[dvblast-devel] Compile failure on x86_64

[Georgi Chorbadzhiyski]

Around 10/02/2012 12:25 PM, Alexei Takaseev scribbled:
>> On 10/2/12 8:11 AM, Alexei Takaseev wrote:
>>> System ALT Linux Sisuphus 01-10-2012
>>> arch x86_64
>>> glibc 2.16
>>> gcc version 4.7.2 20120920 (ALT Linux 4.7.2-alt2) (GCC)
>>>
>>> Compile failure on x86_64 with:
> ....
>>> In file included from /usr/include/string.h:656:0,
>>>                   from en50221.c:30:
>>> In function 'memcpy',
>>>      inlined from 'TPDUSend.constprop.35' at en50221.c:318:19,
>>>      inlined from 'SPDUSend' at en50221.c:500:26:
>>> /usr/include/bits/string3.h:51:3: error: call to
>>> __builtin___memcpy_chk will always overflow destination buffer
>>> make: *** [en50221.o] Error 1
>>> make: Leaving directory `/usr/src/RPM/BUILD/dvblast-2.2'
>>> ===========================================================
>>>
>>> On the i586 architecture there are no compilation errors.
>>>
>>> Has anyone successfully compiled with the combination of x86_64 +
>>> gcc 4.7 + glibc 2.16 + last dvblast of git?
>>
>> Ok, I don't see it:
>>
>>      313     case T_DATA_LAST:
>>      314     case T_DATA_MORE:
>>      315     {
>>      316         /* i_length <= MAX_TPDU_DATA */
>>      317         uint8_t *p = p_data + 3;
>>      318         p = SetLength( p, i_length + 1 );
>>      319         *p++ = i_tcid;
>>      320
>>      321         if ( i_length )
>>      322             memcpy( p, p_content, i_length );
>>      323             i_size = i_length + (p - p_data);
>>      324         }
>>      325         break;
>>
>> The memcpy will overflow if i_length is > MAX_TPDU_DATA but we
>> never called this function with more than MAX_TPDU_DATA set as
>> i_length.
>> Am I missing something?
>>
>> This patch probably wrong, but please try it to see if the error goes
>> away:
>>
>> diff --git a/en50221.c b/en50221.c
>> index 0724fb3..049c5c2 100644
>> --- a/en50221.c
>> +++ b/en50221.c
>> @@ -205,7 +205,7 @@ static uint8_t *SetLength( uint8_t *p_data, int
>> i_length )
>>    */
>>
>>   #define MAX_TPDU_SIZE  4096
>> -#define MAX_TPDU_DATA  (MAX_TPDU_SIZE - 4)
>> +#define MAX_TPDU_DATA  (MAX_TPDU_SIZE - 8)
>>
>>   #define DATA_INDICATOR 0x80
> 
> The compilation process stopped in the same place with the same error.

In that case as far as I can see this not a bug in dvblast.

Try with glibc != 2.16 because the bug probably there. With 2.15 there are
no such problems.

-- 
Georgi Chorbadzhiyski
http://georgi.unixsol.org/