pk.h

00001 /**
00002  * \file pk.h
00003  *
00004  * \brief Public Key abstraction layer
00005  *
00006  *  Copyright (C) 2006-2013, Brainspark B.V.
00007  *
00008  *  This file is part of PolarSSL (http://www.polarssl.org)
00009  *  Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org>
00010  *
00011  *  All rights reserved.
00012  *
00013  *  This program is free software; you can redistribute it and/or modify
00014  *  it under the terms of the GNU General Public License as published by
00015  *  the Free Software Foundation; either version 2 of the License, or
00016  *  (at your option) any later version.
00017  *
00018  *  This program is distributed in the hope that it will be useful,
00019  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
00020  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00021  *  GNU General Public License for more details.
00022  *
00023  *  You should have received a copy of the GNU General Public License along
00024  *  with this program; if not, write to the Free Software Foundation, Inc.,
00025  *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
00026  */
00027 
00028 #ifndef POLARSSL_PK_H
00029 #define POLARSSL_PK_H
00030 
00031 #if !defined(POLARSSL_CONFIG_FILE)
00032 #include "config.h"
00033 #else
00034 #include POLARSSL_CONFIG_FILE
00035 #endif
00036 
00037 #include "md.h"
00038 
00039 #if defined(POLARSSL_RSA_C)
00040 #include "rsa.h"
00041 #endif
00042 
00043 #if defined(POLARSSL_ECP_C)
00044 #include "ecp.h"
00045 #endif
00046 
00047 #if defined(POLARSSL_ECDSA_C)
00048 #include "ecdsa.h"
00049 #endif
00050 
00051 #define POLARSSL_ERR_PK_MALLOC_FAILED       -0x2F80  /**< Memory alloation failed. */
00052 #define POLARSSL_ERR_PK_TYPE_MISMATCH       -0x2F00  /**< Type mismatch, eg attempt to encrypt with an ECDSA key */
00053 #define POLARSSL_ERR_PK_BAD_INPUT_DATA      -0x2E80  /**< Bad input parameters to function. */
00054 #define POLARSSL_ERR_PK_FILE_IO_ERROR       -0x2E00  /**< Read/write of file failed. */
00055 #define POLARSSL_ERR_PK_KEY_INVALID_VERSION -0x2D80  /**< Unsupported key version */
00056 #define POLARSSL_ERR_PK_KEY_INVALID_FORMAT  -0x2D00  /**< Invalid key tag or value. */
00057 #define POLARSSL_ERR_PK_UNKNOWN_PK_ALG      -0x2C80  /**< Key algorithm is unsupported (only RSA and EC are supported). */
00058 #define POLARSSL_ERR_PK_PASSWORD_REQUIRED   -0x2C00  /**< Private key password can't be empty. */
00059 #define POLARSSL_ERR_PK_PASSWORD_MISMATCH   -0x2B80  /**< Given private key password does not allow for correct decryption. */
00060 #define POLARSSL_ERR_PK_INVALID_PUBKEY      -0x2B00  /**< The pubkey tag or value is invalid (only RSA and EC are supported). */
00061 #define POLARSSL_ERR_PK_INVALID_ALG         -0x2A80  /**< The algorithm tag or value is invalid. */
00062 #define POLARSSL_ERR_PK_UNKNOWN_NAMED_CURVE -0x2A00  /**< Elliptic curve is unsupported (only NIST curves are supported). */
00063 #define POLARSSL_ERR_PK_FEATURE_UNAVAILABLE -0x2980  /**< Unavailable feature, e.g. RSA disabled for RSA key. */
00064 #define POLARSSL_ERR_PK_SIG_LEN_MISMATCH    -0x2000  /**< The signature is valid but its length is less than expected. */
00065 
00066 
00067 #if defined(POLARSSL_RSA_C)
00068 /**
00069  * Quick access to an RSA context inside a PK context.
00070  *
00071  * \warning You must make sure the PK context actually holds an RSA context
00072  * before using this macro!
00073  */
00074 #define pk_rsa( pk )        ( (rsa_context *) (pk).pk_ctx )
00075 #endif /* POLARSSL_RSA_C */
00076 
00077 #if defined(POLARSSL_ECP_C)
00078 /**
00079  * Quick access to an EC context inside a PK context.
00080  *
00081  * \warning You must make sure the PK context actually holds an EC context
00082  * before using this macro!
00083  */
00084 #define pk_ec( pk )         ( (ecp_keypair *) (pk).pk_ctx )
00085 #endif /* POLARSSL_ECP_C */
00086 
00087 
00088 #ifdef __cplusplus
00089 extern "C" {
00090 #endif
00091 
00092 /**
00093  * \brief          Public key types
00094  */
00095 typedef enum {
00096     POLARSSL_PK_NONE=0,
00097     POLARSSL_PK_RSA,
00098     POLARSSL_PK_ECKEY,
00099     POLARSSL_PK_ECKEY_DH,
00100     POLARSSL_PK_ECDSA,
00101     POLARSSL_PK_RSA_ALT,
00102 } pk_type_t;
00103 
00104 /**
00105  * \brief           Types for interfacing with the debug module
00106  */
00107 typedef enum
00108 {
00109     POLARSSL_PK_DEBUG_NONE = 0,
00110     POLARSSL_PK_DEBUG_MPI,
00111     POLARSSL_PK_DEBUG_ECP,
00112 } pk_debug_type;
00113 
00114 /**
00115  * \brief           Item to send to the debug module
00116  */
00117 typedef struct
00118 {
00119     pk_debug_type type;
00120     const char *name;
00121     void *value;
00122 } pk_debug_item;
00123 
00124 /** Maximum number of item send for debugging, plus 1 */
00125 #define POLARSSL_PK_DEBUG_MAX_ITEMS 3
00126 
00127 /**
00128  * \brief           Public key information and operations
00129  */
00130 typedef struct
00131 {
00132     /** Public key type */
00133     pk_type_t type;
00134 
00135     /** Type name */
00136     const char *name;
00137 
00138     /** Get key size in bits */
00139     size_t (*get_size)( const void * );
00140 
00141     /** Tell if the context implements this type (e.g. ECKEY can do ECDSA) */
00142     int (*can_do)( pk_type_t type );
00143 
00144     /** Verify signature */
00145     int (*verify_func)( void *ctx, md_type_t md_alg,
00146                         const unsigned char *hash, size_t hash_len,
00147                         const unsigned char *sig, size_t sig_len );
00148 
00149     /** Make signature */
00150     int (*sign_func)( void *ctx, md_type_t md_alg,
00151                       const unsigned char *hash, size_t hash_len,
00152                       unsigned char *sig, size_t *sig_len,
00153                       int (*f_rng)(void *, unsigned char *, size_t),
00154                       void *p_rng );
00155 
00156     /** Decrypt message */
00157     int (*decrypt_func)( void *ctx, const unsigned char *input, size_t ilen,
00158                          unsigned char *output, size_t *olen, size_t osize,
00159                          int (*f_rng)(void *, unsigned char *, size_t),
00160                          void *p_rng );
00161 
00162     /** Encrypt message */
00163     int (*encrypt_func)( void *ctx, const unsigned char *input, size_t ilen,
00164                          unsigned char *output, size_t *olen, size_t osize,
00165                          int (*f_rng)(void *, unsigned char *, size_t),
00166                          void *p_rng );
00167 
00168     /** Allocate a new context */
00169     void * (*ctx_alloc_func)( void );
00170 
00171     /** Free the given context */
00172     void (*ctx_free_func)( void *ctx );
00173 
00174     /** Interface with the debug module */
00175     void (*debug_func)( const void *ctx, pk_debug_item *items );
00176 
00177 } pk_info_t;
00178 
00179 /**
00180  * \brief           Public key container
00181  */
00182 typedef struct
00183 {
00184     const pk_info_t *   pk_info;    /**< Public key informations        */
00185     void *              pk_ctx;     /**< Underlying public key context  */
00186 } pk_context;
00187 
00188 /**
00189  * \brief           Types for RSA-alt abstraction
00190  */
00191 typedef int (*pk_rsa_alt_decrypt_func)( void *ctx, int mode, size_t *olen,
00192                     const unsigned char *input, unsigned char *output,
00193                     size_t output_max_len );
00194 typedef int (*pk_rsa_alt_sign_func)( void *ctx,
00195                     int (*f_rng)(void *, unsigned char *, size_t), void *p_rng,
00196                     int mode, md_type_t md_alg, unsigned int hashlen,
00197                     const unsigned char *hash, unsigned char *sig );
00198 typedef size_t (*pk_rsa_alt_key_len_func)( void *ctx );
00199 
00200 /**
00201  * \brief           Return information associated with the given PK type
00202  *
00203  * \param pk_type   PK type to search for.
00204  *
00205  * \return          The PK info associated with the type or NULL if not found.
00206  */
00207 const pk_info_t *pk_info_from_type( pk_type_t pk_type );
00208 
00209 /**
00210  * \brief           Initialize a pk_context (as NONE)
00211  */
00212 void pk_init( pk_context *ctx );
00213 
00214 /**
00215  * \brief           Free a pk_context
00216  */
00217 void pk_free( pk_context *ctx );
00218 
00219 /**
00220  * \brief           Initialize a PK context with the information given
00221  *                  and allocates the type-specific PK subcontext.
00222  *
00223  * \param ctx       Context to initialize. Must be empty (type NONE).
00224  * \param info      Information to use
00225  *
00226  * \return          0 on success,
00227  *                  POLARSSL_ERR_PK_BAD_INPUT_DATA on invalid input,
00228  *                  POLARSSL_ERR_PK_MALLOC_FAILED on allocation failure.
00229  *
00230  * \note            For contexts holding an RSA-alt key, use
00231  *                  \c pk_init_ctx_rsa_alt() instead.
00232  */
00233 int pk_init_ctx( pk_context *ctx, const pk_info_t *info );
00234 
00235 /**
00236  * \brief           Initialize an RSA-alt context
00237  *
00238  * \param ctx       Context to initialize. Must be empty (type NONE).
00239  * \param key       RSA key pointer
00240  * \param decrypt_func  Decryption function
00241  * \param sign_func     Signing function
00242  * \param key_len_func  Function returning key length in bytes
00243  *
00244  * \return          0 on success, or POLARSSL_ERR_PK_BAD_INPUT_DATA if the
00245  *                  context wasn't already initialized as RSA_ALT.
00246  *
00247  * \note            This function replaces \c pk_init_ctx() for RSA-alt.
00248  */
00249 int pk_init_ctx_rsa_alt( pk_context *ctx, void * key,
00250                          pk_rsa_alt_decrypt_func decrypt_func,
00251                          pk_rsa_alt_sign_func sign_func,
00252                          pk_rsa_alt_key_len_func key_len_func );
00253 
00254 /**
00255  * \brief           Get the size in bits of the underlying key
00256  *
00257  * \param ctx       Context to use
00258  *
00259  * \return          Key size in bits, or 0 on error
00260  */
00261 size_t pk_get_size( const pk_context *ctx );
00262 
00263 /**
00264  * \brief           Get the length in bytes of the underlying key
00265  * \param ctx       Context to use
00266  *
00267  * \return          Key length in bytes, or 0 on error
00268  */
00269 static inline size_t pk_get_len( const pk_context *ctx )
00270 {
00271     return( ( pk_get_size( ctx ) + 7 ) / 8 );
00272 }
00273 
00274 /**
00275  * \brief           Tell if a context can do the operation given by type
00276  *
00277  * \param ctx       Context to test
00278  * \param type      Target type
00279  *
00280  * \return          0 if context can't do the operations,
00281  *                  1 otherwise.
00282  */
00283 int pk_can_do( pk_context *ctx, pk_type_t type );
00284 
00285 /**
00286  * \brief           Verify signature
00287  *
00288  * \param ctx       PK context to use
00289  * \param md_alg    Hash algorithm used (see notes)
00290  * \param hash      Hash of the message to sign
00291  * \param hash_len  Hash length or 0 (see notes)
00292  * \param sig       Signature to verify
00293  * \param sig_len   Signature length
00294  *
00295  * \return          0 on success (signature is valid),
00296  *                  POLARSSL_ERR_PK_SIG_LEN_MISMATCH if the signature is
00297  *                  valid but its actual length is less than sig_len,
00298  *                  or a specific error code.
00299  *
00300  * \note            If hash_len is 0, then the length associated with md_alg
00301  *                  is used instead, or an error returned if it is invalid.
00302  *
00303  * \note            md_alg may be POLARSSL_MD_NONE, only if hash_len != 0
00304  */
00305 int pk_verify( pk_context *ctx, md_type_t md_alg,
00306                const unsigned char *hash, size_t hash_len,
00307                const unsigned char *sig, size_t sig_len );
00308 
00309 /**
00310  * \brief           Make signature
00311  *
00312  * \param ctx       PK context to use
00313  * \param md_alg    Hash algorithm used (see notes)
00314  * \param hash      Hash of the message to sign
00315  * \param hash_len  Hash length or 0 (see notes)
00316  * \param sig       Place to write the signature
00317  * \param sig_len   Number of bytes written
00318  * \param f_rng     RNG function
00319  * \param p_rng     RNG parameter
00320  *
00321  * \return          0 on success, or a specific error code.
00322  *
00323  * \note            If hash_len is 0, then the length associated with md_alg
00324  *                  is used instead, or an error returned if it is invalid.
00325  *
00326  * \note            md_alg may be POLARSSL_MD_NONE, only if hash_len != 0
00327  */
00328 int pk_sign( pk_context *ctx, md_type_t md_alg,
00329              const unsigned char *hash, size_t hash_len,
00330              unsigned char *sig, size_t *sig_len,
00331              int (*f_rng)(void *, unsigned char *, size_t), void *p_rng );
00332 
00333 /**
00334  * \brief           Decrypt message
00335  *
00336  * \param ctx       PK context to use
00337  * \param input     Input to decrypt
00338  * \param ilen      Input size
00339  * \param output    Decrypted output
00340  * \param olen      Decrypted message length
00341  * \param osize     Size of the output buffer
00342  * \param f_rng     RNG function
00343  * \param p_rng     RNG parameter
00344  *
00345  * \return          0 on success, or a specific error code.
00346  */
00347 int pk_decrypt( pk_context *ctx,
00348                 const unsigned char *input, size_t ilen,
00349                 unsigned char *output, size_t *olen, size_t osize,
00350                 int (*f_rng)(void *, unsigned char *, size_t), void *p_rng );
00351 
00352 /**
00353  * \brief           Encrypt message
00354  *
00355  * \param ctx       PK context to use
00356  * \param input     Message to encrypt
00357  * \param ilen      Message size
00358  * \param output    Encrypted output
00359  * \param olen      Encrypted output length
00360  * \param osize     Size of the output buffer
00361  * \param f_rng     RNG function
00362  * \param p_rng     RNG parameter
00363  *
00364  * \return          0 on success, or a specific error code.
00365  */
00366 int pk_encrypt( pk_context *ctx,
00367                 const unsigned char *input, size_t ilen,
00368                 unsigned char *output, size_t *olen, size_t osize,
00369                 int (*f_rng)(void *, unsigned char *, size_t), void *p_rng );
00370 
00371 /**
00372  * \brief           Export debug information
00373  *
00374  * \param ctx       Context to use
00375  * \param items     Place to write debug items
00376  *
00377  * \return          0 on success or POLARSSL_ERR_PK_BAD_INPUT_DATA
00378  */
00379 int pk_debug( const pk_context *ctx, pk_debug_item *items );
00380 
00381 /**
00382  * \brief           Access the type name
00383  *
00384  * \param ctx       Context to use
00385  *
00386  * \return          Type name on success, or "invalid PK"
00387  */
00388 const char * pk_get_name( const pk_context *ctx );
00389 
00390 /**
00391  * \brief           Get the key type
00392  *
00393  * \param ctx       Context to use
00394  *
00395  * \return          Type on success, or POLARSSL_PK_NONE
00396  */
00397 pk_type_t pk_get_type( const pk_context *ctx );
00398 
00399 #if defined(POLARSSL_PK_PARSE_C)
00400 /** \ingroup pk_module */
00401 /**
00402  * \brief           Parse a private key
00403  *
00404  * \param ctx       key to be initialized
00405  * \param key       input buffer
00406  * \param keylen    size of the buffer
00407  * \param pwd       password for decryption (optional)
00408  * \param pwdlen    size of the password
00409  *
00410  * \note            On entry, ctx must be empty, either freshly initialised
00411  *                  with pk_init() or reset with pk_free(). If you need a
00412  *                  specific key type, check the result with pk_can_do().
00413  *
00414  * \note            The key is also checked for correctness.
00415  *
00416  * \return          0 if successful, or a specific PK or PEM error code
00417  */
00418 int pk_parse_key( pk_context *ctx,
00419                   const unsigned char *key, size_t keylen,
00420                   const unsigned char *pwd, size_t pwdlen );
00421 
00422 /** \ingroup pk_module */
00423 /**
00424  * \brief           Parse a public key
00425  *
00426  * \param ctx       key to be initialized
00427  * \param key       input buffer
00428  * \param keylen    size of the buffer
00429  *
00430  * \note            On entry, ctx must be empty, either freshly initialised
00431  *                  with pk_init() or reset with pk_free(). If you need a
00432  *                  specific key type, check the result with pk_can_do().
00433  *
00434  * \note            The key is also checked for correctness.
00435  *
00436  * \return          0 if successful, or a specific PK or PEM error code
00437  */
00438 int pk_parse_public_key( pk_context *ctx,
00439                          const unsigned char *key, size_t keylen );
00440 
00441 #if defined(POLARSSL_FS_IO)
00442 /** \ingroup pk_module */
00443 /**
00444  * \brief           Load and parse a private key
00445  *
00446  * \param ctx       key to be initialized
00447  * \param path      filename to read the private key from
00448  * \param password  password to decrypt the file (can be NULL)
00449  *
00450  * \note            On entry, ctx must be empty, either freshly initialised
00451  *                  with pk_init() or reset with pk_free(). If you need a
00452  *                  specific key type, check the result with pk_can_do().
00453  *
00454  * \note            The key is also checked for correctness.
00455  *
00456  * \return          0 if successful, or a specific PK or PEM error code
00457  */
00458 int pk_parse_keyfile( pk_context *ctx,
00459                       const char *path, const char *password );
00460 
00461 /** \ingroup pk_module */
00462 /**
00463  * \brief           Load and parse a public key
00464  *
00465  * \param ctx       key to be initialized
00466  * \param path      filename to read the private key from
00467  *
00468  * \note            On entry, ctx must be empty, either freshly initialised
00469  *                  with pk_init() or reset with pk_free(). If you need a
00470  *                  specific key type, check the result with pk_can_do().
00471  *
00472  * \note            The key is also checked for correctness.
00473  *
00474  * \return          0 if successful, or a specific PK or PEM error code
00475  */
00476 int pk_parse_public_keyfile( pk_context *ctx, const char *path );
00477 #endif /* POLARSSL_FS_IO */
00478 #endif /* POLARSSL_PK_PARSE_C */
00479 
00480 #if defined(POLARSSL_PK_WRITE_C)
00481 /**
00482  * \brief           Write a private key to a PKCS#1 or SEC1 DER structure
00483  *                  Note: data is written at the end of the buffer! Use the
00484  *                        return value to determine where you should start
00485  *                        using the buffer
00486  *
00487  * \param ctx       private to write away
00488  * \param buf       buffer to write to
00489  * \param size      size of the buffer
00490  *
00491  * \return          length of data written if successful, or a specific
00492  *                  error code
00493  */
00494 int pk_write_key_der( pk_context *ctx, unsigned char *buf, size_t size );
00495 
00496 /**
00497  * \brief           Write a public key to a SubjectPublicKeyInfo DER structure
00498  *                  Note: data is written at the end of the buffer! Use the
00499  *                        return value to determine where you should start
00500  *                        using the buffer
00501  *
00502  * \param ctx       public key to write away
00503  * \param buf       buffer to write to
00504  * \param size      size of the buffer
00505  *
00506  * \return          length of data written if successful, or a specific
00507  *                  error code
00508  */
00509 int pk_write_pubkey_der( pk_context *ctx, unsigned char *buf, size_t size );
00510 
00511 #if defined(POLARSSL_PEM_WRITE_C)
00512 /**
00513  * \brief           Write a public key to a PEM string
00514  *
00515  * \param ctx       public key to write away
00516  * \param buf       buffer to write to
00517  * \param size      size of the buffer
00518  *
00519  * \return          0 successful, or a specific error code
00520  */
00521 int pk_write_pubkey_pem( pk_context *ctx, unsigned char *buf, size_t size );
00522 
00523 /**
00524  * \brief           Write a private key to a PKCS#1 or SEC1 PEM string
00525  *
00526  * \param ctx       private to write away
00527  * \param buf       buffer to write to
00528  * \param size      size of the buffer
00529  *
00530  * \return          0 successful, or a specific error code
00531  */
00532 int pk_write_key_pem( pk_context *ctx, unsigned char *buf, size_t size );
00533 #endif /* POLARSSL_PEM_WRITE_C */
00534 #endif /* POLARSSL_PK_WRITE_C */
00535 
00536 /*
00537  * WARNING: Low-level functions. You probably do not want to use these unless
00538  *          you are certain you do ;)
00539  */
00540 
00541 #if defined(POLARSSL_PK_PARSE_C)
00542 /**
00543  * \brief           Parse a SubjectPublicKeyInfo DER structure
00544  *
00545  * \param p         the position in the ASN.1 data
00546  * \param end       end of the buffer
00547  * \param pk        the key to fill
00548  *
00549  * \return          0 if successful, or a specific PK error code
00550  */
00551 int pk_parse_subpubkey( unsigned char **p, const unsigned char *end,
00552                         pk_context *pk );
00553 #endif /* POLARSSL_PK_PARSE_C */
00554 
00555 #if defined(POLARSSL_PK_WRITE_C)
00556 /**
00557  * \brief           Write a subjectPublicKey to ASN.1 data
00558  *                  Note: function works backwards in data buffer
00559  *
00560  * \param p         reference to current position pointer
00561  * \param start     start of the buffer (for bounds-checking)
00562  * \param key       public key to write away
00563  *
00564  * \return          the length written or a negative error code
00565  */
00566 int pk_write_pubkey( unsigned char **p, unsigned char *start,
00567                      const pk_context *key );
00568 #endif /* POLARSSL_PK_WRITE_C */
00569 
00570 #ifdef __cplusplus
00571 }
00572 #endif
00573 
00574 #endif /* POLARSSL_PK_H */
00575 
00576