从PKCS11读取C ++结构有什么问题？

Question

I'm trying to use PKCS11 lib. I've got a wrong structure data on Windows10 x64 from C_GetInfo function.

My code

CK_C_GetInfo f_C_GetInfo = (CK_C_GetInfo)dlsym(__pkcs11->dlHandle, "C_GetInfo");
CK_C_Finalize f_C_Finalize = (CK_C_Finalize)dlsym(__pkcs11->dlHandle, "C_Finalize");

CK_INFO _info;
rv = f_C_GetInfo(&_info);

C++ declarations

/* an unsigned value, at least 32 bits long */
// typedef unsigned long int CK_ULONG;
typedef unsigned long int CK_ULONG;

/* at least 32 bits; each bit is a Boolean flag */
typedef CK_ULONG          CK_FLAGS;

typedef struct CK_VERSION {
    CK_BYTE       major;  /* integer portion of version number */
    CK_BYTE       minor;  /* 1/100ths portion of version number */
} CK_VERSION;

typedef CK_VERSION CK_PTR CK_VERSION_PTR;

typedef struct CK_INFO {
    CK_VERSION    cryptokiVersion;     /* Cryptoki interface ver */
    CK_UTF8CHAR   manufacturerID[32];  /* blank padded */
    CK_FLAGS      flags;               /* must be zero */

    CK_UTF8CHAR   libraryDescription[32];  /* blank padded */
    CK_VERSION    libraryVersion;          /* version of library */
} CK_INFO;

typedef CK_INFO CK_PTR    CK_INFO_PTR;

// Function C_GetInfo
CK_RV C_GetInfo ( CK_INFO_PTR pInfo );

Information from debugger

Wrong structure data starts from parameter flags , it MUST be 0 (Hex: 00 00 00 00 ). But it has hex value 00 00 52 75 .

I can fix this error if I change type of parameter flags to char[4]

What is wrong? Why is PKCS11 interface wrong for this structure?

Answer 1

The first two elements cryptokiVersion and manufacturerID take up 34 bytes.

manufacturerID mentions that its blank padded, if you look at the bytes, there is a series of 0x20 which is UTF-8 for .

Followed by 4 0x00

Followed by 52 75 74 ....

There is no padding in the data between manufacturerID and flags , but your structure definition contains 2 bytes of padding to align the unsigned long with the next boundary, which would be at 36 bytes.

Try removing the padding from your structure.

#pragma pack(push, p1, 1)

typedef struct CK_INFO {
    CK_VERSION    cryptokiVersion;     /* Cryptoki interface ver */
    CK_UTF8CHAR   manufacturerID[32];  /* blank padded */
    CK_FLAGS      flags;               /* must be zero */

    CK_UTF8CHAR   libraryDescription[32];  /* blank padded */
    CK_VERSION    libraryVersion;          /* version of library */
} CK_INFO;

#pragma pack(pop, p1)

Answer 2

It is extremely important to remember, that according to PKCS#11 all structures are packed to the minimal size, supported by the platform, and not aligned to 4 or 8 bytes. Not doing this makes PKCS#11 drivers incompatible with applications. PKCS#11 standard is strict on this.