[PATCH v3 11/18] crypto: Scaffolding for RSA-PSS signature style

Varad Gautam
2021-04-20T11:53:08Z

Add a crypto_template for rsa-psspad, hidden behind
CONFIG_CRYPTO_RSASSA_PSS. Set the sign/verify/encrypt/decrypt
operations to return -EOPNOTSUPP, to be implemented in the future

Signed-off-by: Varad Gautam <varad.gautam@suse.com>
---
crypto/Kconfig | 6 ++++++
crypto/Makefile | 1 +
crypto/rsa-psspad.c | 39 +++++++++++++++++++++++++++++++++++
crypto/rsa.c | 20 +++++++++++++++---
include/crypto/internal/rsa.h | 3 +++
5 files changed, 66 insertions(+), 3 deletions(-)
create mode 100644 crypto/rsa-psspad.c

diff --git a/crypto/Kconfig b/crypto/Kconfig
index 5809cc198fa7c..3aedb40aa08f1 100644
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -224,6 +224,12 @@ config CRYPTO_RSA
help
Generic implementation of the RSA public key algorithm.

+config CRYPTO_RSASSA_PSS
+ bool "RSASSA-PSS algorithm"
+ select CRYPTO_RSA
+ help
+ RSASSA-PSS signature verification scheme.
+
config CRYPTO_DH
tristate "Diffie-Hellman algorithm"
select CRYPTO_KPP
diff --git a/crypto/Makefile b/crypto/Makefile
index 57a85b2b3429b..88be24b9bcb24 100644
--- a/crypto/Makefile
+++ b/crypto/Makefile
@@ -42,6 +42,7 @@ rsa_generic-y += rsa_helper.o
rsa_generic-y += rsa-common.o
rsa_generic-y += rsa-pkcs1pad.o
obj-$(CONFIG_CRYPTO_RSA) += rsa_generic.o
+obj-$(CONFIG_CRYPTO_RSASSA_PSS) += rsa-psspad.o

$(obj)/sm2signature.asn1.o: $(obj)/sm2signature.asn1.c $(obj)/sm2signature.asn1.h
$(obj)/sm2.o: $(obj)/sm2signature.asn1.h
diff --git a/crypto/rsa-psspad.c b/crypto/rsa-psspad.c
new file mode 100644
index 0000000000000..0e5422b05c081
--- /dev/null
+++ b/crypto/rsa-psspad.c
@@ -0,0 +1,39 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * RSASSA-PSS signature scheme.
+ *
+ * Copyright (C) 2021, SUSE
+ * Authors: Varad Gautam <varad.gautam@suse.com>
+ */
+
+#include <crypto/internal/akcipher.h>
+#include <crypto/internal/rsa-common.h>
+
+static int psspad_s_v_e_d(struct akcipher_request *req)
+{
+ return -EOPNOTSUPP;
+}
+
+static struct akcipher_alg psspad_alg = {
+ .init = rsapad_akcipher_init_tfm,
+ .exit = rsapad_akcipher_exit_tfm,
+
+ .encrypt = psspad_s_v_e_d,
+ .decrypt = psspad_s_v_e_d,
+ .sign = psspad_s_v_e_d,
+ .verify = psspad_s_v_e_d,
+ .set_pub_key = rsapad_set_pub_key,
+ .set_priv_key = rsapad_set_priv_key,
+ .max_size = rsapad_get_max_size
+};
+
+static int psspad_create(struct crypto_template *tmpl, struct rtattr **tb)
+{
+ return rsapad_akcipher_create(tmpl, tb, &psspad_alg);
+}
+
+struct crypto_template rsa_psspad_tmpl = {
+ .name = "psspad",
+ .create = psspad_create,
+ .module = THIS_MODULE,
+};
diff --git a/crypto/rsa.c b/crypto/rsa.c
index 5c4eece5b8028..de4ad34f9cd95 100644
--- a/crypto/rsa.c
+++ b/crypto/rsa.c
@@ -258,17 +258,31 @@ static int rsa_init(void)
return err;

err = crypto_register_template(&rsa_pkcs1pad_tmpl);
+ if (err)
+ goto out_err;
+
+#ifdef CONFIG_CRYPTO_RSASSA_PSS
+ err = crypto_register_template(&rsa_psspad_tmpl);
if (err) {
- crypto_unregister_akcipher(&rsa);
- return err;
+ crypto_unregister_template(&rsa_pkcs1pad_tmpl);
+ goto out_err;
}
+#endif

- return 0;
+ goto out;
+
+out_err:
+ crypto_unregister_akcipher(&rsa);
+out:
+ return err;
}

static void rsa_exit(void)
{
crypto_unregister_template(&rsa_pkcs1pad_tmpl);
+#ifdef CONFIG_CRYPTO_RSASSA_PSS
+ crypto_unregister_template(&rsa_psspad_tmpl);
+#endif
crypto_unregister_akcipher(&rsa);
}

diff --git a/include/crypto/internal/rsa.h b/include/crypto/internal/rsa.h
index e73c61f788e68..4c168ea2f050a 100644
--- a/include/crypto/internal/rsa.h
+++ b/include/crypto/internal/rsa.h
@@ -61,4 +61,7 @@ struct rsa_mpi_key {
};

extern struct crypto_template rsa_pkcs1pad_tmpl;
+#ifdef CONFIG_CRYPTO_RSASSA_PSS
+extern struct crypto_template rsa_psspad_tmpl;
+#endif /* CONFIG_CRYPTO_RSASSA_PSS */
#endif
--
2.30.2