pk.h

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/*
 *  Copyright The Mbed TLS Contributors
 *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
 */
 
#ifndef MBEDTLS_PK_H
#define MBEDTLS_PK_H
#include "mbedtls/private_access.h"
 
#include "mbedtls/build_info.h"
 
#include "mbedtls/md.h"
 
#if defined(MBEDTLS_RSA_C)
#include "mbedtls/rsa.h"
#endif
 
#if defined(MBEDTLS_ECP_C)
#include "mbedtls/ecp.h"
#endif
 
#if defined(MBEDTLS_ECDSA_C)
#include "mbedtls/ecdsa.h"
#endif
 
#if defined(MBEDTLS_PSA_CRYPTO_CLIENT)
#include "psa/crypto.h"
#endif

#define MBEDTLS_ERR_PK_ALLOC_FAILED        -0x3F80
#define MBEDTLS_ERR_PK_TYPE_MISMATCH       -0x3F00
#define MBEDTLS_ERR_PK_BAD_INPUT_DATA      -0x3E80
#define MBEDTLS_ERR_PK_FILE_IO_ERROR       -0x3E00
#define MBEDTLS_ERR_PK_KEY_INVALID_VERSION -0x3D80
#define MBEDTLS_ERR_PK_KEY_INVALID_FORMAT  -0x3D00
#define MBEDTLS_ERR_PK_UNKNOWN_PK_ALG      -0x3C80
#define MBEDTLS_ERR_PK_PASSWORD_REQUIRED   -0x3C00
#define MBEDTLS_ERR_PK_PASSWORD_MISMATCH   -0x3B80
#define MBEDTLS_ERR_PK_INVALID_PUBKEY      -0x3B00
#define MBEDTLS_ERR_PK_INVALID_ALG         -0x3A80
#define MBEDTLS_ERR_PK_UNKNOWN_NAMED_CURVE -0x3A00
#define MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE -0x3980
#define MBEDTLS_ERR_PK_SIG_LEN_MISMATCH    -0x3900
#define MBEDTLS_ERR_PK_BUFFER_TOO_SMALL    -0x3880
 
#ifdef __cplusplus
extern "C" {
#endif

typedef enum {
    MBEDTLS_PK_NONE=0,
    MBEDTLS_PK_RSA,
    MBEDTLS_PK_ECKEY,
    MBEDTLS_PK_ECKEY_DH,
    MBEDTLS_PK_ECDSA,
    MBEDTLS_PK_RSA_ALT,
    MBEDTLS_PK_RSASSA_PSS,
    MBEDTLS_PK_OPAQUE,
} mbedtls_pk_type_t;

typedef struct mbedtls_pk_rsassa_pss_options {
    mbedtls_md_type_t mgf1_hash_id;

    int expected_salt_len;
 
} mbedtls_pk_rsassa_pss_options;

/* We need to set MBEDTLS_PK_SIGNATURE_MAX_SIZE to the maximum signature
 * size among the supported signature types. Do it by starting at 0,
 * then incrementally increasing to be large enough for each supported
 * signature mechanism.
 *
 * The resulting value can be 0, for example if MBEDTLS_ECDH_C is enabled
 * (which allows the pk module to be included) but neither MBEDTLS_ECDSA_C
 * nor MBEDTLS_RSA_C nor any opaque signature mechanism (PSA or RSA_ALT).
 */
#define MBEDTLS_PK_SIGNATURE_MAX_SIZE 0
 
#if (defined(MBEDTLS_RSA_C) || defined(MBEDTLS_PK_RSA_ALT_SUPPORT)) && \
    MBEDTLS_MPI_MAX_SIZE > MBEDTLS_PK_SIGNATURE_MAX_SIZE
/* For RSA, the signature can be as large as the bignum module allows.
 * For RSA_ALT, the signature size is not necessarily tied to what the
 * bignum module can do, but in the absence of any specific setting,
 * we use that (rsa_alt_sign_wrap in library/pk_wrap.h will check). */
#undef MBEDTLS_PK_SIGNATURE_MAX_SIZE
#define MBEDTLS_PK_SIGNATURE_MAX_SIZE MBEDTLS_MPI_MAX_SIZE
#endif
 
#if defined(MBEDTLS_ECDSA_C) &&                                 \
    MBEDTLS_ECDSA_MAX_LEN > MBEDTLS_PK_SIGNATURE_MAX_SIZE
/* For ECDSA, the ecdsa module exports a constant for the maximum
 * signature size. */
#undef MBEDTLS_PK_SIGNATURE_MAX_SIZE
#define MBEDTLS_PK_SIGNATURE_MAX_SIZE MBEDTLS_ECDSA_MAX_LEN
#endif
 
#if defined(MBEDTLS_USE_PSA_CRYPTO)
#if PSA_SIGNATURE_MAX_SIZE > MBEDTLS_PK_SIGNATURE_MAX_SIZE
/* PSA_SIGNATURE_MAX_SIZE is the maximum size of a signature made
 * through the PSA API in the PSA representation. */
#undef MBEDTLS_PK_SIGNATURE_MAX_SIZE
#define MBEDTLS_PK_SIGNATURE_MAX_SIZE PSA_SIGNATURE_MAX_SIZE
#endif
 
#if PSA_VENDOR_ECDSA_SIGNATURE_MAX_SIZE + 11 > MBEDTLS_PK_SIGNATURE_MAX_SIZE
/* The Mbed TLS representation is different for ECDSA signatures:
 * PSA uses the raw concatenation of r and s,
 * whereas Mbed TLS uses the ASN.1 representation (SEQUENCE of two INTEGERs).
 * Add the overhead of ASN.1: up to (1+2) + 2 * (1+2+1) for the
 * types, lengths (represented by up to 2 bytes), and potential leading
 * zeros of the INTEGERs and the SEQUENCE. */
#undef MBEDTLS_PK_SIGNATURE_MAX_SIZE
#define MBEDTLS_PK_SIGNATURE_MAX_SIZE (PSA_VENDOR_ECDSA_SIGNATURE_MAX_SIZE + 11)
#endif
#endif /* defined(MBEDTLS_USE_PSA_CRYPTO) */
 
/* Internal helper to define which fields in the pk_context structure below
 * should be used for EC keys: legacy ecp_keypair or the raw (PSA friendly)
 * format. It should be noted that this only affects how data is stored, not
 * which functions are used for various operations. The overall picture looks
 * like this:
 * - if USE_PSA is not defined and ECP_C is defined then use ecp_keypair data
 *   structure and legacy functions
 * - if USE_PSA is defined and
 *     - if ECP_C then use ecp_keypair structure, convert data to a PSA friendly
 *       format and use PSA functions
 *     - if !ECP_C then use new raw data and PSA functions directly.
 *
 * The main reason for the "intermediate" (USE_PSA + ECP_C) above is that as long
 * as ECP_C is defined mbedtls_pk_ec() gives the user a read/write access to the
 * ecp_keypair structure inside the pk_context so they can modify it using
 * ECP functions which are not under PK module's control.
 */
#if defined(MBEDTLS_USE_PSA_CRYPTO) && defined(PSA_WANT_KEY_TYPE_ECC_PUBLIC_KEY) && \
    !defined(MBEDTLS_ECP_C)
#define MBEDTLS_PK_USE_PSA_EC_DATA
#endif

typedef enum {
    MBEDTLS_PK_DEBUG_NONE = 0,
    MBEDTLS_PK_DEBUG_MPI,
    MBEDTLS_PK_DEBUG_ECP,
    MBEDTLS_PK_DEBUG_PSA_EC,
} mbedtls_pk_debug_type;

typedef struct mbedtls_pk_debug_item {
    mbedtls_pk_debug_type MBEDTLS_PRIVATE(type);
    const char *MBEDTLS_PRIVATE(name);
    void *MBEDTLS_PRIVATE(value);
} mbedtls_pk_debug_item;

#define MBEDTLS_PK_DEBUG_MAX_ITEMS 3

typedef struct mbedtls_pk_info_t mbedtls_pk_info_t;
 
#define MBEDTLS_PK_MAX_EC_PUBKEY_RAW_LEN \
    PSA_KEY_EXPORT_ECC_PUBLIC_KEY_MAX_SIZE(PSA_VENDOR_ECC_MAX_CURVE_BITS)

typedef struct mbedtls_pk_context {
    const mbedtls_pk_info_t *MBEDTLS_PRIVATE(pk_info);
    void *MBEDTLS_PRIVATE(pk_ctx);
 
    /* The following field is used to store the ID of a private key in the
     * following cases:
     * - opaque key when MBEDTLS_USE_PSA_CRYPTO is defined
     * - normal key when MBEDTLS_PK_USE_PSA_EC_DATA is defined. In this case:
     *    - the pk_ctx above is not not used to store the private key anymore.
     *      Actually that field not populated at all in this case because also
     *      the public key will be stored in raw format as explained below
     *    - this ID is used for all private key operations (ex: sign, check
     *      key pair, key write, etc) using PSA functions
     *
     * Note: this private key storing solution only affects EC keys, not the
     *       other ones. The latters still use the pk_ctx to store their own
     *       context. */
#if defined(MBEDTLS_USE_PSA_CRYPTO)
    mbedtls_svc_key_id_t MBEDTLS_PRIVATE(priv_id);      
#endif /* MBEDTLS_USE_PSA_CRYPTO */
    /* The following fields are meant for storing the public key in raw format
     * which is handy for:
     * - easily importing it into the PSA context
     * - reducing the ECP module dependencies in the PK one.
     *
     * When MBEDTLS_PK_USE_PSA_EC_DATA is enabled:
     * - the pk_ctx above is not used anymore for storing the public key
     *   inside the ecp_keypair structure
     * - the following fields are used for all public key operations: signature
     *   verify, key pair check and key write.
     * - For a key pair, priv_id contains the private key. For a public key,
     *   priv_id is null.
     * Of course, when MBEDTLS_PK_USE_PSA_EC_DATA is not enabled, the legacy
     * ecp_keypair structure is used for storing the public key and performing
     * all the operations.
     *
     * Note: This new public key storing solution only works for EC keys, not
     *       other ones. The latters still use pk_ctx to store their own
     *       context.
     */
#if defined(MBEDTLS_PK_USE_PSA_EC_DATA)
    uint8_t MBEDTLS_PRIVATE(pub_raw)[MBEDTLS_PK_MAX_EC_PUBKEY_RAW_LEN]; 
    size_t MBEDTLS_PRIVATE(pub_raw_len);            
    psa_ecc_family_t MBEDTLS_PRIVATE(ec_family);    
    size_t MBEDTLS_PRIVATE(ec_bits);                
#endif /* MBEDTLS_PK_USE_PSA_EC_DATA */
} mbedtls_pk_context;
 
#if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE)
typedef struct {
    const mbedtls_pk_info_t *MBEDTLS_PRIVATE(pk_info);    
    void *MBEDTLS_PRIVATE(rs_ctx);                        
} mbedtls_pk_restart_ctx;
#else /* MBEDTLS_ECDSA_C && MBEDTLS_ECP_RESTARTABLE */
/* Now we can declare functions that take a pointer to that */
typedef void mbedtls_pk_restart_ctx;
#endif /* MBEDTLS_ECDSA_C && MBEDTLS_ECP_RESTARTABLE */
 
#if defined(MBEDTLS_PK_RSA_ALT_SUPPORT)
typedef int (*mbedtls_pk_rsa_alt_decrypt_func)(void *ctx, size_t *olen,
                                               const unsigned char *input, unsigned char *output,
                                               size_t output_max_len);
typedef int (*mbedtls_pk_rsa_alt_sign_func)(void *ctx,
                                            mbedtls_f_rng_t *f_rng,
                                            void *p_rng,
                                            mbedtls_md_type_t md_alg, unsigned int hashlen,
                                            const unsigned char *hash, unsigned char *sig);
typedef size_t (*mbedtls_pk_rsa_alt_key_len_func)(void *ctx);
#endif /* MBEDTLS_PK_RSA_ALT_SUPPORT */

const mbedtls_pk_info_t *mbedtls_pk_info_from_type(mbedtls_pk_type_t pk_type);

void mbedtls_pk_init(mbedtls_pk_context *ctx);

void mbedtls_pk_free(mbedtls_pk_context *ctx);
 
#if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE)
void mbedtls_pk_restart_init(mbedtls_pk_restart_ctx *ctx);

void mbedtls_pk_restart_free(mbedtls_pk_restart_ctx *ctx);
#endif /* MBEDTLS_ECDSA_C && MBEDTLS_ECP_RESTARTABLE */

int mbedtls_pk_setup(mbedtls_pk_context *ctx, const mbedtls_pk_info_t *info);
 
#if defined(MBEDTLS_USE_PSA_CRYPTO)
int mbedtls_pk_setup_opaque(mbedtls_pk_context *ctx,
                            const mbedtls_svc_key_id_t key);
#endif /* MBEDTLS_USE_PSA_CRYPTO */
 
#if defined(MBEDTLS_PK_RSA_ALT_SUPPORT)
int mbedtls_pk_setup_rsa_alt(mbedtls_pk_context *ctx, void *key,
                             mbedtls_pk_rsa_alt_decrypt_func decrypt_func,
                             mbedtls_pk_rsa_alt_sign_func sign_func,
                             mbedtls_pk_rsa_alt_key_len_func key_len_func);
#endif /* MBEDTLS_PK_RSA_ALT_SUPPORT */

size_t mbedtls_pk_get_bitlen(const mbedtls_pk_context *ctx);

static inline size_t mbedtls_pk_get_len(const mbedtls_pk_context *ctx)
{
    return (mbedtls_pk_get_bitlen(ctx) + 7) / 8;
}

int mbedtls_pk_can_do(const mbedtls_pk_context *ctx, mbedtls_pk_type_t type);
 
#if defined(MBEDTLS_USE_PSA_CRYPTO)
int mbedtls_pk_can_do_ext(const mbedtls_pk_context *ctx, psa_algorithm_t alg,
                          psa_key_usage_t usage);
#endif /* MBEDTLS_USE_PSA_CRYPTO */
 
#if defined(MBEDTLS_PSA_CRYPTO_CLIENT)
int mbedtls_pk_get_psa_attributes(const mbedtls_pk_context *pk,
                                  psa_key_usage_t usage,
                                  psa_key_attributes_t *attributes);

int mbedtls_pk_import_into_psa(const mbedtls_pk_context *pk,
                               const psa_key_attributes_t *attributes,
                               mbedtls_svc_key_id_t *key_id);

int mbedtls_pk_copy_from_psa(mbedtls_svc_key_id_t key_id, mbedtls_pk_context *pk);

int mbedtls_pk_copy_public_from_psa(mbedtls_svc_key_id_t key_id, mbedtls_pk_context *pk);
#endif /* MBEDTLS_PSA_CRYPTO_CLIENT */

int mbedtls_pk_verify(mbedtls_pk_context *ctx, mbedtls_md_type_t md_alg,
                      const unsigned char *hash, size_t hash_len,
                      const unsigned char *sig, size_t sig_len);

int mbedtls_pk_verify_restartable(mbedtls_pk_context *ctx,
                                  mbedtls_md_type_t md_alg,
                                  const unsigned char *hash, size_t hash_len,
                                  const unsigned char *sig, size_t sig_len,
                                  mbedtls_pk_restart_ctx *rs_ctx);

int mbedtls_pk_verify_ext(mbedtls_pk_type_t type, const void *options,
                          mbedtls_pk_context *ctx, mbedtls_md_type_t md_alg,
                          const unsigned char *hash, size_t hash_len,
                          const unsigned char *sig, size_t sig_len);

int mbedtls_pk_sign(mbedtls_pk_context *ctx, mbedtls_md_type_t md_alg,
                    const unsigned char *hash, size_t hash_len,
                    unsigned char *sig, size_t sig_size, size_t *sig_len,
                    mbedtls_f_rng_t *f_rng, void *p_rng);

int mbedtls_pk_sign_ext(mbedtls_pk_type_t pk_type,
                        mbedtls_pk_context *ctx,
                        mbedtls_md_type_t md_alg,
                        const unsigned char *hash, size_t hash_len,
                        unsigned char *sig, size_t sig_size, size_t *sig_len,
                        mbedtls_f_rng_t *f_rng,
                        void *p_rng);

int mbedtls_pk_sign_restartable(mbedtls_pk_context *ctx,
                                mbedtls_md_type_t md_alg,
                                const unsigned char *hash, size_t hash_len,
                                unsigned char *sig, size_t sig_size, size_t *sig_len,
                                mbedtls_f_rng_t *f_rng, void *p_rng,
                                mbedtls_pk_restart_ctx *rs_ctx);

int mbedtls_pk_decrypt(mbedtls_pk_context *ctx,
                       const unsigned char *input, size_t ilen,
                       unsigned char *output, size_t *olen, size_t osize,
                       mbedtls_f_rng_t *f_rng, void *p_rng);

int mbedtls_pk_encrypt(mbedtls_pk_context *ctx,
                       const unsigned char *input, size_t ilen,
                       unsigned char *output, size_t *olen, size_t osize,
                       mbedtls_f_rng_t *f_rng, void *p_rng);

int mbedtls_pk_check_pair(const mbedtls_pk_context *pub,
                          const mbedtls_pk_context *prv,
                          mbedtls_f_rng_t *f_rng,
                          void *p_rng);

int mbedtls_pk_debug(const mbedtls_pk_context *ctx, mbedtls_pk_debug_item *items);

const char *mbedtls_pk_get_name(const mbedtls_pk_context *ctx);

mbedtls_pk_type_t mbedtls_pk_get_type(const mbedtls_pk_context *ctx);
 
#if defined(MBEDTLS_RSA_C)
static inline mbedtls_rsa_context *mbedtls_pk_rsa(const mbedtls_pk_context pk)
{
    switch (mbedtls_pk_get_type(&pk)) {
        case MBEDTLS_PK_RSA:
            return (mbedtls_rsa_context *) (pk).MBEDTLS_PRIVATE(pk_ctx);
        default:
            return NULL;
    }
}
#endif /* MBEDTLS_RSA_C */
 
#if defined(MBEDTLS_ECP_C)
static inline mbedtls_ecp_keypair *mbedtls_pk_ec(const mbedtls_pk_context pk)
{
    switch (mbedtls_pk_get_type(&pk)) {
        case MBEDTLS_PK_ECKEY:
        case MBEDTLS_PK_ECKEY_DH:
        case MBEDTLS_PK_ECDSA:
            return (mbedtls_ecp_keypair *) (pk).MBEDTLS_PRIVATE(pk_ctx);
        default:
            return NULL;
    }
}
#endif /* MBEDTLS_ECP_C */
 
#if defined(MBEDTLS_PK_PARSE_C)
int mbedtls_pk_parse_key(mbedtls_pk_context *ctx,
                         const unsigned char *key, size_t keylen,
                         const unsigned char *pwd, size_t pwdlen,
                         mbedtls_f_rng_t *f_rng, void *p_rng);

int mbedtls_pk_parse_public_key(mbedtls_pk_context *ctx,
                                const unsigned char *key, size_t keylen);
 
#if defined(MBEDTLS_FS_IO)
int mbedtls_pk_parse_keyfile(mbedtls_pk_context *ctx,
                             const char *path, const char *password,
                             mbedtls_f_rng_t *f_rng, void *p_rng);

int mbedtls_pk_parse_public_keyfile(mbedtls_pk_context *ctx, const char *path);
#endif /* MBEDTLS_FS_IO */
#endif /* MBEDTLS_PK_PARSE_C */
 
#if defined(MBEDTLS_PK_WRITE_C)
int mbedtls_pk_write_key_der(const mbedtls_pk_context *ctx, unsigned char *buf, size_t size);

int mbedtls_pk_write_pubkey_der(const mbedtls_pk_context *ctx, unsigned char *buf, size_t size);
 
#if defined(MBEDTLS_PEM_WRITE_C)
int mbedtls_pk_write_pubkey_pem(const mbedtls_pk_context *ctx, unsigned char *buf, size_t size);

int mbedtls_pk_write_key_pem(const mbedtls_pk_context *ctx, unsigned char *buf, size_t size);
#endif /* MBEDTLS_PEM_WRITE_C */
#endif /* MBEDTLS_PK_WRITE_C */
 
/*
 * WARNING: Low-level functions. You probably do not want to use these unless
 *          you are certain you do ;)
 */
 
#if defined(MBEDTLS_PK_PARSE_C)
int mbedtls_pk_parse_subpubkey(unsigned char **p, const unsigned char *end,
                               mbedtls_pk_context *pk);
#endif /* MBEDTLS_PK_PARSE_C */
 
#if defined(MBEDTLS_PK_WRITE_C)
int mbedtls_pk_write_pubkey(unsigned char **p, unsigned char *start,
                            const mbedtls_pk_context *key);
#endif /* MBEDTLS_PK_WRITE_C */
 
#ifdef __cplusplus
}
#endif
 
#endif /* MBEDTLS_PK_H */