From mboxrd@z Thu Jan  1 00:00:00 1970
From: Maxime Coquelin <maxime.coquelin@redhat.com>
Subject: Re: [PATCH] examples/vhost_scsi: fix buffer not
	terminated
Date: Mon, 2 Oct 2017 17:07:22 +0200
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References: <20170922130734.7256-1-michalx.k.jastrzebski@intel.com>
 <60ABE07DBB3A454EB7FAD707B4BB158213C40F16@IRSMSX109.ger.corp.intel.com>
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Cc: "dev@dpdk.org" <dev@dpdk.org>, "Jain, Deepak K"
 <deepak.k.jain@intel.com>, "Piasecki, JacekX" <jacekx.piasecki@intel.com>,
 "Liu, Changpeng" <changpeng.liu@intel.com>, "stable@dpdk.org"
 <stable@dpdk.org>
To: "Jastrzebski, MichalX K" <michalx.k.jastrzebski@intel.com>,
 "yliu@fridaylinux.org" <yliu@fridaylinux.org>
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On 10/02/2017 03:50 PM, Jastrzebski, MichalX K wrote:
>> -----Original Message-----
>> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Michal Jastrzebski
>> Sent: Friday, September 22, 2017 3:08 PM
>> To: yliu@fridaylinux.org; maxime.coquelin@redhat.com
>> Cc: dev@dpdk.org; Jain, Deepak K <deepak.k.jain@intel.com>; Piasecki,
>> JacekX <jacekx.piasecki@intel.com>; Liu, Changpeng
>> <changpeng.liu@intel.com>; stable@dpdk.org
>> Subject: [dpdk-dev] [PATCH] examples/vhost_scsi: fix buffer not terminated
>>
>> From: Jacek Piasecki <jacekx.piasecki@intel.com>
>>
>> Fix size of buffer in strcpy. There was possible to get
>> not terminated string after copy operation.
>>
>> Coverity issue: 158631
>> Fixes: db75c7af19bb ("examples/vhost_scsi: introduce a new sample app")
>> Cc: changpeng.liu@intel.com
>> Cc: stable@dpdk.org
>>
>> Signed-off-by: Jacek Piasecki <jacekx.piasecki@intel.com>
>> ---
>>   examples/vhost_scsi/scsi.c | 3 ++-
>>   1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/examples/vhost_scsi/scsi.c b/examples/vhost_scsi/scsi.c
>> index 54d3104..de9639a 100644
>> --- a/examples/vhost_scsi/scsi.c
>> +++ b/examples/vhost_scsi/scsi.c
>> @@ -307,7 +307,8 @@
>>   		strncpy((char *)inqdata->t10_vendor_id, "INTEL", 8);
>>
>>   		/* PRODUCT IDENTIFICATION */
>> -		strncpy((char *)inqdata->product_id, bdev->product_name,
>> 16);
>> +		strncpy((char *)inqdata->product_id, bdev->product_name,
>> +				ARRAY_SIZE(inqdata->product_id) - 1);

Does it assume that product_id is memzero'ed before?
IIUC strncpy manpage, it wouldn't protect against non-null terminated
strings if it is not the case:

"
        A simple implementation of strncpy() might be:

            char *
            strncpy(char *dest, const char *src, size_t n)
            {
                size_t i;

                for (i = 0; i < n && src[i] != '\0'; i++)
                    dest[i] = src[i];
                for ( ; i < n; i++)
                    dest[i] = '\0';

                return dest;
            }
"

Cheers,
Maxime

>>
>>   		/* PRODUCT REVISION LEVEL */
>>   		strncpy((char *)inqdata->product_rev, "0001", 4);
>> --
>> 1.9.1
> 
> Hi Yu / Maxime,
> I would like to ask for a feedback regarding proposed fix.
> If everything is ok with it, please send acked-by.
> 
> Best regards
> Michal.
>