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* [PATCHv2] scsi: ibmvscsis: Fix a stringop-overflow warning
@ 2018-09-11 18:05 Laura Abbott
  2018-09-11 18:24 ` Kees Cook
  0 siblings, 1 reply; 3+ messages in thread
From: Laura Abbott @ 2018-09-11 18:05 UTC (permalink / raw)
  To: Bryant G. Ly, Michael Cyr
  Cc: Laura Abbott, James E.J. Bottomley, Martin K. Petersen,
	linux-scsi, target-devel, linux-kernel, Kees Cook,
	Prarit Bhargava


There's currently a warning about string overflow with strncat:

drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c: In function 'ibmvscsis_probe':
drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c:3479:2: error: 'strncat' specified
bound 64 equals destination size [-Werror=stringop-overflow=]
  strncat(vscsi->eye, vdev->name, MAX_EYE);
  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Switch to a single snprintf instead of a strcpy + strcat to handle this
cleanly.

Signed-off-by: Laura Abbott <labbott@redhat.com>
---
v2: Swtich to using snprintf per suggestion of Kees
---
 drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c b/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c
index fac377320158..9305440a00a1 100644
--- a/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c
+++ b/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c
@@ -3474,8 +3474,7 @@ static int ibmvscsis_probe(struct vio_dev *vdev,
 		vscsi->dds.window[LOCAL].liobn,
 		vscsi->dds.window[REMOTE].liobn);
 
-	strcpy(vscsi->eye, "VSCSI ");
-	strncat(vscsi->eye, vdev->name, MAX_EYE);
+	snprintf(vscsi->eye, sizeof(vscsi->eye), "VSCSI%s", vdev->name);
 
 	vscsi->dds.unit_id = vdev->unit_address;
 	strncpy(vscsi->dds.partition_name, partition_name,
-- 
2.17.1


^ permalink raw reply related	[flat|nested] 3+ messages in thread

* Re: [PATCHv2] scsi: ibmvscsis: Fix a stringop-overflow warning
  2018-09-11 18:05 [PATCHv2] scsi: ibmvscsis: Fix a stringop-overflow warning Laura Abbott
@ 2018-09-11 18:24 ` Kees Cook
  2018-09-11 18:27   ` Kees Cook
  0 siblings, 1 reply; 3+ messages in thread
From: Kees Cook @ 2018-09-11 18:24 UTC (permalink / raw)
  To: Laura Abbott
  Cc: Bryant G. Ly, Michael Cyr, James E.J. Bottomley,
	Martin K. Petersen, linux-scsi, target-devel, LKML,
	Prarit Bhargava

On Tue, Sep 11, 2018 at 11:05 AM, Laura Abbott <labbott@redhat.com> wrote:
>
> There's currently a warning about string overflow with strncat:
>
> drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c: In function 'ibmvscsis_probe':
> drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c:3479:2: error: 'strncat' specified
> bound 64 equals destination size [-Werror=stringop-overflow=]
>   strncat(vscsi->eye, vdev->name, MAX_EYE);
>   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> Switch to a single snprintf instead of a strcpy + strcat to handle this
> cleanly.
>
> Signed-off-by: Laura Abbott <labbott@redhat.com>

Reviewed-by: Kees Cook <keescook@chromium.org>

-Kees

> ---
> v2: Swtich to using snprintf per suggestion of Kees
> ---
>  drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c b/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c
> index fac377320158..9305440a00a1 100644
> --- a/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c
> +++ b/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c
> @@ -3474,8 +3474,7 @@ static int ibmvscsis_probe(struct vio_dev *vdev,
>                 vscsi->dds.window[LOCAL].liobn,
>                 vscsi->dds.window[REMOTE].liobn);
>
> -       strcpy(vscsi->eye, "VSCSI ");
> -       strncat(vscsi->eye, vdev->name, MAX_EYE);
> +       snprintf(vscsi->eye, sizeof(vscsi->eye), "VSCSI%s", vdev->name);
>
>         vscsi->dds.unit_id = vdev->unit_address;
>         strncpy(vscsi->dds.partition_name, partition_name,
> --
> 2.17.1
>



-- 
Kees Cook
Pixel Security

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCHv2] scsi: ibmvscsis: Fix a stringop-overflow warning
  2018-09-11 18:24 ` Kees Cook
@ 2018-09-11 18:27   ` Kees Cook
  0 siblings, 0 replies; 3+ messages in thread
From: Kees Cook @ 2018-09-11 18:27 UTC (permalink / raw)
  To: Laura Abbott
  Cc: Bryant G. Ly, Michael Cyr, James E.J. Bottomley,
	Martin K. Petersen, linux-scsi, target-devel, LKML,
	Prarit Bhargava

On Tue, Sep 11, 2018 at 11:24 AM, Kees Cook <keescook@chromium.org> wrote:
> On Tue, Sep 11, 2018 at 11:05 AM, Laura Abbott <labbott@redhat.com> wrote:
>>
>> There's currently a warning about string overflow with strncat:
>>
>> drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c: In function 'ibmvscsis_probe':
>> drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c:3479:2: error: 'strncat' specified
>> bound 64 equals destination size [-Werror=stringop-overflow=]
>>   strncat(vscsi->eye, vdev->name, MAX_EYE);
>>   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>
>> Switch to a single snprintf instead of a strcpy + strcat to handle this
>> cleanly.
>>
>> Signed-off-by: Laura Abbott <labbott@redhat.com>
>
> Reviewed-by: Kees Cook <keescook@chromium.org>
>
> -Kees
>
>> ---
>> v2: Swtich to using snprintf per suggestion of Kees
>> ---
>>  drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c | 3 +--
>>  1 file changed, 1 insertion(+), 2 deletions(-)
>>
>> diff --git a/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c b/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c
>> index fac377320158..9305440a00a1 100644
>> --- a/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c
>> +++ b/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c
>> @@ -3474,8 +3474,7 @@ static int ibmvscsis_probe(struct vio_dev *vdev,
>>                 vscsi->dds.window[LOCAL].liobn,
>>                 vscsi->dds.window[REMOTE].liobn);
>>
>> -       strcpy(vscsi->eye, "VSCSI ");
>> -       strncat(vscsi->eye, vdev->name, MAX_EYE);
>> +       snprintf(vscsi->eye, sizeof(vscsi->eye), "VSCSI%s", vdev->name);

Eek. No, I take it back: Nick Desaulniers has better eyes than me and
pointed out that there should be a space after VSCSI.

-Kees

>>
>>         vscsi->dds.unit_id = vdev->unit_address;
>>         strncpy(vscsi->dds.partition_name, partition_name,
>> --
>> 2.17.1
>>
>
>
>
> --
> Kees Cook
> Pixel Security



-- 
Kees Cook
Pixel Security

^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2018-09-11 18:28 UTC | newest]

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2018-09-11 18:05 [PATCHv2] scsi: ibmvscsis: Fix a stringop-overflow warning Laura Abbott
2018-09-11 18:24 ` Kees Cook
2018-09-11 18:27   ` Kees Cook

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