Re: Problem with RSA test from testmgr

On Tue, Feb 28, 2017 at 11:35:04PM +0100, Stephan Müller wrote:

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

Hi Corentin,

quoted

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.

I got the following:

[    1.086228] alg: akcipher: encrypt test failed. Invalid output
[    1.092196] 00000000: 6e 7c 8a 75 e7 30 80 d1 5e ab 9b db a2 cf ed db
[    1.098882] 00000010: c9 b2 db 43 bd 9a b9 75 27 f3 73 d9 73 b7 81 8c
[    1.105524] 00000020: 49 e8 45 fc 43 44 f5 6d f0 f7 b8 f2 ae 6b ae 49
[    1.112090] 00000030: 1b 8e 50 c6 88 4e 99 09 78 14 f2 5d 99 c3 7f f9
[    1.118747] alg: akcipher: test 1 failed for rsa-generic, err=-22
(Exactly the output of my hardare and openssl test)

So the problem is just that my hardware does not handle non-padded data.

Thanks
Regards
Corentin Labbe