From: Tadeusz Struk <tadeusz.struk@intel.com>
To: Mat Martineau <mathew.j.martineau@linux.intel.com>
Cc: dhowells@redhat.com, herbert@gondor.apana.org.au,
smueller@chronox.de, linux-api@vger.kernel.org,
marcel@holtmann.org, linux-kernel@vger.kernel.org,
keyrings@vger.kernel.org, linux-crypto@vger.kernel.org,
dwmw2@infradead.org, davem@davemloft.net
Subject: Re: [PATCH v6 6/6] crypto: AF_ALG - add support for key_id
Date: Tue, 31 May 2016 10:44:03 -0700 [thread overview]
Message-ID: <304aa8f1-ef22-3f2d-53e5-3c020f7ceb40@intel.com> (raw)
In-Reply-To: <alpine.OSX.2.20.1605251640370.12130@mjmartin-mac01.local>
Hi Mat,
On 05/25/2016 05:45 PM, Mat Martineau wrote:
>
> On Sat, 14 May 2016, Tadeusz Struk wrote:
>
>> diff --git a/crypto/algif_akcipher.c b/crypto/algif_akcipher.c
>> index e00793d..6733df1 100644
>> --- a/crypto/algif_akcipher.c
>> +++ b/crypto/algif_akcipher.c
>> +static int asym_key_verify(const struct key *key, struct akcipher_request *req)
>> +{
>> + struct public_key_signature sig;
>> + char *src = NULL, *in;
>> + int ret;
>> +
>> + if (!sg_is_last(req->src)) {
>> + src = kmalloc(req->src_len, GFP_KERNEL);
>> + if (!src)
>> + return -ENOMEM;
>> + scatterwalk_map_and_copy(src, req->src, 0, req->src_len, 0);
>> + in = src;
>> + } else {
>> + in = sg_virt(req->src);
>> + }
>> + sig.pkey_algo = "rsa";
>> + sig.encoding = "pkcs1";
>> + /* Need to find a way to pass the hash param */
>
> Are you referring to sig.digest here? It looks like you will hit a BUG_ON() in public_key_verify_signature() if sig.digest is 0. However, sig.digest is unlikely to be 0 because the struct is not cleared - should fix this, since public_key_verify_signature() will try to follow that random pointer.
>
Right, I need to have a local buffer for the digest here.
>> + sig.hash_algo = "sha1";
>> + sig.digest_size = 20;
>> + sig.s_size = req->src_len;
>> + sig.s = src;
>> + ret = verify_signature(key, NULL, &sig);
>
> Is the idea to write the signature to the socket, and then read out the expected digest (the digest comparison being done elsewhere)? Is that something that will be supported by a future hardware asymmetric key subtype?
After the verify operation the output will be copied to the user,
and the user needs to verify it.
>
> verify_signature() ends up calling public_key_verify_signature(), which currently expects to get both the digest and signature as input and returns an error if verification fails. The output of crypto_akcipher_verify() is discarded before public_key_verify_signature() returns so nothing ends up in req->dst to read from the socket.
>
> ALG_OP_VERIFY should behave the same whether using ALG_SET_PUBKEY or ALG_SET_PUBKEY_ID, and they aren't right now.
>
> If sig.digest is 0, verify_signature() could return the expected digest in the sig structure and skip the digest comparison it currently does. Then that data could be packaged up in req as if crypto_akcipher_verify() had been called. I don't know if this change confuses the semantics of verify_signature() too much, maybe a new function is required with all the requisite plumbing to the asymmetric key subtype.
>
We need to copy output to the user to verify because we don't have it.
That will be consistent for both ALG_SET_PUBKEY and ALG_SET_PUBKEY_ID.
Thanks for your comments and sorry for the delayed response. I'll will send v7 soon.
--
TS
next prev parent reply other threads:[~2016-05-31 17:45 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-05 19:50 [PATCH RESEND v5 0/6] crypto: algif - add akcipher Tadeusz Struk
2016-05-05 19:50 ` [PATCH RESEND v5 1/6] crypto: AF_ALG -- add sign/verify API Tadeusz Struk
2016-05-06 10:36 ` Stephan Mueller
2016-05-05 19:50 ` [PATCH RESEND v5 2/6] crypto: AF_ALG -- add setpubkey setsockopt call Tadeusz Struk
2016-05-05 19:51 ` [PATCH RESEND v5 3/6] crypto: AF_ALG -- add asymmetric cipher interface Tadeusz Struk
2016-05-05 19:51 ` [PATCH RESEND v5 4/6] crypto: algif_akcipher - enable compilation Tadeusz Struk
2016-05-05 19:51 ` [PATCH RESEND v5 5/6] crypto: algif_akcipher - add ops_nokey Tadeusz Struk
2016-05-05 19:51 ` [PATCH RESEND v5 6/6] crypto: AF_ALG - add support for key_id Tadeusz Struk
2016-05-06 11:46 ` Stephan Mueller
2016-05-13 23:32 ` Mat Martineau
2016-05-16 14:23 ` Tadeusz Struk
2016-05-11 14:25 ` [PATCH RESEND v5 0/6] crypto: algif - add akcipher David Howells
2016-05-15 4:16 ` [PATCH v6 " Tadeusz Struk
2016-05-15 4:16 ` [PATCH v6 1/6] crypto: AF_ALG -- add sign/verify API Tadeusz Struk
2016-05-15 4:16 ` [PATCH v6 2/6] crypto: AF_ALG -- add setpubkey setsockopt call Tadeusz Struk
2016-05-15 4:17 ` [PATCH v6 3/6] crypto: AF_ALG -- add asymmetric cipher interface Tadeusz Struk
2016-06-08 0:28 ` Mat Martineau
2016-06-08 5:31 ` Stephan Mueller
2016-06-08 19:14 ` Mat Martineau
2016-06-09 9:28 ` Stephan Mueller
2016-06-09 18:18 ` Mat Martineau
2016-06-09 18:24 ` Stephan Mueller
2016-06-09 18:27 ` Mat Martineau
2016-06-09 18:36 ` Stephan Mueller
2016-06-10 14:42 ` Tadeusz Struk
2016-06-22 22:45 ` Mat Martineau
2016-06-23 5:07 ` Stephan Mueller
2016-06-23 15:22 ` Denis Kenzior
2016-06-13 22:16 ` Andrew Zaborowski
2016-06-14 5:12 ` Stephan Mueller
2016-06-14 7:42 ` Andrew Zaborowski
2016-06-16 8:05 ` Stephan Mueller
2016-06-16 14:59 ` Andrew Zaborowski
2016-06-16 15:38 ` Stephan Mueller
2016-06-17 0:39 ` Andrew Zaborowski
2016-06-14 17:22 ` Mat Martineau
2016-06-15 7:04 ` Stephan Mueller
2016-05-15 4:17 ` [PATCH v6 4/6] crypto: algif_akcipher - enable compilation Tadeusz Struk
2016-05-15 4:17 ` [PATCH v6 5/6] crypto: algif_akcipher - add ops_nokey Tadeusz Struk
2016-05-15 4:17 ` [PATCH v6 6/6] crypto: AF_ALG - add support for key_id Tadeusz Struk
2016-05-26 0:45 ` Mat Martineau
2016-05-31 17:44 ` Tadeusz Struk [this message]
2016-05-15 11:59 ` [PATCH v6 0/6] crypto: algif - add akcipher Stephan Mueller
2016-05-16 20:46 ` Tadeusz Struk
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