diff --git a/ChangeLog b/ChangeLog index 37373a23c..5032be6a4 100644 --- a/ChangeLog +++ b/ChangeLog @@ -2,6 +2,13 @@ mbed TLS ChangeLog (Sorted per branch, date) = mbed TLS x.x.x branch released xxxx-xx-xx +Security + * When writing a private EC key, use a constant size for the private + value, as specified in RFC 5915. Previously, the value was written + as an ASN.1 INTEGER, which caused the size of the key to leak + about 1 bit of information on average and could cause the value to be + 1 byte too large for the output buffer. + Features * Add the Any Policy certificate policy oid, as defined in rfc 5280 section 4.2.1.4. @@ -32,6 +39,15 @@ Features MBEDTLS_SSL_DTLS_CONNECTION_ID (disabled by default), and at run-time through the new APIs mbedtls_ssl_conf_cid() and mbedtls_ssl_set_cid(). +API Changes + * Extend the MBEDTLS_SSL_EXPORT_KEYS to export the handshake randbytes, + and the used tls-prf. + * Add public API for tls-prf function, according to requested enum. + * Add DER-encoded test CRTs to library/certs.c, allowing + the example programs ssl_server2 and ssl_client2 to be run + if MBEDTLS_FS_IO and MBEDTLS_PEM_PARSE_C are unset. Fixes #2254. + * The HAVEGE state type now uses uint32_t elements instead of int. + Bugfix * Fix private key DER output in the key_app_writer example. File contents were shifted by one byte, creating an invalid ASN.1 tag. Fixed by @@ -80,15 +96,6 @@ Bugfix in mbedtls_x509write_crt_der() to 2Kb. Reported by soccerGB in #2631. * Fix partial zeroing in x509_get_other_name. Found and fixed by ekse, #2716. -API Changes - * Extend the MBEDTLS_SSL_EXPORT_KEYS to export the handshake randbytes, - and the used tls-prf. - * Add public API for tls-prf function, according to requested enum. - * Add DER-encoded test CRTs to library/certs.c, allowing - the example programs ssl_server2 and ssl_client2 to be run - if MBEDTLS_FS_IO and MBEDTLS_PEM_PARSE_C are unset. Fixes #2254. - * The HAVEGE state type now uses uint32_t elements instead of int. - Changes * Server's RSA certificate in certs.c was SHA-1 signed. In the default mbedTLS configuration only SHA-2 signed certificates are accepted. diff --git a/library/pkwrite.c b/library/pkwrite.c index b87f81b8b..aff8246b1 100644 --- a/library/pkwrite.c +++ b/library/pkwrite.c @@ -38,7 +38,9 @@ #include "mbedtls/rsa.h" #endif #if defined(MBEDTLS_ECP_C) +#include "mbedtls/bignum.h" #include "mbedtls/ecp.h" +#include "mbedtls/platform_util.h" #endif #if defined(MBEDTLS_ECDSA_C) #include "mbedtls/ecdsa.h" @@ -154,6 +156,26 @@ static int pk_write_ec_param( unsigned char **p, unsigned char *start, return( (int) len ); } + +/* + * privateKey OCTET STRING -- always of length ceil(log2(n)/8) + */ +static int pk_write_ec_private( unsigned char **p, unsigned char *start, + mbedtls_ecp_keypair *ec ) +{ + int ret; + size_t byte_length = ( ec->grp.pbits + 7 ) / 8; + unsigned char tmp[MBEDTLS_ECP_MAX_BYTES]; + + ret = mbedtls_mpi_write_binary( &ec->d, tmp, byte_length ); + if( ret != 0 ) + goto exit; + ret = mbedtls_asn1_write_octet_string( p, start, tmp, byte_length ); + +exit: + mbedtls_platform_zeroize( tmp, byte_length ); + return( ret ); +} #endif /* MBEDTLS_ECP_C */ int mbedtls_pk_write_pubkey( unsigned char **p, unsigned char *start, @@ -425,9 +447,8 @@ int mbedtls_pk_write_key_der( mbedtls_pk_context *key, unsigned char *buf, size_ MBEDTLS_ASN1_CONTEXT_SPECIFIC | MBEDTLS_ASN1_CONSTRUCTED | 0 ) ); len += par_len; - /* privateKey: write as MPI then fix tag */ - MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_mpi( &c, buf, &ec->d ) ); - *c = MBEDTLS_ASN1_OCTET_STRING; + /* privateKey */ + MBEDTLS_ASN1_CHK_ADD( len, pk_write_ec_private( &c, buf, ec ) ); /* version */ MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_int( &c, buf, 1 ) ); diff --git a/tests/data_files/ec_256_long_prv.pem b/tests/data_files/ec_256_long_prv.pem new file mode 100644 index 000000000..5141e30b4 --- /dev/null +++ b/tests/data_files/ec_256_long_prv.pem @@ -0,0 +1,5 @@ +-----BEGIN EC PRIVATE KEY----- +MHcCAQEEIIcex4mqXsQamUKTVf8vXmTAJrQvGjh5mXG8p9+OR4xAoAoGCCqGSM49 +AwEHoUQDQgAEqJ2HQjPpc6fDwE/vSa6U35USXawkTo98y4U6NsAl+rOGuqMPEFXf +P1Srm/Jrzwa/RuppRL5kgyAsGJTUmwZEzQ== +-----END EC PRIVATE KEY----- diff --git a/tests/data_files/ec_521_short_prv.pem b/tests/data_files/ec_521_short_prv.pem new file mode 100644 index 000000000..427b7ad47 --- /dev/null +++ b/tests/data_files/ec_521_short_prv.pem @@ -0,0 +1,7 @@ +-----BEGIN EC PRIVATE KEY----- +MIHcAgEBBEIAOXdk7W+Hf5L7Hc9fKe44wmpaRNs5ERFTkv5CrlXv/Bu3y28M673q +vBNo7a/UE/6NNQHu2pQODEYFpMg6R34b5SigBwYFK4EEACOhgYkDgYYABAFUMHXV +KPA4vkMgq+pFgDoH96XoM517gF2GJFV6h2gLhykzIHL/otAyEpAStw7MBvbU0V21 +ixB+hjqzO7Snxaj9mwB8g87OKxm5eGfsqvJNPdJ0RZ/EKy06Ukg6KThlhQeyrtIk +g5PTCrPnNszlffAy6/jCOe3Moi59g15H13sSzwfX6g== +-----END EC PRIVATE KEY----- diff --git a/tests/suites/test_suite_pkwrite.data b/tests/suites/test_suite_pkwrite.data index c8ff1773c..e0101ccdf 100644 --- a/tests/suites/test_suite_pkwrite.data +++ b/tests/suites/test_suite_pkwrite.data @@ -30,10 +30,18 @@ Private key write check EC 192 bits depends_on:MBEDTLS_ECP_C:MBEDTLS_BASE64_C:MBEDTLS_ECP_DP_SECP192R1_ENABLED pk_write_key_check:"data_files/ec_prv.sec1.pem" +Private key write check EC 256 bits (top bit set) +depends_on:MBEDTLS_ECP_C:MBEDTLS_BASE64_C:MBEDTLS_ECP_DP_SECP256R1_ENABLED +pk_write_key_check:"data_files/ec_256_long_prv.pem" + Private key write check EC 521 bits depends_on:MBEDTLS_ECP_C:MBEDTLS_BASE64_C:MBEDTLS_ECP_DP_SECP521R1_ENABLED pk_write_key_check:"data_files/ec_521_prv.pem" +Private key write check EC 521 bits (top byte is 0) +depends_on:MBEDTLS_ECP_C:MBEDTLS_BASE64_C:MBEDTLS_ECP_DP_SECP521R1_ENABLED +pk_write_key_check:"data_files/ec_521_short_prv.pem" + Private key write check EC Brainpool 512 bits depends_on:MBEDTLS_ECP_C:MBEDTLS_BASE64_C:MBEDTLS_ECP_DP_BP512R1_ENABLED pk_write_key_check:"data_files/ec_bp512_prv.pem"