[PATCH v2 1/2] wifi: rtw88: fix incorrect error codes in rtw_debugfs_copy_from_user

[PATCH v2 1/2] wifi: rtw88: fix incorrect error codes in rtw_debugfs_copy_from_user

[Zhang Shurong]

If there is a failure during copy_from_user, rtw_debugfs_copy_from_user
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.

Signed-off-by: Zhang Shurong <zhang_shurong@foxmail.com>
---
 drivers/net/wireless/realtek/rtw88/debug.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/realtek/rtw88/debug.c b/drivers/net/wireless/realtek/rtw88/debug.c
index fa3d73b333ba..3da477e1ebd3 100644
--- a/drivers/net/wireless/realtek/rtw88/debug.c
+++ b/drivers/net/wireless/realtek/rtw88/debug.c
@@ -183,8 +183,8 @@ static int rtw_debugfs_copy_from_user(char tmp[], int size,
 
 	tmp_len = (count > size - 1 ? size - 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';
 
-- 
2.40.0

RE: [PATCH v2 1/2] wifi: rtw88: fix incorrect error codes in rtw_debugfs_copy_from_user

[Ping-Ke Shih]

> -----Original Message-----
> From: Zhang Shurong <zhang_shurong@foxmail.com>
> Sent: Wednesday, April 26, 2023 12:24 AM
> To: tony0620emma@gmail.com
> Cc: kvalo@kernel.org; davem@davemloft.net; edumazet@google.com; kuba@kernel.org; pabeni@redhat.com;
> linux-wireless@vger.kernel.org; netdev@vger.kernel.org; linux-kernel@vger.kernel.org; Zhang Shurong
> <zhang_shurong@foxmail.com>
> Subject: [PATCH v2 1/2] wifi: rtw88: fix incorrect error codes in rtw_debugfs_copy_from_user
> 
> If there is a failure during copy_from_user, rtw_debugfs_copy_from_user
> 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.
> 
> Signed-off-by: Zhang Shurong <zhang_shurong@foxmail.com>

Reviewed-by: Ping-Ke Shih <pkshih@realtek.com>

> ---
>  drivers/net/wireless/realtek/rtw88/debug.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/wireless/realtek/rtw88/debug.c b/drivers/net/wireless/realtek/rtw88/debug.c
> index fa3d73b333ba..3da477e1ebd3 100644
> --- a/drivers/net/wireless/realtek/rtw88/debug.c
> +++ b/drivers/net/wireless/realtek/rtw88/debug.c
> @@ -183,8 +183,8 @@ static int rtw_debugfs_copy_from_user(char tmp[], int size,
> 
>         tmp_len = (count > size - 1 ? size - 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';
> 
> --
> 2.40.0

RE: [PATCH v2 1/2] wifi: rtw88: fix incorrect error codes in rtw_debugfs_copy_from_user

[Ping-Ke Shih]

> -----Original Message-----
> From: Ping-Ke Shih <pkshih@realtek.com>
> Sent: Wednesday, April 26, 2023 12:29 PM
> To: Zhang Shurong <zhang_shurong@foxmail.com>; tony0620emma@gmail.com
> Cc: kvalo@kernel.org; davem@davemloft.net; edumazet@google.com; kuba@kernel.org; pabeni@redhat.com;
> linux-wireless@vger.kernel.org; netdev@vger.kernel.org; linux-kernel@vger.kernel.org
> Subject: RE: [PATCH v2 1/2] wifi: rtw88: fix incorrect error codes in rtw_debugfs_copy_from_user
> 
> > -----Original Message-----
> > From: Zhang Shurong <zhang_shurong@foxmail.com>
> > Sent: Wednesday, April 26, 2023 12:24 AM
> > To: tony0620emma@gmail.com
> > Cc: kvalo@kernel.org; davem@davemloft.net; edumazet@google.com; kuba@kernel.org; pabeni@redhat.com;
> > linux-wireless@vger.kernel.org; netdev@vger.kernel.org; linux-kernel@vger.kernel.org; Zhang Shurong
> > <zhang_shurong@foxmail.com>
> > Subject: [PATCH v2 1/2] wifi: rtw88: fix incorrect error codes in rtw_debugfs_copy_from_user
> >
> > If there is a failure during copy_from_user, rtw_debugfs_copy_from_user
> > 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.
> >
> > Signed-off-by: Zhang Shurong <zhang_shurong@foxmail.com>
> 
> Reviewed-by: Ping-Ke Shih <pkshih@realtek.com>

I would take back this temporarily because of below. 

> 
> > ---
> >  drivers/net/wireless/realtek/rtw88/debug.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/net/wireless/realtek/rtw88/debug.c b/drivers/net/wireless/realtek/rtw88/debug.c
> > index fa3d73b333ba..3da477e1ebd3 100644
> > --- a/drivers/net/wireless/realtek/rtw88/debug.c
> > +++ b/drivers/net/wireless/realtek/rtw88/debug.c
> > @@ -183,8 +183,8 @@ static int rtw_debugfs_copy_from_user(char tmp[], int size,
> >
> >         tmp_len = (count > size - 1 ? size - 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';
> >

In the second patch, you check 'ret < 0' instead of 'ret'. That looks like
you can possibly return positive value (e.g. count), but actually only
return 0 or - EFAULT after this patch. So, I would like change first or second
patch to make them intuitive. 

return 0 or -EFAULT          --> check by if (ret)
return 0 or -EFAULT or count --> check by if (ret < 0)


+       ret = rtw_debugfs_copy_from_user(tmp, sizeof(tmp), buffer, count, 2);
+       if (ret < 0)
+               return ret;

[PATCH v2 2/2] wifi: rtw88: fix incorrect error codes in rtw_debugfs_set_*

[Zhang Shurong]

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

Fix this bug by returning correct error code.

Signed-off-by: Zhang Shurong <zhang_shurong@foxmail.com>
---
 drivers/net/wireless/realtek/rtw88/debug.c | 55 ++++++++++++++++------
 1 file changed, 41 insertions(+), 14 deletions(-)

diff --git a/drivers/net/wireless/realtek/rtw88/debug.c b/drivers/net/wireless/realtek/rtw88/debug.c
index 3da477e1ebd3..786669a092f1 100644
--- a/drivers/net/wireless/realtek/rtw88/debug.c
+++ b/drivers/net/wireless/realtek/rtw88/debug.c
@@ -201,13 +201,16 @@ static ssize_t rtw_debugfs_set_read_reg(struct file *filp,
 	char tmp[32 + 1];
 	u32 addr, len;
 	int num;
+	int ret;
 
-	rtw_debugfs_copy_from_user(tmp, sizeof(tmp), buffer, count, 2);
+	ret = rtw_debugfs_copy_from_user(tmp, sizeof(tmp), buffer, count, 2);
+	if (ret < 0)
+		return ret;
 
 	num = sscanf(tmp, "%x %x", &addr, &len);
 
 	if (num !=  2)
-		return count;
+		return -EINVAL;
 
 	if (len != 1 && len != 2 && len != 4) {
 		rtw_warn(rtwdev, "read reg setting wrong len\n");
@@ -288,8 +291,11 @@ static ssize_t rtw_debugfs_set_rsvd_page(struct file *filp,
 	char tmp[32 + 1];
 	u32 offset, page_num;
 	int num;
+	int ret;
 
-	rtw_debugfs_copy_from_user(tmp, sizeof(tmp), buffer, count, 2);
+	ret = rtw_debugfs_copy_from_user(tmp, sizeof(tmp), buffer, count, 2);
+	if (ret < 0)
+		return ret;
 
 	num = sscanf(tmp, "%d %d", &offset, &page_num);
 
@@ -314,8 +320,11 @@ static ssize_t rtw_debugfs_set_single_input(struct file *filp,
 	char tmp[32 + 1];
 	u32 input;
 	int num;
+	int ret;
 
-	rtw_debugfs_copy_from_user(tmp, sizeof(tmp), buffer, count, 1);
+	ret = rtw_debugfs_copy_from_user(tmp, sizeof(tmp), buffer, count, 1);
+	if (ret < 0)
+		return ret;
 
 	num = kstrtoint(tmp, 0, &input);
 
@@ -338,14 +347,17 @@ static ssize_t rtw_debugfs_set_write_reg(struct file *filp,
 	char tmp[32 + 1];
 	u32 addr, val, len;
 	int num;
+	int ret;
 
-	rtw_debugfs_copy_from_user(tmp, sizeof(tmp), buffer, count, 3);
+	ret = rtw_debugfs_copy_from_user(tmp, sizeof(tmp), buffer, count, 3);
+	if (ret < 0)
+		return ret;
 
 	/* write BB/MAC register */
 	num = sscanf(tmp, "%x %x %x", &addr, &val, &len);
 
 	if (num !=  3)
-		return count;
+		return -EINVAL;
 
 	switch (len) {
 	case 1:
@@ -381,8 +393,11 @@ static ssize_t rtw_debugfs_set_h2c(struct file *filp,
 	char tmp[32 + 1];
 	u8 param[8];
 	int num;
+	int ret;
 
-	rtw_debugfs_copy_from_user(tmp, sizeof(tmp), buffer, count, 3);
+	ret = rtw_debugfs_copy_from_user(tmp, sizeof(tmp), buffer, count, 3);
+	if (ret < 0)
+		return ret;
 
 	num = sscanf(tmp, "%hhx,%hhx,%hhx,%hhx,%hhx,%hhx,%hhx,%hhx",
 		     &param[0], &param[1], &param[2], &param[3],
@@ -408,14 +423,17 @@ static ssize_t rtw_debugfs_set_rf_write(struct file *filp,
 	char tmp[32 + 1];
 	u32 path, addr, mask, val;
 	int num;
+	int ret;
 
-	rtw_debugfs_copy_from_user(tmp, sizeof(tmp), buffer, count, 4);
+	ret = rtw_debugfs_copy_from_user(tmp, sizeof(tmp), buffer, count, 4);
+	if (ret < 0)
+		return ret;
 
 	num = sscanf(tmp, "%x %x %x %x", &path, &addr, &mask, &val);
 
 	if (num !=  4) {
 		rtw_warn(rtwdev, "invalid args, [path] [addr] [mask] [val]\n");
-		return count;
+		return -EINVAL;
 	}
 
 	mutex_lock(&rtwdev->mutex);
@@ -438,14 +456,17 @@ static ssize_t rtw_debugfs_set_rf_read(struct file *filp,
 	char tmp[32 + 1];
 	u32 path, addr, mask;
 	int num;
+	int ret;
 
-	rtw_debugfs_copy_from_user(tmp, sizeof(tmp), buffer, count, 3);
+	ret = rtw_debugfs_copy_from_user(tmp, sizeof(tmp), buffer, count, 3);
+	if (ret < 0)
+		return ret;
 
 	num = sscanf(tmp, "%x %x %x", &path, &addr, &mask);
 
 	if (num !=  3) {
 		rtw_warn(rtwdev, "invalid args, [path] [addr] [mask] [val]\n");
-		return count;
+		return -EINVAL;
 	}
 
 	debugfs_priv->rf_path = path;
@@ -467,7 +488,9 @@ static ssize_t rtw_debugfs_set_fix_rate(struct file *filp,
 	char tmp[32 + 1];
 	int ret;
 
-	rtw_debugfs_copy_from_user(tmp, sizeof(tmp), buffer, count, 1);
+	ret = rtw_debugfs_copy_from_user(tmp, sizeof(tmp), buffer, count, 1);
+	if (ret < 0)
+		return ret;
 
 	ret = kstrtou8(tmp, 0, &fix_rate);
 	if (ret) {
@@ -860,7 +883,9 @@ static ssize_t rtw_debugfs_set_coex_enable(struct file *filp,
 	bool enable;
 	int ret;
 
-	rtw_debugfs_copy_from_user(tmp, sizeof(tmp), buffer, count, 1);
+	ret = rtw_debugfs_copy_from_user(tmp, sizeof(tmp), buffer, count, 1);
+	if (ret < 0)
+		return ret;
 
 	ret = kstrtobool(tmp, &enable);
 	if (ret) {
@@ -930,7 +955,9 @@ static ssize_t rtw_debugfs_set_fw_crash(struct file *filp,
 	bool input;
 	int ret;
 
-	rtw_debugfs_copy_from_user(tmp, sizeof(tmp), buffer, count, 1);
+	ret = rtw_debugfs_copy_from_user(tmp, sizeof(tmp), buffer, count, 1);
+	if (ret < 0)
+		return ret;
 
 	ret = kstrtobool(tmp, &input);
 	if (ret)
-- 
2.40.0