* [PATCH -next] s390/hmcdrv: Switch to memdup_user_nul() helper
@ 2023-08-15 11:55 Ruan Jinjie
2023-08-15 12:13 ` Heiko Carstens
0 siblings, 1 reply; 2+ messages in thread
From: Ruan Jinjie @ 2023-08-15 11:55 UTC (permalink / raw)
To: linux-s390, Heiko Carstens, Vasily Gorbik, Alexander Gordeev,
Christian Borntraeger, Sven Schnelle
Cc: ruanjinjie
Use memdup_user_nul() helper instead of open-coding
to simplify the code.
Signed-off-by: Ruan Jinjie <ruanjinjie@huawei.com>
---
drivers/s390/char/hmcdrv_dev.c | 17 +++++------------
1 file changed, 5 insertions(+), 12 deletions(-)
diff --git a/drivers/s390/char/hmcdrv_dev.c b/drivers/s390/char/hmcdrv_dev.c
index 8d50c894711f..504cdbf9998d 100644
--- a/drivers/s390/char/hmcdrv_dev.c
+++ b/drivers/s390/char/hmcdrv_dev.c
@@ -252,19 +252,12 @@ static ssize_t hmcdrv_dev_write(struct file *fp, const char __user *ubuf,
fp, (long long) *pos, len);
if (!fp->private_data) { /* first expect a cmd write */
- fp->private_data = kmalloc(len + 1, GFP_KERNEL);
-
- if (!fp->private_data)
- return -ENOMEM;
-
- if (!copy_from_user(fp->private_data, ubuf, len)) {
- ((char *)fp->private_data)[len] = '\0';
- return len;
+ fp->private_data = memdup_user_nul(ubuf, len);
+ if (IS_ERR(fp->private_data)) {
+ fp->private_data = NULL;
+ return PTR_ERR(fp->private_data);
}
-
- kfree(fp->private_data);
- fp->private_data = NULL;
- return -EFAULT;
+ return len;
}
retlen = hmcdrv_dev_transfer((char *) fp->private_data,
--
2.34.1
^ permalink raw reply related [flat|nested] 2+ messages in thread* Re: [PATCH -next] s390/hmcdrv: Switch to memdup_user_nul() helper
2023-08-15 11:55 [PATCH -next] s390/hmcdrv: Switch to memdup_user_nul() helper Ruan Jinjie
@ 2023-08-15 12:13 ` Heiko Carstens
0 siblings, 0 replies; 2+ messages in thread
From: Heiko Carstens @ 2023-08-15 12:13 UTC (permalink / raw)
To: Ruan Jinjie
Cc: linux-s390, Vasily Gorbik, Alexander Gordeev,
Christian Borntraeger, Sven Schnelle
On Tue, Aug 15, 2023 at 07:55:46PM +0800, Ruan Jinjie wrote:
> Use memdup_user_nul() helper instead of open-coding
> to simplify the code.
>
> Signed-off-by: Ruan Jinjie <ruanjinjie@huawei.com>
> ---
> drivers/s390/char/hmcdrv_dev.c | 17 +++++------------
> 1 file changed, 5 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/s390/char/hmcdrv_dev.c b/drivers/s390/char/hmcdrv_dev.c
> index 8d50c894711f..504cdbf9998d 100644
> --- a/drivers/s390/char/hmcdrv_dev.c
> +++ b/drivers/s390/char/hmcdrv_dev.c
> @@ -252,19 +252,12 @@ static ssize_t hmcdrv_dev_write(struct file *fp, const char __user *ubuf,
> fp, (long long) *pos, len);
>
> if (!fp->private_data) { /* first expect a cmd write */
> - fp->private_data = kmalloc(len + 1, GFP_KERNEL);
> -
> - if (!fp->private_data)
> - return -ENOMEM;
> -
> - if (!copy_from_user(fp->private_data, ubuf, len)) {
> - ((char *)fp->private_data)[len] = '\0';
> - return len;
> + fp->private_data = memdup_user_nul(ubuf, len);
> + if (IS_ERR(fp->private_data)) {
> + fp->private_data = NULL;
> + return PTR_ERR(fp->private_data);
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
This is obviously broken. Sorry, but I'm not willing to review such
"trivial" cleanup patches for subtle bugs anymore - maybe you would
sooner or later succeed and I would apply such a broken patch.
Just don't send such patches; at least I won't take them.
^ permalink raw reply [flat|nested] 2+ messages in thread
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