netlink: have length check of rtnl msg before deref

When the legacy array rtm_min still exists, the length check within
these functions is covered by rtm_min[RTM_NEWTFILTER],
rtm_min[RTM_NEWQDISC] and rtm_min[RTM_NEWTCLASS].

But after Thomas Graf removed rtm_min several days ago, these checks
are missing. Other doit functions should be OK.

Signed-off-by: Hong Zhiguo <honkiko@gmail.com>
Acked-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
index 9a04b98..9d71d4d 100644 (file)
--- a/net/sched/cls_api.c
+++ b/net/sched/cls_api.c
@@ -141,7 +141,12 @@ static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n)
 
        if ((n->nlmsg_type != RTM_GETTFILTER) && !capable(CAP_NET_ADMIN))
                return -EPERM;
+
 replay:
+       err = nlmsg_parse(n, sizeof(*t), tca, TCA_MAX, NULL);
+       if (err < 0)
+               return err;
+
        t = nlmsg_data(n);
        protocol = TC_H_MIN(t->tcm_info);
        prio = TC_H_MAJ(t->tcm_info);
@@ -164,10 +169,6 @@ replay:
        if (dev == NULL)
                return -ENODEV;
 
-       err = nlmsg_parse(n, sizeof(*t), tca, TCA_MAX, NULL);
-       if (err < 0)
-               return err;
-
        /* Find qdisc */
        if (!parent) {
                q = dev->qdisc;

diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index 0bbce22..d7468ba 100644 (file)
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -977,7 +977,7 @@ static int tc_get_qdisc(struct sk_buff *skb, struct nlmsghdr *n)
        struct tcmsg *tcm = nlmsg_data(n);
        struct nlattr *tca[TCA_MAX + 1];
        struct net_device *dev;
-       u32 clid = tcm->tcm_parent;
+       u32 clid;
        struct Qdisc *q = NULL;
        struct Qdisc *p = NULL;
        int err;
@@ -985,14 +985,15 @@ static int tc_get_qdisc(struct sk_buff *skb, struct nlmsghdr *n)
        if ((n->nlmsg_type != RTM_GETQDISC) && !capable(CAP_NET_ADMIN))
                return -EPERM;
 
-       dev = __dev_get_by_index(net, tcm->tcm_ifindex);
-       if (!dev)
-               return -ENODEV;
-
        err = nlmsg_parse(n, sizeof(*tcm), tca, TCA_MAX, NULL);
        if (err < 0)
                return err;
 
+       dev = __dev_get_by_index(net, tcm->tcm_ifindex);
+       if (!dev)
+               return -ENODEV;
+
+       clid = tcm->tcm_parent;
        if (clid) {
                if (clid != TC_H_ROOT) {
                        if (TC_H_MAJ(clid) != TC_H_MAJ(TC_H_INGRESS)) {
@@ -1053,6 +1054,10 @@ static int tc_modify_qdisc(struct sk_buff *skb, struct nlmsghdr *n)
 
 replay:
        /* Reinit, just in case something touches this. */
+       err = nlmsg_parse(n, sizeof(*tcm), tca, TCA_MAX, NULL);
+       if (err < 0)
+               return err;
+
        tcm = nlmsg_data(n);
        clid = tcm->tcm_parent;
        q = p = NULL;
@@ -1061,9 +1066,6 @@ replay:
        if (!dev)
                return -ENODEV;
 
-       err = nlmsg_parse(n, sizeof(*tcm), tca, TCA_MAX, NULL);
-       if (err < 0)
-               return err;
 
        if (clid) {
                if (clid != TC_H_ROOT) {
@@ -1382,22 +1384,22 @@ static int tc_ctl_tclass(struct sk_buff *skb, struct nlmsghdr *n)
        const struct Qdisc_class_ops *cops;
        unsigned long cl = 0;
        unsigned long new_cl;
-       u32 portid = tcm->tcm_parent;
-       u32 clid = tcm->tcm_handle;
-       u32 qid = TC_H_MAJ(clid);
+       u32 portid;
+       u32 clid;
+       u32 qid;
        int err;
 
        if ((n->nlmsg_type != RTM_GETTCLASS) && !capable(CAP_NET_ADMIN))
                return -EPERM;
 
-       dev = __dev_get_by_index(net, tcm->tcm_ifindex);
-       if (!dev)
-               return -ENODEV;
-
        err = nlmsg_parse(n, sizeof(*tcm), tca, TCA_MAX, NULL);
        if (err < 0)
                return err;
 
+       dev = __dev_get_by_index(net, tcm->tcm_ifindex);
+       if (!dev)
+               return -ENODEV;
+
        /*
           parent == TC_H_UNSPEC - unspecified parent.
           parent == TC_H_ROOT   - class is root, which has no parent.
@@ -1413,6 +1415,10 @@ static int tc_ctl_tclass(struct sk_buff *skb, struct nlmsghdr *n)
 
        /* Step 1. Determine qdisc handle X:0 */
 
+       portid = tcm->tcm_parent;
+       clid = tcm->tcm_handle;
+       qid = TC_H_MAJ(clid);
+
        if (portid != TC_H_ROOT) {
                u32 qid1 = TC_H_MAJ(portid);