LabVIEW crashes _dll

[supriyav]

I’ve a C dll which I’m going to invoke in my vi.

The C dll consists of 4 functions in that I’m going to use only 2 functions. AES_set_encrypt_key and AES_encrypt

Prototypes of that 2 functions are

int AES_set_encrypt_key(const unsigned char *userKey, const int bits,

AES_KEY *key);

void AES_encrypt(const unsigned char *in, unsigned char *out,

const AES_KEY *key);

userkey---pointer to an U8 array

Key---- pointer to a structure AES_KEY

Below is the structure:

struct aes_key_st {

#ifdef AES_LONG

unsigned long rd_key[4 *(AES_MAXNR + 1)];

#else

unsigned int rd_key[4 *(AES_MAXNR + 1)];

#endif

int rounds;

};

typedef struct aes_key_st AES_KEY;

In the AES_set_encrypt_key function the first two arguments are input and the third is the output.

The output (key) of this AES_set_encrypt_key function is going to used by the AES_encrypt_ function as input.

In the AES_encrypt_ function the first and third arguments are input and the second is the output.

I’ve created a vi set_encrypt.vi in which

Parameter Type Data Type Format/Pass

userkey Array Unsigned 8-bit Integer Array Data Pointer

Bits Numeric signed 16-bit Integer Value

Key Array Unsigned 32-bit Integer Array Data Pointer

This vi actually crashes. I thought this is crashing since the Key is a pointer to a structure but I’ve configured that argument to Array Pointer.

So I’ve created cluster2.vi using cluster for the third parameter and converting this to U32

Key Array Unsigned 32-bit Integer Array Data Pointer

This also crashes.

The calling Convention for the dll and for the Call Library function are the same.

So I’ve created cluster3.vi using cluster for the third parameter and changed the type to Adapt To Type.

Key Adapt to Type Pointers to handles

But even this also crashes.

The calling Convention for the dll and for the Call Library function is the same.

Pls find the attached vis and dll.

Pls guide me in this regard

Thanks And Regards

SupriyaV

Download File:post-2648-1137846998.zip

Download File:post-2648-1137847028.zip

[Rolf Kalbermatter]

int AES_set_encrypt_key(const unsigned char *userKey, const int bits,

AES_KEY *key);

void AES_encrypt(const unsigned char *in, unsigned char *out,

const AES_KEY *key);

userkey---pointer to an U8 array

Key---- pointer to a structure AES_KEY

Below is the structure:

struct aes_key_st {

#ifdef AES_LONG

unsigned long rd_key[4 *(AES_MAXNR + 1)];

#else

unsigned int rd_key[4 *(AES_MAXNR + 1)];

#endif

int rounds;

};

typedef struct aes_key_st AES_KEY;

In the AES_set_encrypt_key function the first two arguments are input and the third is the output.

The output (key) of this AES_set_encrypt_key function is going to used by the AES_encrypt_ function as input.

In the AES_encrypt_ function the first and third arguments are input and the second is the output.

I?ve created a vi set_encrypt.vi in which

Parameter Type Data Type Format/Pass

userkey Array Unsigned 8-bit Integer Array Data Pointer

Bits Numeric signed 16-bit Integer Value

Key Array Unsigned 32-bit Integer Array Data Pointer

This vi actually crashes. I thought this is crashing since the Key is a pointer to a structure but I?ve configured that argument to Array Pointer.

So I?ve created cluster2.vi using cluster for the third parameter and converting this to U32

Key Array Unsigned 32-bit Integer Array Data Pointer

This also crashes.

The calling Convention for the dll and for the Call Library function are the same.

So I?ve created cluster3.vi using cluster for the third parameter and changed the type to Adapt To Type.

Key Adapt to Type Pointers to handles

But even this also crashes.

The calling Convention for the dll and for the Call Library function is the same.

Pls find the attached vis and dll.

Pls guide me in this regard

Thanks And Regards

SupriyaV

First an int in modern Windows is always 32 bit and not 16 as you have assumed for the Bits parameter of the first function. This probably will neck you as well in the third parameter since you need to provide enough memory for the function to write into and if you assumed 16bit for the values in there your buffer is likely calculated to small.

Second while you have this time properly documented the type of AES_KEY you still missed to provide important information. Without knowing the value of AES_MAXNR one can NOT calculate the size of the buffer you need to allocate in LabVIEW for this parameter. Basically the needed size is 4 * (AES_MAXNR + 1) + 4 bytes. A single byte to small can either crash your system immediately or after some time or when you try to close your LabVIEW app but most importantly could also corrupt some data that is vital to LabVIEW or your VI and when saved to disc might corrupt your VI to the point where you have to start over.

My advice is still to go to www.visecurity.com and get the CryptoG toolkit that has a ready to use AES encryption and decryption routine out of the box.

Rolf Kalbermatter