Merge pull request #5725 from tom-daubney-arm/x25519_program
Rewrite x25519 example program
diff --git a/ChangeLog.d/fix-x25519-program.txt b/ChangeLog.d/fix-x25519-program.txt
new file mode 100644
index 0000000..af60465
--- /dev/null
+++ b/ChangeLog.d/fix-x25519-program.txt
@@ -0,0 +1,4 @@
+Bugfix
+ * Fix a bug in x25519 example program where the removal of
+ MBEDTLS_ECDH_LEGACY_CONTEXT caused the program not to run. Fixes #4901 and
+ #3191.
diff --git a/programs/pkey/ecdh_curve25519.c b/programs/pkey/ecdh_curve25519.c
index dff5480..281a26b 100644
--- a/programs/pkey/ecdh_curve25519.c
+++ b/programs/pkey/ecdh_curve25519.c
@@ -30,12 +30,12 @@
#define MBEDTLS_EXIT_FAILURE EXIT_FAILURE
#endif /* MBEDTLS_PLATFORM_C */
-#if !defined(MBEDTLS_ECDH_C) || !defined(MBEDTLS_ECDH_LEGACY_CONTEXT) || \
+#if !defined(MBEDTLS_ECDH_C) || \
!defined(MBEDTLS_ECP_DP_CURVE25519_ENABLED) || \
!defined(MBEDTLS_ENTROPY_C) || !defined(MBEDTLS_CTR_DRBG_C)
int main( void )
{
- mbedtls_printf( "MBEDTLS_ECDH_C and/or MBEDTLS_ECDH_LEGACY_CONTEXT and/or "
+ mbedtls_printf( "MBEDTLS_ECDH_C and/or "
"MBEDTLS_ECP_DP_CURVE25519_ENABLED and/or "
"MBEDTLS_ENTROPY_C and/or MBEDTLS_CTR_DRBG_C "
"not defined\n" );
@@ -47,6 +47,8 @@
#include "mbedtls/ctr_drbg.h"
#include "mbedtls/ecdh.h"
+#include <string.h>
+
int main( int argc, char *argv[] )
{
@@ -55,8 +57,15 @@
mbedtls_ecdh_context ctx_cli, ctx_srv;
mbedtls_entropy_context entropy;
mbedtls_ctr_drbg_context ctr_drbg;
- unsigned char cli_to_srv[32], srv_to_cli[32];
+ unsigned char cli_to_srv[36], srv_to_cli[33];
const char pers[] = "ecdh";
+
+ size_t srv_olen;
+ size_t cli_olen;
+ unsigned char secret_cli[32] = { 0 };
+ unsigned char secret_srv[32] = { 0 };
+ const unsigned char *p_cli_to_srv = cli_to_srv;
+
((void) argc);
((void) argv);
@@ -67,15 +76,17 @@
/*
* Initialize random number generation
*/
- mbedtls_printf( " . Seeding the random number generator..." );
+ mbedtls_printf( " . Seed the random number generator..." );
fflush( stdout );
mbedtls_entropy_init( &entropy );
- if( ( ret = mbedtls_ctr_drbg_seed( &ctr_drbg, mbedtls_entropy_func, &entropy,
- (const unsigned char *) pers,
- sizeof pers ) ) != 0 )
+ if( ( ret = mbedtls_ctr_drbg_seed( &ctr_drbg, mbedtls_entropy_func,
+ &entropy,
+ (const unsigned char *) pers,
+ sizeof pers ) ) != 0 )
{
- mbedtls_printf( " failed\n ! mbedtls_ctr_drbg_seed returned %d\n", ret );
+ mbedtls_printf( " failed\n ! mbedtls_ctr_drbg_seed returned %d\n",
+ ret );
goto exit;
}
@@ -84,28 +95,23 @@
/*
* Client: initialize context and generate keypair
*/
- mbedtls_printf( " . Setting up client context..." );
+ mbedtls_printf( " . Set up client context, generate EC key pair..." );
fflush( stdout );
- ret = mbedtls_ecp_group_load( &ctx_cli.MBEDTLS_PRIVATE(grp), MBEDTLS_ECP_DP_CURVE25519 );
+ ret = mbedtls_ecdh_setup( &ctx_cli, MBEDTLS_ECP_DP_CURVE25519 );
if( ret != 0 )
{
- mbedtls_printf( " failed\n ! mbedtls_ecp_group_load returned %d\n", ret );
+ mbedtls_printf( " failed\n ! mbedtls_ecdh_setup returned %d\n", ret );
goto exit;
}
- ret = mbedtls_ecdh_gen_public( &ctx_cli.MBEDTLS_PRIVATE(grp), &ctx_cli.MBEDTLS_PRIVATE(d), &ctx_cli.MBEDTLS_PRIVATE(Q),
- mbedtls_ctr_drbg_random, &ctr_drbg );
+ ret = mbedtls_ecdh_make_params( &ctx_cli, &cli_olen, cli_to_srv,
+ sizeof( cli_to_srv ),
+ mbedtls_ctr_drbg_random, &ctr_drbg );
if( ret != 0 )
{
- mbedtls_printf( " failed\n ! mbedtls_ecdh_gen_public returned %d\n", ret );
- goto exit;
- }
-
- ret = mbedtls_mpi_write_binary( &ctx_cli.MBEDTLS_PRIVATE(Q).MBEDTLS_PRIVATE(X), cli_to_srv, 32 );
- if( ret != 0 )
- {
- mbedtls_printf( " failed\n ! mbedtls_mpi_write_binary returned %d\n", ret );
+ mbedtls_printf( " failed\n ! mbedtls_ecdh_make_params returned %d\n",
+ ret );
goto exit;
}
@@ -114,90 +120,70 @@
/*
* Server: initialize context and generate keypair
*/
- mbedtls_printf( " . Setting up server context..." );
+ mbedtls_printf( " . Server: read params, generate public key..." );
fflush( stdout );
- ret = mbedtls_ecp_group_load( &ctx_srv.MBEDTLS_PRIVATE(grp), MBEDTLS_ECP_DP_CURVE25519 );
+ ret = mbedtls_ecdh_read_params( &ctx_srv, &p_cli_to_srv,
+ p_cli_to_srv + sizeof( cli_to_srv ) );
if( ret != 0 )
{
- mbedtls_printf( " failed\n ! mbedtls_ecp_group_load returned %d\n", ret );
+ mbedtls_printf( " failed\n ! mbedtls_ecdh_read_params returned %d\n",
+ ret );
goto exit;
}
- ret = mbedtls_ecdh_gen_public( &ctx_srv.MBEDTLS_PRIVATE(grp), &ctx_srv.MBEDTLS_PRIVATE(d), &ctx_srv.MBEDTLS_PRIVATE(Q),
- mbedtls_ctr_drbg_random, &ctr_drbg );
+ ret = mbedtls_ecdh_make_public( &ctx_srv, &srv_olen, srv_to_cli,
+ sizeof( srv_to_cli ),
+ mbedtls_ctr_drbg_random, &ctr_drbg );
if( ret != 0 )
{
- mbedtls_printf( " failed\n ! mbedtls_ecdh_gen_public returned %d\n", ret );
- goto exit;
- }
-
- ret = mbedtls_mpi_write_binary( &ctx_srv.MBEDTLS_PRIVATE(Q).MBEDTLS_PRIVATE(X), srv_to_cli, 32 );
- if( ret != 0 )
- {
- mbedtls_printf( " failed\n ! mbedtls_mpi_write_binary returned %d\n", ret );
+ mbedtls_printf( " failed\n ! mbedtls_ecdh_make_public returned %d\n",
+ ret );
goto exit;
}
mbedtls_printf( " ok\n" );
/*
- * Server: read peer's key and generate shared secret
+ * Client: read public key
*/
- mbedtls_printf( " . Server reading client key and computing secret..." );
+ mbedtls_printf( " . Client: read public key..." );
fflush( stdout );
- ret = mbedtls_mpi_lset( &ctx_srv.MBEDTLS_PRIVATE(Qp).MBEDTLS_PRIVATE(Z), 1 );
+ ret = mbedtls_ecdh_read_public( &ctx_cli, srv_to_cli,
+ sizeof( srv_to_cli ) );
if( ret != 0 )
{
- mbedtls_printf( " failed\n ! mbedtls_mpi_lset returned %d\n", ret );
- goto exit;
- }
-
- ret = mbedtls_mpi_read_binary( &ctx_srv.MBEDTLS_PRIVATE(Qp).MBEDTLS_PRIVATE(X), cli_to_srv, 32 );
- if( ret != 0 )
- {
- mbedtls_printf( " failed\n ! mbedtls_mpi_read_binary returned %d\n", ret );
- goto exit;
- }
-
- ret = mbedtls_ecdh_compute_shared( &ctx_srv.MBEDTLS_PRIVATE(grp), &ctx_srv.MBEDTLS_PRIVATE(z),
- &ctx_srv.MBEDTLS_PRIVATE(Qp), &ctx_srv.MBEDTLS_PRIVATE(d),
- mbedtls_ctr_drbg_random, &ctr_drbg );
- if( ret != 0 )
- {
- mbedtls_printf( " failed\n ! mbedtls_ecdh_compute_shared returned %d\n", ret );
+ mbedtls_printf( " failed\n ! mbedtls_ecdh_read_public returned %d\n",
+ ret );
goto exit;
}
mbedtls_printf( " ok\n" );
/*
- * Client: read peer's key and generate shared secret
+ * Calculate secrets
*/
- mbedtls_printf( " . Client reading server key and computing secret..." );
+ mbedtls_printf( " . Calculate secrets..." );
fflush( stdout );
- ret = mbedtls_mpi_lset( &ctx_cli.MBEDTLS_PRIVATE(Qp).MBEDTLS_PRIVATE(Z), 1 );
+ ret = mbedtls_ecdh_calc_secret( &ctx_cli, &cli_olen, secret_cli,
+ sizeof( secret_cli ),
+ mbedtls_ctr_drbg_random, &ctr_drbg );
if( ret != 0 )
{
- mbedtls_printf( " failed\n ! mbedtls_mpi_lset returned %d\n", ret );
+ mbedtls_printf( " failed\n ! mbedtls_ecdh_calc_secret returned %d\n",
+ ret );
goto exit;
}
- ret = mbedtls_mpi_read_binary( &ctx_cli.MBEDTLS_PRIVATE(Qp).MBEDTLS_PRIVATE(X), srv_to_cli, 32 );
+ ret = mbedtls_ecdh_calc_secret( &ctx_srv, &srv_olen, secret_srv,
+ sizeof( secret_srv ),
+ mbedtls_ctr_drbg_random, &ctr_drbg );
if( ret != 0 )
{
- mbedtls_printf( " failed\n ! mbedtls_mpi_read_binary returned %d\n", ret );
- goto exit;
- }
-
- ret = mbedtls_ecdh_compute_shared( &ctx_cli.MBEDTLS_PRIVATE(grp), &ctx_cli.MBEDTLS_PRIVATE(z),
- &ctx_cli.MBEDTLS_PRIVATE(Qp), &ctx_cli.MBEDTLS_PRIVATE(d),
- mbedtls_ctr_drbg_random, &ctr_drbg );
- if( ret != 0 )
- {
- mbedtls_printf( " failed\n ! mbedtls_ecdh_compute_shared returned %d\n", ret );
+ mbedtls_printf( " failed\n ! mbedtls_ecdh_calc_secret returned %d\n",
+ ret );
goto exit;
}
@@ -206,13 +192,13 @@
/*
* Verification: are the computed secrets equal?
*/
- mbedtls_printf( " . Checking if both computed secrets are equal..." );
+ mbedtls_printf( " . Check if both calculated secrets are equal..." );
fflush( stdout );
- ret = mbedtls_mpi_cmp_mpi( &ctx_cli.MBEDTLS_PRIVATE(z), &ctx_srv.MBEDTLS_PRIVATE(z) );
- if( ret != 0 )
+ ret = memcmp( secret_srv, secret_cli, srv_olen );
+ if( ret != 0 || ( cli_olen != srv_olen ) )
{
- mbedtls_printf( " failed\n ! mbedtls_ecdh_compute_shared returned %d\n", ret );
+ mbedtls_printf( " failed\n ! Shared secrets not equal.\n" );
goto exit;
}
