staging: rtl8188eu: fix potential leak in rtw_mp_pwrtrk()

Function rtw_mp_pwrtrk() dynamically allocates a temporary buffer that
is not freed in all error paths. Use a centralized exit path and make sure
that all memory is freed correctly. Detected by Coverity - 1077715.

Signed-off-by: Christian Engelmayer <cengelma@gmx.at>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/rtl8188eu/os_dep/ioctl_linux.c b/drivers/staging/rtl8188eu/os_dep/ioctl_linux.c
index ea5e1f8..f04aaa3 100644 (file)
--- a/drivers/staging/rtl8188eu/os_dep/ioctl_linux.c
+++ b/drivers/staging/rtl8188eu/os_dep/ioctl_linux.c
@@ -7119,15 +7119,15 @@ static int rtw_mp_pwrtrk(struct net_device *dev,
 {
        u8 enable;
        u32 thermal;
-       s32 ret;
        struct adapter *padapter = rtw_netdev_priv(dev);
        char    *input = kmalloc(wrqu->length, GFP_KERNEL);
+       int ret = 0;
 
        if (!input)
                return -ENOMEM;
        if (copy_from_user(input, wrqu->pointer, wrqu->length)) {
-               kfree(input);
-               return -EFAULT;
+               ret = -EFAULT;
+               goto exit;
        }
        _rtw_memset(extra, 0, wrqu->length);
 
@@ -7138,22 +7138,28 @@ static int rtw_mp_pwrtrk(struct net_device *dev,
                        sprintf(extra, "mp tx power tracking stop");
                } else if (sscanf(input, "ther =%d", &thermal)) {
                                ret = Hal_SetThermalMeter(padapter, (u8)thermal);
-                               if (ret == _FAIL)
-                                       return -EPERM;
+                               if (ret == _FAIL) {
+                                       ret = -EPERM;
+                                       goto exit;
+                               }
                                sprintf(extra, "mp tx power tracking start, target value =%d ok ", thermal);
                } else {
-                       kfree(input);
-                       return -EINVAL;
+                       ret = -EINVAL;
+                       goto exit;
                }
        }
 
-       kfree(input);
        ret = Hal_SetPowerTracking(padapter, enable);
-       if (ret == _FAIL)
-               return -EPERM;
+       if (ret == _FAIL) {
+               ret = -EPERM;
+               goto exit;
+       }
 
        wrqu->length = strlen(extra);
-       return 0;
+
+exit:
+       kfree(input);
+       return ret;
 }
 
 static int rtw_mp_psd(struct net_device *dev,