diff --git a/programs/psa/aead_non_psa.c b/programs/psa/aead_non_psa.c index 4b48b3a989..00c7f0ef44 100644 --- a/programs/psa/aead_non_psa.c +++ b/programs/psa/aead_non_psa.c @@ -1,8 +1,29 @@ -/* - * This is a companion to aead_psa.c, doing the same operations with the - * legacy Cipher API. The goal is that comparing the two programs will help people - * migrating to the PSA Crypto API. +/** + * Cipher API multi-part AEAD demonstration. * + * This program AEAD-encrypts a message, using the algorithm and key size + * specified on the command line, using the multi-part API. + * + * It comes with a companion program aead_psa.c, which does the same + * operations with the PSA Crypto API. The goal is that comparing the two + * programs will help people migrating to the PSA Crypto API. + * + * When used with multi-part AEAD operations, the `mbedtls_cipher_context` + * serves a triple purpose (1) hold the key, (2) store the algorithm when no + * operation is active, and (3) save progress information for the current + * operation. With PSA those roles are held by disinct objects: (1) a + * psa_key_id_t to hold the key, a (2) psa_algorithm_t to represent the + * algorithm, and (3) a psa_operation_t for multi-part progress. + * + * On the other hand, with PSA, the algorithms encodes the desired tag length; + * with Cipher the desired tag length needs to be tracked separately. + * + * This program and its companion aead_psa.c illustrate this by doing the + * same sequence of multi-part AEAD computation with both APIs; looking at the + * two side by side should make the differences and similarities clear. + */ + +/* * Copyright The Mbed TLS Contributors * SPDX-License-Identifier: Apache-2.0 * @@ -19,26 +40,18 @@ * limitations under the License. */ -/* - * When used with multi-part AEAD operations, the `mbedtls_cipher_context` - * serves a triple purpose (1) hold the key, (2) store the algorithm when no - * operation is active, and (3) save progress information for the current - * operation. With PSA those roles are held by disinct objects: (1) a - * psa_key_id_t to hold the key, a (2) psa_algorithm_t to represent the - * algorithm, and (3) a psa_operation_t for multi-part progress. - * - * On the other hand, with PSA, the algorithms encodes the desired tag length; - * with Cipher the desired tag length needs to be tracked separately. - * - * This program and its compation aead_psa.c illustrate this by doing the - * same sequence of multi-part AEAD computation with both APIs; looking at the - * two side by side should make the differences and similarities clear. - */ - -#include - +/* First include Mbed TLS headers to get the Mbed TLS configuration and + * platform definitions that we'll use in this program. Also include + * standard C headers for functions we'll use here. */ #include "mbedtls/build_info.h" +#include "mbedtls/cipher.h" + +#include +#include +#include + +/* If the build options we need are not enabled, compile a placeholder. */ #if !defined(MBEDTLS_CIPHER_C) || \ !defined(MBEDTLS_AES_C) || !defined(MBEDTLS_GCM_C) || \ !defined(MBEDTLS_CHACHAPOLY_C) @@ -51,52 +64,67 @@ int main( void ) } #else -#include +/* The real program starts here. */ -#include "mbedtls/cipher.h" - -/* - * Dummy data and helper functions - */ -const char usage[] = "Usage: aead_non_psa [aes128-gcm|aes256-gcm|aes128-gcm_8|chachapoly]"; +const char usage[] = "Usage: aead_psa [aes128-gcm|aes256-gcm|aes128-gcm_8|chachapoly]"; +/* Dummy data for encryption: IV/nonce, additional data, 2-part message */ const unsigned char iv1[12] = { 0x00 }; const unsigned char add_data1[] = { 0x01, 0x02 }; const unsigned char msg1_part1[] = { 0x03, 0x04 }; const unsigned char msg1_part2[] = { 0x05, 0x06, 0x07 }; +/* Dummy data (2nd message) */ const unsigned char iv2[12] = { 0x10 }; const unsigned char add_data2[] = { 0x11, 0x12 }; const unsigned char msg2_part1[] = { 0x13, 0x14 }; const unsigned char msg2_part2[] = { 0x15, 0x16, 0x17 }; +/* This must at least the sum of the length of the 2 parts for each message. + * This is a macro for the sake of compilers with insufficient C99 support. */ #define MSG_MAX_SIZE 5 +/* Dummy key material - never do this in production! + * 32-byte is enough to all the key size supported by this program. */ const unsigned char key_bytes[32] = { 0x2a }; -void print_out( const char *title, unsigned char *out, size_t len ) +/* Print the contents of a buffer in hex */ +void print_buf( const char *title, unsigned char *buf, size_t len ) { printf( "%s:", title ); for( size_t i = 0; i < len; i++ ) - printf( " %02x", out[i] ); + printf( " %02x", buf[i] ); printf( "\n" ); } -#define CHK( code ) \ - do { \ - ret = code; \ - if( ret != 0 ) { \ - printf( "%03d: ret = -0x%04x\n", __LINE__, (unsigned) -ret ); \ - goto exit; \ - } \ +/* Run an Mbed TLS function and bail out if it fails. */ +#define CHK( expr ) \ + do \ + { \ + ret = ( expr ); \ + if( ret != 0 ) \ + { \ + printf( "Error %d at line %d: %s\n", \ + ret, \ + __LINE__, \ + #expr ); \ + goto exit; \ + } \ } while( 0 ) +/* + * Prepare encryption material: + * - interpret command-line argument + * - set up key + * - outputs: context and tag length, which together hold all the information + */ static int aead_prepare( const char *info, mbedtls_cipher_context_t *ctx, size_t *tag_len ) { int ret; + /* Convert arg to type + tag_len */ mbedtls_cipher_type_t type; if( strcmp( info, "aes128-gcm" ) == 0 ) { type = MBEDTLS_CIPHER_AES_128_GCM; @@ -115,9 +143,11 @@ static int aead_prepare( const char *info, return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); } + /* Prepare context for the given type */ CHK( mbedtls_cipher_setup( ctx, mbedtls_cipher_info_from_type( type ) ) ); + /* Import key */ int key_len = mbedtls_cipher_get_key_bitlen( ctx ); CHK( mbedtls_cipher_setkey( ctx, key_bytes, key_len, MBEDTLS_ENCRYPT ) ); @@ -125,9 +155,15 @@ exit: return( ret ); } +/* + * Print out some information. + * + * All of this information was present in the command line argument, but his + * function demonstrates how each piece can be recovered from (ctx, tag_len). + */ static void aead_info( const mbedtls_cipher_context_t *ctx, size_t tag_len ) { - // no convenient way to get the cipher type (for example, AES) + // no convenient way to get the just cipher type (for example, AES) const char *ciph = "???"; int key_bits = mbedtls_cipher_get_key_bitlen( ctx ); mbedtls_cipher_mode_t mode = mbedtls_cipher_get_cipher_mode( ctx ); @@ -139,6 +175,9 @@ static void aead_info( const mbedtls_cipher_context_t *ctx, size_t tag_len ) printf( "cipher: %s, %d, %s, %u\n", ciph, key_bits, mode_str, (unsigned) tag_len ); } +/* + * Encrypt a 2-part message. + */ static int aead_encrypt( mbedtls_cipher_context_t *ctx, size_t tag_len, const unsigned char *iv, size_t iv_len, const unsigned char *ad, size_t ad_len, @@ -163,12 +202,15 @@ static int aead_encrypt( mbedtls_cipher_context_t *ctx, size_t tag_len, p += tag_len; olen = p - out; - print_out( "cipher", out, olen ); + print_buf( "cipher", out, olen ); exit: return( ret ); } +/* + * AEAD demo: set up key/alg, print out info, encrypt messages. + */ static int aead_demo( const char *info ) { int ret = 0; @@ -203,13 +245,20 @@ exit: */ int main( int argc, char **argv ) { + /* Check usage */ if( argc != 2 ) { puts( usage ); return( 1 ); } - aead_demo( argv[1] ); + int ret; + + /* Run the demo */ + CHK( aead_demo( argv[1] ) ); + +exit: + return( ret == 0 ? EXIT_SUCCESS : EXIT_FAILURE ); } #endif diff --git a/programs/psa/aead_psa.c b/programs/psa/aead_psa.c index 5ed32a5f6a..2f0663d838 100644 --- a/programs/psa/aead_psa.c +++ b/programs/psa/aead_psa.c @@ -1,9 +1,29 @@ -/* - * This is a simple example of multi-part AEAD computation using the PSA - * Crypto API. It comes with a companion program aead_non_psa.c, which does - * the same operations with the legacy Cipher API. The goal is that comparing the - * two programs will help people migrating to the PSA Crypto API. +/** + * PSA API multi-part AEAD demonstration. * + * This program AEAD-encrypts a message, using the algorithm and key size + * specified on the command line, using the multi-part API. + * + * It comes with a companion program aead_non_psa.c, which does the same + * operations with the legacy Cipher API. The goal is that comparing the two + * programs will help people migrating to the PSA Crypto API. + * + * When used with multi-part AEAD operations, the `mbedtls_cipher_context` + * serves a triple purpose (1) hold the key, (2) store the algorithm when no + * operation is active, and (3) save progress information for the current + * operation. With PSA those roles are held by disinct objects: (1) a + * psa_key_id_t to hold the key, a (2) psa_algorithm_t to represent the + * algorithm, and (3) a psa_operation_t for multi-part progress. + * + * On the other hand, with PSA, the algorithms encodes the desired tag length; + * with Cipher the desired tag length needs to be tracked separately. + * + * This program and its companion aead_non_psa.c illustrate this by doing the + * same sequence of multi-part AEAD computation with both APIs; looking at the + * two side by side should make the differences and similarities clear. + */ + +/* * Copyright The Mbed TLS Contributors * SPDX-License-Identifier: Apache-2.0 * @@ -20,26 +40,18 @@ * limitations under the License. */ -/* - * When used with multi-part AEAD operations, the `mbedtls_cipher_context` - * serves a triple purpose (1) hold the key, (2) store the algorithm when no - * operation is active, and (3) save progress information for the current - * operation. With PSA those roles are held by disinct objects: (1) a - * psa_key_id_t to hold the key, a (2) psa_algorithm_t to represent the - * algorithm, and (3) a psa_operation_t for multi-part progress. - * - * On the other hand, with PSA, the algorithms encodes the desired tag length; - * with Cipher the desired tag length needs to be tracked separately. - * - * This program and its compation aead_non_psa.c illustrate this by doing the - * same sequence of multi-part AEAD computation with both APIs; looking at the - * two side by side should make the differences and similarities clear. - */ - -#include - +/* First include Mbed TLS headers to get the Mbed TLS configuration and + * platform definitions that we'll use in this program. Also include + * standard C headers for functions we'll use here. */ #include "mbedtls/build_info.h" +#include "psa/crypto.h" + +#include +#include +#include + +/* If the build options we need are not enabled, compile a placeholder. */ #if !defined(MBEDTLS_PSA_CRYPTO_C) || \ !defined(MBEDTLS_AES_C) || !defined(MBEDTLS_GCM_C) || \ !defined(MBEDTLS_CHACHAPOLY_C) || \ @@ -54,52 +66,68 @@ int main( void ) } #else -#include +/* The real program starts here. */ -#include "psa/crypto.h" - -/* - * Dummy data and helper functions - */ const char usage[] = "Usage: aead_psa [aes128-gcm|aes256-gcm|aes128-gcm_8|chachapoly]"; +/* Dummy data for encryption: IV/nonce, additional data, 2-part message */ const unsigned char iv1[12] = { 0x00 }; const unsigned char add_data1[] = { 0x01, 0x02 }; const unsigned char msg1_part1[] = { 0x03, 0x04 }; const unsigned char msg1_part2[] = { 0x05, 0x06, 0x07 }; +/* Dummy data (2nd message) */ const unsigned char iv2[12] = { 0x10 }; const unsigned char add_data2[] = { 0x11, 0x12 }; const unsigned char msg2_part1[] = { 0x13, 0x14 }; const unsigned char msg2_part2[] = { 0x15, 0x16, 0x17 }; +/* This must at least the sum of the length of the 2 parts for each message. + * This is a macro for the sake of compilers with insufficient C99 support. */ #define MSG_MAX_SIZE 5 +/* Dummy key material - never do this in production! + * 32-byte is enough to all the key size supported by this program. */ const unsigned char key_bytes[32] = { 0x2a }; -void print_out( const char *title, unsigned char *out, size_t len ) +/* Print the contents of a buffer in hex */ +void print_buf( const char *title, uint8_t *buf, size_t len ) { printf( "%s:", title ); for( size_t i = 0; i < len; i++ ) - printf( " %02x", out[i] ); + printf( " %02x", buf[i] ); printf( "\n" ); } -#define CHK( code ) \ - do { \ - status = code; \ - if( status != PSA_SUCCESS ) { \ - printf( "%03d: status = %d\n", __LINE__, status ); \ - goto exit; \ - } \ - } while( 0 ) +/* Run a PSA function and bail out if it fails. */ +#define PSA_CHECK( expr ) \ + do \ + { \ + status = ( expr ); \ + if( status != PSA_SUCCESS ) \ + { \ + printf( "Error %d at line %d: %s\n", \ + (int) status, \ + __LINE__, \ + #expr ); \ + goto exit; \ + } \ + } \ + while( 0 ) +/* + * Prepare encryption material: + * - interpret command-line argument + * - set up key + * - outputs: key and algorithm, which together hold all the information + */ static psa_status_t aead_prepare( const char *info, psa_key_id_t *key, psa_algorithm_t *alg ) { psa_status_t status; + /* Convert arg to alg + key_bits + key_type */ size_t key_bits; psa_key_type_t key_type; if( strcmp( info, "aes128-gcm" ) == 0 ) { @@ -123,18 +151,26 @@ static psa_status_t aead_prepare( const char *info, return( PSA_ERROR_INVALID_ARGUMENT ); } + /* Prepare key attibutes */ psa_key_attributes_t attributes = PSA_KEY_ATTRIBUTES_INIT; psa_set_key_usage_flags( &attributes, PSA_KEY_USAGE_ENCRYPT ); psa_set_key_algorithm( &attributes, *alg ); psa_set_key_type( &attributes, key_type ); - psa_set_key_bits( &attributes, key_bits ); + psa_set_key_bits( &attributes, key_bits ); // optional - CHK( psa_import_key( &attributes, key_bytes, key_bits / 8, key ) ); + /* Import key */ + PSA_CHECK( psa_import_key( &attributes, key_bytes, key_bits / 8, key ) ); exit: return( status ); } +/* + * Print out some information. + * + * All of this information was present in the command line argument, but his + * function demonstrates how each piece can be recovered from (key, alg). + */ static void aead_info( psa_key_id_t key, psa_algorithm_t alg ) { psa_key_attributes_t attr = PSA_KEY_ATTRIBUTES_INIT; @@ -155,6 +191,9 @@ static void aead_info( psa_key_id_t key, psa_algorithm_t alg ) type_str, (unsigned) key_bits, base_str, (unsigned) tag_len ); } +/* + * Encrypt a 2-part message. + */ static int aead_encrypt( psa_key_id_t key, psa_algorithm_t alg, const unsigned char *iv, size_t iv_len, const unsigned char *ad, size_t ad_len, @@ -168,29 +207,31 @@ static int aead_encrypt( psa_key_id_t key, psa_algorithm_t alg, unsigned char tag[PSA_AEAD_TAG_MAX_SIZE]; psa_aead_operation_t op = PSA_AEAD_OPERATION_INIT; - CHK( psa_aead_encrypt_setup( &op, key, alg ) ); + PSA_CHECK( psa_aead_encrypt_setup( &op, key, alg ) ); - CHK( psa_aead_set_nonce( &op, iv, iv_len ) ); - CHK( psa_aead_update_ad( &op, ad, ad_len ) ); - CHK( psa_aead_update( &op, pa, pa_len, p, end - p, &olen ) ); + PSA_CHECK( psa_aead_set_nonce( &op, iv, iv_len ) ); + PSA_CHECK( psa_aead_update_ad( &op, ad, ad_len ) ); + PSA_CHECK( psa_aead_update( &op, pa, pa_len, p, end - p, &olen ) ); p += olen; - CHK( psa_aead_update( &op, pb, pb_len, p, end - p, &olen ) ); + PSA_CHECK( psa_aead_update( &op, pb, pb_len, p, end - p, &olen ) ); p += olen; - CHK( psa_aead_finish( &op, p, end - p, &olen, + PSA_CHECK( psa_aead_finish( &op, p, end - p, &olen, tag, sizeof( tag ), &olen_tag ) ); p += olen; memcpy( p, tag, olen_tag ); p += olen_tag; olen = p - out; - print_out( "out", out, olen ); + print_buf( "out", out, olen ); exit: - /* required on errors, harmless on success */ - psa_aead_abort( &op ); + psa_aead_abort( &op ); // required on errors, harmless on success return( status ); } +/* + * AEAD demo: set up key/alg, print out info, encrypt messages. + */ static psa_status_t aead_demo( const char *info ) { psa_status_t status; @@ -198,15 +239,15 @@ static psa_status_t aead_demo( const char *info ) psa_key_id_t key; psa_algorithm_t alg; - CHK( aead_prepare( info, &key, &alg ) ); + PSA_CHECK( aead_prepare( info, &key, &alg ) ); aead_info( key, alg ); - CHK( aead_encrypt( key, alg, + PSA_CHECK( aead_encrypt( key, alg, iv1, sizeof( iv1 ), add_data1, sizeof( add_data1 ), msg1_part1, sizeof( msg1_part1 ), msg1_part2, sizeof( msg1_part2 ) ) ); - CHK( aead_encrypt( key, alg, + PSA_CHECK( aead_encrypt( key, alg, iv2, sizeof( iv2 ), add_data2, sizeof( add_data2 ), msg2_part1, sizeof( msg2_part1 ), msg2_part2, sizeof( msg2_part2 ) ) ); @@ -222,17 +263,26 @@ exit: */ int main( int argc, char **argv ) { + psa_status_t status = PSA_SUCCESS; + + /* Check usage */ if( argc != 2 ) { puts( usage ); - return( 1 ); + return( EXIT_FAILURE ); } - psa_status_t status = psa_crypto_init(); - if( status != PSA_SUCCESS ) - printf( "psa init: %d\n", status ); + /* Initialize the PSA crypto library. */ + PSA_CHECK( psa_crypto_init( ) ); - aead_demo( argv[1] ); + /* Run the demo */ + PSA_CHECK( aead_demo( argv[1] ) ); + + /* Deinitialize the PSA crypto library. */ + mbedtls_psa_crypto_free( ); + +exit: + return( status == PSA_SUCCESS ? EXIT_SUCCESS : EXIT_FAILURE ); } #endif