[GIT PULL for-4.4 04/25] mac80211_hwsim: check HWSIM_ATTR_RADIO_NAME length

[Levin, Alexander (Sasha Levin)]

From: Johannes Berg <johannes.b...@intel.com>

[ Upstream commit ff4dd73dd2b4806419f8ff65cbce11d5019548d0 ]

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.zaborow...@intel.com>
Signed-off-by: Johannes Berg <johannes.b...@intel.com>
Signed-off-by: Sasha Levin <alexander.le...@verizon.com>
---
 drivers/net/wireless/mac80211_hwsim.c | 28 +++++++++++++++++++++-------
 1 file changed, 21 insertions(+), 7 deletions(-)

diff --git a/drivers/net/wireless/mac80211_hwsim.c 
b/drivers/net/wireless/mac80211_hwsim.c
index 019d7165a045..2a996a68fc2b 100644
--- a/drivers/net/wireless/mac80211_hwsim.c
+++ b/drivers/net/wireless/mac80211_hwsim.c
@@ -2884,6 +2884,7 @@ 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];
@@ -2897,8 +2898,14 @@ 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;
@@ -2926,11 +2933,15 @@ 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);
@@ -2939,7 +2950,8 @@ 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;
                }
 
@@ -2947,10 +2959,12 @@ 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;
 }
 
-- 
2.11.0