2024-05-25 06:37:26

by Shichao Lai

[permalink] [raw]
Subject: [PATCH v4] usb-storage: Check whether the media is initialized successfully

The member "uzonesize" of struct alauda_info will remain 0
if alauda_init_media() fails, potentially causing divide errors
in alauda_read_data() and alauda_write_lba().
- Add a member "initialized" to struct alauda_info as a symbol
for media initialization.
- Change a condition in alauda_check_media() to ensure the
first initialization.
- Add an error check for the return value of alauda_init_media().

Reported-by: xingwei lee <[email protected]>
Reported-by: yue sun <[email protected]>
Suggested-by: Oliver Neukum <[email protected]>
Signed-off-by: Shichao Lai <[email protected]>
---
Changes since v1:
- Check the initialization of alauda_check_media()
which is the root cause.

drivers/usb/storage/alauda.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/storage/alauda.c b/drivers/usb/storage/alauda.c
index 115f05a6201a..ddf0da203481 100644
--- a/drivers/usb/storage/alauda.c
+++ b/drivers/usb/storage/alauda.c
@@ -105,6 +105,8 @@ struct alauda_info {
unsigned char sense_key;
unsigned long sense_asc; /* additional sense code */
unsigned long sense_ascq; /* additional sense code qualifier */
+
+ bool initialized; /* true if the media is initialized */
};

#define short_pack(lsb,msb) ( ((u16)(lsb)) | ( ((u16)(msb))<<8 ) )
@@ -476,11 +478,12 @@ static int alauda_check_media(struct us_data *us)
}

/* Check for media change */
- if (status[0] & 0x08) {
+ if (status[0] & 0x08 || !info->initialized) {
usb_stor_dbg(us, "Media change detected\n");
alauda_free_maps(&MEDIA_INFO(us));
- alauda_init_media(us);
-
+ rc = alauda_init_media(us);
+ if (rc == USB_STOR_TRANSPORT_GOOD)
+ info->initialized = true;
info->sense_key = UNIT_ATTENTION;
info->sense_asc = 0x28;
info->sense_ascq = 0x00;
@@ -1120,6 +1123,7 @@ static int init_alauda(struct us_data *us)
info->wr_ep = usb_sndbulkpipe(us->pusb_dev,
altsetting->endpoint[0].desc.bEndpointAddress
& USB_ENDPOINT_NUMBER_MASK);
+ info->initialized = false;

return 0;
}
--
2.34.1



2024-05-25 13:32:51

by Alan Stern

[permalink] [raw]
Subject: Re: [PATCH v4] usb-storage: Check whether the media is initialized successfully

On Sat, May 25, 2024 at 02:36:53PM +0800, Shichao Lai wrote:
> The member "uzonesize" of struct alauda_info will remain 0
> if alauda_init_media() fails, potentially causing divide errors
> in alauda_read_data() and alauda_write_lba().
> - Add a member "initialized" to struct alauda_info as a symbol
> for media initialization.
> - Change a condition in alauda_check_media() to ensure the
> first initialization.
> - Add an error check for the return value of alauda_init_media().
>
> Reported-by: xingwei lee <[email protected]>
> Reported-by: yue sun <[email protected]>
> Suggested-by: Oliver Neukum <[email protected]>

Oliver did not suggest that the patch be written this way.

> Signed-off-by: Shichao Lai <[email protected]>
> ---
> Changes since v1:
> - Check the initialization of alauda_check_media()
> which is the root cause.
>
> drivers/usb/storage/alauda.c | 10 +++++++---
> 1 file changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/usb/storage/alauda.c b/drivers/usb/storage/alauda.c
> index 115f05a6201a..ddf0da203481 100644
> --- a/drivers/usb/storage/alauda.c
> +++ b/drivers/usb/storage/alauda.c
> @@ -105,6 +105,8 @@ struct alauda_info {
> unsigned char sense_key;
> unsigned long sense_asc; /* additional sense code */
> unsigned long sense_ascq; /* additional sense code qualifier */
> +
> + bool initialized; /* true if the media is initialized */

Now with the patch written out, I think a better name for this variable
would be media_initialized. That is a better description of what it
means (it doesn't mean that the driver or the device is initialized).
And then you could remove the comment, because it would be obvious.

> };
>
> #define short_pack(lsb,msb) ( ((u16)(lsb)) | ( ((u16)(msb))<<8 ) )
> @@ -476,11 +478,12 @@ static int alauda_check_media(struct us_data *us)
> }
>
> /* Check for media change */
> - if (status[0] & 0x08) {
> + if (status[0] & 0x08 || !info->initialized) {
> usb_stor_dbg(us, "Media change detected\n");
> alauda_free_maps(&MEDIA_INFO(us));
> - alauda_init_media(us);
> -
> + rc = alauda_init_media(us);
> + if (rc == USB_STOR_TRANSPORT_GOOD)
> + info->initialized = true;
> info->sense_key = UNIT_ATTENTION;
> info->sense_asc = 0x28;
> info->sense_ascq = 0x00;
> @@ -1120,6 +1123,7 @@ static int init_alauda(struct us_data *us)
> info->wr_ep = usb_sndbulkpipe(us->pusb_dev,
> altsetting->endpoint[0].desc.bEndpointAddress
> & USB_ENDPOINT_NUMBER_MASK);
> + info->initialized = false;

You don't need to do this. The info pointer is an alias for us->extra,
which is allocated by kzalloc(), which clears all the memory it
allocates to zero.

Alan Stern

2024-05-25 13:47:07

by Shichao Lai

[permalink] [raw]
Subject: Re: [PATCH v4] usb-storage: Check whether the media is initialized successfully

> Oliver did not suggest that the patch be written this way.
>
> Now with the patch written out, I think a better name for this variable
> would be media_initialized. That is a better description of what it
> means (it doesn't mean that the driver or the device is initialized).
> And then you could remove the comment, because it would be obvious.
>
> You don't need to do this. The info pointer is an alias for us->extra,
> which is allocated by kzalloc(), which clears all the memory it
> allocates to zero.
>
> Alan Stern

Thanks for your patient feedback!
I will rewrite the patch soon.