Merge remote-tracking branch 'restricted/pr/552' into development
Ensure this merge passes tests by auto-generating query_config.c, adding
MBEDTLS_ECDH_LEGACY_CONTEXT to it.
* restricted/pr/552:
Fix mbedtls_ecdh_get_params with new ECDH context
Test undefining MBEDTLS_ECDH_LEGACY_CONTEXT in all.sh
Define MBEDTLS_ECDH_LEGACY_CONTEXT in config.h
Add changelog entry for mbedtls_ecdh_get_params robustness
Fix ecdh_get_params with mismatching group
Add test case for ecdh_get_params with mismatching group
Add test case for ecdh_calc_secret
Fix typo in documentation
diff --git a/ChangeLog b/ChangeLog
index 5d9927c..d4e945a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -50,6 +50,14 @@
mbedtls_ssl_session structure which otherwise stores the peer's
certificate.
+Security
+ * Make mbedtls_ecdh_get_params return an error if the second key
+ belongs to a different group from the first. Before, if an application
+ passed keys that belonged to different group, the first key's data was
+ interpreted according to the second group, which could lead to either
+ an error or a meaningless output from mbedtls_ecdh_get_params. In the
+ latter case, this could expose at most 5 bits of the private key.
+
Bugfix
* Fix a compilation issue with mbedtls_ecp_restart_ctx not being defined
when MBEDTLS_ECP_ALT is defined. Reported by jwhui. Fixes #2242.
diff --git a/include/mbedtls/check_config.h b/include/mbedtls/check_config.h
index c1450db..0fa74f0 100644
--- a/include/mbedtls/check_config.h
+++ b/include/mbedtls/check_config.h
@@ -125,6 +125,11 @@
#error "MBEDTLS_ECP_RESTARTABLE defined, but it cannot coexist with an alternative or PSA-based ECP implementation"
#endif
+#if defined(MBEDTLS_ECP_RESTARTABLE) && \
+ ! defined(MBEDTLS_ECDH_LEGACY_CONTEXT)
+#error "MBEDTLS_ECP_RESTARTABLE defined, but not MBEDTLS_ECDH_LEGACY_CONTEXT"
+#endif
+
#if defined(MBEDTLS_ECDSA_DETERMINISTIC) && !defined(MBEDTLS_HMAC_DRBG_C)
#error "MBEDTLS_ECDSA_DETERMINISTIC defined, but not all prerequisites"
#endif
diff --git a/include/mbedtls/config.h b/include/mbedtls/config.h
index 31a3059..0fe2574 100644
--- a/include/mbedtls/config.h
+++ b/include/mbedtls/config.h
@@ -760,11 +760,40 @@
*
* \note This option only works with the default software implementation of
* elliptic curve functionality. It is incompatible with
- * MBEDTLS_ECP_ALT, MBEDTLS_ECDH_XXX_ALT and MBEDTLS_ECDSA_XXX_ALT.
+ * MBEDTLS_ECP_ALT, MBEDTLS_ECDH_XXX_ALT, MBEDTLS_ECDSA_XXX_ALT
+ * and MBEDTLS_ECDH_LEGACY_CONTEXT.
*/
//#define MBEDTLS_ECP_RESTARTABLE
/**
+ * \def MBEDTLS_ECDH_LEGACY_CONTEXT
+ *
+ * Use a backward compatible ECDH context.
+ *
+ * Mbed TLS supports two formats for ECDH contexts (#mbedtls_ecdh_context
+ * defined in `ecdh.h`). For most applications, the choice of format makes
+ * no difference, since all library functions can work with either format,
+ * except that the new format is incompatible with MBEDTLS_ECP_RESTARTABLE.
+
+ * The new format used when this option is disabled is smaller
+ * (56 bytes on a 32-bit platform). In future versions of the library, it
+ * will support alternative implementations of ECDH operations.
+ * The new format is incompatible with applications that access
+ * context fields directly and with restartable ECP operations.
+ *
+ * Define this macro if you enable MBEDTLS_ECP_RESTARTABLE or if you
+ * want to access ECDH context fields directly. Otherwise you should
+ * comment out this macro definition.
+ *
+ * This option has no effect if #MBEDTLS_ECDH_C is not enabled.
+ *
+ * \note This configuration option is experimental. Future versions of the
+ * library may modify the way the ECDH context layout is configured
+ * and may modify the layout of the new context type.
+ */
+#define MBEDTLS_ECDH_LEGACY_CONTEXT
+
+/**
* \def MBEDTLS_ECDSA_DETERMINISTIC
*
* Enable deterministic ECDSA (RFC 6979).
diff --git a/include/mbedtls/ecdh.h b/include/mbedtls/ecdh.h
index 4479a1d..384c3dc 100644
--- a/include/mbedtls/ecdh.h
+++ b/include/mbedtls/ecdh.h
@@ -42,18 +42,6 @@
#include "ecp.h"
-/*
- * Use a backward compatible ECDH context.
- *
- * This flag is always enabled for now and future versions might add a
- * configuration option that conditionally undefines this flag.
- * The configuration option in question may have a different name.
- *
- * Features undefining this flag, must have a warning in their description in
- * config.h stating that the feature breaks backward compatibility.
- */
-#define MBEDTLS_ECDH_LEGACY_CONTEXT
-
#ifdef __cplusplus
extern "C" {
#endif
diff --git a/include/mbedtls/ecp.h b/include/mbedtls/ecp.h
index 2401778..065a4cc 100644
--- a/include/mbedtls/ecp.h
+++ b/include/mbedtls/ecp.h
@@ -482,7 +482,7 @@
*
* \note After this function is called, domain parameters
* for various ECP groups can be loaded through the
- * mbedtls_ecp_load() or mbedtls_ecp_tls_read_group()
+ * mbedtls_ecp_group_load() or mbedtls_ecp_tls_read_group()
* functions.
*/
void mbedtls_ecp_group_init( mbedtls_ecp_group *grp );
diff --git a/library/ecdh.c b/library/ecdh.c
index da95c60..c572687 100644
--- a/library/ecdh.c
+++ b/library/ecdh.c
@@ -49,6 +49,16 @@
typedef mbedtls_ecdh_context mbedtls_ecdh_context_mbed;
#endif
+static mbedtls_ecp_group_id mbedtls_ecdh_grp_id(
+ const mbedtls_ecdh_context *ctx )
+{
+#if defined(MBEDTLS_ECDH_LEGACY_CONTEXT)
+ return( ctx->grp.id );
+#else
+ return( ctx->grp_id );
+#endif
+}
+
#if !defined(MBEDTLS_ECDH_GEN_PUBLIC_ALT)
/*
* Generate public key (restartable version)
@@ -442,8 +452,21 @@
ECDH_VALIDATE_RET( side == MBEDTLS_ECDH_OURS ||
side == MBEDTLS_ECDH_THEIRS );
- if( ( ret = mbedtls_ecdh_setup( ctx, key->grp.id ) ) != 0 )
- return( ret );
+ if( mbedtls_ecdh_grp_id( ctx ) == MBEDTLS_ECP_DP_NONE )
+ {
+ /* This is the first call to get_params(). Set up the context
+ * for use with the group. */
+ if( ( ret = mbedtls_ecdh_setup( ctx, key->grp.id ) ) != 0 )
+ return( ret );
+ }
+ else
+ {
+ /* This is not the first call to get_params(). Check that the
+ * current key's group is the same as the context's, which was set
+ * from the first key's group. */
+ if( mbedtls_ecdh_grp_id( ctx ) != key->grp.id )
+ return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
+ }
#if defined(MBEDTLS_ECDH_LEGACY_CONTEXT)
return( ecdh_get_params_internal( ctx, key, side ) );
diff --git a/library/version_features.c b/library/version_features.c
index 1be0e0f..59eacc4 100644
--- a/library/version_features.c
+++ b/library/version_features.c
@@ -351,6 +351,9 @@
#if defined(MBEDTLS_ECP_RESTARTABLE)
"MBEDTLS_ECP_RESTARTABLE",
#endif /* MBEDTLS_ECP_RESTARTABLE */
+#if defined(MBEDTLS_ECDH_LEGACY_CONTEXT)
+ "MBEDTLS_ECDH_LEGACY_CONTEXT",
+#endif /* MBEDTLS_ECDH_LEGACY_CONTEXT */
#if defined(MBEDTLS_ECDSA_DETERMINISTIC)
"MBEDTLS_ECDSA_DETERMINISTIC",
#endif /* MBEDTLS_ECDSA_DETERMINISTIC */
diff --git a/programs/ssl/query_config.c b/programs/ssl/query_config.c
index f272676..6ea9012 100644
--- a/programs/ssl/query_config.c
+++ b/programs/ssl/query_config.c
@@ -978,6 +978,14 @@
}
#endif /* MBEDTLS_ECP_RESTARTABLE */
+#if defined(MBEDTLS_ECDH_LEGACY_CONTEXT)
+ if( strcmp( "MBEDTLS_ECDH_LEGACY_CONTEXT", config ) == 0 )
+ {
+ MACRO_EXPANSION_TO_STR( MBEDTLS_ECDH_LEGACY_CONTEXT );
+ return( 0 );
+ }
+#endif /* MBEDTLS_ECDH_LEGACY_CONTEXT */
+
#if defined(MBEDTLS_ECDSA_DETERMINISTIC)
if( strcmp( "MBEDTLS_ECDSA_DETERMINISTIC", config ) == 0 )
{
diff --git a/tests/scripts/all.sh b/tests/scripts/all.sh
index 301dc52..2b443b7 100755
--- a/tests/scripts/all.sh
+++ b/tests/scripts/all.sh
@@ -678,6 +678,23 @@
if_build_succeeded tests/compat.sh -t RSA
}
+component_test_new_ecdh_context () {
+ msg "build: new ECDH context (ASan build)" # ~ 6 min
+ scripts/config.pl unset MBEDTLS_ECDH_LEGACY_CONTEXT
+ CC=gcc cmake -D CMAKE_BUILD_TYPE:String=Asan .
+ make
+
+ msg "test: new ECDH context - main suites (inc. selftests) (ASan build)" # ~ 50s
+ make test
+
+ msg "test: new ECDH context - ECDH-related part of ssl-opt.sh (ASan build)" # ~ 5s
+ if_build_succeeded tests/ssl-opt.sh -f ECDH
+
+ msg "test: new ECDH context - compat.sh with some ECDH ciphersuites (ASan build)" # ~ 3 min
+ # Exclude some symmetric ciphers that are redundant here to gain time.
+ if_build_succeeded tests/compat.sh -f ECDH -V NO -e 'ARCFOUR\|ARIA\|CAMELLIA\|CHACHA\|DES\|RC4'
+}
+
component_test_small_ssl_out_content_len () {
msg "build: small SSL_OUT_CONTENT_LEN (ASan build)"
scripts/config.pl set MBEDTLS_SSL_IN_CONTENT_LEN 16384
diff --git a/tests/suites/test_suite_ecdh.data b/tests/suites/test_suite_ecdh.data
index fe24ed4..af25359 100644
--- a/tests/suites/test_suite_ecdh.data
+++ b/tests/suites/test_suite_ecdh.data
@@ -79,3 +79,19 @@
ECDH exchange legacy context
depends_on:MBEDTLS_ECP_DP_SECP192R1_ENABLED
ecdh_exchange_legacy:MBEDTLS_ECP_DP_SECP192R1
+
+ECDH calc_secret: ours first, SECP256R1 (RFC 5903)
+depends_on:MBEDTLS_ECP_DP_SECP256R1_ENABLED
+ecdh_exchange_calc_secret:MBEDTLS_ECP_DP_SECP256R1:"c6ef9c5d78ae012a011164acb397ce2088685d8f06bf9be0b283ab46476bee53":"04dad0b65394221cf9b051e1feca5787d098dfe637fc90b9ef945d0c37725811805271a0461cdb8252d61f1c456fa3e59ab1f45b33accf5f58389e0577b8990bb3":0:"d6840f6b42f6edafd13116e0e12565202fef8e9ece7dce03812464d04b9442de"
+
+ECDH calc_secret: theirs first, SECP256R1 (RFC 5903)
+depends_on:MBEDTLS_ECP_DP_SECP256R1_ENABLED
+ecdh_exchange_calc_secret:MBEDTLS_ECP_DP_SECP256R1:"c6ef9c5d78ae012a011164acb397ce2088685d8f06bf9be0b283ab46476bee53":"04dad0b65394221cf9b051e1feca5787d098dfe637fc90b9ef945d0c37725811805271a0461cdb8252d61f1c456fa3e59ab1f45b33accf5f58389e0577b8990bb3":1:"d6840f6b42f6edafd13116e0e12565202fef8e9ece7dce03812464d04b9442de"
+
+ECDH get_params with mismatched groups: our BP256R1, their SECP256R1
+depends_on:MBEDTLS_ECP_DP_SECP256R1_ENABLED:MBEDTLS_ECP_DP_BP256R1_ENABLED
+ecdh_exchange_get_params_fail:MBEDTLS_ECP_DP_BP256R1:"1234567812345678123456781234567812345678123456781234567812345678":MBEDTLS_ECP_DP_SECP256R1:"04dad0b65394221cf9b051e1feca5787d098dfe637fc90b9ef945d0c37725811805271a0461cdb8252d61f1c456fa3e59ab1f45b33accf5f58389e0577b8990bb3":0:MBEDTLS_ERR_ECP_BAD_INPUT_DATA
+
+ECDH get_params with mismatched groups: their SECP256R1, our BP256R1
+depends_on:MBEDTLS_ECP_DP_SECP256R1_ENABLED:MBEDTLS_ECP_DP_BP256R1_ENABLED
+ecdh_exchange_get_params_fail:MBEDTLS_ECP_DP_BP256R1:"1234567812345678123456781234567812345678123456781234567812345678":MBEDTLS_ECP_DP_SECP256R1:"04dad0b65394221cf9b051e1feca5787d098dfe637fc90b9ef945d0c37725811805271a0461cdb8252d61f1c456fa3e59ab1f45b33accf5f58389e0577b8990bb3":1:MBEDTLS_ERR_ECP_BAD_INPUT_DATA
diff --git a/tests/suites/test_suite_ecdh.function b/tests/suites/test_suite_ecdh.function
index 7db0ed1..1a33d81 100644
--- a/tests/suites/test_suite_ecdh.function
+++ b/tests/suites/test_suite_ecdh.function
@@ -1,5 +1,41 @@
/* BEGIN_HEADER */
#include "mbedtls/ecdh.h"
+
+static int load_public_key( int grp_id, data_t *point,
+ mbedtls_ecp_keypair *ecp )
+{
+ int ok = 0;
+ TEST_ASSERT( mbedtls_ecp_group_load( &ecp->grp, grp_id ) == 0 );
+ TEST_ASSERT( mbedtls_ecp_point_read_binary( &ecp->grp,
+ &ecp->Q,
+ point->x,
+ point->len ) == 0 );
+ TEST_ASSERT( mbedtls_ecp_check_pubkey( &ecp->grp,
+ &ecp->Q ) == 0 );
+ ok = 1;
+exit:
+ return( ok );
+}
+
+static int load_private_key( int grp_id, data_t *private_key,
+ mbedtls_ecp_keypair *ecp,
+ rnd_pseudo_info *rnd_info )
+{
+ int ok = 0;
+ TEST_ASSERT( mbedtls_ecp_group_load( &ecp->grp, grp_id ) == 0 );
+ TEST_ASSERT( mbedtls_mpi_read_binary( &ecp->d,
+ private_key->x,
+ private_key->len ) == 0 );
+ TEST_ASSERT( mbedtls_ecp_check_privkey( &ecp->grp, &ecp->d ) == 0 );
+ /* Calculate the public key from the private key. */
+ TEST_ASSERT( mbedtls_ecp_mul( &ecp->grp, &ecp->Q, &ecp->d,
+ &ecp->grp.G,
+ &rnd_pseudo_rand, rnd_info ) == 0 );
+ ok = 1;
+exit:
+ return( ok );
+}
+
/* END_HEADER */
/* BEGIN_DEPENDENCIES
@@ -464,3 +500,107 @@
mbedtls_ecdh_free( &cli );
}
/* END_CASE */
+
+/* BEGIN_CASE */
+void ecdh_exchange_calc_secret( int grp_id,
+ data_t *our_private_key,
+ data_t *their_point,
+ int ours_first,
+ data_t *expected )
+{
+ rnd_pseudo_info rnd_info;
+ mbedtls_ecp_keypair our_key;
+ mbedtls_ecp_keypair their_key;
+ mbedtls_ecdh_context ecdh;
+ unsigned char shared_secret[MBEDTLS_ECP_MAX_BYTES];
+ size_t shared_secret_length = 0;
+
+ memset( &rnd_info, 0x00, sizeof( rnd_pseudo_info ) );
+ mbedtls_ecdh_init( &ecdh );
+ mbedtls_ecp_keypair_init( &our_key );
+ mbedtls_ecp_keypair_init( &their_key );
+
+ if( ! load_private_key( grp_id, our_private_key, &our_key, &rnd_info ) )
+ goto exit;
+ if( ! load_public_key( grp_id, their_point, &their_key ) )
+ goto exit;
+
+ /* Import the keys to the ECDH calculation. */
+ if( ours_first )
+ {
+ TEST_ASSERT( mbedtls_ecdh_get_params(
+ &ecdh, &our_key, MBEDTLS_ECDH_OURS ) == 0 );
+ TEST_ASSERT( mbedtls_ecdh_get_params(
+ &ecdh, &their_key, MBEDTLS_ECDH_THEIRS ) == 0 );
+ }
+ else
+ {
+ TEST_ASSERT( mbedtls_ecdh_get_params(
+ &ecdh, &their_key, MBEDTLS_ECDH_THEIRS ) == 0 );
+ TEST_ASSERT( mbedtls_ecdh_get_params(
+ &ecdh, &our_key, MBEDTLS_ECDH_OURS ) == 0 );
+ }
+
+ /* Perform the ECDH calculation. */
+ TEST_ASSERT( mbedtls_ecdh_calc_secret(
+ &ecdh,
+ &shared_secret_length,
+ shared_secret, sizeof( shared_secret ),
+ &rnd_pseudo_rand, &rnd_info ) == 0 );
+ TEST_ASSERT( shared_secret_length == expected->len );
+ TEST_ASSERT( memcmp( expected->x, shared_secret,
+ shared_secret_length ) == 0 );
+
+exit:
+ mbedtls_ecdh_free( &ecdh );
+ mbedtls_ecp_keypair_free( &our_key );
+ mbedtls_ecp_keypair_free( &their_key );
+}
+/* END_CASE */
+
+/* BEGIN_CASE */
+void ecdh_exchange_get_params_fail( int our_grp_id,
+ data_t *our_private_key,
+ int their_grp_id,
+ data_t *their_point,
+ int ours_first,
+ int expected_ret )
+{
+ rnd_pseudo_info rnd_info;
+ mbedtls_ecp_keypair our_key;
+ mbedtls_ecp_keypair their_key;
+ mbedtls_ecdh_context ecdh;
+
+ memset( &rnd_info, 0x00, sizeof( rnd_pseudo_info ) );
+ mbedtls_ecdh_init( &ecdh );
+ mbedtls_ecp_keypair_init( &our_key );
+ mbedtls_ecp_keypair_init( &their_key );
+
+ if( ! load_private_key( our_grp_id, our_private_key, &our_key, &rnd_info ) )
+ goto exit;
+ if( ! load_public_key( their_grp_id, their_point, &their_key ) )
+ goto exit;
+
+ if( ours_first )
+ {
+ TEST_ASSERT( mbedtls_ecdh_get_params(
+ &ecdh, &our_key, MBEDTLS_ECDH_OURS ) == 0 );
+ TEST_ASSERT( mbedtls_ecdh_get_params(
+ &ecdh, &their_key, MBEDTLS_ECDH_THEIRS ) ==
+ expected_ret );
+ }
+ else
+ {
+ TEST_ASSERT( mbedtls_ecdh_get_params(
+ &ecdh, &their_key, MBEDTLS_ECDH_THEIRS ) == 0 );
+ TEST_ASSERT( mbedtls_ecdh_get_params(
+ &ecdh, &our_key, MBEDTLS_ECDH_OURS ) ==
+ expected_ret );
+ }
+
+exit:
+ mbedtls_ecdh_free( &ecdh );
+ mbedtls_ecp_keypair_free( &our_key );
+ mbedtls_ecp_keypair_free( &their_key );
+}
+/* END_CASE */