ASN.1 template is required for TPM2 asymmetric keys, as it needs to be
piggy-packed with the input data before applying TPM2_RSA_Decrypt. This
patch prepares crypto subsystem for the addition of those keys.

Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
---
 crypto/rsa-pkcs1pad.c         | 16 ++++++++++------
 include/crypto/rsa-pkcs1pad.h | 20 ++++++++++++++++++++
 2 files changed, 30 insertions(+), 6 deletions(-)
 create mode 100644 include/crypto/rsa-pkcs1pad.h

diff --git a/crypto/rsa-pkcs1pad.c b/crypto/rsa-pkcs1pad.c
index cd501195f34a..00b6c14f861c 100644
--- a/crypto/rsa-pkcs1pad.c
+++ b/crypto/rsa-pkcs1pad.c
@@ -7,6 +7,7 @@
 
 #include <crypto/algapi.h>
 #include <crypto/akcipher.h>
+#include <crypto/rsa-pkcs1pad.h>
 #include <crypto/internal/akcipher.h>
 #include <crypto/internal/rsa.h>
 #include <linux/err.h>
@@ -79,11 +80,7 @@ static const u8 rsa_digest_info_sha3_512[] = {
 	0x05, 0x00, 0x04, 0x40
 };
 
-static const struct rsa_asn1_template {
-	const char	*name;
-	const u8	*data;
-	size_t		size;
-} rsa_asn1_templates[] = {
+static const struct rsa_asn1_template rsa_asn1_templates[] = {
 #define _(X) { #X, rsa_digest_info_##X, sizeof(rsa_digest_info_##X) }
 	_(md5),
 	_(sha1),
@@ -101,7 +98,13 @@ static const struct rsa_asn1_template {
 	{ NULL }
 };
 
-static const struct rsa_asn1_template *rsa_lookup_asn1(const char *name)
+/**
+ * rsa_lookup_asn1() - Lookup the ASN.1 digest info given the hash
+ * name:	hash algorithm name
+ *
+ * Returns the ASN.1 digest info on success, and NULL on failure.
+ */
+const struct rsa_asn1_template *rsa_lookup_asn1(const char *name)
 {
 	const struct rsa_asn1_template *p;
 
@@ -110,6 +113,7 @@ static const struct rsa_asn1_template *rsa_lookup_asn1(const char *name)
 			return p;
 	return NULL;
 }
+EXPORT_SYMBOL_GPL(rsa_lookup_asn1);
 
 struct pkcs1pad_ctx {
 	struct crypto_akcipher *child;
diff --git a/include/crypto/rsa-pkcs1pad.h b/include/crypto/rsa-pkcs1pad.h
new file mode 100644
index 000000000000..32c7453ff644
--- /dev/null
+++ b/include/crypto/rsa-pkcs1pad.h
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * RSA padding templates.
+ */
+
+#ifndef _CRYPTO_RSA_PKCS1PAD_H
+#define _CRYPTO_RSA_PKCS1PAD_H
+
+/*
+ * Hash algorithm name to ASN.1 template mapping.
+ */
+struct rsa_asn1_template {
+	const char *name;
+	const u8 *data;
+	size_t size;
+};
+
+const struct rsa_asn1_template *rsa_lookup_asn1(const char *name);
+
+#endif /* _CRYPTO_RSA_PKCS1PAD_H */
-- 
2.45.1

On 5/28/24 17:08, Jarkko Sakkinen wrote:
> ASN.1 template is required for TPM2 asymmetric keys, as it needs to be
> piggy-packed with the input data before applying TPM2_RSA_Decrypt. This

piggy-backed

> patch prepares crypto subsystem for the addition of those keys.
> 
> Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>

Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>

> ---
>   crypto/rsa-pkcs1pad.c         | 16 ++++++++++------
>   include/crypto/rsa-pkcs1pad.h | 20 ++++++++++++++++++++
>   2 files changed, 30 insertions(+), 6 deletions(-)
>   create mode 100644 include/crypto/rsa-pkcs1pad.h
> 
> diff --git a/crypto/rsa-pkcs1pad.c b/crypto/rsa-pkcs1pad.c
> index cd501195f34a..00b6c14f861c 100644
> --- a/crypto/rsa-pkcs1pad.c
> +++ b/crypto/rsa-pkcs1pad.c
> @@ -7,6 +7,7 @@
>   
>   #include <crypto/algapi.h>
>   #include <crypto/akcipher.h>
> +#include <crypto/rsa-pkcs1pad.h>
>   #include <crypto/internal/akcipher.h>
>   #include <crypto/internal/rsa.h>
>   #include <linux/err.h>
> @@ -79,11 +80,7 @@ static const u8 rsa_digest_info_sha3_512[] = {
>   	0x05, 0x00, 0x04, 0x40
>   };
>   
> -static const struct rsa_asn1_template {
> -	const char	*name;
> -	const u8	*data;
> -	size_t		size;
> -} rsa_asn1_templates[] = {
> +static const struct rsa_asn1_template rsa_asn1_templates[] = {
>   #define _(X) { #X, rsa_digest_info_##X, sizeof(rsa_digest_info_##X) }
>   	_(md5),
>   	_(sha1),
> @@ -101,7 +98,13 @@ static const struct rsa_asn1_template {
>   	{ NULL }
>   };
>   
> -static const struct rsa_asn1_template *rsa_lookup_asn1(const char *name)
> +/**
> + * rsa_lookup_asn1() - Lookup the ASN.1 digest info given the hash
> + * name:	hash algorithm name
> + *
> + * Returns the ASN.1 digest info on success, and NULL on failure.
> + */
> +const struct rsa_asn1_template *rsa_lookup_asn1(const char *name)
>   {
>   	const struct rsa_asn1_template *p;
>   
> @@ -110,6 +113,7 @@ static const struct rsa_asn1_template *rsa_lookup_asn1(const char *name)
>   			return p;
>   	return NULL;
>   }
> +EXPORT_SYMBOL_GPL(rsa_lookup_asn1);
>   
>   struct pkcs1pad_ctx {
>   	struct crypto_akcipher *child;
> diff --git a/include/crypto/rsa-pkcs1pad.h b/include/crypto/rsa-pkcs1pad.h
> new file mode 100644
> index 000000000000..32c7453ff644
> --- /dev/null
> +++ b/include/crypto/rsa-pkcs1pad.h
> @@ -0,0 +1,20 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * RSA padding templates.
> + */
> +
> +#ifndef _CRYPTO_RSA_PKCS1PAD_H
> +#define _CRYPTO_RSA_PKCS1PAD_H
> +
> +/*
> + * Hash algorithm name to ASN.1 template mapping.
> + */
> +struct rsa_asn1_template {
> +	const char *name;
> +	const u8 *data;
> +	size_t size;
> +};
> +
> +const struct rsa_asn1_template *rsa_lookup_asn1(const char *name);
> +
> +#endif /* _CRYPTO_RSA_PKCS1PAD_H */

On Wed May 29, 2024 at 2:20 AM EEST, Stefan Berger wrote:
>
>
> On 5/28/24 17:08, Jarkko Sakkinen wrote:
> > ASN.1 template is required for TPM2 asymmetric keys, as it needs to be
> > piggy-packed with the input data before applying TPM2_RSA_Decrypt. This
>
> piggy-backed

Right! I consciously wrote it that way, i.e. have used wrong spelling
up to this day :-)

Thanks for the review! This is not likely to change that much. Would
not tag any other patches tho before up to p521 have been tested...

BR, Jarkko