Patchwork eicon: make buffer larger

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Submitter Dan Carpenter
Date Oct. 4, 2010, 7:24 p.m.
Message ID <20101004192459.GE5692@bicker>
Download mbox | patch
Permalink /patch/66726/
State Accepted
Delegated to: David Miller
Headers show

Comments

Dan Carpenter - Oct. 4, 2010, 7:24 p.m.
In diva_mnt_add_xdi_adapter() we do this:
  strcpy (clients[id].drvName,     tmp);
  strcpy (clients[id].Dbg.drvName, tmp);

The "clients[id].drvName" is a 128 character buffer and
"clients[id].Dbg.drvName" was originally a 16 character buffer but I've
changed it to 128 as well.  We don't actually use 128 characters but we
do use more than 16.

I've also changed the size of "tmp" to 128 characters instead of 256.

Signed-off-by: Dan Carpenter <error27@gmail.com>

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Armin Schindler - Oct. 6, 2010, 7:25 a.m.
On Mon, 4 Oct 2010, Dan Carpenter wrote:
> In diva_mnt_add_xdi_adapter() we do this:
>  strcpy (clients[id].drvName,     tmp);
>  strcpy (clients[id].Dbg.drvName, tmp);
>
> The "clients[id].drvName" is a 128 character buffer and
> "clients[id].Dbg.drvName" was originally a 16 character buffer but I've
> changed it to 128 as well.  We don't actually use 128 characters but we
> do use more than 16.

I don't see any reason for that change. The driver names here do not use 
more than 16 characters and when filled, the length is checked anyway.
Please avoid changing the size of that structure.

Armin

> I've also changed the size of "tmp" to 128 characters instead of 256.
>
> Signed-off-by: Dan Carpenter <error27@gmail.com>
>
> diff --git a/drivers/isdn/hardware/eicon/debuglib.h b/drivers/isdn/hardware/eicon/debuglib.h
> index 8ea5877..02eed6b 100644
> --- a/drivers/isdn/hardware/eicon/debuglib.h
> +++ b/drivers/isdn/hardware/eicon/debuglib.h
> @@ -249,7 +249,7 @@ typedef struct _DbgHandle_
>  }     regTime ;  /* timestamp for registration       */
>  void               *pIrp ;   /* ptr to pending i/o request       */
>  unsigned long       dbgMask ;  /* current debug mask               */
> - char                drvName[16] ; /* ASCII name of registered driver  */
> + char                drvName[128] ; /* ASCII name of registered driver  */
>  char                drvTag[64] ; /* revision string     */
>  DbgEnd              dbg_end ;  /* function for debug closing       */
>  DbgLog              dbg_prt ;  /* function for debug appending     */
> diff --git a/drivers/isdn/hardware/eicon/debug.c b/drivers/isdn/hardware/eicon/debug.c
> index 33ce89e..3626401 100644
> --- a/drivers/isdn/hardware/eicon/debug.c
> +++ b/drivers/isdn/hardware/eicon/debug.c
> @@ -862,7 +862,7 @@ void diva_mnt_add_xdi_adapter (const DESCRIPTOR* d) {
>   diva_os_spin_lock_magic_t old_irql, old_irql1;
>   dword sec, usec, logical, serial, org_mask;
>   int id, best_id = 0, free_id = -1;
> -  char tmp[256];
> +  char tmp[128];
>   diva_dbg_entry_head_t* pmsg = NULL;
>   int len;
>   word size;
>
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Dan Carpenter - Oct. 6, 2010, 7:47 a.m.
On Wed, Oct 06, 2010 at 09:25:44AM +0200, Armin Schindler wrote:
> On Mon, 4 Oct 2010, Dan Carpenter wrote:
>> In diva_mnt_add_xdi_adapter() we do this:
>>  strcpy (clients[id].drvName,     tmp);
>>  strcpy (clients[id].Dbg.drvName, tmp);
>>
>> The "clients[id].drvName" is a 128 character buffer and
>> "clients[id].Dbg.drvName" was originally a 16 character buffer but I've
>> changed it to 128 as well.  We don't actually use 128 characters but we
>> do use more than 16.
>
> I don't see any reason for that change. The driver names here do not use  
> more than 16 characters and when filled, the length is checked anyway.
> Please avoid changing the size of that structure.
>

drivers/isdn/hardware/eicon/debug.c diva_mnt_add_xdi_adapter()
   874      sprintf (tmp, "ADAPTER:%d SN:%u-%d",
                           12345678 90123 45 67

	That's a minimum 17 characters.

   875               (int)logical,
   876               serial & 0x00ffffff,
   877               (byte)(((serial & 0xff000000) >> 24) + 1));
   878    } else {
   879      sprintf (tmp, "ADAPTER:%d SN:%u", (int)logical, serial);
   880    }

regards,
dan carpenter

> Armin

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walter harms - Oct. 6, 2010, 8:16 a.m.
Dan Carpenter schrieb:
> On Wed, Oct 06, 2010 at 09:25:44AM +0200, Armin Schindler wrote:
>> On Mon, 4 Oct 2010, Dan Carpenter wrote:
>>> In diva_mnt_add_xdi_adapter() we do this:
>>>  strcpy (clients[id].drvName,     tmp);
>>>  strcpy (clients[id].Dbg.drvName, tmp);
>>>
>>> The "clients[id].drvName" is a 128 character buffer and
>>> "clients[id].Dbg.drvName" was originally a 16 character buffer but I've
>>> changed it to 128 as well.  We don't actually use 128 characters but we
>>> do use more than 16.
>> I don't see any reason for that change. The driver names here do not use  
>> more than 16 characters and when filled, the length is checked anyway.
>> Please avoid changing the size of that structure.
>>
> 
> drivers/isdn/hardware/eicon/debug.c diva_mnt_add_xdi_adapter()
>    874      sprintf (tmp, "ADAPTER:%d SN:%u-%d",
>                            12345678 90123 45 67
> 
> 	That's a minimum 17 characters.
> 
>    875               (int)logical,
>    876               serial & 0x00ffffff,
>    877               (byte)(((serial & 0xff000000) >> 24) + 1));
>    878    } else {
>    879      sprintf (tmp, "ADAPTER:%d SN:%u", (int)logical, serial);
>    880    }
> 


for that reason i am a fan of kasprintf().
Maybe this a solution here also ? samething like:

kasprintf (&buf, "ADAPTER:%d SN:%u-%d",12345678,90123,45,67):
...
kstrncpy(tmp,buf,sizeof(buf));
....
free(buf);

that would keep overflows away until the changes in the structure are ready.

re,
 wh
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Armin Schindler - Oct. 6, 2010, 8:21 a.m.
On Wed, 6 Oct 2010, Dan Carpenter wrote:
> On Wed, Oct 06, 2010 at 09:25:44AM +0200, Armin Schindler wrote:
>> On Mon, 4 Oct 2010, Dan Carpenter wrote:
>>> In diva_mnt_add_xdi_adapter() we do this:
>>>  strcpy (clients[id].drvName,     tmp);
>>>  strcpy (clients[id].Dbg.drvName, tmp);
>>>
>>> The "clients[id].drvName" is a 128 character buffer and
>>> "clients[id].Dbg.drvName" was originally a 16 character buffer but I've
>>> changed it to 128 as well.  We don't actually use 128 characters but we
>>> do use more than 16.
>>
>> I don't see any reason for that change. The driver names here do not use
>> more than 16 characters and when filled, the length is checked anyway.
>> Please avoid changing the size of that structure.
>>
>
> drivers/isdn/hardware/eicon/debug.c diva_mnt_add_xdi_adapter()
>   874      sprintf (tmp, "ADAPTER:%d SN:%u-%d",
>                           12345678 90123 45 67
>
> 	That's a minimum 17 characters.
>
>   875               (int)logical,
>   876               serial & 0x00ffffff,
>   877               (byte)(((serial & 0xff000000) >> 24) + 1));
>   878    } else {
>   879      sprintf (tmp, "ADAPTER:%d SN:%u", (int)logical, serial);
>   880    }

this is tmp with a bigger size. It seems you are mixing the sizes of 
drvName and tmp.

Armin
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Dan Carpenter - Oct. 6, 2010, 8:31 a.m.
On Wed, Oct 06, 2010 at 10:21:02AM +0200, Armin Schindler wrote:
> On Wed, 6 Oct 2010, Dan Carpenter wrote:
>> On Wed, Oct 06, 2010 at 09:25:44AM +0200, Armin Schindler wrote:
>>> On Mon, 4 Oct 2010, Dan Carpenter wrote:
>>>> In diva_mnt_add_xdi_adapter() we do this:
>>>>  strcpy (clients[id].drvName,     tmp);
>>>>  strcpy (clients[id].Dbg.drvName, tmp);
>>>>
>>>> The "clients[id].drvName" is a 128 character buffer and
>>>> "clients[id].Dbg.drvName" was originally a 16 character buffer but I've
>>>> changed it to 128 as well.  We don't actually use 128 characters but we
>>>> do use more than 16.
>>>
>>> I don't see any reason for that change. The driver names here do not use
>>> more than 16 characters and when filled, the length is checked anyway.
>>> Please avoid changing the size of that structure.
>>>
>>
>> drivers/isdn/hardware/eicon/debug.c diva_mnt_add_xdi_adapter()
>>   874      sprintf (tmp, "ADAPTER:%d SN:%u-%d",
>>                           12345678 90123 45 67
>>
>> 	That's a minimum 17 characters.
>>
>>   875               (int)logical,
>>   876               serial & 0x00ffffff,
>>   877               (byte)(((serial & 0xff000000) >> 24) + 1));
>>   878    } else {
>>   879      sprintf (tmp, "ADAPTER:%d SN:%u", (int)logical, serial);
>>   880    }
>
> this is tmp with a bigger size. It seems you are mixing the sizes of  
> drvName and tmp.
>

What I mean is that later on we use strcpy() to copy "tmp" into
"clients[id].Dbg.drvName"

   927    strcpy (clients[id].drvName,     tmp);
   928    strcpy (clients[id].Dbg.drvName, tmp);
                               ^
                    this buffer is only 16 chars

regards,
dan carpenter

> Armin
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Armin Schindler - Oct. 6, 2010, 8:44 a.m.
On Wed, 6 Oct 2010, Dan Carpenter wrote:
> On Wed, Oct 06, 2010 at 10:21:02AM +0200, Armin Schindler wrote:
>> On Wed, 6 Oct 2010, Dan Carpenter wrote:
>>> On Wed, Oct 06, 2010 at 09:25:44AM +0200, Armin Schindler wrote:
>>>> On Mon, 4 Oct 2010, Dan Carpenter wrote:
>>>>> In diva_mnt_add_xdi_adapter() we do this:
>>>>>  strcpy (clients[id].drvName,     tmp);
>>>>>  strcpy (clients[id].Dbg.drvName, tmp);
>>>>>
>>>>> The "clients[id].drvName" is a 128 character buffer and
>>>>> "clients[id].Dbg.drvName" was originally a 16 character buffer but I've
>>>>> changed it to 128 as well.  We don't actually use 128 characters but we
>>>>> do use more than 16.
>>>>
>>>> I don't see any reason for that change. The driver names here do not use
>>>> more than 16 characters and when filled, the length is checked anyway.
>>>> Please avoid changing the size of that structure.
>>>>
>>>
>>> drivers/isdn/hardware/eicon/debug.c diva_mnt_add_xdi_adapter()
>>>   874      sprintf (tmp, "ADAPTER:%d SN:%u-%d",
>>>                           12345678 90123 45 67
>>>
>>> 	That's a minimum 17 characters.
>>>
>>>   875               (int)logical,
>>>   876               serial & 0x00ffffff,
>>>   877               (byte)(((serial & 0xff000000) >> 24) + 1));
>>>   878    } else {
>>>   879      sprintf (tmp, "ADAPTER:%d SN:%u", (int)logical, serial);
>>>   880    }
>>
>> this is tmp with a bigger size. It seems you are mixing the sizes of
>> drvName and tmp.
>>
>
> What I mean is that later on we use strcpy() to copy "tmp" into
> "clients[id].Dbg.drvName"
>
>   927    strcpy (clients[id].drvName,     tmp);
>   928    strcpy (clients[id].Dbg.drvName, tmp);
>                               ^
>                    this buffer is only 16 chars

Now I understand. You are right. So the fix would be to change these 
strcpy() to e.g. strncpy() or similar.

Armin

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Dan Carpenter - Oct. 6, 2010, 12:11 p.m.
On Wed, Oct 06, 2010 at 10:44:47AM +0200, Armin Schindler wrote:
>>   927    strcpy (clients[id].drvName,     tmp);
>>   928    strcpy (clients[id].Dbg.drvName, tmp);
>>                               ^
>>                    this buffer is only 16 chars
>
> Now I understand. You are right. So the fix would be to change these  
> strcpy() to e.g. strncpy() or similar.
>

We need more than 16 characters to store the information.  What is the
problem with just making the buffer larger?

regards,
dan carpenter

> Armin
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Armin Schindler - Oct. 6, 2010, 12:49 p.m.
On Wed, 6 Oct 2010, Dan Carpenter wrote:
> On Wed, Oct 06, 2010 at 10:44:47AM +0200, Armin Schindler wrote:
>>>   927    strcpy (clients[id].drvName,     tmp);
>>>   928    strcpy (clients[id].Dbg.drvName, tmp);
>>>                               ^
>>>                    this buffer is only 16 chars
>>
>> Now I understand. You are right. So the fix would be to change these
>> strcpy() to e.g. strncpy() or similar.
>>
>
> We need more than 16 characters to store the information.  What is the
> problem with just making the buffer larger?

The larger buffer is not really needed. Later versions of the driver will 
use the strcpy/memcpy with checked size anyway.
I just want to avoid a change in the debug structure which is used in more than one module/tool.

But it shouldn't be a real problem.

Armin


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David Miller - Oct. 7, 2010, 6:30 a.m.
From: Dan Carpenter <error27@gmail.com>
Date: Mon, 4 Oct 2010 21:24:59 +0200

> In diva_mnt_add_xdi_adapter() we do this:
>   strcpy (clients[id].drvName,     tmp);
>   strcpy (clients[id].Dbg.drvName, tmp);
> 
> The "clients[id].drvName" is a 128 character buffer and
> "clients[id].Dbg.drvName" was originally a 16 character buffer but I've
> changed it to 128 as well.  We don't actually use 128 characters but we
> do use more than 16.
> 
> I've also changed the size of "tmp" to 128 characters instead of 256.
> 
> Signed-off-by: Dan Carpenter <error27@gmail.com>

Applied.
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Patch

diff --git a/drivers/isdn/hardware/eicon/debuglib.h b/drivers/isdn/hardware/eicon/debuglib.h
index 8ea5877..02eed6b 100644
--- a/drivers/isdn/hardware/eicon/debuglib.h
+++ b/drivers/isdn/hardware/eicon/debuglib.h
@@ -249,7 +249,7 @@  typedef struct _DbgHandle_
  }     regTime ;  /* timestamp for registration       */
  void               *pIrp ;   /* ptr to pending i/o request       */
  unsigned long       dbgMask ;  /* current debug mask               */
- char                drvName[16] ; /* ASCII name of registered driver  */
+ char                drvName[128] ; /* ASCII name of registered driver  */
  char                drvTag[64] ; /* revision string     */
  DbgEnd              dbg_end ;  /* function for debug closing       */
  DbgLog              dbg_prt ;  /* function for debug appending     */
diff --git a/drivers/isdn/hardware/eicon/debug.c b/drivers/isdn/hardware/eicon/debug.c
index 33ce89e..3626401 100644
--- a/drivers/isdn/hardware/eicon/debug.c
+++ b/drivers/isdn/hardware/eicon/debug.c
@@ -862,7 +862,7 @@  void diva_mnt_add_xdi_adapter (const DESCRIPTOR* d) {
   diva_os_spin_lock_magic_t old_irql, old_irql1;
   dword sec, usec, logical, serial, org_mask;
   int id, best_id = 0, free_id = -1;
-  char tmp[256];
+  char tmp[128];
   diva_dbg_entry_head_t* pmsg = NULL;
   int len;
   word size;