSG_OK(hdr, len))
                        break;
 
-               DBG("%s len %d type %d flags 0x%04x seq %d",
+               DBG("%s len %d type %d flags 0x%04x seq %d pid %d",
                                        type2string(hdr->nlmsg_type),
                                        hdr->nlmsg_len, hdr->nlmsg_type,
-                                       hdr->nlmsg_flags, hdr->nlmsg_seq);
+                                       hdr->nlmsg_flags, hdr->nlmsg_seq,
+                                       hdr->nlmsg_pid);
 
                switch (hdr->nlmsg_type) {
                case NLMSG_NOOP:
@@ -1417,27 +1418,37 @@ static gboolean netlink_event(GIOChannel *chan,
                                GIOCondition cond, gpointer data)
 {
        unsigned char buf[4096];
-       gsize len;
-       GIOStatus status;
+       struct sockaddr_nl nladdr;
+       socklen_t addr_len = sizeof(nladdr);
+       ssize_t status;
+       int fd;
 
        if (cond & (G_IO_NVAL | G_IO_HUP | G_IO_ERR))
                return FALSE;
 
        memset(buf, 0, sizeof(buf));
+       memset(&nladdr, 0, sizeof(nladdr));
 
-       status = g_io_channel_read_chars(chan, (gchar *) buf,
-                                               sizeof(buf), &len, NULL);
+       fd = g_io_channel_unix_get_fd(chan);
+
+       status = recvfrom(fd, buf, sizeof(buf), 0,
+                       (struct sockaddr *) &nladdr, &addr_len);
+       if (status < 0) {
+               if (errno == EINTR || errno == EAGAIN)
+                       return TRUE;
 
-       switch (status) {
-       case G_IO_STATUS_NORMAL:
-               break;
-       case G_IO_STATUS_AGAIN:
-               return TRUE;
-       default:
                return FALSE;
        }
 
-       rtnl_message(buf, len);
+       if (status == 0)
+               return FALSE;
+
+       if (nladdr.nl_pid != 0) { /* not sent by kernel, ignore */
+               DBG("Received msg from %u, ignoring it", nladdr.nl_pid);
+               return TRUE;
+       }
+
+       rtnl_message(buf, status);
 
        return TRUE;
 }