Start parsing RSASSA-PSS parameters

include/polarssl/x509.h

@@ -256,6 +256,8 @@ int x509_get_alg_null( unsigned char **p, const unsigned char *end,
                        x509_buf *alg );
 int x509_get_alg( unsigned char **p, const unsigned char *end,
                   x509_buf *alg, x509_buf *params );
+int x509_get_rsassa_pss_params( const x509_buf *params, md_type_t *md_alg,
+                                int *salt_len, int *trailer_field );
 int x509_get_sig( unsigned char **p, const unsigned char *end, x509_buf *sig );
 int x509_get_sig_alg( const x509_buf *sig_oid, md_type_t *md_alg,
                       pk_type_t *pk_alg );

library/x509.c

@@ -132,6 +132,92 @@ int x509_get_alg( unsigned char **p, const unsigned char *end,
     return( 0 );
 }
 
+/*
+ *    RSASSA-PSS-params  ::=  SEQUENCE  {
+ *       hashAlgorithm     [0] HashAlgorithm DEFAULT sha1Identifier,
+ *       maskGenAlgorithm  [1] MaskGenAlgorithm DEFAULT mgf1SHA1Identifier,
+ *       saltLength        [2] INTEGER DEFAULT 20,
+ *       trailerField      [3] INTEGER DEFAULT 1  }
+ *    -- Note that the tags in this Sequence are explicit.
+ */
+int x509_get_rsassa_pss_params( const x509_buf *params,
+                                md_type_t *md_alg,
+                                int *salt_len,
+                                int *trailer_field )
+{
+    int ret;
+    unsigned char *p;
+    const unsigned char *end;
+    size_t len;
+    x509_buf alg_id;
+
+    /* First set everything to defaults */
+    *md_alg = POLARSSL_MD_SHA1;
+    *salt_len = 20;
+    *trailer_field = 1;
+
+    /* Make sure params is a SEQUENCE and setup bounds */
+    if( params->tag != ( ASN1_CONSTRUCTED | ASN1_SEQUENCE ) )
+        return( POLARSSL_ERR_X509_INVALID_ALG +
+                POLARSSL_ERR_ASN1_UNEXPECTED_TAG );
+
+    p = (unsigned char *) params->p;
+    end = p + params->len;
+
+    if( p == end )
+        return( 0 );
+
+    if( ( ret = asn1_get_tag( &p, end, &len,
+                    ASN1_CONTEXT_SPECIFIC | ASN1_CONSTRUCTED | 0 ) ) == 0 )
+    {
+        /* HashAlgorithm  ::=  AlgorithmIdentifier (without parameters) */
+        // TODO: WIP
+    }
+    else if( ret != POLARSSL_ERR_ASN1_UNEXPECTED_TAG )
+        return( POLARSSL_ERR_X509_INVALID_ALG + ret );
+
+    if( ( ret = asn1_get_tag( &p, end, &len,
+                    ASN1_CONTEXT_SPECIFIC | ASN1_CONSTRUCTED | 1 ) ) == 0 )
+    {
+        /* MaskGenAlgorithm  ::=  AlgorithmIdentifier */
+        // TODO: WIP
+    }
+    else if( ret != POLARSSL_ERR_ASN1_UNEXPECTED_TAG )
+        return( POLARSSL_ERR_X509_INVALID_ALG + ret );
+
+    if( p == end )
+        return( 0 );
+
+    if( ( ret = asn1_get_tag( &p, end, &len,
+                    ASN1_CONTEXT_SPECIFIC | ASN1_CONSTRUCTED | 2 ) ) == 0 )
+    {
+        /* salt_len */
+        if( ( ret = asn1_get_int( &p, p + len, salt_len ) ) != 0 )
+            return( POLARSSL_ERR_X509_INVALID_ALG + ret );
+    }
+    else if( ret != POLARSSL_ERR_ASN1_UNEXPECTED_TAG )
+        return( POLARSSL_ERR_X509_INVALID_ALG + ret );
+
+    if( p == end )
+        return( 0 );
+
+    if( ( ret = asn1_get_tag( &p, end, &len,
+                    ASN1_CONTEXT_SPECIFIC | ASN1_CONSTRUCTED | 3 ) ) == 0 )
+    {
+        /* trailer_field */
+        if( ( ret = asn1_get_int( &p, p + len, trailer_field ) ) != 0 )
+            return( POLARSSL_ERR_X509_INVALID_ALG + ret );
+    }
+    else if( ret != POLARSSL_ERR_ASN1_UNEXPECTED_TAG )
+        return( POLARSSL_ERR_X509_INVALID_ALG + ret );
+
+    if( p != end )
+        return( POLARSSL_ERR_X509_INVALID_ALG +
+                POLARSSL_ERR_ASN1_LENGTH_MISMATCH );
+
+    return( 0 );
+}
+
 /*
  *  AttributeTypeAndValue ::= SEQUENCE {
  *    type     AttributeType,

library/x509_crt.c

@@ -617,6 +617,22 @@ static int x509_crt_parse_der_core( x509_crt *crt, const unsigned char *buf,
         return( ret );
     }
 
+    if( crt->sig_pk == POLARSSL_PK_RSASSA_PSS )
+    {
+        int salt_len, trailer_field;
+
+        if( ( ret = x509_get_rsassa_pss_params( &crt->sig_params,
+                        &crt->sig_md, &salt_len, &trailer_field ) ) != 0 )
+            return( ret );
+    }
+    else
+    {
+        /* Make sure parameters were absent or NULL */
+        if( ( crt->sig_params.tag != ASN1_NULL && crt->sig_params.tag != 0 ) ||
+              crt->sig_params.len != 0 )
+        return( POLARSSL_ERR_X509_INVALID_ALG );
+    }
+
     /*
      * issuer               Name
      */
@@ -1166,6 +1182,21 @@ int x509_crt_info( char *buf, size_t size, const char *prefix,
         ret = snprintf( p, n, "%s", desc );
     SAFE_SNPRINTF();
 
+    if( crt->sig_pk == POLARSSL_PK_RSASSA_PSS )
+    {
+        md_type_t md_alg;
+        int salt_len, trailer_field;
+
+        if( ( ret = x509_get_rsassa_pss_params( &crt->sig_params,
+                        &md_alg, &salt_len, &trailer_field ) ) != 0 )
+            return( ret );
+
+        // TODO: SHA1 harcoded twice (WIP)
+        ret = snprintf( p, n, " (SHA1, MGF1-SHA1, %d, %d)",
+                              salt_len, trailer_field );
+        SAFE_SNPRINTF();
+    }
+
     if( ( ret = x509_key_size_helper( key_size_str, BEFORE_COLON,
                                       pk_get_name( &crt->pk ) ) ) != 0 )
     {

tests/suites/test_suite_x509parse.data

@@ -44,7 +44,7 @@ x509_cert_info:"data_files/cert_sha512.crt":"cert. version \: 3\nserial number \
 
 X509 Certificate information RSA-PSS, SHA1 Digest
 depends_on:POLARSSL_PEM_PARSE_C:POLARSSL_RSA_C
-x509_cert_info:"data_files/server9.crt":"cert. version \: 3\nserial number \: 16\nissuer name   \: C=NL, O=PolarSSL, CN=PolarSSL Test CA\nsubject name  \: C=NL, O=PolarSSL, CN=localhost\nissued  on    \: 2014-01-20 13\:38\:16\nexpires on    \: 2024-01-18 13\:38\:16\nsigned using  \: RSASSA-PSS\nRSA key size  \: 1024 bits\n"
+x509_cert_info:"data_files/server9.crt":"cert. version \: 3\nserial number \: 16\nissuer name   \: C=NL, O=PolarSSL, CN=PolarSSL Test CA\nsubject name  \: C=NL, O=PolarSSL, CN=localhost\nissued  on    \: 2014-01-20 13\:38\:16\nexpires on    \: 2024-01-18 13\:38\:16\nsigned using  \: RSASSA-PSS (SHA1, MGF1-SHA1, 234, 1)\nRSA key size  \: 1024 bits\n"
 
 X509 Certificate information EC, SHA1 Digest
 depends_on:POLARSSL_PEM_PARSE_C:POLARSSL_ECP_C