From: Varad Gautam <varad.gautam@suse.com>
To: linux-crypto@vger.kernel.org
Cc: varad.gautam@suse.com, dhowells@redhat.com,
herbert@gondor.apana.org.au, davem@davemloft.net,
vt@altlinux.org, tianjia.zhang@linux.alibaba.com,
keyrings@vger.kernel.org, linux-kernel@vger.kernel.org,
jarkko@kernel.org
Subject: [PATCH v3 14/18] crypto: Implement MGF1 Mask Generation Function for RSASSA-PSS
Date: Tue, 20 Apr 2021 13:41:19 +0200 [thread overview]
Message-ID: <20210420114124.9684-15-varad.gautam@suse.com> (raw)
In-Reply-To: <20210420114124.9684-1-varad.gautam@suse.com>
This generates a "mask" byte array of size mask_len bytes as a
concatenation of digests, where each digest is calculated on a
concatenation of an input seed and a running counter to fill up
mask_len bytes - as described by RFC8017 sec B.2.1. "MGF1".
The mask is useful for RSA signing/verification process with
encoding RSASSA-PSS.
Reference: https://tools.ietf.org/html/rfc8017#appendix-B.2.1
Signed-off-by: Varad Gautam <varad.gautam@suse.com>
---
crypto/rsa-psspad.c | 54 +++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 54 insertions(+)
diff --git a/crypto/rsa-psspad.c b/crypto/rsa-psspad.c
index 0a9c0f9e9f0fe..990c2cda552a7 100644
--- a/crypto/rsa-psspad.c
+++ b/crypto/rsa-psspad.c
@@ -70,6 +70,60 @@ static int psspad_set_sig_params(struct crypto_akcipher *tfm,
return 0;
}
+/* MGF1 per RFC8017 B.2.1. */
+static int pkcs1_mgf1(u8 *seed, unsigned int seed_len,
+ struct shash_desc *desc,
+ u8 *mask, unsigned int mask_len)
+{
+ unsigned int pos, h_len, i, c;
+ u8 *tmp;
+ int ret = 0;
+
+ h_len = crypto_shash_digestsize(desc->tfm);
+
+ pos = i = 0;
+ while ((i < (mask_len / h_len) + 1) && pos < mask_len) {
+ /* Compute T = T || Hash(mgfSeed || C) into mask at pos. */
+ c = cpu_to_be32(i);
+
+ ret = crypto_shash_init(desc);
+ if (ret < 0)
+ goto out_err;
+
+ ret = crypto_shash_update(desc, seed, seed_len);
+ if (ret < 0)
+ goto out_err;
+
+ ret = crypto_shash_update(desc, (u8 *) &c, sizeof(c));
+ if (ret < 0)
+ goto out_err;
+
+ if (mask_len - pos >= h_len) {
+ ret = crypto_shash_final(desc, mask + pos);
+ pos += h_len;
+ } else {
+ tmp = kzalloc(h_len, GFP_KERNEL);
+ if (!tmp) {
+ ret = -ENOMEM;
+ goto out_err;
+ }
+ ret = crypto_shash_final(desc, tmp);
+ /* copy the last hash */
+ memcpy(mask + pos, tmp, mask_len - pos);
+ kfree(tmp);
+ pos = mask_len;
+ }
+ if (ret < 0) {
+ goto out_err;
+ }
+
+ i++;
+ }
+
+out_err:
+ return ret;
+}
+
static int psspad_s_v_e_d(struct akcipher_request *req)
{
return -EOPNOTSUPP;
--
2.30.2
next prev parent reply other threads:[~2021-04-20 11:47 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-20 11:41 [PATCH v3 00/18] Implement RSASSA-PSS signature verification Varad Gautam
2021-04-20 11:41 ` [PATCH v3 01/18] X.509: Parse RSASSA-PSS style certificates Varad Gautam
2021-04-20 11:41 ` [PATCH v3 02/18] crypto: rsa-pkcs1pad: Rename pkcs1pad-specific functions to rsapad Varad Gautam
2021-04-20 11:41 ` [PATCH v3 03/18] crypto: rsa-pkcs1pad: Extract pkcs1pad_create into a generic helper Varad Gautam
2021-04-20 11:41 ` [PATCH v3 04/18] crypto: rsa-pkcs1pad: Pull out child req processing code into helpers Varad Gautam
2021-04-20 11:41 ` [PATCH v3 05/18] crypto: rsa-pkcs1pad: Rename pkcs1pad_* structs to rsapad_* Varad Gautam
2021-04-20 11:41 ` [PATCH v3 06/18] crypto: rsa: Start moving RSA common code to rsa-common Varad Gautam
2021-04-20 11:41 ` [PATCH v3 07/18] crypto: rsa: Move more " Varad Gautam
2021-04-20 11:41 ` [PATCH v3 08/18] crypto: rsa: Move rsapad_akcipher_setup_child and callback " Varad Gautam
2021-04-20 11:41 ` [PATCH v3 09/18] crypto: Extend akcipher API to pass signature parameters Varad Gautam
2021-04-20 11:41 ` [PATCH v3 10/18] crypto: rsa: Move struct rsa_mpi_key definition to rsa.h Varad Gautam
2021-04-20 11:41 ` [PATCH v3 11/18] crypto: Scaffolding for RSA-PSS signature style Varad Gautam
2021-04-20 11:41 ` [PATCH v3 12/18] crypto: rsa-psspad: Introduce shash alloc/dealloc helpers Varad Gautam
2021-04-20 11:41 ` [PATCH v3 13/18] crypto: rsa-psspad: Get signature parameters from a given signature Varad Gautam
2021-05-14 10:45 ` Herbert Xu
2021-07-05 9:39 ` Varad Gautam
2023-09-20 17:12 ` Dimitri John Ledkov
2021-04-20 11:41 ` Varad Gautam [this message]
2021-04-20 11:41 ` [PATCH v3 15/18] crypto: rsa-psspad: Provide PSS signature verify operation Varad Gautam
2021-04-20 11:41 ` [PATCH v3 16/18] crypto: rsa-psspad: Implement signature verify callback Varad Gautam
2021-04-20 11:41 ` [PATCH v3 17/18] crypto: Accept pss as valid encoding during signature verification Varad Gautam
2021-04-20 11:41 ` [PATCH v3 18/18] keyctl_pkey: Add pkey parameters saltlen and mgfhash for PSS Varad Gautam
2021-04-20 13:27 ` Ben Boeckel
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