2024-05-23 07:23:33

by Shichao Lai

Subject: [PATCH] Check whether divisor is non-zero before division

Since uzonesize may be zero, so a judgement for non-zero is nessesary.

Reported-by: xingwei lee <[email protected]>
Reported-by: yue sun <[email protected]>
Signed-off-by: Shichao Lai <[email protected]>
---
drivers/usb/storage/alauda.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/usb/storage/alauda.c b/drivers/usb/storage/alauda.c
index 115f05a6201a..db075a8c03cb 100644
--- a/drivers/usb/storage/alauda.c
+++ b/drivers/usb/storage/alauda.c
@@ -947,6 +947,8 @@ static int alauda_read_data(struct us_data *us, unsigned long address,
sg = NULL;

while (sectors > 0) {
+ if (!uzonesize)
+ return USB_STOR_TRANSPORT_ERROR;
unsigned int zone = lba / uzonesize; /* integer division */
unsigned int lba_offset = lba - (zone * uzonesize);
unsigned int pages;
--
2.34.1

2024-05-23 07:36:34

by Greg Kroah-Hartman

Subject: Re: [PATCH] Check whether divisor is non-zero before division

On Thu, May 23, 2024 at 03:22:42PM +0800, Shichao Lai wrote:
> Since uzonesize may be zero, so a judgement for non-zero is nessesary.
>
> Reported-by: xingwei lee <[email protected]>
> Reported-by: yue sun <[email protected]>
> Signed-off-by: Shichao Lai <[email protected]>
> ---
> drivers/usb/storage/alauda.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/usb/storage/alauda.c b/drivers/usb/storage/alauda.c
> index 115f05a6201a..db075a8c03cb 100644
> --- a/drivers/usb/storage/alauda.c
> +++ b/drivers/usb/storage/alauda.c
> @@ -947,6 +947,8 @@ static int alauda_read_data(struct us_data *us, unsigned long address,
> sg = NULL;
>
> while (sectors > 0) {
> + if (!uzonesize)
> + return USB_STOR_TRANSPORT_ERROR;
> unsigned int zone = lba / uzonesize; /* integer division */
> unsigned int lba_offset = lba - (zone * uzonesize);
> unsigned int pages;
> --
> 2.34.1
>
>

Looks good, thanks! I'll queue this up after 6.10-rc1 is out.

greg k-h

2024-05-23 08:18:21

by Oliver Neukum

Subject: Re: [PATCH] Check whether divisor is non-zero before division

On 23.05.24 09:22, Shichao Lai wrote:

Hi,

> Since uzonesize may be zero, so a judgement for non-zero is nessesary.
>
> Reported-by: xingwei lee <[email protected]>
> Reported-by: yue sun <[email protected]>
> Signed-off-by: Shichao Lai <[email protected]>
> ---
> drivers/usb/storage/alauda.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/usb/storage/alauda.c b/drivers/usb/storage/alauda.c
> index 115f05a6201a..db075a8c03cb 100644
> --- a/drivers/usb/storage/alauda.c
> +++ b/drivers/usb/storage/alauda.c
> @@ -947,6 +947,8 @@ static int alauda_read_data(struct us_data *us, unsigned long address,
> sg = NULL;
>
> while (sectors > 0) {
> + if (!uzonesize)
> + return USB_STOR_TRANSPORT_ERROR;

May I point out that uzonesize does not change in this function?
There is no need to retest within the loop.

> unsigned int zone = lba / uzonesize; /* integer division */
> unsigned int lba_offset = lba - (zone * uzonesize);
> unsigned int pages;

Secondly, alauda_write_lba() has the same issue.
You also need to check in alauda_write_data().

Regards
Oliver

2024-05-23 09:13:02

by Shichao Lai

Subject: Re: [PATCH] Check whether divisor is non-zero before division

On Thu, May 23, 2024 at 4:18 PM Oliver Neukum <[email protected]> wrote:
>
> On 23.05.24 09:22, Shichao Lai wrote:
>
> Hi,
>
> > Since uzonesize may be zero, so a judgement for non-zero is nessesary.
> >
> > Reported-by: xingwei lee <[email protected]>
> > Reported-by: yue sun <[email protected]>
> > Signed-off-by: Shichao Lai <[email protected]>
> > ---
> > drivers/usb/storage/alauda.c | 2 ++
> > 1 file changed, 2 insertions(+)
> >
> > diff --git a/drivers/usb/storage/alauda.c b/drivers/usb/storage/alauda.c
> > index 115f05a6201a..db075a8c03cb 100644
> > --- a/drivers/usb/storage/alauda.c
> > +++ b/drivers/usb/storage/alauda.c
> > @@ -947,6 +947,8 @@ static int alauda_read_data(struct us_data *us, unsigned long address,
> > sg = NULL;
> >
> > while (sectors > 0) {
> > + if (!uzonesize)
> > + return USB_STOR_TRANSPORT_ERROR;
>
> May I point out that uzonesize does not change in this function?
> There is no need to retest within the loop.
>
> > unsigned int zone = lba / uzonesize; /* integer division */
> > unsigned int lba_offset = lba - (zone * uzonesize);
> > unsigned int pages;
>
> Secondly, alauda_write_lba() has the same issue.
> You also need to check in alauda_write_data().
>
> Regards
> Oliver


Thanks for the helpful tip!
I reviewed the code. Your suggestions can actually avoid repeated checks.
And there is also such a problem in alauda_write_lba().
I am a beginner at making patches. May I commit a patch again which
fixes both issues you mentioned?

2024-05-23 09:15:44

by Oliver Neukum

Subject: Re: [PATCH] Check whether divisor is non-zero before division

On 23.05.24 11:12, shichao lai wrote:

> Thanks for the helpful tip!
> I reviewed the code. Your suggestions can actually avoid repeated checks.
> And there is also such a problem in alauda_write_lba().
> I am a beginner at making patches. May I commit a patch again which
> fixes both issues you mentioned?


Hi,

yes, you usually are supposed to change the "[PATCH]" in the
subject line to "[PATCHv2]" and add a line in the log describing
the difference between the first and second version.

HTH
Oliver