Complete x509parse_public_key_ec()
Warning: due to a bug in oid_descriptor_from_buf(), keys associated to some curves (secp224r1, secp384r1, secp521r1) are incorrectly rejected, since their namedCurve OID contains a nul byte.
This commit is contained in:
Manuel Pégourié-Gonnard
parent
f838eeda09
commit
73c0cda346
3 changed files with 95 additions and 22 deletions
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@ -233,6 +233,40 @@ static int x509_get_ecparams( unsigned char **p, const unsigned char *end,
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return( 0 );
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}
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/*
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* subjectPublicKey BIT STRING
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* -- which, in our case, contains
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* ECPoint ::= octet string (not ASN.1)
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*/
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static int x509_get_subpubkey_ec( unsigned char **p, const unsigned char *end,
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const ecp_group *grp, ecp_point *pt )
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{
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int ret;
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size_t len;
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if( ( ret = asn1_get_tag( p, end, &len, ASN1_BIT_STRING ) ) != 0 )
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return( POLARSSL_ERR_X509_KEY_INVALID_FORMAT + ret );
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if( *p + len != end )
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return( POLARSSL_ERR_X509_KEY_INVALID_FORMAT +
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POLARSSL_ERR_ASN1_LENGTH_MISMATCH );
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/*
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* First byte in the content of BIT STRING is the nummber of padding bit.
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* Here it is always 0 since ECPoint is an octet string, so skip it.
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*/
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++*p;
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--len;
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if( ( ret = ecp_point_read_binary( grp, pt,
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(const unsigned char *) *p, len ) ) != 0 )
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{
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return( POLARSSL_ERR_X509_KEY_INVALID_FORMAT + ret );
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}
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return( 0 );
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}
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/*
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* AttributeTypeAndValue ::= SEQUENCE {
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* type AttributeType,
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@ -2633,6 +2667,59 @@ int x509parse_key_ec( ecp_keypair *eckey,
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return( POLARSSL_ERR_X509_KEY_INVALID_FORMAT );
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}
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/*
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* Parse a public EC key in RFC 5480 format, der-encoded
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*/
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static int x509parse_public_key_ec_der( ecp_keypair *key,
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const unsigned char *buf, size_t len )
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{
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int ret;
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ecp_group_id grp_id;
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x509_buf alg_oid;
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pk_type_t alg = POLARSSL_PK_NONE;
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unsigned char *p = (unsigned char *) buf;
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unsigned char *end = p + len;
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const unsigned char *params_end;
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/*
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* SubjectPublicKeyInfo ::= SEQUENCE {
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* algorithm AlgorithmIdentifier,
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* subjectPublicKey BIT STRING
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* }
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* -- algorithm parameters are ECParameters
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* -- subjectPublicKey is an ECPoint
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*/
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if( ( ret = asn1_get_tag( &p, end, &len,
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ASN1_CONSTRUCTED | ASN1_SEQUENCE ) ) != 0 )
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{
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return( POLARSSL_ERR_X509_CERT_INVALID_FORMAT + ret );
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}
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if( ( ret = x509_get_alg( &p, end, &alg_oid, ¶ms_end ) ) != 0 )
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return( ret );
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if( oid_get_pk_alg( &alg_oid, &alg ) != 0 )
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return( POLARSSL_ERR_X509_UNKNOWN_PK_ALG );
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if( alg != POLARSSL_PK_ECKEY && alg != POLARSSL_PK_ECKEY_DH )
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return( POLARSSL_ERR_X509_UNKNOWN_PK_ALG );
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if ( alg == POLARSSL_PK_ECKEY_DH )
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key->alg = POLARSSL_ECP_KEY_ALG_ECDH;
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if( ( ret = x509_get_ecparams( &p, params_end, &grp_id ) ) != 0 )
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return( ret );
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if( ( ret = ecp_use_known_dp( &key->grp, grp_id ) ) != 0 )
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return( ret );
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if( ( ret = x509_get_subpubkey_ec( &p, end, &key->grp, &key->Q ) ) != 0 )
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{
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return( ret );
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}
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return( 0 );
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}
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/*
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* Parse a public EC key
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*/
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@ -2640,14 +2727,12 @@ int x509parse_public_key_ec( ecp_keypair *eckey,
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const unsigned char *key, size_t keylen )
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{
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int ret;
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size_t len;
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unsigned char *p, *end;
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x509_buf alg_oid;
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#if defined(POLARSSL_PEM_C)
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size_t len;
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pem_context pem;
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pem_init( &pem );
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ret = pem_read_buffer( &pem, /* TODO: check header */
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ret = pem_read_buffer( &pem,
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"-----BEGIN PUBLIC KEY-----",
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"-----END PUBLIC KEY-----",
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key, NULL, 0, &len );
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@ -2657,6 +2742,7 @@ int x509parse_public_key_ec( ecp_keypair *eckey,
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/*
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* Was PEM encoded
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*/
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key = pem.buf;
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keylen = pem.buflen;
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}
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else if( ret != POLARSSL_ERR_PEM_NO_HEADER_FOOTER_PRESENT )
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@ -2664,32 +2750,19 @@ int x509parse_public_key_ec( ecp_keypair *eckey,
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pem_free( &pem );
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return( ret );
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}
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p = ( ret == 0 ) ? pem.buf : (unsigned char *) key;
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#else
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p = (unsigned char *) key;
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#endif
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end = p + keylen;
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/* TODO: parse key */
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(void) alg_oid;
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(void) end;
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(void) eckey;
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if( ( ret = ecp_check_pubkey( &eckey->grp, &eckey->Q ) ) != 0 )
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if( ( ret = x509parse_public_key_ec_der ( eckey, key, keylen ) ) != 0 ||
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( ret = ecp_check_pubkey( &eckey->grp, &eckey->Q ) ) != 0 )
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{
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#if defined(POLARSSL_PEM_C)
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pem_free( &pem );
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#endif
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ecp_keypair_free( eckey );
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return( ret );
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}
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#if defined(POLARSSL_PEM_C)
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pem_free( &pem );
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#endif
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return( 0 );
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return( ret );
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}
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#endif /* defined(POLARSSL_ECP_C) */
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Binary file not shown.
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@ -1,4 +1,4 @@
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-----BEGIN PUBLIC KEY-----
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ME4wEAYHKoZIzj0CAQYFK4EEACEDOgAEb3GKqedAJ2/1CRdhjIRhQO+4erL49GlI
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QrBg7frKWrc6ZrnjgXgdHt68Tux/2IyRuff+lvGn32s=
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MEkwEwYHKoZIzj0CAQYIKoZIzj0DAQEDMgAEvHl9s65/COw9SWtPtBGz9iClWKUB
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4CItCM/g3Irsixp78kvpKVHMW6G+uyR0kJrg
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-----END PUBLIC KEY-----
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