linux/include/crypto/sig.h
Lukas Wunner a2471684da crypto: ecdsa - Move X9.62 signature size calculation into template
software_key_query() returns the maximum signature and digest size for a
given key to user space.  When it only supported RSA keys, calculating
those sizes was trivial as they were always equivalent to the key size.

However when ECDSA was added, the function grew somewhat complicated
calculations which take the ASN.1 encoding and curve into account.
This doesn't scale well and adjusting the calculations is easily
forgotten when adding support for new encodings or curves.  In fact,
when NIST P521 support was recently added, the function was initially
not amended:

https://lore.kernel.org/all/b749d5ee-c3b8-4cbd-b252-7773e4536e07@linux.ibm.com/

Introduce a ->max_size() callback to struct sig_alg and take advantage
of it to move the signature size calculations to ecdsa-x962.c.

Introduce a ->digest_size() callback to struct sig_alg and move the
maximum ECDSA digest size to ecdsa.c.  It is common across ecdsa-x962.c
and the upcoming ecdsa-p1363.c and thus inherited by both of them.

For all other algorithms, continue using the key size as maximum
signature and digest size.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2024-10-05 13:22:04 +08:00

265 lines
8.2 KiB
C

/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* Public Key Signature Algorithm
*
* Copyright (c) 2023 Herbert Xu <herbert@gondor.apana.org.au>
*/
#ifndef _CRYPTO_SIG_H
#define _CRYPTO_SIG_H
#include <linux/crypto.h>
/**
* struct crypto_sig - user-instantiated objects which encapsulate
* algorithms and core processing logic
*
* @base: Common crypto API algorithm data structure
*/
struct crypto_sig {
struct crypto_tfm base;
};
/**
* struct sig_alg - generic public key signature algorithm
*
* @sign: Function performs a sign operation as defined by public key
* algorithm. Optional.
* @verify: Function performs a complete verify operation as defined by
* public key algorithm, returning verification status. Optional.
* @set_pub_key: Function invokes the algorithm specific set public key
* function, which knows how to decode and interpret
* the BER encoded public key and parameters. Mandatory.
* @set_priv_key: Function invokes the algorithm specific set private key
* function, which knows how to decode and interpret
* the BER encoded private key and parameters. Optional.
* @key_size: Function returns key size. Mandatory.
* @digest_size: Function returns maximum digest size. Optional.
* @max_size: Function returns maximum signature size. Optional.
* @init: Initialize the cryptographic transformation object.
* This function is used to initialize the cryptographic
* transformation object. This function is called only once at
* the instantiation time, right after the transformation context
* was allocated. In case the cryptographic hardware has some
* special requirements which need to be handled by software, this
* function shall check for the precise requirement of the
* transformation and put any software fallbacks in place.
* @exit: Deinitialize the cryptographic transformation object. This is a
* counterpart to @init, used to remove various changes set in
* @init.
*
* @base: Common crypto API algorithm data structure
*/
struct sig_alg {
int (*sign)(struct crypto_sig *tfm,
const void *src, unsigned int slen,
void *dst, unsigned int dlen);
int (*verify)(struct crypto_sig *tfm,
const void *src, unsigned int slen,
const void *digest, unsigned int dlen);
int (*set_pub_key)(struct crypto_sig *tfm,
const void *key, unsigned int keylen);
int (*set_priv_key)(struct crypto_sig *tfm,
const void *key, unsigned int keylen);
unsigned int (*key_size)(struct crypto_sig *tfm);
unsigned int (*digest_size)(struct crypto_sig *tfm);
unsigned int (*max_size)(struct crypto_sig *tfm);
int (*init)(struct crypto_sig *tfm);
void (*exit)(struct crypto_sig *tfm);
struct crypto_alg base;
};
/**
* DOC: Generic Public Key Signature API
*
* The Public Key Signature API is used with the algorithms of type
* CRYPTO_ALG_TYPE_SIG (listed as type "sig" in /proc/crypto)
*/
/**
* crypto_alloc_sig() - allocate signature tfm handle
* @alg_name: is the cra_name / name or cra_driver_name / driver name of the
* signing algorithm e.g. "ecdsa"
* @type: specifies the type of the algorithm
* @mask: specifies the mask for the algorithm
*
* Allocate a handle for public key signature algorithm. The returned struct
* crypto_sig is the handle that is required for any subsequent
* API invocation for signature operations.
*
* Return: allocated handle in case of success; IS_ERR() is true in case
* of an error, PTR_ERR() returns the error code.
*/
struct crypto_sig *crypto_alloc_sig(const char *alg_name, u32 type, u32 mask);
static inline struct crypto_tfm *crypto_sig_tfm(struct crypto_sig *tfm)
{
return &tfm->base;
}
static inline struct crypto_sig *__crypto_sig_tfm(struct crypto_tfm *tfm)
{
return container_of(tfm, struct crypto_sig, base);
}
static inline struct sig_alg *__crypto_sig_alg(struct crypto_alg *alg)
{
return container_of(alg, struct sig_alg, base);
}
static inline struct sig_alg *crypto_sig_alg(struct crypto_sig *tfm)
{
return __crypto_sig_alg(crypto_sig_tfm(tfm)->__crt_alg);
}
/**
* crypto_free_sig() - free signature tfm handle
*
* @tfm: signature tfm handle allocated with crypto_alloc_sig()
*
* If @tfm is a NULL or error pointer, this function does nothing.
*/
static inline void crypto_free_sig(struct crypto_sig *tfm)
{
crypto_destroy_tfm(tfm, crypto_sig_tfm(tfm));
}
/**
* crypto_sig_keysize() - Get key size
*
* Function returns the key size in bytes.
* Function assumes that the key is already set in the transformation. If this
* function is called without a setkey or with a failed setkey, you may end up
* in a NULL dereference.
*
* @tfm: signature tfm handle allocated with crypto_alloc_sig()
*/
static inline unsigned int crypto_sig_keysize(struct crypto_sig *tfm)
{
struct sig_alg *alg = crypto_sig_alg(tfm);
return alg->key_size(tfm);
}
/**
* crypto_sig_digestsize() - Get maximum digest size
*
* Function returns the maximum digest size in bytes.
* Function assumes that the key is already set in the transformation. If this
* function is called without a setkey or with a failed setkey, you may end up
* in a NULL dereference.
*
* @tfm: signature tfm handle allocated with crypto_alloc_sig()
*/
static inline unsigned int crypto_sig_digestsize(struct crypto_sig *tfm)
{
struct sig_alg *alg = crypto_sig_alg(tfm);
return alg->digest_size(tfm);
}
/**
* crypto_sig_maxsize() - Get maximum signature size
*
* Function returns the maximum signature size in bytes.
* Function assumes that the key is already set in the transformation. If this
* function is called without a setkey or with a failed setkey, you may end up
* in a NULL dereference.
*
* @tfm: signature tfm handle allocated with crypto_alloc_sig()
*/
static inline unsigned int crypto_sig_maxsize(struct crypto_sig *tfm)
{
struct sig_alg *alg = crypto_sig_alg(tfm);
return alg->max_size(tfm);
}
/**
* crypto_sig_sign() - Invoke signing operation
*
* Function invokes the specific signing operation for a given algorithm
*
* @tfm: signature tfm handle allocated with crypto_alloc_sig()
* @src: source buffer
* @slen: source length
* @dst: destination obuffer
* @dlen: destination length
*
* Return: zero on success; error code in case of error
*/
static inline int crypto_sig_sign(struct crypto_sig *tfm,
const void *src, unsigned int slen,
void *dst, unsigned int dlen)
{
struct sig_alg *alg = crypto_sig_alg(tfm);
return alg->sign(tfm, src, slen, dst, dlen);
}
/**
* crypto_sig_verify() - Invoke signature verification
*
* Function invokes the specific signature verification operation
* for a given algorithm.
*
* @tfm: signature tfm handle allocated with crypto_alloc_sig()
* @src: source buffer
* @slen: source length
* @digest: digest
* @dlen: digest length
*
* Return: zero on verification success; error code in case of error.
*/
static inline int crypto_sig_verify(struct crypto_sig *tfm,
const void *src, unsigned int slen,
const void *digest, unsigned int dlen)
{
struct sig_alg *alg = crypto_sig_alg(tfm);
return alg->verify(tfm, src, slen, digest, dlen);
}
/**
* crypto_sig_set_pubkey() - Invoke set public key operation
*
* Function invokes the algorithm specific set key function, which knows
* how to decode and interpret the encoded key and parameters
*
* @tfm: tfm handle
* @key: BER encoded public key, algo OID, paramlen, BER encoded
* parameters
* @keylen: length of the key (not including other data)
*
* Return: zero on success; error code in case of error
*/
static inline int crypto_sig_set_pubkey(struct crypto_sig *tfm,
const void *key, unsigned int keylen)
{
struct sig_alg *alg = crypto_sig_alg(tfm);
return alg->set_pub_key(tfm, key, keylen);
}
/**
* crypto_sig_set_privkey() - Invoke set private key operation
*
* Function invokes the algorithm specific set key function, which knows
* how to decode and interpret the encoded key and parameters
*
* @tfm: tfm handle
* @key: BER encoded private key, algo OID, paramlen, BER encoded
* parameters
* @keylen: length of the key (not including other data)
*
* Return: zero on success; error code in case of error
*/
static inline int crypto_sig_set_privkey(struct crypto_sig *tfm,
const void *key, unsigned int keylen)
{
struct sig_alg *alg = crypto_sig_alg(tfm);
return alg->set_priv_key(tfm, key, keylen);
}
#endif