Patch "wifi: rtlwifi: fix incorrect error codes in rtl_debugfs_set_write_rfreg()" has been added to the 5.4-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

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

to the 5.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     wifi-rtlwifi-fix-incorrect-error-codes-in-rtl_debugf.patch
and it can be found in the queue-5.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit db259efc6ff59623a866e46330b249bd1f2b6253
Author: Wei Chen <harperchen1110@xxxxxxxxx>
Date:   Sun Mar 26 05:31:38 2023 +0000

    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@xxxxxxxxx>
    Reviewed-by: Simon Horman <simon.horman@xxxxxxxxxxxx>
    Signed-off-by: Kalle Valo <kvalo@xxxxxxxxxx>
    Link: https://lore.kernel.org/r/20230326053138.91338-1-harperchen1110@xxxxxxxxx
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/net/wireless/realtek/rtlwifi/debug.c b/drivers/net/wireless/realtek/rtlwifi/debug.c
index a7a5d8fa3cc0c..c8db166a7dc80 100644
--- a/drivers/net/wireless/realtek/rtlwifi/debug.c
+++ b/drivers/net/wireless/realtek/rtlwifi/debug.c
@@ -395,8 +395,8 @@ 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';
 
@@ -406,7 +406,7 @@ 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);