mac80211_hwsim: check HWSIM_ATTR_RADIO_NAME length

Unfortunately, the nla policy was defined to have HWSIM_ATTR_RADIO_NAME
as an NLA_STRING, rather than NLA_NUL_STRING, so we can't use it as a
NUL-terminated string in the kernel.

Rather than break the API, kasprintf() the string to a new buffer to
guarantee NUL termination.

Reported-by: Andrew Zaborowski <andrew.zaborowski@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/drivers/net/wireless/mac80211_hwsim.c b/drivers/net/wireless/mac80211_hwsim.c
index 0889fc81ce9e47e4c63731588e5732123a8aabf6..50c219fb1a52b9799d502470c6a5bea08ba7174a 100644 (file)
--- a/drivers/net/wireless/mac80211_hwsim.c
+++ b/drivers/net/wireless/mac80211_hwsim.c
@@ -3056,6 +3056,7 @@ static int hwsim_register_received_nl(struct sk_buff *skb_2,
 static int hwsim_new_radio_nl(struct sk_buff *msg, struct genl_info *info)
 {
        struct hwsim_new_radio_params param = { 0 };
+       const char *hwname = NULL;
 
        param.reg_strict = info->attrs[HWSIM_ATTR_REG_STRICT_REG];
        param.p2p_device = info->attrs[HWSIM_ATTR_SUPPORT_P2P_DEVICE];
@@ -3069,8 +3070,14 @@ static int hwsim_new_radio_nl(struct sk_buff *msg, struct genl_info *info)
        if (info->attrs[HWSIM_ATTR_NO_VIF])
                param.no_vif = true;
 
-       if (info->attrs[HWSIM_ATTR_RADIO_NAME])
-               param.hwname = nla_data(info->attrs[HWSIM_ATTR_RADIO_NAME]);
+       if (info->attrs[HWSIM_ATTR_RADIO_NAME]) {
+               hwname = kasprintf(GFP_KERNEL, "%.*s",
+                                  nla_len(info->attrs[HWSIM_ATTR_RADIO_NAME]),
+                                  (char *)nla_data(info->attrs[HWSIM_ATTR_RADIO_NAME]));
+               if (!hwname)
+                       return -ENOMEM;
+               param.hwname = hwname;
+       }
 
        if (info->attrs[HWSIM_ATTR_USE_CHANCTX])
                param.use_chanctx = true;
@@ -3098,11 +3105,15 @@ static int hwsim_del_radio_nl(struct sk_buff *msg, struct genl_info *info)
        s64 idx = -1;
        const char *hwname = NULL;
 
-       if (info->attrs[HWSIM_ATTR_RADIO_ID])
+       if (info->attrs[HWSIM_ATTR_RADIO_ID]) {
                idx = nla_get_u32(info->attrs[HWSIM_ATTR_RADIO_ID]);
-       else if (info->attrs[HWSIM_ATTR_RADIO_NAME])
-               hwname = (void *)nla_data(info->attrs[HWSIM_ATTR_RADIO_NAME]);
-       else
+       } else if (info->attrs[HWSIM_ATTR_RADIO_NAME]) {
+               hwname = kasprintf(GFP_KERNEL, "%.*s",
+                                  nla_len(info->attrs[HWSIM_ATTR_RADIO_NAME]),
+                                  (char *)nla_data(info->attrs[HWSIM_ATTR_RADIO_NAME]));
+               if (!hwname)
+                       return -ENOMEM;
+       } else
                return -EINVAL;
 
        spin_lock_bh(&hwsim_radio_lock);
@@ -3111,7 +3122,8 @@ static int hwsim_del_radio_nl(struct sk_buff *msg, struct genl_info *info)
                        if (data->idx != idx)
                                continue;
                } else {
-                       if (strcmp(hwname, wiphy_name(data->hw->wiphy)))
+                       if (!hwname ||
+                           strcmp(hwname, wiphy_name(data->hw->wiphy)))
                                continue;
                }
 
@@ -3122,10 +3134,12 @@ static int hwsim_del_radio_nl(struct sk_buff *msg, struct genl_info *info)
                spin_unlock_bh(&hwsim_radio_lock);
                mac80211_hwsim_del_radio(data, wiphy_name(data->hw->wiphy),
                                         info);
+               kfree(hwname);
                return 0;
        }
        spin_unlock_bh(&hwsim_radio_lock);
 
+       kfree(hwname);
        return -ENODEV;
 }