linux-kernel - Re: [PATCH] IDE-TAPE NULL terminate strings.

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Message-ID: <20080923074845.GB5656@gollum.tnic>
Date:	Tue, 23 Sep 2008 09:48:45 +0200
From:	Borislav Petkov <petkovbb@...glemail.com>
To:	Sergei Shtylyov <sshtylyov@...mvista.com>
Cc:	Mark de Wever <koraq@...all.nl>,
	Gadi Oxman <gadio@...vision.net.il>,
	Bartlomiej Zolnierkiewicz <bzolnier@...il.com>,
	linux-ide@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] IDE-TAPE NULL terminate strings.

On Tue, Sep 23, 2008 at 01:08:25AM +0400, Sergei Shtylyov wrote:
> Hello.
>
> Mark de Wever wrote:
>
>>> .. and I know why :). Those ide_tape_obj members (char fw_rev[6], vendor_id[10],
>>> product_id[18]) were used only once in idetape_get_inquiry_results() so I moved
>>> them there as local stack variables. Originally, they were kzalloc'ed as part of
>>> struct ide_tape_obj and now they contain stack garbage therefore the funny
>>> values. The simple solution would be to zero them out or:
>>>
>>>
>>> Does the following patch help?
>>>     
>>
>> Yes feel free to add my tested-by.
>>   
>
>   And my NAK too. :-)
>
>> Only not sure whether the static is the best solution, the following
>> patch also works, by zeroing the memory as you suggested.
>>
>> Signed-off-by: Mark de Wever <koraq@...all.nl>
>>
>> diff --git a/drivers/ide/ide-tape.c b/drivers/ide/ide-tape.c
>> index 1bce84b..c41f5b1 100644
>> --- a/drivers/ide/ide-tape.c
>> +++ b/drivers/ide/ide-tape.c
>> @@ -2338,7 +2338,7 @@ static void idetape_get_inquiry_results(ide_drive_t *drive)
>>  {
>>  	idetape_tape_t *tape = drive->driver_data;
>>  	struct ide_atapi_pc pc;
>> -	char fw_rev[6], vendor_id[10], product_id[18];
>> +	char fw_rev[6] = {'\0'}, vendor_id[10] = {'\0'}, product_id[18] = {'\0'};
>>   
>
>   Do you realize how much *absolutely unnecessary* code will this bring  
> in? This is certainly worse than your initial patch (if it was correct).

Yep, Sergei's right. Both of our patches are dumb.

> Ugh, looks like I'll have t submit the patch myself to stop this ugliness...

Is this what you had in mind?

---
diff --git a/drivers/ide/ide-tape.c b/drivers/ide/ide-tape.c
index 1bce84b..3833189 100644
--- a/drivers/ide/ide-tape.c
+++ b/drivers/ide/ide-tape.c
@@ -2338,7 +2338,7 @@ static void idetape_get_inquiry_results(ide_drive_t *drive)
 {
 	idetape_tape_t *tape = drive->driver_data;
 	struct ide_atapi_pc pc;
-	char fw_rev[6], vendor_id[10], product_id[18];
+	char fw_rev[4], vendor_id[8], product_id[16];
 
 	idetape_create_inquiry_cmd(&pc);
 	if (idetape_queue_pc_tail(drive, &pc)) {
@@ -2350,11 +2350,11 @@ static void idetape_get_inquiry_results(ide_drive_t *drive)
 	memcpy(product_id, &pc.buf[16], 16);
 	memcpy(fw_rev, &pc.buf[32], 4);
 
-	ide_fixstring(vendor_id, 10, 0);
-	ide_fixstring(product_id, 18, 0);
-	ide_fixstring(fw_rev, 6, 0);
+	ide_fixstring(vendor_id, 8, 0);
+	ide_fixstring(product_id, 16, 0);
+	ide_fixstring(fw_rev, 4, 0);
 
-	printk(KERN_INFO "ide-tape: %s <-> %s: %s %s rev %s\n",
+	printk(KERN_INFO "ide-tape: %s <-> %s: %.8s %.16s rev %.4s\n",
 			drive->name, tape->name, vendor_id, product_id, fw_rev);
 }
 


-- 
Regards/Gruss,
    Boris.
--
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