Merge branch 'mbedtls-1.3-iotssl-1071-ca-flags'

Fixes a regression introduced by an earlier commit that modified
x509_crt_verify_top() to ensure that valid certificates that are after past or
future valid in the chain are processed. However the change introduced a change
in behaviour that caused the verification flags MBEDTLS_X509_BADCERT_EXPIRED and
MBEDTLS_BADCERT_FUTURE to always be set whenever there is a failure in the
verification regardless of the cause.

The fix maintains both behaviours:

 * Ensure that valid certificates after future and past are verified
 * Ensure that the correct verification flags are set.

ChangeLog

@@ -15,6 +15,11 @@ Security
      Microsoft.
 
 Bugfix
+   * Fix output certificate verification flags set by x509_crt_verify_top() when
+     traversing a chain of trusted CA. The issue would cause both flags,
+     BADCERT_NOT_TRUSTED and BADCERT_EXPIRED, to be set when the verification
+     conditions are not met regardless of the cause. Found by Harm Verhagen and
+     inestlerode. #665 #561
    * Fixed multiple buffer overreads in mbedtls_pem_read_buffer() when parsing
      the input string in PEM format to extract the different components. Found
      by Eyal Itkin.

library/x509_crt.c

@@ -1775,6 +1775,7 @@ static int x509_crt_verify_top(
     int ca_flags = 0, check_path_cnt;
     unsigned char hash[POLARSSL_MD_MAX_SIZE];
     const md_info_t *md_info;
+    x509_crt *future_past_ca = NULL;
 
     if( x509_time_expired( &child->valid_to ) )
         *flags |= BADCERT_EXPIRED;
@@ -1823,16 +1824,6 @@ static int x509_crt_verify_top(
             continue;
         }
 
-        if( x509_time_expired( &trust_ca->valid_to ) )
-        {
-            continue;
-        }
-
-        if( x509_time_future( &trust_ca->valid_from ) )
-        {
-            continue;
-        }
-
         if( pk_verify_ext( child->sig_pk, child->sig_opts, &trust_ca->pk,
                            child->sig_md, hash, md_info->size,
                            child->sig.p, child->sig.len ) != 0 )
@@ -1840,11 +1831,23 @@ static int x509_crt_verify_top(
             continue;
         }
 
+        if( x509_time_expired( &trust_ca->valid_to ) ||
+            x509_time_future( &trust_ca->valid_from ) )
+        {
+            if( future_past_ca == NULL )
+                future_past_ca = trust_ca;
+            continue;
+        }
+
+        break;
+    }
+
+    if( trust_ca != NULL || ( trust_ca = future_past_ca ) != NULL )
+    {
         /*
          * Top of chain is signed by a trusted CA
          */
         *flags &= ~BADCERT_NOT_TRUSTED;
-        break;
     }
 
     /*
@@ -1864,6 +1867,12 @@ static int x509_crt_verify_top(
         ((void) ca_crl);
 #endif
 
+        if( x509_time_expired( &trust_ca->valid_to ) )
+            ca_flags |= BADCERT_EXPIRED;
+
+        if( x509_time_future( &trust_ca->valid_from ) )
+            ca_flags |= BADCERT_FUTURE;
+
         if( NULL != f_vrfy )
         {
             if( ( ret = f_vrfy( p_vrfy, trust_ca, path_cnt + 1,

tests/data_files/test-ca2_cat-future-invalid.crt

@@ -0,0 +1,27 @@
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----

tests/data_files/test-ca2_cat-past-invalid.crt

@@ -0,0 +1,27 @@
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----

tests/suites/test_suite_x509parse.data

@@ -715,6 +715,14 @@ X509 Certificate verification #85 (Not yet valid CA and valid CA)
 depends_on:POLARSSL_PEM_PARSE_C:POLARSSL_ECP_C:POLARSSL_ECP_DP_SECP256R1_ENABLED:POLARSSL_ECP_DP_SECP384R1_ENABLED
 x509_verify:"data_files/server5.crt":"data_files/test-ca2_cat-past-present.crt":"data_files/crl-ec-sha1.pem":"NULL":0:0:"NULL"
 
+X509 Certificate verification #86 (Not yet valid CA and invalid CA)
+depends_on:POLARSSL_PEM_PARSE_C:POLARSSL_ECP_C:POLARSSL_ECP_DP_SECP256R1_ENABLED:POLARSSL_ECP_DP_SECP384R1_ENABLED:POLARSSL_SHA1_C:POLARSSL_SHA256_C
+x509_verify:"data_files/server5.crt":"data_files/test-ca2_cat-future-invalid.crt":"data_files/crl-ec-sha1.pem":"NULL":POLARSSL_ERR_X509_CERT_VERIFY_FAILED:BADCERT_FUTURE:"NULL"
+
+X509 Certificate verification #87 (Expired CA and invalid CA)
+depends_on:POLARSSL_PEM_PARSE_C:POLARSSL_ECP_C:POLARSSL_ECP_DP_SECP256R1_ENABLED:POLARSSL_ECP_DP_SECP384R1_ENABLED:POLARSSL_SHA1_C:POLARSSL_SHA256_C
+x509_verify:"data_files/server5.crt":"data_files/test-ca2_cat-past-invalid.crt":"data_files/crl-ec-sha1.pem":"NULL":POLARSSL_ERR_X509_CERT_VERIFY_FAILED:BADCERT_EXPIRED:"NULL"
+
 X509 Certificate verification callback: trusted EE cert
 depends_on:POLARSSL_PEM_PARSE_C:POLARSSL_ECDSA_C:POLARSSL_SHA256_C:POLARSSL_ECP_DP_SECP256R1_ENABLED
 x509_verify_callback:"data_files/server5-selfsigned.crt":"data_files/server5-selfsigned.crt":0:"depth 0 - serial 53\:A2\:CB\:4B\:12\:4E\:AD\:83\:7D\:A8\:94\:B2 - subject CN=selfsigned, OU=testing, O=PolarSSL, C=NL\n"