rtw89: fix potentially access out of range of RF register array

The RF register array is used to help firmware to restore RF settings.
The original code can potentially access out of range, if the size is
between (RTW89_H2C_RF_PAGE_SIZE * RTW89_H2C_RF_PAGE_NUM + 1) to
((RTW89_H2C_RF_PAGE_SIZE + 1) * RTW89_H2C_RF_PAGE_NUM). Fortunately,
current used size doesn't fall into the wrong case, and the size will not
change if we don't update RF parameter.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20211119055729.12826-1-pkshih@realtek.com

diff --git a/drivers/net/wireless/realtek/rtw89/phy.c b/drivers/net/wireless/realtek/rtw89/phy.c
index abb4cdc..312d9a0 100644 (file)
--- a/drivers/net/wireless/realtek/rtw89/phy.c
+++ b/drivers/net/wireless/realtek/rtw89/phy.c
@@ -654,6 +654,12 @@ rtw89_phy_cofig_rf_reg_store(struct rtw89_dev *rtwdev,
        u16 idx = info->curr_idx % RTW89_H2C_RF_PAGE_SIZE;
        u8 page = info->curr_idx / RTW89_H2C_RF_PAGE_SIZE;
 
+       if (page >= RTW89_H2C_RF_PAGE_NUM) {
+               rtw89_warn(rtwdev, "RF parameters exceed size. path=%d, idx=%d",
+                          rf_path, info->curr_idx);
+               return;
+       }
+
        info->rtw89_phy_config_rf_h2c[page][idx] =
                cpu_to_le32((reg->addr << 20) | reg->data);
        info->curr_idx++;
@@ -662,30 +668,29 @@ rtw89_phy_cofig_rf_reg_store(struct rtw89_dev *rtwdev,
 static int rtw89_phy_config_rf_reg_fw(struct rtw89_dev *rtwdev,
                                      struct rtw89_fw_h2c_rf_reg_info *info)
 {
-       u16 page = info->curr_idx / RTW89_H2C_RF_PAGE_SIZE;
-       u16 len = (info->curr_idx % RTW89_H2C_RF_PAGE_SIZE) * 4;
+       u16 remain = info->curr_idx;
+       u16 len = 0;
        u8 i;
        int ret = 0;
 
-       if (page > RTW89_H2C_RF_PAGE_NUM) {
+       if (remain > RTW89_H2C_RF_PAGE_NUM * RTW89_H2C_RF_PAGE_SIZE) {
                rtw89_warn(rtwdev,
-                          "rf reg h2c total page num %d larger than %d (RTW89_H2C_RF_PAGE_NUM)\n",
-                          page, RTW89_H2C_RF_PAGE_NUM);
-               return -EINVAL;
+                          "rf reg h2c total len %d larger than %d\n",
+                          remain, RTW89_H2C_RF_PAGE_NUM * RTW89_H2C_RF_PAGE_SIZE);
+               ret = -EINVAL;
+               goto out;
        }
 
-       for (i = 0; i < page; i++) {
-               ret = rtw89_fw_h2c_rf_reg(rtwdev, info,
-                                         RTW89_H2C_RF_PAGE_SIZE * 4, i);
+       for (i = 0; i < RTW89_H2C_RF_PAGE_NUM && remain; i++, remain -= len) {
+               len = remain > RTW89_H2C_RF_PAGE_SIZE ? RTW89_H2C_RF_PAGE_SIZE : remain;
+               ret = rtw89_fw_h2c_rf_reg(rtwdev, info, len * 4, i);
                if (ret)
-                       return ret;
+                       goto out;
        }
-       ret = rtw89_fw_h2c_rf_reg(rtwdev, info, len, i);
-       if (ret)
-               return ret;
+out:
        info->curr_idx = 0;
 
-       return 0;
+       return ret;
 }
 
 static void rtw89_phy_config_rf_reg(struct rtw89_dev *rtwdev,