wifi: rtlwifi: fix incorrect error codes in rtl_debugfs_set_write_rfreg()

[ Upstream commit 905a9241e4e8c15d2c084fee916280514848fe35 ]

If there is a failure during copy_from_user or user-provided data buffer
is invalid, rtl_debugfs_set_write_rfreg should return negative error code
instead of a positive value count.

Fix this bug by returning correct error code. Moreover, the check of buffer
against null is removed since it will be handled by copy_from_user.

Fixes: 610247f46feb ("rtlwifi: Improve debugging by using debugfs")
Signed-off-by: Wei Chen <harperchen1110@gmail.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20230326053138.91338-1-harperchen1110@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/net/wireless/realtek/rtlwifi/debug.c b/drivers/net/wireless/realtek/rtlwifi/debug.c
index 0b1bc04..6027179 100644 (file)
--- a/drivers/net/wireless/realtek/rtlwifi/debug.c
+++ b/drivers/net/wireless/realtek/rtlwifi/debug.c
@@ -375,8 +375,8 @@ static ssize_t rtl_debugfs_set_write_rfreg(struct file *filp,
 
        tmp_len = (count > sizeof(tmp) - 1 ? sizeof(tmp) - 1 : count);
 
-       if (!buffer || copy_from_user(tmp, buffer, tmp_len))
-               return count;
+       if (copy_from_user(tmp, buffer, tmp_len))
+               return -EFAULT;
 
        tmp[tmp_len] = '\0';
 
@@ -386,7 +386,7 @@ static ssize_t rtl_debugfs_set_write_rfreg(struct file *filp,
        if (num != 4) {
                rtl_dbg(rtlpriv, COMP_ERR, DBG_DMESG,
                        "Format is <path> <addr> <mask> <data>\n");
-               return count;
+               return -EINVAL;
        }
 
        rtl_set_rfreg(hw, path, addr, bitmask, data);