On Tue, Sep 24, 2013 at 4:37 PM, David Raynor <dray...@sourcefire.com>wrote:
> On Tue, Sep 24, 2013 at 2:05 AM, Tsutomu Oyamada
> <oyam...@promark-inc.com>wrote:
>
>> Hi,
>>
>> I investigated the value using the following programs.
>>
>> ----
>> #include "stdlib.h"
>> #include "bignum_fast.h"
>>
>> int main(int argc, char **argv) {
>>
>> printf("fp_digit: %d\n",sizeof(fp_digit));
>> printf("unsigned long: %d\n",sizeof(unsigned long));
>>
>> #ifdef FP_64BIT
>> printf("FP_64BIT: %d\n",FP_64BIT);
>> #else
>> printf("FP_64BIT not defined\n");
>> #endif
>>
>> #ifdef DIGIT_BIT
>> printf("DIGIT_BIT: %d\n",DIGIT_BIT);
>> #else
>> printf("DIGIT_BIT not defined\n");
>> #endif
>>
>> #ifdef CHAR_BIT
>> printf("CHAR_BIT: %d\n",CHAR_BIT);
>> #else
>> printf("CHAR_BIT not defined\n");
>> #endif
>>
>> #ifdef FP_MAX_SIZE
>> printf("FP_MAX_SIZE: %d\n",FP_MAX_SIZE);
>> #else
>> printf("FP_MAX_SIZE not defined\n");
>> #endif
>>
>> #ifdef FP_SIZE
>> printf("FP_SIZE: %d\n",FP_SIZE);
>> #else
>> printf("FP_SIZE not defined\n");
>> #endif
>>
>> #ifdef TFM_ASM
>> printf("TFM_ASM: defined\n");
>> #else
>> printf("TFM_ASM not defined\n");
>> #endif
>>
>> exit(0);
>> }
>> ----
>>
>> The result was as follows.
>>
>> fp_digit: 8
>> unsigned long: 8
>> FP_64BIT not defined
>> DIGIT_BIT: 64
>> CHAR_BIT: 8
>> FP_MAX_SIZE: 8704
>> FP_SIZE: 136
>> TFM_ASM not defined
>>
>> Can you find a problem by this result?
>>
>> Thanks.
>>
>> --
>> T.Oyamada
>>
>> _______________________________________________
>> http://lurker.clamav.net/list/clamav-devel.html
>> Please submit your patches to our Bugzilla: http://bugs.clamav.net
>>
>
> I do not have an immediate fix, but that information does give me some
> leads.
>
> Basic issue: the tomsfastmath code must be falling through to the code
> block on lines 280-302 of fp_mul_comba.c.
> 1) The right shift causing the warning is DIGIT_BIT (64).
> 2) The datatype being shifted is fp_word.
> 3) fp_word defined as "typedef ulong64 fp_word;" from bignum_fast.h line
> 253
> 4) ulong64 defined as "typedef unsigned long long ulong64;" from
> bignum_fast.h line 248
>
> I think the problem is one of three issues:
> A) fp_word is not defined as a 64-bit datatype.
> B) line 301 of tomsfastmath/mul/fp_mul_comba.c is mistakenly downcasting t
> from fp_word to fp_digit before shifting.
> C) s390 is not allowing use of all 64 bits of fp_word.
>
> Problems A or B are easier fixed than C.
>
> Please add these lines to your test and re-run:
>
> printf("fp_word: %d\n",sizeof(fp_word));
> printf("ulong64: %d\n",sizeof(ulong64));
> printf("unsigned long long: %d\n",sizeof(unsigned long long));
> #ifdef CRYPT
> printf("CRYPT: defined\n");
> #else
> printf("CRYPT not defined\n");
> #endif
>
> I would like to see the config.log file generated by running configure. It
> would also be useful to have the full output from running make. The log
> snip shows line 91, but I expect that it first warned about line 15.
>
> The easiest way to continue and share logfiles is via Bugzilla. Please
> open a bug report on bugzilla.clamav.net on this issue. You can then
> attach the files to that bug.
>
> Hope this helps,
>
>
> Dave R.
>
> --
> ---
> Dave Raynor
> Sourcefire Vulnerability Research Team
> dray...@sourcefire.com
>
I think I read something wrong, and I think I have an idea. It still needs
to be confirmed by the additional test lines above. Re-reading the output,
I think that the code is depending on fp_word being twice the size of
fp_digit. Based on fp_digit size of 8 that means it would expect it to be
16. If sizeof(fp_word) is resolving to 8 and sizeof(fp_digit) is 8, that
could be the problem. Then the fix would depend on whether fp_word can be
made size 16 or must be constrained to size 8.
Let me know what you find,
Dave R.
--
---
Dave Raynor
Sourcefire Vulnerability Research Team
dray...@sourcefire.com
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