[DECNET] address: Convert to new netlink interface

Extends the netlink interface to support the __le16 type and
converts address addition, deletion and, dumping to use the
new netlink interface.

Fixes multiple occasions of possible illegal memory references
due to not validated netlink attributes.

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

diff --git a/include/net/netlink.h b/include/net/netlink.h
index 3002133..fd75fd6 100644 (file)
--- a/include/net/netlink.h
+++ b/include/net/netlink.h
@@ -829,6 +829,9 @@ static inline int nla_put_msecs(struct sk_buff *skb, int attrtype,
 #define NLA_PUT_U16(skb, attrtype, value) \
        NLA_PUT_TYPE(skb, u16, attrtype, value)
 
+#define NLA_PUT_LE16(skb, attrtype, value) \
+       NLA_PUT_TYPE(skb, __le16, attrtype, value)
+
 #define NLA_PUT_U32(skb, attrtype, value) \
        NLA_PUT_TYPE(skb, u32, attrtype, value)
 
@@ -874,6 +877,15 @@ static inline u16 nla_get_u16(struct nlattr *nla)
        return *(u16 *) nla_data(nla);
 }
 
+/**
+ * nla_get_le16 - return payload of __le16 attribute
+ * @nla: __le16 netlink attribute
+ */
+static inline __le16 nla_get_le16(struct nlattr *nla)
+{
+       return *(__le16 *) nla_data(nla);
+}
+
 /**
  * nla_get_u8 - return payload of u8 attribute
  * @nla: u8 netlink attribute

diff --git a/net/decnet/dn_dev.c b/net/decnet/dn_dev.c
index 309b2c7..0b9d4c9 100644 (file)
--- a/net/decnet/dn_dev.c
+++ b/net/decnet/dn_dev.c
@@ -645,41 +645,62 @@ static struct dn_dev *dn_dev_by_index(int ifindex)
        return dn_dev;
 }
 
-static int dn_dev_rtm_deladdr(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
+static struct nla_policy dn_ifa_policy[IFA_MAX+1] __read_mostly = {
+       [IFA_ADDRESS]           = { .type = NLA_U16 },
+       [IFA_LOCAL]             = { .type = NLA_U16 },
+       [IFA_LABEL]             = { .type = NLA_STRING,
+                                   .len = IFNAMSIZ - 1 },
+};
+
+static int dn_nl_deladdr(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
 {
-       struct rtattr **rta = arg;
+       struct nlattr *tb[IFA_MAX+1];
        struct dn_dev *dn_db;
-       struct ifaddrmsg *ifm = NLMSG_DATA(nlh);
+       struct ifaddrmsg *ifm;
        struct dn_ifaddr *ifa, **ifap;
+       int err = -EADDRNOTAVAIL;
+
+       err = nlmsg_parse(nlh, sizeof(*ifm), tb, IFA_MAX, dn_ifa_policy);
+       if (err < 0)
+               goto errout;
 
+       ifm = nlmsg_data(nlh);
        if ((dn_db = dn_dev_by_index(ifm->ifa_index)) == NULL)
-               return -EADDRNOTAVAIL;
+               goto errout;
+
+       for (ifap = &dn_db->ifa_list; (ifa = *ifap); ifap = &ifa->ifa_next) {
+               if (tb[IFA_LOCAL] &&
+                   nla_memcmp(tb[IFA_LOCAL], &ifa->ifa_local, 2))
+                       continue;
 
-       for(ifap = &dn_db->ifa_list; (ifa=*ifap) != NULL; ifap = &ifa->ifa_next) {
-               void *tmp = rta[IFA_LOCAL-1];
-               if ((tmp && memcmp(RTA_DATA(tmp), &ifa->ifa_local, 2)) ||
-                   (rta[IFA_LABEL-1] && rtattr_strcmp(rta[IFA_LABEL-1], ifa->ifa_label)))
+               if (tb[IFA_LABEL] && nla_strcmp(tb[IFA_LABEL], ifa->ifa_label))
                        continue;
 
                dn_dev_del_ifa(dn_db, ifap, 1);
                return 0;
        }
 
-       return -EADDRNOTAVAIL;
+errout:
+       return err;
 }
 
-static int dn_dev_rtm_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
+static int dn_nl_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
 {
-       struct rtattr **rta = arg;
+       struct nlattr *tb[IFA_MAX+1];
        struct net_device *dev;
        struct dn_dev *dn_db;
-       struct ifaddrmsg *ifm = NLMSG_DATA(nlh);
+       struct ifaddrmsg *ifm;
        struct dn_ifaddr *ifa;
-       int rv;
+       int err;
+
+       err = nlmsg_parse(nlh, sizeof(*ifm), tb, IFA_MAX, dn_ifa_policy);
+       if (err < 0)
+               return err;
 
-       if (rta[IFA_LOCAL-1] == NULL)
+       if (tb[IFA_LOCAL] == NULL)
                return -EINVAL;
 
+       ifm = nlmsg_data(nlh);
        if ((dev = __dev_get_by_index(ifm->ifa_index)) == NULL)
                return -ENODEV;
 
@@ -693,22 +714,25 @@ static int dn_dev_rtm_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh, void *a
        if ((ifa = dn_dev_alloc_ifa()) == NULL)
                return -ENOBUFS;
 
-       if (!rta[IFA_ADDRESS - 1])
-               rta[IFA_ADDRESS - 1] = rta[IFA_LOCAL - 1];
-       memcpy(&ifa->ifa_local, RTA_DATA(rta[IFA_LOCAL-1]), 2);
-       memcpy(&ifa->ifa_address, RTA_DATA(rta[IFA_ADDRESS-1]), 2);
+       if (tb[IFA_ADDRESS] == NULL)
+               tb[IFA_ADDRESS] = tb[IFA_LOCAL];
+
+       ifa->ifa_local = nla_get_le16(tb[IFA_LOCAL]);
+       ifa->ifa_address = nla_get_le16(tb[IFA_ADDRESS]);
        ifa->ifa_flags = ifm->ifa_flags;
        ifa->ifa_scope = ifm->ifa_scope;
        ifa->ifa_dev = dn_db;
-       if (rta[IFA_LABEL-1])
-               rtattr_strlcpy(ifa->ifa_label, rta[IFA_LABEL-1], IFNAMSIZ);
+
+       if (tb[IFA_LABEL])
+               nla_strlcpy(ifa->ifa_label, tb[IFA_LABEL], IFNAMSIZ);
        else
                memcpy(ifa->ifa_label, dev->name, IFNAMSIZ);
 
-       rv = dn_dev_insert_ifa(dn_db, ifa);
-       if (rv)
+       err = dn_dev_insert_ifa(dn_db, ifa);
+       if (err)
                dn_dev_free_ifa(ifa);
-       return rv;
+
+       return err;
 }
 
 static inline size_t dn_ifaddr_nlmsg_size(void)
@@ -719,34 +743,34 @@ static inline size_t dn_ifaddr_nlmsg_size(void)
               + nla_total_size(2); /* IFA_LOCAL */
 }
 
-static int dn_dev_fill_ifaddr(struct sk_buff *skb, struct dn_ifaddr *ifa,
-                               u32 pid, u32 seq, int event, unsigned int flags)
+static int dn_nl_fill_ifaddr(struct sk_buff *skb, struct dn_ifaddr *ifa,
+                            u32 pid, u32 seq, int event, unsigned int flags)
 {
        struct ifaddrmsg *ifm;
        struct nlmsghdr *nlh;
-       unsigned char *b = skb->tail;
 
-       nlh = NLMSG_NEW(skb, pid, seq, event, sizeof(*ifm), flags);
-       ifm = NLMSG_DATA(nlh);
+       nlh = nlmsg_put(skb, pid, seq, event, sizeof(*ifm), flags);
+       if (nlh == NULL)
+               return -ENOBUFS;
 
+       ifm = nlmsg_data(nlh);
        ifm->ifa_family = AF_DECnet;
        ifm->ifa_prefixlen = 16;
        ifm->ifa_flags = ifa->ifa_flags | IFA_F_PERMANENT;
        ifm->ifa_scope = ifa->ifa_scope;
        ifm->ifa_index = ifa->ifa_dev->dev->ifindex;
+
        if (ifa->ifa_address)
-               RTA_PUT(skb, IFA_ADDRESS, 2, &ifa->ifa_address);
+               NLA_PUT_LE16(skb, IFA_ADDRESS, ifa->ifa_address);
        if (ifa->ifa_local)
-               RTA_PUT(skb, IFA_LOCAL, 2, &ifa->ifa_local);
+               NLA_PUT_LE16(skb, IFA_LOCAL, ifa->ifa_local);
        if (ifa->ifa_label[0])
-               RTA_PUT(skb, IFA_LABEL, IFNAMSIZ, &ifa->ifa_label);
-       nlh->nlmsg_len = skb->tail - b;
-       return skb->len;
+               NLA_PUT_STRING(skb, IFA_LABEL, ifa->ifa_label);
 
-nlmsg_failure:
-rtattr_failure:
-        skb_trim(skb, b - skb->data);
-        return -1;
+       return nlmsg_end(skb, nlh);
+
+nla_put_failure:
+       return nlmsg_cancel(skb, nlh);
 }
 
 static void dn_ifaddr_notify(int event, struct dn_ifaddr *ifa)
@@ -758,7 +782,7 @@ static void dn_ifaddr_notify(int event, struct dn_ifaddr *ifa)
        if (skb == NULL)
                goto errout;
 
-       err = dn_dev_fill_ifaddr(skb, ifa, 0, 0, event, 0);
+       err = dn_nl_fill_ifaddr(skb, ifa, 0, 0, event, 0);
        /* failure implies BUG in dn_ifaddr_nlmsg_size() */
        BUG_ON(err < 0);
 
@@ -768,39 +792,43 @@ errout:
                rtnl_set_sk_err(RTNLGRP_DECnet_IFADDR, err);
 }
 
-static int dn_dev_dump_ifaddr(struct sk_buff *skb, struct netlink_callback *cb)
+static int dn_nl_dump_ifaddr(struct sk_buff *skb, struct netlink_callback *cb)
 {
-       int idx, dn_idx;
-       int s_idx, s_dn_idx;
+       int idx, dn_idx = 0, skip_ndevs, skip_naddr;
        struct net_device *dev;
        struct dn_dev *dn_db;
        struct dn_ifaddr *ifa;
 
-       s_idx = cb->args[0];
-       s_dn_idx = dn_idx = cb->args[1];
+       skip_ndevs = cb->args[0];
+       skip_naddr = cb->args[1];
+
        read_lock(&dev_base_lock);
-       for(dev = dev_base, idx = 0; dev; dev = dev->next, idx++) {
-               if (idx < s_idx)
+       for (dev = dev_base, idx = 0; dev; dev = dev->next, idx++) {
+               if (idx < skip_ndevs)
                        continue;
-               if (idx > s_idx)
-                       s_dn_idx = 0;
+               else if (idx > skip_ndevs) {
+                       /* Only skip over addresses for first dev dumped
+                        * in this iteration (idx == skip_ndevs) */
+                       skip_naddr = 0;
+               }
+
                if ((dn_db = dev->dn_ptr) == NULL)
                        continue;
 
-               for(ifa = dn_db->ifa_list, dn_idx = 0; ifa; ifa = ifa->ifa_next, dn_idx++) {
-                       if (dn_idx < s_dn_idx)
+               for (ifa = dn_db->ifa_list, dn_idx = 0; ifa;
+                    ifa = ifa->ifa_next, dn_idx++) {
+                       if (dn_idx < skip_naddr)
                                continue;
 
-                       if (dn_dev_fill_ifaddr(skb, ifa,
-                                              NETLINK_CB(cb->skb).pid,
-                                              cb->nlh->nlmsg_seq,
-                                              RTM_NEWADDR,
-                                              NLM_F_MULTI) <= 0)
+                       if (dn_nl_fill_ifaddr(skb, ifa, NETLINK_CB(cb->skb).pid,
+                                             cb->nlh->nlmsg_seq, RTM_NEWADDR,
+                                             NLM_F_MULTI) < 0)
                                goto done;
                }
        }
 done:
        read_unlock(&dev_base_lock);
+
        cb->args[0] = idx;
        cb->args[1] = dn_idx;
 
@@ -1417,9 +1445,9 @@ static struct file_operations dn_dev_seq_fops = {
 
 static struct rtnetlink_link dnet_rtnetlink_table[RTM_NR_MSGTYPES] =
 {
-       [RTM_NEWADDR  - RTM_BASE] = { .doit     = dn_dev_rtm_newaddr,   },
-       [RTM_DELADDR  - RTM_BASE] = { .doit     = dn_dev_rtm_deladdr,   },
-       [RTM_GETADDR  - RTM_BASE] = { .dumpit   = dn_dev_dump_ifaddr,   },
+       [RTM_NEWADDR  - RTM_BASE] = { .doit     = dn_nl_newaddr,        },
+       [RTM_DELADDR  - RTM_BASE] = { .doit     = dn_nl_deladdr,        },
+       [RTM_GETADDR  - RTM_BASE] = { .dumpit   = dn_nl_dump_ifaddr,    },
 #ifdef CONFIG_DECNET_ROUTER
        [RTM_NEWROUTE - RTM_BASE] = { .doit     = dn_fib_rtm_newroute,  },
        [RTM_DELROUTE - RTM_BASE] = { .doit     = dn_fib_rtm_delroute,  },