Re: Problem with RSA test from testmgr

Am Dienstag, 28. Februar 2017, 17:45:53 CET schrieb Corentin Labbe:

Hi Corentin,

On Tue, Feb 28, 2017 at 05:08:35PM +0100, Stephan Müller wrote:

quoted

Am Dienstag, 28. Februar 2017, 16:59:53 CET schrieb Corentin Labbe:

Hi Corentin,

quoted

hello

I work on the sun8i-ce crypto accelerator and I have some problem with
the
RSA part.

The RSA register fail at the first RSA test (encrypt 512bit) with this
output: [ 8480.146843] alg: akcipher: encrypt test failed. Invalid
output
[ 8480.146871] 00000000: 6e 7c 8a 75 e7 30 80 d1 5e ab 9b db a2 cf ed db
[ 8480.146897] 00000010: c9 b2 db 43 bd 9a b9 75 27 f3 73 d9 73 b7 81 8c
[ 8480.146921] 00000020: 49 e8 45 fc 43 44 f5 6d f0 f7 b8 f2 ae 6b ae 49
[ 8480.146946] 00000030: 1b 8e 50 c6 88 4e 99 09 78 14 f2 5d 99 c3 7f f9
[ 8480.146995] alg: akcipher: test 1 failed for rsa-sun8i-ce, err=-22

But with the same parameters (msg, n, e) openssl give me exactly this
output.

So what I miss for made it work ?
In which format testmgr expect the output data ?

The output should be simply the binary string from the modular
exponentiation operation.

What I am wondering is: the output logged above is not found in the
expected values of testmgr.h. Which input data or test vectors do you
use?

Ciao
Stephan

I use the first test from rsa_tv_template in crypto/testmgr.h
The test fail on the encrypt operation.

I have put below the openssl program that give me the same output than my
hardware accelerator with the same parameters.

I would think the issue is that the OpenSSL BIGNUM lib has some issues: when 
calculating m^e mod n, m has to be equal to the key size. The kernel's MPI 
code handles the case where m is smaller than the key size.

Note, in your code below, ptext is the 8 bytes from ptext_ex plus trailing 
zeroes whereas the kernel uses just the 8 bytes.

It seems that your implementation has the same issue.

What about the following test: change vector->m to be 64 bytes (i.e. 
RSA_size(key) in size in testmgr.h and check the output of crypto/rsa.c, 
openssl's output with the app below and your RSA hardware.

Regards


#include <stdio.h>
#include <string.h>
#include <openssl/crypto.h>
#include <openssl/err.h>
#include <openssl/bn.h>
#include <openssl/rsa.h>

static const unsigned char n[] =
"\x00\xAA\x36\xAB\xCE\x88\xAC\xFD\xFF\x55\x52\x3C\x7F\xC4\x52\x3F"
"\x90\xEF\xA0\x0D\xF3\x77\x4A\x25\x9F\x2E\x62\xB4\xC5\xD9\x9C\xB5"
"\xAD\xB3\x00\xA0\x28\x5E\x53\x01\x93\x0E\x0C\x70\xFB\x68\x76\x93"
"\x9C\xE6\x16\xCE\x62\x4A\x11\xE0\x08\x6D\x34\x1E\xBC\xAC\xA0\xA1"
"\xF5";
static const unsigned char e[] = "\x11";

int main(int argc, char *argv[])
{
	static unsigned char ptext_ex[] = "\x54\x85\x9b\x34\x2c\x49\xea\x2a";
	RSA *key;
	int num, i;
	int plen = sizeof(ptext_ex) - 1;
	unsigned char *ctext = malloc(256);
	unsigned char *ptext = malloc(256);
	unsigned char *ptextp = malloc(256);

	CRYPTO_malloc_debug_init();
	CRYPTO_dbg_set_options(V_CRYPTO_MDEBUG_ALL);
        CRYPTO_mem_ctrl(CRYPTO_MEM_CHECK_ON);

	memset(ptextp, 0, 256);
	memcpy(ptextp, ptext_ex, plen);

	key = RSA_new();

	key->n = BN_bin2bn(n, sizeof(n)-1, key->n);
	key->e = BN_bin2bn(e, sizeof(e)-1, key->e);

	num = RSA_public_encrypt(RSA_size(key), ptextp, ctext, key,
RSA_NO_PADDING);

	printf("Result %d plen=%d\n", num, plen);
	for (i = 0; i < num; i++)
		printf("%02x ", ctext[i]);
	printf("\n");
	return 0;
}

Ciao
Stephan