genetlink: introduce and use genl_family_attrbuf()

This helper function allows family implementations to access
their family's attrbuf. This gets rid of the attrbuf usage
in families, and also adds locking validation, since it's not
valid to use the attrbuf with parallel_ops or outside of the
dumpit callback.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/genetlink.h b/include/net/genetlink.h
index 8d4608ce8716360924ae68a24ffb25c0171187fc..ef9defb3f5bc0ac0a7bbf0512392b71d15bea424 100644 (file)
--- a/include/net/genetlink.h
+++ b/include/net/genetlink.h
@@ -73,6 +73,8 @@ struct genl_family {
        struct module           *module;
 };
 
+struct nlattr **genl_family_attrbuf(struct genl_family *family);
+
 /**
  * struct genl_info - receiving information
  * @snd_seq: sending sequence number

diff --git a/net/ieee802154/nl802154.c b/net/ieee802154/nl802154.c
index d90a4ed5b8a037e1dacef4cac0c44b158efabbb8..21aabadccd0ee1b37163f286d7768aaec8f31725 100644 (file)
--- a/net/ieee802154/nl802154.c
+++ b/net/ieee802154/nl802154.c
@@ -263,13 +263,14 @@ nl802154_prepare_wpan_dev_dump(struct sk_buff *skb,
 
        if (!cb->args[0]) {
                err = nlmsg_parse(cb->nlh, GENL_HDRLEN + nl802154_fam.hdrsize,
-                                 nl802154_fam.attrbuf, nl802154_fam.maxattr,
+                                 genl_family_attrbuf(&nl802154_fam),
+                                 nl802154_fam.maxattr,
                                  nl802154_policy);
                if (err)
                        goto out_unlock;
 
                *wpan_dev = __cfg802154_wpan_dev_from_attrs(sock_net(skb->sk),
-                                                           nl802154_fam.attrbuf);
+                                                           genl_family_attrbuf(&nl802154_fam));
                if (IS_ERR(*wpan_dev)) {
                        err = PTR_ERR(*wpan_dev);
                        goto out_unlock;
@@ -575,7 +576,7 @@ static int nl802154_dump_wpan_phy_parse(struct sk_buff *skb,
                                        struct netlink_callback *cb,
                                        struct nl802154_dump_wpan_phy_state *state)
 {
-       struct nlattr **tb = nl802154_fam.attrbuf;
+       struct nlattr **tb = genl_family_attrbuf(&nl802154_fam);
        int ret = nlmsg_parse(cb->nlh, GENL_HDRLEN + nl802154_fam.hdrsize,
                              tb, nl802154_fam.maxattr, nl802154_policy);
 

diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index 23cc12639ba769ac67714f5e5f5f9549a4417c38..01291b7a27bb6401b884367a6453d0167d6d6aaa 100644 (file)
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -1096,6 +1096,25 @@ problem:
 
 subsys_initcall(genl_init);
 
+/**
+ * genl_family_attrbuf - return family's attrbuf
+ * @family: the family
+ *
+ * Return the family's attrbuf, while validating that it's
+ * actually valid to access it.
+ *
+ * You cannot use this function with a family that has parallel_ops
+ * and you can only use it within (pre/post) doit/dumpit callbacks.
+ */
+struct nlattr **genl_family_attrbuf(struct genl_family *family)
+{
+       if (!WARN_ON(family->parallel_ops))
+               lockdep_assert_held(&genl_mutex);
+
+       return family->attrbuf;
+}
+EXPORT_SYMBOL(genl_family_attrbuf);
+
 static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group,
                         gfp_t flags)
 {

diff --git a/net/nfc/netlink.c b/net/nfc/netlink.c
index ea023b35f1c24b3069be02796b24bfad7805352e..79786bf62b88c2036b461a3a4b631d159dad92fd 100644 (file)
--- a/net/nfc/netlink.c
+++ b/net/nfc/netlink.c
@@ -120,21 +120,20 @@ nla_put_failure:
 
 static struct nfc_dev *__get_device_from_cb(struct netlink_callback *cb)
 {
+       struct nlattr **attrbuf = genl_family_attrbuf(&nfc_genl_family);
        struct nfc_dev *dev;
        int rc;
        u32 idx;
 
        rc = nlmsg_parse(cb->nlh, GENL_HDRLEN + nfc_genl_family.hdrsize,
-                        nfc_genl_family.attrbuf,
-                        nfc_genl_family.maxattr,
-                        nfc_genl_policy);
+                        attrbuf, nfc_genl_family.maxattr, nfc_genl_policy);
        if (rc < 0)
                return ERR_PTR(rc);
 
-       if (!nfc_genl_family.attrbuf[NFC_ATTR_DEVICE_INDEX])
+       if (!attrbuf[NFC_ATTR_DEVICE_INDEX])
                return ERR_PTR(-EINVAL);
 
-       idx = nla_get_u32(nfc_genl_family.attrbuf[NFC_ATTR_DEVICE_INDEX]);
+       idx = nla_get_u32(attrbuf[NFC_ATTR_DEVICE_INDEX]);
 
        dev = nfc_get_device(idx);
        if (!dev)

diff --git a/net/tipc/netlink.c b/net/tipc/netlink.c
index 3200059d14b2b60b1e5728bc2f5bd00c59d35f4b..4b94f3cfe3af41225a31157e904780be0d914928 100644 (file)
--- a/net/tipc/netlink.c
+++ b/net/tipc/netlink.c
@@ -262,7 +262,7 @@ int tipc_nlmsg_parse(const struct nlmsghdr *nlh, struct nlattr ***attr)
 {
        u32 maxattr = tipc_genl_family.maxattr;
 
-       *attr = tipc_genl_family.attrbuf;
+       *attr = genl_family_attrbuf(&tipc_genl_family);
        if (!*attr)
                return -EOPNOTSUPP;
 

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index c510810f0b7c14909fc3b83ec31ce6c4ac45dfc2..7d8cb3330c8631f677df0df2e4d29fb8e3263b58 100644 (file)
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -551,13 +551,14 @@ static int nl80211_prepare_wdev_dump(struct sk_buff *skb,
 
        if (!cb->args[0]) {
                err = nlmsg_parse(cb->nlh, GENL_HDRLEN + nl80211_fam.hdrsize,
-                                 nl80211_fam.attrbuf, nl80211_fam.maxattr,
-                                 nl80211_policy);
+                                 genl_family_attrbuf(&nl80211_fam),
+                                 nl80211_fam.maxattr, nl80211_policy);
                if (err)
                        goto out_unlock;
 
-               *wdev = __cfg80211_wdev_from_attrs(sock_net(skb->sk),
-                                                  nl80211_fam.attrbuf);
+               *wdev = __cfg80211_wdev_from_attrs(
+                                       sock_net(skb->sk),
+                                       genl_family_attrbuf(&nl80211_fam));
                if (IS_ERR(*wdev)) {
                        err = PTR_ERR(*wdev);
                        goto out_unlock;
@@ -1881,7 +1882,7 @@ static int nl80211_dump_wiphy_parse(struct sk_buff *skb,
                                    struct netlink_callback *cb,
                                    struct nl80211_dump_wiphy_state *state)
 {
-       struct nlattr **tb = nl80211_fam.attrbuf;
+       struct nlattr **tb = genl_family_attrbuf(&nl80211_fam);
        int ret = nlmsg_parse(cb->nlh, GENL_HDRLEN + nl80211_fam.hdrsize,
                              tb, nl80211_fam.maxattr, nl80211_policy);
        /* ignore parse errors for backward compatibility */
@@ -7643,6 +7644,7 @@ static int nl80211_send_survey(struct sk_buff *msg, u32 portid, u32 seq,
 
 static int nl80211_dump_survey(struct sk_buff *skb, struct netlink_callback *cb)
 {
+       struct nlattr **attrbuf = genl_family_attrbuf(&nl80211_fam);
        struct survey_info survey;
        struct cfg80211_registered_device *rdev;
        struct wireless_dev *wdev;
@@ -7655,7 +7657,7 @@ static int nl80211_dump_survey(struct sk_buff *skb, struct netlink_callback *cb)
                return res;
 
        /* prepare_wdev_dump parsed the attributes */
-       radio_stats = nl80211_fam.attrbuf[NL80211_ATTR_SURVEY_RADIO_STATS];
+       radio_stats = attrbuf[NL80211_ATTR_SURVEY_RADIO_STATS];
 
        if (!wdev->netdev) {
                res = -EINVAL;
@@ -8478,14 +8480,14 @@ static int nl80211_testmode_dump(struct sk_buff *skb,
                 */
                phy_idx = cb->args[0] - 1;
        } else {
+               struct nlattr **attrbuf = genl_family_attrbuf(&nl80211_fam);
+
                err = nlmsg_parse(cb->nlh, GENL_HDRLEN + nl80211_fam.hdrsize,
-                                 nl80211_fam.attrbuf, nl80211_fam.maxattr,
-                                 nl80211_policy);
+                                 attrbuf, nl80211_fam.maxattr, nl80211_policy);
                if (err)
                        goto out_err;
 
-               rdev = __cfg80211_rdev_from_attrs(sock_net(skb->sk),
-                                                 nl80211_fam.attrbuf);
+               rdev = __cfg80211_rdev_from_attrs(sock_net(skb->sk), attrbuf);
                if (IS_ERR(rdev)) {
                        err = PTR_ERR(rdev);
                        goto out_err;
@@ -8493,9 +8495,8 @@ static int nl80211_testmode_dump(struct sk_buff *skb,
                phy_idx = rdev->wiphy_idx;
                rdev = NULL;
 
-               if (nl80211_fam.attrbuf[NL80211_ATTR_TESTDATA])
-                       cb->args[1] =
-                               (long)nl80211_fam.attrbuf[NL80211_ATTR_TESTDATA];
+               if (attrbuf[NL80211_ATTR_TESTDATA])
+                       cb->args[1] = (long)attrbuf[NL80211_ATTR_TESTDATA];
        }
 
        if (cb->args[1]) {
@@ -11277,6 +11278,7 @@ static int nl80211_prepare_vendor_dump(struct sk_buff *skb,
                                       struct cfg80211_registered_device **rdev,
                                       struct wireless_dev **wdev)
 {
+       struct nlattr **attrbuf = genl_family_attrbuf(&nl80211_fam);
        u32 vid, subcmd;
        unsigned int i;
        int vcmd_idx = -1;
@@ -11312,31 +11314,28 @@ static int nl80211_prepare_vendor_dump(struct sk_buff *skb,
        }
 
        err = nlmsg_parse(cb->nlh, GENL_HDRLEN + nl80211_fam.hdrsize,
-                         nl80211_fam.attrbuf, nl80211_fam.maxattr,
-                         nl80211_policy);
+                         attrbuf, nl80211_fam.maxattr, nl80211_policy);
        if (err)
                goto out_unlock;
 
-       if (!nl80211_fam.attrbuf[NL80211_ATTR_VENDOR_ID] ||
-           !nl80211_fam.attrbuf[NL80211_ATTR_VENDOR_SUBCMD]) {
+       if (!attrbuf[NL80211_ATTR_VENDOR_ID] ||
+           !attrbuf[NL80211_ATTR_VENDOR_SUBCMD]) {
                err = -EINVAL;
                goto out_unlock;
        }
 
-       *wdev = __cfg80211_wdev_from_attrs(sock_net(skb->sk),
-                                          nl80211_fam.attrbuf);
+       *wdev = __cfg80211_wdev_from_attrs(sock_net(skb->sk), attrbuf);
        if (IS_ERR(*wdev))
                *wdev = NULL;
 
-       *rdev = __cfg80211_rdev_from_attrs(sock_net(skb->sk),
-                                          nl80211_fam.attrbuf);
+       *rdev = __cfg80211_rdev_from_attrs(sock_net(skb->sk), attrbuf);
        if (IS_ERR(*rdev)) {
                err = PTR_ERR(*rdev);
                goto out_unlock;
        }
 
-       vid = nla_get_u32(nl80211_fam.attrbuf[NL80211_ATTR_VENDOR_ID]);
-       subcmd = nla_get_u32(nl80211_fam.attrbuf[NL80211_ATTR_VENDOR_SUBCMD]);
+       vid = nla_get_u32(attrbuf[NL80211_ATTR_VENDOR_ID]);
+       subcmd = nla_get_u32(attrbuf[NL80211_ATTR_VENDOR_SUBCMD]);
 
        for (i = 0; i < (*rdev)->wiphy.n_vendor_commands; i++) {
                const struct wiphy_vendor_command *vcmd;
@@ -11360,9 +11359,9 @@ static int nl80211_prepare_vendor_dump(struct sk_buff *skb,
                goto out_unlock;
        }
 
-       if (nl80211_fam.attrbuf[NL80211_ATTR_VENDOR_DATA]) {
-               data = nla_data(nl80211_fam.attrbuf[NL80211_ATTR_VENDOR_DATA]);
-               data_len = nla_len(nl80211_fam.attrbuf[NL80211_ATTR_VENDOR_DATA]);
+       if (attrbuf[NL80211_ATTR_VENDOR_DATA]) {
+               data = nla_data(attrbuf[NL80211_ATTR_VENDOR_DATA]);
+               data_len = nla_len(attrbuf[NL80211_ATTR_VENDOR_DATA]);
        }
 
        /* 0 is the first index - add 1 to parse only once */