[BRIDGE] netlink: Convert bridge netlink code to new netlink interface

Removes dependency on buggy rta_buf, fixes a memory corruption bug due to
a unvalidated netlink attribute, and simplifies the code.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
index 15d6efbe7519b66bc184e9d45e133302f7f6dbc4..a9139682c49bf1aa9697fdbf1c4e5d2ebe29222a 100644 (file)
--- a/net/bridge/br_netlink.c
+++ b/net/bridge/br_netlink.c
@@ -36,51 +36,43 @@ static int br_fill_ifinfo(struct sk_buff *skb, const struct net_bridge_port *por
 {
        const struct net_bridge *br = port->br;
        const struct net_device *dev = port->dev;
-       struct ifinfomsg *r;
+       struct ifinfomsg *hdr;
        struct nlmsghdr *nlh;
-       unsigned char *b = skb->tail;
-       u32 mtu = dev->mtu;
        u8 operstate = netif_running(dev) ? dev->operstate : IF_OPER_DOWN;
-       u8 portstate = port->state;
 
        pr_debug("br_fill_info event %d port %s master %s\n",
                 event, dev->name, br->dev->name);
 
-       nlh = NLMSG_NEW(skb, pid, seq, event, sizeof(*r), flags);
-       r = NLMSG_DATA(nlh);
-       r->ifi_family = AF_BRIDGE;
-       r->__ifi_pad = 0;
-       r->ifi_type = dev->type;
-       r->ifi_index = dev->ifindex;
-       r->ifi_flags = dev_get_flags(dev);
-       r->ifi_change = 0;
+       nlh = nlmsg_put(skb, pid, seq, event, sizeof(*hdr), flags);
+       if (nlh == NULL)
+               return -ENOBUFS;
 
-       RTA_PUT(skb, IFLA_IFNAME, strlen(dev->name)+1, dev->name);
+       hdr = nlmsg_data(nlh);
+       hdr->ifi_family = AF_BRIDGE;
+       hdr->__ifi_pad = 0;
+       hdr->ifi_type = dev->type;
+       hdr->ifi_index = dev->ifindex;
+       hdr->ifi_flags = dev_get_flags(dev);
+       hdr->ifi_change = 0;
 
-       RTA_PUT(skb, IFLA_MASTER, sizeof(int), &br->dev->ifindex);
+       NLA_PUT_STRING(skb, IFLA_IFNAME, dev->name);
+       NLA_PUT_U32(skb, IFLA_MASTER, br->dev->ifindex);
+       NLA_PUT_U32(skb, IFLA_MTU, dev->mtu);
+       NLA_PUT_U8(skb, IFLA_OPERSTATE, operstate);
 
        if (dev->addr_len)
-               RTA_PUT(skb, IFLA_ADDRESS, dev->addr_len, dev->dev_addr);
+               NLA_PUT(skb, IFLA_ADDRESS, dev->addr_len, dev->dev_addr);
 
-       RTA_PUT(skb, IFLA_MTU, sizeof(mtu), &mtu);
        if (dev->ifindex != dev->iflink)
-               RTA_PUT(skb, IFLA_LINK, sizeof(int), &dev->iflink);
-
-
-       RTA_PUT(skb, IFLA_OPERSTATE, sizeof(operstate), &operstate);
+               NLA_PUT_U32(skb, IFLA_LINK, dev->iflink);
 
        if (event == RTM_NEWLINK)
-               RTA_PUT(skb, IFLA_PROTINFO, sizeof(portstate), &portstate);
-
-       nlh->nlmsg_len = skb->tail - b;
+               NLA_PUT_U8(skb, IFLA_PROTINFO, port->state);
 
-       return skb->len;
-
-nlmsg_failure:
-rtattr_failure:
+       return nlmsg_end(skb, nlh);
 
-       skb_trim(skb, b - skb->data);
-       return -EINVAL;
+nla_put_failure:
+       return nlmsg_cancel(skb, nlh);
 }
 
 /*
@@ -113,25 +105,18 @@ static int br_dump_ifinfo(struct sk_buff *skb, struct netlink_callback *cb)
 {
        struct net_device *dev;
        int idx;
-       int s_idx = cb->args[0];
-       int err = 0;
 
        read_lock(&dev_base_lock);
        for (dev = dev_base, idx = 0; dev; dev = dev->next) {
-               struct net_bridge_port *p = dev->br_port;
-
                /* not a bridge port */
-               if (!p)
-                       continue;
+               if (dev->br_port == NULL || idx < cb->args[0])
+                       goto skip;
 
-               if (idx < s_idx)
-                       goto cont;
-
-               err = br_fill_ifinfo(skb, p, NETLINK_CB(cb->skb).pid,
-                                    cb->nlh->nlmsg_seq, RTM_NEWLINK, NLM_F_MULTI);
-               if (err <= 0)
+               if (br_fill_ifinfo(skb, dev->br_port, NETLINK_CB(cb->skb).pid,
+                                  cb->nlh->nlmsg_seq, RTM_NEWLINK,
+                                  NLM_F_MULTI) < 0)
                        break;
-cont:
+skip:
                ++idx;
        }
        read_unlock(&dev_base_lock);
@@ -147,26 +132,27 @@ cont:
  */
 static int br_rtm_setlink(struct sk_buff *skb,  struct nlmsghdr *nlh, void *arg)
 {
-       struct rtattr  **rta = arg;
-       struct ifinfomsg *ifm = NLMSG_DATA(nlh);
+       struct ifinfomsg *ifm;
+       struct nlattr *protinfo;
        struct net_device *dev;
        struct net_bridge_port *p;
        u8 new_state;
 
+       if (nlmsg_len(nlh) < sizeof(*ifm))
+               return -EINVAL;
+
+       ifm = nlmsg_data(nlh);
        if (ifm->ifi_family != AF_BRIDGE)
                return -EPFNOSUPPORT;
 
-       /* Must pass valid state as PROTINFO */
-       if (rta[IFLA_PROTINFO-1]) {
-               u8 *pstate = RTA_DATA(rta[IFLA_PROTINFO-1]);
-               new_state = *pstate;
-       } else
+       protinfo = nlmsg_find_attr(nlh, sizeof(*ifm), IFLA_PROTINFO);
+       if (!protinfo || nla_len(protinfo) < sizeof(u8))
                return -EINVAL;
 
+       new_state = nla_get_u8(protinfo);
        if (new_state > BR_STATE_BLOCKING)
                return -EINVAL;
 
-       /* Find bridge port */
        dev = __dev_get_by_index(ifm->ifi_index);
        if (!dev)
                return -ENODEV;
@@ -179,10 +165,8 @@ static int br_rtm_setlink(struct sk_buff *skb,  struct nlmsghdr *nlh, void *arg)
        if (p->br->stp_enabled)
                return -EBUSY;
 
-       if (!netif_running(dev))
-               return -ENETDOWN;
-
-       if (!netif_carrier_ok(dev) && new_state != BR_STATE_DISABLED)
+       if (!netif_running(dev) ||
+           (!netif_carrier_ok(dev) && new_state != BR_STATE_DISABLED))
                return -ENETDOWN;
 
        p->state = new_state;