[libdvdnav-devel] [PATCH] sprintf -> strcpy

[Lawrence D'Oliveiro]

On Wed, 09 Sep 2015 12:23:09 +0300, Petri Hintukainen wrote:

> On ke, 2015-09-09 at 19:57 +1200, Lawrence D'Oliveiro wrote:
>
>> On Wed,  9 Sep 2015 10:11:16 +0300, Petri Hintukainen wrote:
>> 
>>> -    sprintf( filename, "/VIDEO_TS/VIDEO_TS.VOB" );
>>> +    strcpy( filename, "/VIDEO_TS/VIDEO_TS.VOB" );
>> [etc]
>> 
>> I would not use either. I would use strncpy instead.
> 
> Why ?
> 
> Constant string is copied to constant-size buffer. Buffer overflow
> checks should be done at compile time, not runtime.

    ldo at theon:c_try> cat overflow.c
    #include <string.h>

    int main(void)
      {
        char buf[5];
        strcpy(buf, "THIS STRING IS MUCH TOO LARGE");
        return
            0;
      } /*main*/
    ldo at theon:c_try> gcc -c overflow.c 
    ldo at theon:c_try> 

As you can see, there is no error reported.

What compile-time option should I use to ask for one?