When I use VC++ 6.0(with SP5.0) like this:
char temp[2];
memset(temp,0,sizeof(temp));
strcpy(temp,"This is a test\0");
MessageBox(0,temp,temp,MB_OK);
The result in temp[2] is "This is a test".There is only two bytes of memory,why can copy more than 2 bytes char
Question about C++ char Pointer
KevinMacDonald
One problem with using the secure CRT functions is that you cannot target multiple compilers with the same code base. We have a library that's to work on VC6, 7.1 and 2005, and we had to wrap the string functions so that they'd compile without warnings on all 3 compilers. Pretty much of a pain in the rear it was too :-)
Krishnan MSFT
I can see a demand for a reverse-engineered (or semi-so) Secure CRT for people to write portable code.
Dan Crowell
To add to what Chris said, I believe you are running the debug build. You may get a crash and/or corrupted variables in a release build.
jigee
Also, you should use: strcpy_s as strcpy has been deprecated.
strcpy_s requires you to pass in the size of the block you are writing to as well as the number of bytes being written so that it can perform a check and prevent overflow.
snark112
VS 2003 (VC7.1) and VS 2005 (VC8) compilers feature a /GS switch (off by default in 2003, on by default in 2005) that causes some code to be injected into each epilog to check for stack buffer overwrites. Not only do stack buffer overwrites clobber data in general, but also presents the kind of attack where the function return address slot on the stack can be written with an address of a malicilous payload.
Security wasn't a hot issue back in the VC6 days.
Brian
Sudheer_Dhulipalla_MSFT
It probably overflows to the next char buffer, as strcpy doesn’t have buffer checking.
Regards,
-chris
Kate O
I'm in the same boat. Rather than even attempting what you did, in my shared header I put in the lines below. I don't think I've ever run into a case where the Secure CRT would have caught a bug in my code anyway. (For large mission critical code bases, I can see the need for the Secure CRT, otherwise it's a pain as you say.)
#ifndef _SECURE_SCL
#define _SECURE_SCL 0
#endif
#ifndef _CRT_SECURE_NO_DEPRECATE
#define _CRT_SECURE_NO_DEPRECATE
#endif
#ifndef _CRT_NONSTDC_NO_DEPRECATE
#define _CRT_NONSTDC_NO_DEPRECATE
#endif
#ifndef _SCL_SECURE_NO_DEPRECATE
#define _SCL_SECURE_NO_DEPRECATE
#endif
renz2k7
Our product is a source code library, so we cannot do that - because our clients may actually want the secure CRT warnings enabled. That's why we had to wrap them all!
Cyn2255
Regards,
-chris
Tristao