iwlwifi: add range checking in tm sram read command

The size of sram may alter according to ucode type.
Retrieve the maximum sram size by current ucode
type for range checking to prevent wrong data access.
Signed-off-by: Kenny Hsu <kenny.hsu@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/iwlwifi/iwl-sv-open.c

@@ -680,7 +680,7 @@ static int iwl_testmode_ownership(struct ieee80211_hw *hw, struct nlattr **tb)
 static int iwl_testmode_sram(struct ieee80211_hw *hw, struct nlattr **tb)
 {
 	struct iwl_priv *priv = hw->priv;
-	u32 base, ofs, size;
+	u32 base, ofs, size, maxsize;
 
 	if (priv->testmode_sram.sram_readed)
 		return -EBUSY;
@@ -695,6 +695,27 @@ static int iwl_testmode_sram(struct ieee80211_hw *hw, struct nlattr **tb)
 		return -ENOMSG;
 	}
 	size = nla_get_u32(tb[IWL_TM_ATTR_SRAM_SIZE]);
+	switch (priv->ucode_type) {
+	case IWL_UCODE_REGULAR:
+		maxsize = trans(priv)->ucode_rt.data.len;
+		break;
+	case IWL_UCODE_INIT:
+		maxsize = trans(priv)->ucode_init.data.len;
+		break;
+	case IWL_UCODE_WOWLAN:
+		maxsize = trans(priv)->ucode_wowlan.data.len;
+		break;
+	case IWL_UCODE_NONE:
+		IWL_DEBUG_INFO(priv, "Error, uCode does not been loaded\n");
+		return -ENOSYS;
+	default:
+		IWL_DEBUG_INFO(priv, "Error, unsupported uCode type\n");
+		return -ENOSYS;
+	}
+	if ((ofs + size) > maxsize) {
+		IWL_DEBUG_INFO(priv, "Invalid offset/size: out of range\n");
+		return -EINVAL;
+	}
 	priv->testmode_sram.buff_size = (size / 4) * 4;
 	priv->testmode_sram.buff_addr =
 		kmalloc(priv->testmode_sram.buff_size, GFP_KERNEL);