From 3b85875a252dbbd95c2e04d73639719a0a79634e Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Thu, 12 Mar 2009 09:55:09 +0100 Subject: [PATCH] nl80211: rework locking When I added scanning to cfg80211, we got a lock dependency like this: rtnl --> cfg80211_mtx nl80211, on the other hand, has the reverse lock dependency: cfg80211_mtx --> rtnl which clearly is a bad idea. This patch reworks nl80211 to take these two locks in the other order to fix the possible, and easily triggerable, deadlock. Signed-off-by: Johannes Berg Signed-off-by: John W. Linville --- net/wireless/nl80211.c | 271 +++++++++++++++++++++++++---------------- 1 file changed, 166 insertions(+), 105 deletions(-) diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c index 58ee1b1aff8..a3ecf8d7389 100644 --- a/net/wireless/nl80211.c +++ b/net/wireless/nl80211.c @@ -602,9 +602,12 @@ static int nl80211_set_interface(struct sk_buff *skb, struct genl_info *info) memset(¶ms, 0, sizeof(params)); + rtnl_lock(); + err = get_drv_dev_by_info_ifindex(info->attrs, &drv, &dev); if (err) - return err; + goto unlock_rtnl; + ifindex = dev->ifindex; type = dev->ieee80211_ptr->iftype; dev_put(dev); @@ -641,17 +644,17 @@ static int nl80211_set_interface(struct sk_buff *skb, struct genl_info *info) if (!err) flags = &_flags; } - rtnl_lock(); + err = drv->ops->change_virtual_intf(&drv->wiphy, ifindex, type, flags, ¶ms); dev = __dev_get_by_index(&init_net, ifindex); WARN_ON(!dev || (!err && dev->ieee80211_ptr->iftype != type)); - rtnl_unlock(); - unlock: cfg80211_put_dev(drv); + unlock_rtnl: + rtnl_unlock(); return err; } @@ -674,9 +677,13 @@ static int nl80211_new_interface(struct sk_buff *skb, struct genl_info *info) return -EINVAL; } + rtnl_lock(); + drv = cfg80211_get_dev_from_info(info); - if (IS_ERR(drv)) - return PTR_ERR(drv); + if (IS_ERR(drv)) { + err = PTR_ERR(drv); + goto unlock_rtnl; + } if (!drv->ops->add_virtual_intf || !(drv->wiphy.interface_modes & (1 << type))) { @@ -690,18 +697,17 @@ static int nl80211_new_interface(struct sk_buff *skb, struct genl_info *info) params.mesh_id_len = nla_len(info->attrs[NL80211_ATTR_MESH_ID]); } - rtnl_lock(); err = parse_monitor_flags(type == NL80211_IFTYPE_MONITOR ? info->attrs[NL80211_ATTR_MNTR_FLAGS] : NULL, &flags); err = drv->ops->add_virtual_intf(&drv->wiphy, nla_data(info->attrs[NL80211_ATTR_IFNAME]), type, err ? NULL : &flags, ¶ms); - rtnl_unlock(); - unlock: cfg80211_put_dev(drv); + unlock_rtnl: + rtnl_unlock(); return err; } @@ -711,9 +717,11 @@ static int nl80211_del_interface(struct sk_buff *skb, struct genl_info *info) int ifindex, err; struct net_device *dev; + rtnl_lock(); + err = get_drv_dev_by_info_ifindex(info->attrs, &drv, &dev); if (err) - return err; + goto unlock_rtnl; ifindex = dev->ifindex; dev_put(dev); @@ -722,12 +730,12 @@ static int nl80211_del_interface(struct sk_buff *skb, struct genl_info *info) goto out; } - rtnl_lock(); err = drv->ops->del_virtual_intf(&drv->wiphy, ifindex); - rtnl_unlock(); out: cfg80211_put_dev(drv); + unlock_rtnl: + rtnl_unlock(); return err; } @@ -779,9 +787,11 @@ static int nl80211_get_key(struct sk_buff *skb, struct genl_info *info) if (info->attrs[NL80211_ATTR_MAC]) mac_addr = nla_data(info->attrs[NL80211_ATTR_MAC]); + rtnl_lock(); + err = get_drv_dev_by_info_ifindex(info->attrs, &drv, &dev); if (err) - return err; + goto unlock_rtnl; if (!drv->ops->get_key) { err = -EOPNOTSUPP; @@ -809,10 +819,8 @@ static int nl80211_get_key(struct sk_buff *skb, struct genl_info *info) if (mac_addr) NLA_PUT(msg, NL80211_ATTR_MAC, ETH_ALEN, mac_addr); - rtnl_lock(); err = drv->ops->get_key(&drv->wiphy, dev, key_idx, mac_addr, &cookie, get_key_callback); - rtnl_unlock(); if (err) goto out; @@ -830,6 +838,9 @@ static int nl80211_get_key(struct sk_buff *skb, struct genl_info *info) out: cfg80211_put_dev(drv); dev_put(dev); + unlock_rtnl: + rtnl_unlock(); + return err; } @@ -858,9 +869,11 @@ static int nl80211_set_key(struct sk_buff *skb, struct genl_info *info) !info->attrs[NL80211_ATTR_KEY_DEFAULT_MGMT]) return -EINVAL; + rtnl_lock(); + err = get_drv_dev_by_info_ifindex(info->attrs, &drv, &dev); if (err) - return err; + goto unlock_rtnl; if (info->attrs[NL80211_ATTR_KEY_DEFAULT]) func = drv->ops->set_default_key; @@ -872,13 +885,15 @@ static int nl80211_set_key(struct sk_buff *skb, struct genl_info *info) goto out; } - rtnl_lock(); err = func(&drv->wiphy, dev, key_idx); - rtnl_unlock(); out: cfg80211_put_dev(drv); dev_put(dev); + + unlock_rtnl: + rtnl_unlock(); + return err; } @@ -948,22 +963,25 @@ static int nl80211_new_key(struct sk_buff *skb, struct genl_info *info) return -EINVAL; } + rtnl_lock(); + err = get_drv_dev_by_info_ifindex(info->attrs, &drv, &dev); if (err) - return err; + goto unlock_rtnl; if (!drv->ops->add_key) { err = -EOPNOTSUPP; goto out; } - rtnl_lock(); err = drv->ops->add_key(&drv->wiphy, dev, key_idx, mac_addr, ¶ms); - rtnl_unlock(); out: cfg80211_put_dev(drv); dev_put(dev); + unlock_rtnl: + rtnl_unlock(); + return err; } @@ -984,22 +1002,26 @@ static int nl80211_del_key(struct sk_buff *skb, struct genl_info *info) if (info->attrs[NL80211_ATTR_MAC]) mac_addr = nla_data(info->attrs[NL80211_ATTR_MAC]); + rtnl_lock(); + err = get_drv_dev_by_info_ifindex(info->attrs, &drv, &dev); if (err) - return err; + goto unlock_rtnl; if (!drv->ops->del_key) { err = -EOPNOTSUPP; goto out; } - rtnl_lock(); err = drv->ops->del_key(&drv->wiphy, dev, key_idx, mac_addr); - rtnl_unlock(); out: cfg80211_put_dev(drv); dev_put(dev); + + unlock_rtnl: + rtnl_unlock(); + return err; } @@ -1013,9 +1035,11 @@ static int nl80211_addset_beacon(struct sk_buff *skb, struct genl_info *info) struct beacon_parameters params; int haveinfo = 0; + rtnl_lock(); + err = get_drv_dev_by_info_ifindex(info->attrs, &drv, &dev); if (err) - return err; + goto unlock_rtnl; switch (info->genlhdr->cmd) { case NL80211_CMD_NEW_BEACON: @@ -1076,13 +1100,14 @@ static int nl80211_addset_beacon(struct sk_buff *skb, struct genl_info *info) goto out; } - rtnl_lock(); err = call(&drv->wiphy, dev, ¶ms); - rtnl_unlock(); out: cfg80211_put_dev(drv); dev_put(dev); + unlock_rtnl: + rtnl_unlock(); + return err; } @@ -1092,22 +1117,25 @@ static int nl80211_del_beacon(struct sk_buff *skb, struct genl_info *info) int err; struct net_device *dev; + rtnl_lock(); + err = get_drv_dev_by_info_ifindex(info->attrs, &drv, &dev); if (err) - return err; + goto unlock_rtnl; if (!drv->ops->del_beacon) { err = -EOPNOTSUPP; goto out; } - rtnl_lock(); err = drv->ops->del_beacon(&drv->wiphy, dev); - rtnl_unlock(); out: cfg80211_put_dev(drv); dev_put(dev); + unlock_rtnl: + rtnl_unlock(); + return err; } @@ -1273,14 +1301,18 @@ static int nl80211_dump_station(struct sk_buff *skb, return -EINVAL; } - netdev = dev_get_by_index(&init_net, ifidx); - if (!netdev) - return -ENODEV; + rtnl_lock(); + + netdev = __dev_get_by_index(&init_net, ifidx); + if (!netdev) { + err = -ENODEV; + goto out_rtnl; + } dev = cfg80211_get_dev_from_ifindex(ifidx); if (IS_ERR(dev)) { err = PTR_ERR(dev); - goto out_put_netdev; + goto out_rtnl; } if (!dev->ops->dump_station) { @@ -1288,15 +1320,13 @@ static int nl80211_dump_station(struct sk_buff *skb, goto out_err; } - rtnl_lock(); - while (1) { err = dev->ops->dump_station(&dev->wiphy, netdev, sta_idx, mac_addr, &sinfo); if (err == -ENOENT) break; if (err) - goto out_err_rtnl; + goto out_err; if (nl80211_send_station(skb, NETLINK_CB(cb->skb).pid, @@ -1312,12 +1342,10 @@ static int nl80211_dump_station(struct sk_buff *skb, out: cb->args[1] = sta_idx; err = skb->len; - out_err_rtnl: - rtnl_unlock(); out_err: cfg80211_put_dev(dev); - out_put_netdev: - dev_put(netdev); + out_rtnl: + rtnl_unlock(); return err; } @@ -1338,19 +1366,18 @@ static int nl80211_get_station(struct sk_buff *skb, struct genl_info *info) mac_addr = nla_data(info->attrs[NL80211_ATTR_MAC]); + rtnl_lock(); + err = get_drv_dev_by_info_ifindex(info->attrs, &drv, &dev); if (err) - return err; + goto out_rtnl; if (!drv->ops->get_station) { err = -EOPNOTSUPP; goto out; } - rtnl_lock(); err = drv->ops->get_station(&drv->wiphy, dev, mac_addr, &sinfo); - rtnl_unlock(); - if (err) goto out; @@ -1367,10 +1394,12 @@ static int nl80211_get_station(struct sk_buff *skb, struct genl_info *info) out_free: nlmsg_free(msg); - out: cfg80211_put_dev(drv); dev_put(dev); + out_rtnl: + rtnl_unlock(); + return err; } @@ -1438,9 +1467,11 @@ static int nl80211_set_station(struct sk_buff *skb, struct genl_info *info) params.plink_action = nla_get_u8(info->attrs[NL80211_ATTR_STA_PLINK_ACTION]); + rtnl_lock(); + err = get_drv_dev_by_info_ifindex(info->attrs, &drv, &dev); if (err) - return err; + goto out_rtnl; err = get_vlan(info->attrs[NL80211_ATTR_STA_VLAN], drv, ¶ms.vlan); if (err) @@ -1451,15 +1482,16 @@ static int nl80211_set_station(struct sk_buff *skb, struct genl_info *info) goto out; } - rtnl_lock(); err = drv->ops->change_station(&drv->wiphy, dev, mac_addr, ¶ms); - rtnl_unlock(); out: if (params.vlan) dev_put(params.vlan); cfg80211_put_dev(drv); dev_put(dev); + out_rtnl: + rtnl_unlock(); + return err; } @@ -1501,9 +1533,11 @@ static int nl80211_new_station(struct sk_buff *skb, struct genl_info *info) ¶ms.station_flags)) return -EINVAL; + rtnl_lock(); + err = get_drv_dev_by_info_ifindex(info->attrs, &drv, &dev); if (err) - return err; + goto out_rtnl; err = get_vlan(info->attrs[NL80211_ATTR_STA_VLAN], drv, ¶ms.vlan); if (err) @@ -1514,15 +1548,16 @@ static int nl80211_new_station(struct sk_buff *skb, struct genl_info *info) goto out; } - rtnl_lock(); err = drv->ops->add_station(&drv->wiphy, dev, mac_addr, ¶ms); - rtnl_unlock(); out: if (params.vlan) dev_put(params.vlan); cfg80211_put_dev(drv); dev_put(dev); + out_rtnl: + rtnl_unlock(); + return err; } @@ -1536,22 +1571,25 @@ static int nl80211_del_station(struct sk_buff *skb, struct genl_info *info) if (info->attrs[NL80211_ATTR_MAC]) mac_addr = nla_data(info->attrs[NL80211_ATTR_MAC]); + rtnl_lock(); + err = get_drv_dev_by_info_ifindex(info->attrs, &drv, &dev); if (err) - return err; + goto out_rtnl; if (!drv->ops->del_station) { err = -EOPNOTSUPP; goto out; } - rtnl_lock(); err = drv->ops->del_station(&drv->wiphy, dev, mac_addr); - rtnl_unlock(); out: cfg80211_put_dev(drv); dev_put(dev); + out_rtnl: + rtnl_unlock(); + return err; } @@ -1632,14 +1670,18 @@ static int nl80211_dump_mpath(struct sk_buff *skb, return -EINVAL; } - netdev = dev_get_by_index(&init_net, ifidx); - if (!netdev) - return -ENODEV; + rtnl_lock(); + + netdev = __dev_get_by_index(&init_net, ifidx); + if (!netdev) { + err = -ENODEV; + goto out_rtnl; + } dev = cfg80211_get_dev_from_ifindex(ifidx); if (IS_ERR(dev)) { err = PTR_ERR(dev); - goto out_put_netdev; + goto out_rtnl; } if (!dev->ops->dump_mpath) { @@ -1647,15 +1689,13 @@ static int nl80211_dump_mpath(struct sk_buff *skb, goto out_err; } - rtnl_lock(); - while (1) { err = dev->ops->dump_mpath(&dev->wiphy, netdev, path_idx, dst, next_hop, &pinfo); if (err == -ENOENT) break; if (err) - goto out_err_rtnl; + goto out_err; if (nl80211_send_mpath(skb, NETLINK_CB(cb->skb).pid, cb->nlh->nlmsg_seq, NLM_F_MULTI, @@ -1670,12 +1710,10 @@ static int nl80211_dump_mpath(struct sk_buff *skb, out: cb->args[1] = path_idx; err = skb->len; - out_err_rtnl: - rtnl_unlock(); out_err: cfg80211_put_dev(dev); - out_put_netdev: - dev_put(netdev); + out_rtnl: + rtnl_unlock(); return err; } @@ -1697,19 +1735,18 @@ static int nl80211_get_mpath(struct sk_buff *skb, struct genl_info *info) dst = nla_data(info->attrs[NL80211_ATTR_MAC]); + rtnl_lock(); + err = get_drv_dev_by_info_ifindex(info->attrs, &drv, &dev); if (err) - return err; + goto out_rtnl; if (!drv->ops->get_mpath) { err = -EOPNOTSUPP; goto out; } - rtnl_lock(); err = drv->ops->get_mpath(&drv->wiphy, dev, dst, next_hop, &pinfo); - rtnl_unlock(); - if (err) goto out; @@ -1726,10 +1763,12 @@ static int nl80211_get_mpath(struct sk_buff *skb, struct genl_info *info) out_free: nlmsg_free(msg); - out: cfg80211_put_dev(drv); dev_put(dev); + out_rtnl: + rtnl_unlock(); + return err; } @@ -1750,22 +1789,25 @@ static int nl80211_set_mpath(struct sk_buff *skb, struct genl_info *info) dst = nla_data(info->attrs[NL80211_ATTR_MAC]); next_hop = nla_data(info->attrs[NL80211_ATTR_MPATH_NEXT_HOP]); + rtnl_lock(); + err = get_drv_dev_by_info_ifindex(info->attrs, &drv, &dev); if (err) - return err; + goto out_rtnl; if (!drv->ops->change_mpath) { err = -EOPNOTSUPP; goto out; } - rtnl_lock(); err = drv->ops->change_mpath(&drv->wiphy, dev, dst, next_hop); - rtnl_unlock(); out: cfg80211_put_dev(drv); dev_put(dev); + out_rtnl: + rtnl_unlock(); + return err; } static int nl80211_new_mpath(struct sk_buff *skb, struct genl_info *info) @@ -1785,22 +1827,25 @@ static int nl80211_new_mpath(struct sk_buff *skb, struct genl_info *info) dst = nla_data(info->attrs[NL80211_ATTR_MAC]); next_hop = nla_data(info->attrs[NL80211_ATTR_MPATH_NEXT_HOP]); + rtnl_lock(); + err = get_drv_dev_by_info_ifindex(info->attrs, &drv, &dev); if (err) - return err; + goto out_rtnl; if (!drv->ops->add_mpath) { err = -EOPNOTSUPP; goto out; } - rtnl_lock(); err = drv->ops->add_mpath(&drv->wiphy, dev, dst, next_hop); - rtnl_unlock(); out: cfg80211_put_dev(drv); dev_put(dev); + out_rtnl: + rtnl_unlock(); + return err; } @@ -1814,22 +1859,25 @@ static int nl80211_del_mpath(struct sk_buff *skb, struct genl_info *info) if (info->attrs[NL80211_ATTR_MAC]) dst = nla_data(info->attrs[NL80211_ATTR_MAC]); + rtnl_lock(); + err = get_drv_dev_by_info_ifindex(info->attrs, &drv, &dev); if (err) - return err; + goto out_rtnl; if (!drv->ops->del_mpath) { err = -EOPNOTSUPP; goto out; } - rtnl_lock(); err = drv->ops->del_mpath(&drv->wiphy, dev, dst); - rtnl_unlock(); out: cfg80211_put_dev(drv); dev_put(dev); + out_rtnl: + rtnl_unlock(); + return err; } @@ -1862,22 +1910,25 @@ static int nl80211_set_bss(struct sk_buff *skb, struct genl_info *info) nla_len(info->attrs[NL80211_ATTR_BSS_BASIC_RATES]); } + rtnl_lock(); + err = get_drv_dev_by_info_ifindex(info->attrs, &drv, &dev); if (err) - return err; + goto out_rtnl; if (!drv->ops->change_bss) { err = -EOPNOTSUPP; goto out; } - rtnl_lock(); err = drv->ops->change_bss(&drv->wiphy, dev, ¶ms); - rtnl_unlock(); out: cfg80211_put_dev(drv); dev_put(dev); + out_rtnl: + rtnl_unlock(); + return err; } @@ -1972,10 +2023,12 @@ static int nl80211_get_mesh_params(struct sk_buff *skb, struct nlattr *pinfoattr; struct sk_buff *msg; + rtnl_lock(); + /* Look up our device */ err = get_drv_dev_by_info_ifindex(info->attrs, &drv, &dev); if (err) - return err; + goto out_rtnl; if (!drv->ops->get_mesh_params) { err = -EOPNOTSUPP; @@ -1983,9 +2036,7 @@ static int nl80211_get_mesh_params(struct sk_buff *skb, } /* Get the mesh params */ - rtnl_lock(); err = drv->ops->get_mesh_params(&drv->wiphy, dev, &cur_params); - rtnl_unlock(); if (err) goto out; @@ -2034,13 +2085,16 @@ static int nl80211_get_mesh_params(struct sk_buff *skb, err = genlmsg_unicast(msg, info->snd_pid); goto out; -nla_put_failure: + nla_put_failure: genlmsg_cancel(msg, hdr); err = -EMSGSIZE; -out: + out: /* Cleanup */ cfg80211_put_dev(drv); dev_put(dev); + out_rtnl: + rtnl_unlock(); + return err; } @@ -2087,9 +2141,11 @@ static int nl80211_set_mesh_params(struct sk_buff *skb, struct genl_info *info) parent_attr, nl80211_meshconf_params_policy)) return -EINVAL; + rtnl_lock(); + err = get_drv_dev_by_info_ifindex(info->attrs, &drv, &dev); if (err) - return err; + goto out_rtnl; if (!drv->ops->set_mesh_params) { err = -EOPNOTSUPP; @@ -2136,14 +2192,15 @@ static int nl80211_set_mesh_params(struct sk_buff *skb, struct genl_info *info) nla_get_u16); /* Apply changes */ - rtnl_lock(); err = drv->ops->set_mesh_params(&drv->wiphy, dev, &cfg, mask); - rtnl_unlock(); out: /* cleanup */ cfg80211_put_dev(drv); dev_put(dev); + out_rtnl: + rtnl_unlock(); + return err; } @@ -2310,19 +2367,22 @@ static int nl80211_set_mgmt_extra_ie(struct sk_buff *skb, params.ies_len = nla_len(info->attrs[NL80211_ATTR_IE]); } + rtnl_lock(); + err = get_drv_dev_by_info_ifindex(info->attrs, &drv, &dev); if (err) - return err; + goto out_rtnl; - if (drv->ops->set_mgmt_extra_ie) { - rtnl_lock(); + if (drv->ops->set_mgmt_extra_ie) err = drv->ops->set_mgmt_extra_ie(&drv->wiphy, dev, ¶ms); - rtnl_unlock(); - } else + else err = -EOPNOTSUPP; cfg80211_put_dev(drv); dev_put(dev); + out_rtnl: + rtnl_unlock(); + return err; } @@ -2339,9 +2399,11 @@ static int nl80211_trigger_scan(struct sk_buff *skb, struct genl_info *info) enum ieee80211_band band; size_t ie_len; + rtnl_lock(); + err = get_drv_dev_by_info_ifindex(info->attrs, &drv, &dev); if (err) - return err; + goto out_rtnl; wiphy = &drv->wiphy; @@ -2350,11 +2412,9 @@ static int nl80211_trigger_scan(struct sk_buff *skb, struct genl_info *info) goto out; } - rtnl_lock(); - if (drv->scan_req) { err = -EBUSY; - goto out_unlock; + goto out; } if (info->attrs[NL80211_ATTR_SCAN_FREQUENCIES]) { @@ -2362,7 +2422,7 @@ static int nl80211_trigger_scan(struct sk_buff *skb, struct genl_info *info) n_channels++; if (!n_channels) { err = -EINVAL; - goto out_unlock; + goto out; } } else { for (band = 0; band < IEEE80211_NUM_BANDS; band++) @@ -2376,7 +2436,7 @@ static int nl80211_trigger_scan(struct sk_buff *skb, struct genl_info *info) if (n_ssids > wiphy->max_scan_ssids) { err = -EINVAL; - goto out_unlock; + goto out; } if (info->attrs[NL80211_ATTR_IE]) @@ -2390,7 +2450,7 @@ static int nl80211_trigger_scan(struct sk_buff *skb, struct genl_info *info) + ie_len, GFP_KERNEL); if (!request) { err = -ENOMEM; - goto out_unlock; + goto out; } request->channels = (void *)((char *)request + sizeof(*request)); @@ -2461,11 +2521,12 @@ static int nl80211_trigger_scan(struct sk_buff *skb, struct genl_info *info) drv->scan_req = NULL; kfree(request); } - out_unlock: - rtnl_unlock(); out: cfg80211_put_dev(drv); dev_put(dev); + out_rtnl: + rtnl_unlock(); + return err; } -- 2.41.1