Merge remote-tracking branch 'hanno/iotssl-1341-optional-certificate-verification-needs-ca-chain_backport-1.3' into mbedtls-1.3
* hanno/iotssl-1341-optional-certificate-verification-needs-ca-chain_backport-1.3:
Add tests for missing CA chains and bad curves.
Fix implementation of VERIFY_OPTIONAL verification mode
diff --git a/ChangeLog b/ChangeLog
index a64de5d..d33897c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -15,6 +15,12 @@
* Wipe stack buffers in RSA private key operations
(rsa_rsaes_pkcs1_v15_decrypt(), rsa_rsaes_oaep_decrypt).
Found by Laurent Simon.
+ * Accept empty trusted CA chain in authentication mode
+ SSL_VERIFY_OPTIONAL. Fixes #864. Found by jethrogb.
+ * Fix implementation of ssl_parse_certificate
+ to not annihilate fatal errors in authentication mode
+ SSL_VERIFY_OPTIONAL and to reflect bad EC curves
+ within verification result.
= mbed TLS 1.3.19 branch released 2017-03-08
diff --git a/include/polarssl/x509.h b/include/polarssl/x509.h
index cd01539..adaacff 100644
--- a/include/polarssl/x509.h
+++ b/include/polarssl/x509.h
@@ -97,6 +97,8 @@
#define BADCERT_KEY_USAGE 0x0800 /**< Usage does not match the keyUsage extension. */
#define BADCERT_EXT_KEY_USAGE 0x1000 /**< Usage does not match the extendedKeyUsage extension. */
#define BADCERT_NS_CERT_TYPE 0x2000 /**< Usage does not match the nsCertType extension. */
+#define BADCERT_BAD_KEY 0x10000 /**< Bad key (e.g. unsupported elliptic curve in use) */
+
/* \} name */
/* \} addtogroup x509_module */
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 7cf968d..5779229 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -2841,12 +2841,6 @@
if( ssl->authmode != SSL_VERIFY_NONE )
{
- if( ssl->ca_chain == NULL )
- {
- SSL_DEBUG_MSG( 1, ( "got no CA chain" ) );
- return( POLARSSL_ERR_SSL_CA_CHAIN_REQUIRED );
- }
-
/*
* Main check: verify certificate
*/
@@ -2872,6 +2866,8 @@
if( pk_can_do( pk, POLARSSL_PK_ECKEY ) &&
! ssl_curve_is_acceptable( ssl, pk_ec( *pk )->grp.id ) )
{
+ ssl->session_negotiate->verify_result |= BADCERT_BAD_KEY;
+
SSL_DEBUG_MSG( 1, ( "bad certificate (EC key curve)" ) );
if( ret == 0 )
ret = POLARSSL_ERR_SSL_BAD_HS_CERTIFICATE;
@@ -2889,8 +2885,36 @@
ret = POLARSSL_ERR_SSL_BAD_HS_CERTIFICATE;
}
- if( ssl->authmode != SSL_VERIFY_REQUIRED )
+ /* x509_crt_verify_with_profile is supposed to report a
+ * verification failure through POLARSSL_ERR_X509_CERT_VERIFY_FAILED,
+ * with details encoded in the verification flags. All other kinds
+ * of error codes, including those from the user provided f_vrfy
+ * functions, are treated as fatal and lead to a failure of
+ * ssl_parse_certificate even if verification was optional. */
+ if( ssl->authmode == SSL_VERIFY_OPTIONAL &&
+ ( ret == POLARSSL_ERR_X509_CERT_VERIFY_FAILED ||
+ ret == POLARSSL_ERR_SSL_BAD_HS_CERTIFICATE ) )
+ {
ret = 0;
+ }
+
+ if( ssl->ca_chain == NULL && ssl->authmode == SSL_VERIFY_REQUIRED )
+ {
+ SSL_DEBUG_MSG( 1, ( "got no CA chain" ) );
+ ret = POLARSSL_ERR_SSL_CA_CHAIN_REQUIRED;
+ }
+
+#if defined(POLARSSL_DEBUG_C)
+ if( ssl->session_negotiate->verify_result != 0 )
+ {
+ SSL_DEBUG_MSG( 3, ( "! Certificate verification flags %x",
+ ssl->session_negotiate->verify_result ) );
+ }
+ else
+ {
+ SSL_DEBUG_MSG( 3, ( "Certificate verification flags clear" ) );
+ }
+#endif /* POLARSSL_DEBUG_C */
}
SSL_DEBUG_MSG( 2, ( "<= parse certificate" ) );
diff --git a/library/x509_crt.c b/library/x509_crt.c
index a3517f6..16a29b5 100644
--- a/library/x509_crt.c
+++ b/library/x509_crt.c
@@ -1403,6 +1403,7 @@
{ BADCERT_KEY_USAGE, "Usage does not match the keyUsage extension" },
{ BADCERT_EXT_KEY_USAGE, "Usage does not match the extendedKeyUsage extension" },
{ BADCERT_NS_CERT_TYPE, "Usage does not match the nsCertType extension" },
+ { BADCERT_BAD_KEY, "The certificate uses an invalid key (e.g. unsupported elliptic curve)" },
{ 0, NULL }
};
diff --git a/programs/ssl/ssl_client2.c b/programs/ssl/ssl_client2.c
index cdadf59..e302244 100644
--- a/programs/ssl/ssl_client2.c
+++ b/programs/ssl/ssl_client2.c
@@ -92,6 +92,7 @@
#define DFL_RECO_DELAY 0
#define DFL_TICKETS SSL_SESSION_TICKETS_ENABLED
#define DFL_ALPN_STRING NULL
+#define DFL_CURVES NULL
#define DFL_FALLBACK -1
#define DFL_EXTENDED_MS -1
#define DFL_ETM -1
@@ -169,6 +170,17 @@
#define USAGE_ALPN ""
#endif /* POLARSSL_SSL_ALPN */
+#if defined(POLARSSL_SSL_SET_CURVES)
+#define USAGE_CURVES \
+ " curves=a,b,c,d default: \"default\" (library default)\n" \
+ " example: \"secp521r1,brainpoolP512r1\"\n" \
+ " - use \"none\" for empty list\n" \
+ " - see ecp_curve_list()\n" \
+ " for acceptable curve names\n"
+#else
+#define USAGE_CURVES ""
+#endif /* POLARSSL_SSL_SET_CURVES */
+
#if defined(POLARSSL_SSL_FALLBACK_SCSV)
#define USAGE_FALLBACK \
" fallback=0/1 default: (library default: off)\n"
@@ -226,6 +238,7 @@
USAGE_MAX_FRAG_LEN \
USAGE_TRUNC_HMAC \
USAGE_ALPN \
+ USAGE_CURVES \
USAGE_FALLBACK \
USAGE_EMS \
USAGE_ETM \
@@ -285,6 +298,7 @@
int reconnect; /* attempt to resume session */
int reco_delay; /* delay in seconds before resuming session */
int tickets; /* enable / disable session tickets */
+ const char *curves; /* list of supported elliptic curves */
const char *alpn_string; /* ALPN supported protocols */
int fallback; /* is this a fallback connection? */
int extended_ms; /* negotiate extended master secret? */
@@ -373,6 +387,11 @@
#if defined(POLARSSL_SSL_ALPN)
const char *alpn_list[10];
#endif
+#if defined(POLARSSL_SSL_SET_CURVES)
+ ecp_group_id curve_list[20];
+ const ecp_curve_info *curve_cur;
+#endif
+
const char *pers = "ssl_client2";
entropy_context entropy;
@@ -453,6 +472,7 @@
opt.reco_delay = DFL_RECO_DELAY;
opt.tickets = DFL_TICKETS;
opt.alpn_string = DFL_ALPN_STRING;
+ opt.curves = DFL_CURVES;
opt.fallback = DFL_FALLBACK;
opt.extended_ms = DFL_EXTENDED_MS;
opt.etm = DFL_ETM;
@@ -584,6 +604,8 @@
default: goto usage;
}
}
+ else if( strcmp( p, "curves" ) == 0 )
+ opt.curves = q;
else if( strcmp( p, "etm" ) == 0 )
{
switch( atoi( q ) )
@@ -775,6 +797,64 @@
}
#endif /* POLARSSL_KEY_EXCHANGE__SOME__PSK_ENABLED */
+#if defined(POLARSSL_SSL_SET_CURVES)
+ if( opt.curves != NULL )
+ {
+ p = (char *) opt.curves;
+ i = 0;
+
+ if( strcmp( p, "none" ) == 0 )
+ {
+ curve_list[0] = POLARSSL_ECP_DP_NONE;
+ }
+ else if( strcmp( p, "default" ) != 0 )
+ {
+ /* Leave room for a final NULL in curve list */
+ while( i < (int) ( sizeof( curve_list ) / sizeof( *curve_list ) ) - 1
+ && *p != '\0' )
+ {
+ q = p;
+
+ /* Terminate the current string */
+ while( *p != ',' && *p != '\0' )
+ p++;
+ if( *p == ',' )
+ *p++ = '\0';
+
+ if( ( curve_cur = ecp_curve_info_from_name( q ) ) != NULL )
+ {
+ curve_list[i++] = curve_cur->grp_id;
+ }
+ else
+ {
+ polarssl_printf( "unknown curve %s\n", q );
+ polarssl_printf( "supported curves: " );
+ for( curve_cur = ecp_curve_list();
+ curve_cur->grp_id != POLARSSL_ECP_DP_NONE;
+ curve_cur++ )
+ {
+ polarssl_printf( "%s ", curve_cur->name );
+ }
+ polarssl_printf( "\n" );
+ goto exit;
+ }
+ }
+
+ polarssl_printf( "Number of curves: %d\n", i );
+
+ if( i == (int) ( sizeof( curve_list ) / sizeof( *curve_list ) ) - 1
+ && *p != '\0' )
+ {
+ polarssl_printf( "curves list too long, maximum %zu",
+ (size_t) ( sizeof( curve_list ) / sizeof( *curve_list ) - 1 ) );
+ goto exit;
+ }
+
+ curve_list[i] = POLARSSL_ECP_DP_NONE;
+ }
+ }
+#endif /* POLARSSL_SSL_SET_CURVES */
+
#if defined(POLARSSL_SSL_ALPN)
if( opt.alpn_string != NULL )
{
@@ -996,6 +1076,14 @@
}
#endif
+#if defined(POLARSSL_SSL_SET_CURVES)
+ if( opt.curves != NULL &&
+ strcmp( opt.curves, "default" ) != 0 )
+ {
+ ssl_set_curves( &ssl, curve_list );
+ }
+#endif
+
ssl_set_rng( &ssl, ctr_drbg_random, &ctr_drbg );
ssl_set_dbg( &ssl, my_debug, stdout );
diff --git a/programs/ssl/ssl_server2.c b/programs/ssl/ssl_server2.c
index 095fabd..95438f9 100644
--- a/programs/ssl/ssl_server2.c
+++ b/programs/ssl/ssl_server2.c
@@ -106,6 +106,7 @@
#define DFL_CACHE_TIMEOUT -1
#define DFL_SNI NULL
#define DFL_ALPN_STRING NULL
+#define DFL_CURVES NULL
#define DFL_DHM_FILE NULL
#define DFL_EXTENDED_MS -1
#define DFL_ETM -1
@@ -215,6 +216,17 @@
#define USAGE_ALPN ""
#endif /* POLARSSL_SSL_ALPN */
+#if defined(POLARSSL_SSL_SET_CURVES)
+#define USAGE_CURVES \
+ " curves=a,b,c,d default: \"default\" (library default)\n" \
+ " example: \"secp521r1,brainpoolP512r1\"\n" \
+ " - use \"none\" for empty list\n" \
+ " - see ecp_curve_list()\n" \
+ " for acceptable curve names\n"
+#else
+#define USAGE_CURVES ""
+#endif /* POLARSSL_SSL_SET_CURVES */
+
#if defined(POLARSSL_SSL_EXTENDED_MASTER_SECRET)
#define USAGE_EMS \
" extended_ms=0/1 default: (library default: on)\n"
@@ -263,6 +275,7 @@
USAGE_MAX_FRAG_LEN \
USAGE_TRUNC_HMAC \
USAGE_ALPN \
+ USAGE_CURVES \
USAGE_EMS \
USAGE_ETM \
"\n" \
@@ -327,6 +340,7 @@
int cache_max; /* max number of session cache entries */
int cache_timeout; /* expiration delay of session cache entries */
char *sni; /* string describing sni information */
+ const char *curves; /* list of supported elliptic curves */
const char *alpn_string; /* ALPN supported protocols */
const char *dhm_file; /* the file with the DH parameters */
int extended_ms; /* allow negotiation of extended MS? */
@@ -685,6 +699,10 @@
#if defined(POLARSSL_SSL_ALPN)
const char *alpn_list[10];
#endif
+#if defined(POLARSSL_SSL_SET_CURVES)
+ ecp_group_id curve_list[20];
+ const ecp_curve_info *curve_cur;
+#endif
#if defined(POLARSSL_MEMORY_BUFFER_ALLOC_C)
unsigned char alloc_buf[100000];
#endif
@@ -780,6 +798,7 @@
opt.cache_timeout = DFL_CACHE_TIMEOUT;
opt.sni = DFL_SNI;
opt.alpn_string = DFL_ALPN_STRING;
+ opt.curves = DFL_CURVES;
opt.dhm_file = DFL_DHM_FILE;
opt.extended_ms = DFL_EXTENDED_MS;
opt.etm = DFL_ETM;
@@ -987,6 +1006,8 @@
default: goto usage;
}
}
+ else if( strcmp( p, "curves" ) == 0 )
+ opt.curves = q;
else if( strcmp( p, "etm" ) == 0 )
{
switch( atoi( q ) )
@@ -1118,6 +1139,64 @@
}
#endif /* POLARSSL_KEY_EXCHANGE__SOME__PSK_ENABLED */
+#if defined(POLARSSL_SSL_SET_CURVES)
+ if( opt.curves != NULL )
+ {
+ p = (char *) opt.curves;
+ i = 0;
+
+ if( strcmp( p, "none" ) == 0 )
+ {
+ curve_list[0] = POLARSSL_ECP_DP_NONE;
+ }
+ else if( strcmp( p, "default" ) != 0 )
+ {
+ /* Leave room for a final NULL in curve list */
+ while( i < (int) ( sizeof( curve_list ) / sizeof( *curve_list ) ) - 1
+ && *p != '\0' )
+ {
+ q = p;
+
+ /* Terminate the current string */
+ while( *p != ',' && *p != '\0' )
+ p++;
+ if( *p == ',' )
+ *p++ = '\0';
+
+ if( ( curve_cur = ecp_curve_info_from_name( q ) ) != NULL )
+ {
+ curve_list[i++] = curve_cur->grp_id;
+ }
+ else
+ {
+ polarssl_printf( "unknown curve %s\n", q );
+ polarssl_printf( "supported curves: " );
+ for( curve_cur = ecp_curve_list();
+ curve_cur->grp_id != POLARSSL_ECP_DP_NONE;
+ curve_cur++ )
+ {
+ polarssl_printf( "%s ", curve_cur->name );
+ }
+ polarssl_printf( "\n" );
+ goto exit;
+ }
+ }
+
+ polarssl_printf( "Number of curves: %d\n", i );
+
+ if( i == (int) ( sizeof( curve_list ) / sizeof( *curve_list ) ) - 1
+ && *p != '\0' )
+ {
+ polarssl_printf( "curves list too long, maximum %zu",
+ (size_t) ( sizeof( curve_list ) / sizeof( *curve_list ) - 1 ) );
+ goto exit;
+ }
+
+ curve_list[i] = POLARSSL_ECP_DP_NONE;
+ }
+ }
+#endif /* POLARSSL_SSL_SET_CURVES */
+
#if defined(POLARSSL_SSL_ALPN)
if( opt.alpn_string != NULL )
{
@@ -1397,6 +1476,14 @@
}
#endif
+#if defined(POLARSSL_SSL_SET_CURVES)
+ if( opt.curves != NULL &&
+ strcmp( opt.curves, "default" ) != 0 )
+ {
+ ssl_set_curves( &ssl, curve_list );
+ }
+#endif
+
ssl_set_rng( &ssl, ctr_drbg_random, &ctr_drbg );
ssl_set_dbg( &ssl, my_debug, stdout );
diff --git a/tests/ssl-opt.sh b/tests/ssl-opt.sh
index 7bcc412..6e19646 100755
--- a/tests/ssl-opt.sh
+++ b/tests/ssl-opt.sh
@@ -1432,6 +1432,54 @@
-C "! ssl_handshake returned" \
-C "X509 - Certificate verification failed"
+run_test "Authentication: server goodcert, client optional, no trusted CA" \
+ "$P_SRV" \
+ "$P_CLI debug_level=3 auth_mode=optional ca_file=none ca_path=none" \
+ 0 \
+ -c "x509_verify_cert() returned" \
+ -c "! The certificate is not correctly signed by the trusted CA" \
+ -c "! Certificate verification flags"\
+ -C "! ssl_handshake returned" \
+ -C "X509 - Certificate verification failed" \
+ -C "SSL - No CA Chain is set, but required to operate"
+
+run_test "Authentication: server goodcert, client required, no trusted CA" \
+ "$P_SRV" \
+ "$P_CLI debug_level=3 auth_mode=required ca_file=none ca_path=none" \
+ 1 \
+ -c "x509_verify_cert() returned" \
+ -c "! The certificate is not correctly signed by the trusted CA" \
+ -c "! Certificate verification flags"\
+ -c "! ssl_handshake returned" \
+ -c "SSL - No CA Chain is set, but required to operate"
+
+# The purpose of the next two tests is to test the client's behaviour when receiving a server
+# certificate with an unsupported elliptic curve. This should usually not happen because
+# the client informs the server about the supported curves - it does, though, in the
+# corner case of a static ECDH suite, because the server doesn't check the curve on that
+# occasion (to be fixed). If that bug's fixed, the test needs to be altered to use a
+# different means to have the server ignoring the client's supported curve list.
+
+requires_config_enabled POLARSSL_SSL_SET_CURVES
+run_test "Authentication: server ECDH p256v1, client required, p256v1 unsupported" \
+ "$P_SRV debug_level=1 key_file=data_files/server5.key \
+ crt_file=data_files/server5.ku-ka.crt" \
+ "$P_CLI debug_level=3 auth_mode=required curves=secp521r1" \
+ 1 \
+ -c "bad certificate (EC key curve)"\
+ -c "! Certificate verification flags"\
+ -C "bad server certificate (ECDH curve)" # Expect failure at earlier verification stage
+
+requires_config_enabled POLARSSL_SSL_SET_CURVES
+run_test "Authentication: server ECDH p256v1, client optional, p256v1 unsupported" \
+ "$P_SRV debug_level=1 key_file=data_files/server5.key \
+ crt_file=data_files/server5.ku-ka.crt" \
+ "$P_CLI debug_level=3 auth_mode=optional curves=secp521r1" \
+ 1 \
+ -c "bad certificate (EC key curve)"\
+ -c "! Certificate verification flags"\
+ -c "bad server certificate (ECDH curve)" # Expect failure only at ECDH params check
+
run_test "Authentication: server badcert, client none" \
"$P_SRV crt_file=data_files/server5-badsign.crt \
key_file=data_files/server5.key" \
@@ -2420,7 +2468,7 @@
# A test for extensions in SSLv3
-requires_config_enabled MBEDTLS_SSL_PROTO_SSL3
+requires_config_enabled POLARSSL_SSL_PROTO_SSL3
run_test "SSLv3 with extensions, server side" \
"$P_SRV min_version=ssl3 debug_level=3" \
"$P_CLI force_version=ssl3 tickets=1 max_frag_len=4096 alpn=abc,1234" \