Re: Crypto test results unused?

From: Krzysztof Halasa
Date: Tue Jan 12 2010 - 12:55:20 EST

Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> writes:

>> On little-endian IXP4xx 3 hardware-assisted algorithms fail (due to
>> apparently unrelated bug which I will take care of). It seems the kernel
>> is still using these failing algorithms (my debugging code adds extra
>> fields to the /proc output):
> How did you determine that it was still being used? When a kernel
> user requests for an algorithm the system is supposed to skip
> anything which failed the self-test.

cat /proc/crypto shows "selftest: unknown" for those failed tests. I
don't know if that means it's used, but I'd expect "failed" or something
like that. Maybe it's simply a problem in /proc/crypto output.

> CRYPTO_ALG_DEAD is used to mark algorithms deleted from the
> system. However, we don't delete algorithms just because they
> fail the self-test. They remain in the system so you can come
> back and diagnose the problem. They just aren't used by anyone.


Currently the /proc/crypto contains:

- for passed tests: "selftest: passed" (which is of course right)

- for failed tests: "selftest: unknown" (which is a surprise for me):

alg: skcipher: Test 1 failed on encryption for ecb(des)-ixp4xx
00000000: 01 23 45 67 89 ab cd e7

name : ecb(des)
driver : ecb(des)-ixp4xx
module : ixp4xx_crypto
priority : 300
refcnt : 1
selftest : unknown
type : ablkcipher
async : yes
blocksize : 8
min keysize : 8
max keysize : 8
ivsize : 0
geniv : <default>

- for routines without a test: "selftest: passed" (which isn't true

alg: No test for authenc(hmac(md5),cbc(des)) (authenc(hmac(md5),cbc(des))-ixp4xx)

name : authenc(hmac(md5),cbc(des))
driver : authenc(hmac(md5),cbc(des))-ixp4xx
module : ixp4xx_crypto
priority : 300
refcnt : 1
selftest : passed
type : aead
async : yes
blocksize : 8
ivsize : 8
maxauthsize : 16
geniv : <built-in>

I think we need a way to differentiate between "really unknown" and
"failed", do we need another flag for it?
Krzysztof Halasa
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