Hi,
I had earlier posted query on AES_Keywrap() usage and had good response on
the same and got lot of things clarified. Now i am successful in using
AES_wrap_key() API but i am running into a new problem.
I need to wrap 512bit key with 256 bit KEK key. When i do this, i am hitting
seg fault in AES_wrap_key(). When i do gdb, it points to memcpy(). From the
code i didn't see any limitation of not using 512 bit key. Am i missing
something? Below is my sample code which works successfully for 256 bit Key.
Below code can be enabled for 512 bit with the macro KEY512.
#include <stdio.h>
#include <openssl/aes.h>
#include <openssl/bio.h>
//#define KEYBITS 128
//#define KEYLEN 16
#define KEY512 0
#if KEY512
#define KEYLEN 64
#define KEYBITS 512
#else
#define KEYLEN 32
#define KEYBITS 256
#endif
static const unsigned char default_iv[] = {
0xA6, 0xA6, 0xA6, 0xA6, 0xA6, 0xA6, 0xA6, 0xA6,
};
static const unsigned char invalid_iv[] = {
0x16, 0xA6, 0xA6, 0xA6, 0xA6, 0x16, 0xA6, 0xA6,
};
void main()
{
#if (!KEY512)
static const unsigned char kek[] = {
0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f
};
#else
static const unsigned char kek[] = {
0xbc, 0x54, 0xd8, 0xa0, 0x6e, 0xab, 0x3b,
0x4c, 0x06, 0xf5, 0xbe, 0x01, 0xc5, 0x77,
0x28, 0x3d, 0x92, 0xda, 0xfb, 0xe8, 0x3f,
0xe0, 0x59, 0x57, 0xff, 0xbe, 0xfa, 0x5b,
0xe0, 0xd4, 0xfb, 0xb7
};
#endif
/* static const unsigned char key[] = {
0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77,
0x88, 0x99, 0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff,
0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f
};
*/
#if (!KEY512)
static const unsigned char key[] = {
0x46, 0xab, 0x1b, 0xdc, 0x89, 0x38, 0x57, 0x23,
0x47, 0x49, 0xfc, 0xc4, 0x6e, 0x26, 0xf0, 0xae,
0xbd, 0x4b, 0x0b, 0xcf, 0x51, 0x96, 0x21, 0x2c,
0xd4, 0xd0, 0x82, 0x71, 0xa3, 0x8c, 0xcb, 0x3c
};
#else
static const unsigned char key[] = {
0xf5, 0x96, 0x87, 0x3e, 0x53, 0x6d, 0x61,
0xf5, 0x55, 0x53, 0xca, 0x0c, 0xd8, 0xcd,
0x1d, 0x40, 0xcb, 0x66, 0x58, 0xf7, 0x8f,
0xae, 0xbf, 0x9b, 0x78, 0x4d, 0xd1, 0x0f,
0x19, 0xc2, 0x89, 0x5a, 0x47, 0xd9, 0x3c,
0x7e, 0x26, 0x18, 0x2d, 0xd0, 0xce, 0xcb,
0x3a, 0x58, 0x55, 0x59, 0x4e, 0x5b, 0x2a,
0xd3, 0x9a, 0x86, 0x9d, 0x6c, 0x5d, 0x70,
0x21, 0xa7, 0x87, 0xcb, 0xdd, 0xf5, 0xe3,
0xf5
};
#endif
int ret, i;
unsigned char *otmp, *dtmp;
AES_KEY actx, dctx;
printf("\n keylen = %d; kebits= %d", KEYLEN, KEYBITS);
if (AES_set_encrypt_key(kek, KEYBITS, &actx))
printf("\n Error seeting AES key ");
otmp = (unsigned char *) malloc(sizeof(char) * (KEYLEN+8));
dtmp = (unsigned char *) malloc(sizeof(char) * KEYLEN);
ret = AES_wrap_key(&actx, default_iv, otmp, key, KEYLEN);
printf("\n AES wrap ; ret = %d", ret);
if (ret < 0)
printf("\n AES wrap key failed");
printf("\n Wrapped key : ");
for (i = 0; i< (KEYLEN + 8); i++)
printf(" %02x", otmp[i]);
if (AES_set_decrypt_key(kek, KEYBITS, &dctx))
printf("\n Error setting decrypt key ");
ret = AES_unwrap_key(&dctx, default_iv, dtmp, otmp, ret);
printf("\n AES unwrap ; ret = %d", ret);
if (ret == 0)
printf("\n AES unwrapping failed ");
printf("\n Original key : ");
for (i = 0; i < KEYLEN ; i++)
printf(" %02x", dtmp[i]);
printf("\n");
free(otmp);
free(dtmp);
}
Output result when 256 bit key is used
keylen = 32; kebits= 256
AES wrap ; ret = 40
Wrapped key : 0a f2 44 0b 98 e9 7d 65 3d 90 ea aa 4d fd 10 37 24 17 66 82
cb 60 b2 c6 56 cc 83 d9 ad 6b 32 a8 5d aa d1 b7 10 54 1b ea
AES unwrap ; ret = 32
Original key : 46 ab 1b dc 89 38 57 23 47 49 fc c4 6e 26 f0 ae bd 4b 0b cf
51 96 21 2c d4 d0 82 71 a3 8c cb 3c
Ouput when 512 bit is key - Here i hit seg fault
keylen = 64; kebits= 512
Segmentation fault
any help is highly appreciated...
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