Re: [Linux-ima-user] verifying measurements list with PCR10

[adrian g. <adr...@gm...>]

please disregard my last message. i realised that the problem is that the
way i obtain the measurement file (using vim) is also being measured, which
i didn't factor in.

sorry  - adrian

On Tue, Oct 14, 2008 at 3:58 PM, adrian golding <adr...@gm...>wrote:

> hi, i tried again to verify the measurements, this time in C:
> i followed closely to the pseudo code provided in the ima INSTALL file:
>
>     char fileName[50] = "ascii_runtime_measurements";
>     unsigned char*    buf, event;
>
>     memset(PCR, 0, SHA_DIGEST_LENGTH);
>     while(fgets(event, 1024, fd_bin_measurements) != NULL) {
>
>         buf = event + 3; // skip to the start of the hash
>
>         for(j = 0; j < SHA_DIGEST_LENGTH; j++){
>             strncpy(testText, buf + 2*j, 2);
>             intResult = convertToInt(testText);  //change 2 bytes of char,
> take it as a hex number and change it to int
>                                                                 //
> intResult will be between 0 to 255.
>             memset(tempPointer + j, intResult, 1);
>         }
>
>         SHA1_Init(&c);
>         SHA1_Update(&c, PCR, SHA_DIGEST_LENGTH);
>         SHA1_Update(&c, tempPointer, SHA_DIGEST_LENGTH);
>         SHA1_Final(PCR, &c);
>     }
>
> i assume using the ascii file is alright and i checked the convertToInt
> function and it converts correctly.
> i also ran it several times since a new version of my program generates a
> new reading.
>
> thank you- adrian
>
>
> On Wed, Oct 8, 2008 at 10:58 AM, adrian golding <adr...@gm...>wrote:
>
>> i am trying to write a simple python script to verify my measurements list
>> with PCR10 but it doesn't match.  Anybody see the mistake?
>> thank you - adrian
>>
>> previousPCRValue = "0000000000000000000000000000000000000000"
>>
>> for line in obtainedFile.readlines():
>>
>>     lineArray = str.split(line)
>>     # using ascii measurements file, lineArray[1] is the hash value
>>
>>     # concatenation
>>     combineHex    = previousPCRValue + lineArray[1]
>>     # change to binary
>>     combineBinary     = binascii.unhexlify(combineHex)
>>     # hash it
>>     computedHash = hashlib.sha1(combineBinary)
>>     # change it to hex
>>     previousPCRValue = computedHash.hexdigest()
>>
>>
>>
>