Merge pull request #163 from ARMmbed/tls_psk_to_ms_derivation

PSA: Phase 2: Add support for TLS-1.2 PSK-to-MasterSecret derivation
This commit is contained in:
Jaeden Amero 2018-11-19 11:29:22 +00:00 committed by GitHub
commit 7588f78d18
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
4 changed files with 162 additions and 11 deletions

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@ -1201,6 +1201,16 @@ typedef uint32_t psa_algorithm_t;
#define PSA_ALG_TLS12_PRF_BASE ((psa_algorithm_t)0x30000200)
/** Macro to build a TLS-1.2 PRF algorithm.
*
* TLS 1.2 uses a custom pseudorandom function (PRF) for key schedule,
* specified in Section 5 of RFC 5246. It is based on HMAC and can be
* used with either SHA-256 or SHA-384.
*
* For the application to TLS-1.2, the salt and label arguments passed
* to psa_key_derivation() are what's called 'seed' and 'label' in RFC 5246,
* respectively. For example, for TLS key expansion, the salt is the
* concatenation of ServerHello.Random + ClientHello.Random,
* while the label is "key expansion".
*
* For example, `PSA_ALG_TLS12_PRF(PSA_ALG_SHA256)` represents the
* TLS 1.2 PRF using HMAC-SHA-256.
@ -1216,10 +1226,6 @@ typedef uint32_t psa_algorithm_t;
(PSA_ALG_TLS12_PRF_BASE | ((hash_alg) & PSA_ALG_HASH_MASK))
/** Whether the specified algorithm is a TLS-1.2 PRF algorithm.
*
* TLS 1.2 uses a custom pseudorandom function (PRF) for key schedule,
* specified in Section 5 of RFC 5246. It is based on HMAC and can be
* used with either SHA-256 or SHA-384.
*
* \param alg An algorithm identifier (value of type #psa_algorithm_t).
*
@ -1232,6 +1238,46 @@ typedef uint32_t psa_algorithm_t;
#define PSA_ALG_TLS12_PRF_GET_HASH(hkdf_alg) \
(PSA_ALG_CATEGORY_HASH | ((hkdf_alg) & PSA_ALG_HASH_MASK))
#define PSA_ALG_TLS12_PSK_TO_MS_BASE ((psa_algorithm_t)0x30000300)
/** Macro to build a TLS-1.2 PSK-to-MasterSecret algorithm.
*
* In a pure-PSK handshake in TLS 1.2, the master secret is derived
* from the PreSharedKey (PSK) through the application of padding
* (RFC 4279, Section 2) and the TLS-1.2 PRF (RFC 5246, Section 5).
* The latter is based on HMAC and can be used with either SHA-256
* or SHA-384.
*
* For the application to TLS-1.2, the salt passed to psa_key_derivation()
* (and forwarded to the TLS-1.2 PRF) is the concatenation of the
* ClientHello.Random + ServerHello.Random, while the label is "master secret"
* or "extended master secret".
*
* For example, `PSA_ALG_TLS12_PSK_TO_MS(PSA_ALG_SHA256)` represents the
* TLS-1.2 PSK to MasterSecret derivation PRF using HMAC-SHA-256.
*
* \param hash_alg A hash algorithm (\c PSA_ALG_XXX value such that
* #PSA_ALG_IS_HASH(\p hash_alg) is true).
*
* \return The corresponding TLS-1.2 PSK to MS algorithm.
* \return Unspecified if \p alg is not a supported
* hash algorithm.
*/
#define PSA_ALG_TLS12_PSK_TO_MS(hash_alg) \
(PSA_ALG_TLS12_PSK_TO_MS_BASE | ((hash_alg) & PSA_ALG_HASH_MASK))
/** Whether the specified algorithm is a TLS-1.2 PSK to MS algorithm.
*
* \param alg An algorithm identifier (value of type #psa_algorithm_t).
*
* \return 1 if \c alg is a TLS-1.2 PSK to MS algorithm, 0 otherwise.
* This macro may return either 0 or 1 if \c alg is not a supported
* key derivation algorithm identifier.
*/
#define PSA_ALG_IS_TLS12_PSK_TO_MS(alg) \
(((alg) & ~PSA_ALG_HASH_MASK) == PSA_ALG_TLS12_PSK_TO_MS_BASE)
#define PSA_ALG_TLS12_PSK_TO_MS_GET_HASH(hkdf_alg) \
(PSA_ALG_CATEGORY_HASH | ((hkdf_alg) & PSA_ALG_HASH_MASK))
#define PSA_ALG_KEY_DERIVATION_MASK ((psa_algorithm_t)0x010fffff)
/** Use a shared secret as is.

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@ -131,6 +131,22 @@
#define PSA_VENDOR_ECC_MAX_CURVE_BITS 0
#endif
/** \def PSA_ALG_TLS12_PSK_TO_MS_MAX_PSK_LEN
*
* This macro returns the maximum length of the PSK supported
* by the TLS-1.2 PSK-to-MS key derivation.
*
* Quoting RFC 4279, Sect 5.3:
* TLS implementations supporting these ciphersuites MUST support
* arbitrary PSK identities up to 128 octets in length, and arbitrary
* PSKs up to 64 octets in length. Supporting longer identities and
* keys is RECOMMENDED.
*
* Therefore, no implementation should define a value smaller than 64
* for #PSA_ALG_TLS12_PSK_TO_MS_MAX_PSK_LEN.
*/
#define PSA_ALG_TLS12_PSK_TO_MS_MAX_PSK_LEN 128
/** \def PSA_ASYMMETRIC_SIGNATURE_MAX_SIZE
*
* Maximum size of an asymmetric signature.

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@ -3275,7 +3275,9 @@ psa_status_t psa_generator_abort( psa_crypto_generator_t *generator )
mbedtls_free( generator->ctx.hkdf.info );
status = psa_hmac_abort_internal( &generator->ctx.hkdf.hmac );
}
else if( PSA_ALG_IS_TLS12_PRF( generator->alg ) )
else if( PSA_ALG_IS_TLS12_PRF( generator->alg ) ||
/* TLS-1.2 PSK-to-MS KDF uses the same generator as TLS-1.2 PRF */
PSA_ALG_IS_TLS12_PSK_TO_MS( generator->alg ) )
{
if( generator->ctx.tls12_prf.key != NULL )
{
@ -3578,7 +3580,8 @@ psa_status_t psa_generator_read( psa_crypto_generator_t *generator,
status = psa_generator_hkdf_read( &generator->ctx.hkdf, hash_alg,
output, output_length );
}
else if( PSA_ALG_IS_TLS12_PRF( generator->alg ) )
else if( PSA_ALG_IS_TLS12_PRF( generator->alg ) ||
PSA_ALG_IS_TLS12_PSK_TO_MS( generator->alg ) )
{
status = psa_generator_tls12_prf_read( &generator->ctx.tls12_prf,
generator->alg, output,
@ -3749,6 +3752,47 @@ static psa_status_t psa_generator_tls12_prf_setup(
return( PSA_SUCCESS );
}
/* Set up a TLS-1.2-PSK-to-MS-based generator. */
static psa_status_t psa_generator_tls12_psk_to_ms_setup(
psa_tls12_prf_generator_t *tls12_prf,
const unsigned char *psk,
size_t psk_len,
psa_algorithm_t hash_alg,
const uint8_t *salt,
size_t salt_length,
const uint8_t *label,
size_t label_length )
{
psa_status_t status;
unsigned char pms[ 4 + 2 * PSA_ALG_TLS12_PSK_TO_MS_MAX_PSK_LEN ];
if( psk_len > PSA_ALG_TLS12_PSK_TO_MS_MAX_PSK_LEN )
return( PSA_ERROR_INVALID_ARGUMENT );
/* Quoting RFC 4279, Section 2:
*
* The premaster secret is formed as follows: if the PSK is N octets
* long, concatenate a uint16 with the value N, N zero octets, a second
* uint16 with the value N, and the PSK itself.
*/
pms[0] = ( psk_len >> 8 ) & 0xff;
pms[1] = ( psk_len >> 0 ) & 0xff;
memset( pms + 2, 0, psk_len );
pms[2 + psk_len + 0] = pms[0];
pms[2 + psk_len + 1] = pms[1];
memcpy( pms + 4 + psk_len, psk, psk_len );
status = psa_generator_tls12_prf_setup( tls12_prf,
pms, 4 + 2 * psk_len,
hash_alg,
salt, salt_length,
label, label_length );
mbedtls_zeroize( pms, sizeof( pms ) );
return( status );
}
#endif /* MBEDTLS_MD_C */
/* Note that if this function fails, you must call psa_generator_abort()
@ -3799,7 +3843,9 @@ static psa_status_t psa_key_derivation_internal(
salt, salt_length,
label, label_length );
}
else if( PSA_ALG_IS_TLS12_PRF( alg ) )
/* TLS-1.2 PRF and TLS-1.2 PSK-to-MS are very similar, so share code. */
else if( PSA_ALG_IS_TLS12_PRF( alg ) ||
PSA_ALG_IS_TLS12_PSK_TO_MS( alg ) )
{
psa_algorithm_t hash_alg = PSA_ALG_TLS12_PRF_GET_HASH( alg );
size_t hash_size = PSA_HASH_SIZE( hash_alg );
@ -3812,10 +3858,22 @@ static psa_status_t psa_key_derivation_internal(
}
max_capacity = 255 * hash_size;
status = psa_generator_tls12_prf_setup( &generator->ctx.tls12_prf,
secret, secret_length,
hash_alg, salt, salt_length,
label, label_length );
if( PSA_ALG_IS_TLS12_PRF( alg ) )
{
status = psa_generator_tls12_prf_setup( &generator->ctx.tls12_prf,
secret, secret_length,
hash_alg, salt, salt_length,
label, label_length );
}
else
{
status = psa_generator_tls12_psk_to_ms_setup(
&generator->ctx.tls12_prf,
secret, secret_length,
hash_alg, salt, salt_length,
label, label_length );
}
}
else
#endif

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@ -1537,6 +1537,33 @@ PSA key derivation: TLS 1.2 PRF SHA-384, output 74+73
depends_on:MBEDTLS_MD_C:MBEDTLS_SHA512_C
derive_output:PSA_ALG_TLS12_PRF(PSA_ALG_SHA_384):"b80b733d6ceefcdc71566ea48e5567df":"cd665cf6a8447dd6ff8b27555edb7465":"74657374206c6162656c":148:"7b0c18e9ced410ed1804f2cfa34a336a1c14dffb4900bb5fd7942107e81c83cde9ca0faa60be9fe34f82b1233c9146a0e534cb400fed2700884f9dc236f80edd8bfa961144c9e8d792ec":"a722a7b32fc3d416d473ebc2c5fd4abfdad05d9184259b5bf8cd4d90fa0d31e2dec479e4f1a26066f2eea9a69236a3e52655c9e9aee691c8f3a26854308d5eaa3be85e0990703d73e5"
# Test case manually extracted from debug output of TLS-PSK run
# Label: "master secret"
# Salt: Concatenation of ClientHello.Random and ServerHello.Random
PSA key derivation: TLS 1.2 PSK-to-MS, SHA-256, 48+0
depends_on:MBEDTLS_MD_C:MBEDTLS_SHA256_C
derive_output:PSA_ALG_TLS12_PSK_TO_MS(PSA_ALG_SHA_256):"01020304":"5bc0b19b4a8b24b07afe7ec65c471e94a7d518fcef06c3574315255c52afe21b5bc0b19b872b9b26508458f03603744d575f463a11ae7f1b090c012606fd3e9f":"6d617374657220736563726574":48:"5a9dd5ffa78b4d1f28f40d91b4e6e6ed37849042d61ba32ca43d866e744cee7cd1baaa497e1ecd5c2e60f9f13030a710":""
PSA key derivation: TLS 1.2 PSK-to-MS, SHA-256, 24+24
depends_on:MBEDTLS_MD_C:MBEDTLS_SHA256_C
derive_output:PSA_ALG_TLS12_PSK_TO_MS(PSA_ALG_SHA_256):"01020304":"5bc0b19b4a8b24b07afe7ec65c471e94a7d518fcef06c3574315255c52afe21b5bc0b19b872b9b26508458f03603744d575f463a11ae7f1b090c012606fd3e9f":"6d617374657220736563726574":48:"5a9dd5ffa78b4d1f28f40d91b4e6e6ed37849042d61ba32c":"a43d866e744cee7cd1baaa497e1ecd5c2e60f9f13030a710"
PSA key derivation: TLS 1.2 PSK-to-MS, SHA-256, 0+48
depends_on:MBEDTLS_MD_C:MBEDTLS_SHA256_C
derive_output:PSA_ALG_TLS12_PSK_TO_MS(PSA_ALG_SHA_256):"01020304":"5bc0b19b4a8b24b07afe7ec65c471e94a7d518fcef06c3574315255c52afe21b5bc0b19b872b9b26508458f03603744d575f463a11ae7f1b090c012606fd3e9f":"6d617374657220736563726574":48:"":"5a9dd5ffa78b4d1f28f40d91b4e6e6ed37849042d61ba32ca43d866e744cee7cd1baaa497e1ecd5c2e60f9f13030a710"
PSA key derivation: TLS 1.2 PSK-to-MS, SHA-384, 48+0
depends_on:MBEDTLS_MD_C:MBEDTLS_SHA512_C
derive_output:PSA_ALG_TLS12_PSK_TO_MS(PSA_ALG_SHA_384):"01020304":"5bed47716a11a49a6268a8350b085929116ad9ccc8181f09a05b07a7741576d65bed47718dfd82f2d3f57544afe52decae6819b970dc716ada72ae0dd3072e9a":"6d617374657220736563726574":48:"f5a61fbdd2ec415762abb8042a6c16645a53d2edb6dec8c85ca71689301f9f4d875128c87608b75250b20a9550e4fe18":""
PSA key derivation: TLS 1.2 PSK-to-MS, SHA-384, 24+24
depends_on:MBEDTLS_MD_C:MBEDTLS_SHA512_C
derive_output:PSA_ALG_TLS12_PSK_TO_MS(PSA_ALG_SHA_384):"01020304":"5bed47716a11a49a6268a8350b085929116ad9ccc8181f09a05b07a7741576d65bed47718dfd82f2d3f57544afe52decae6819b970dc716ada72ae0dd3072e9a":"6d617374657220736563726574":48:"":"f5a61fbdd2ec415762abb8042a6c16645a53d2edb6dec8c85ca71689301f9f4d875128c87608b75250b20a9550e4fe18"
PSA key derivation: TLS 1.2 PSK-to-MS, SHA-384, 0+48
depends_on:MBEDTLS_MD_C:MBEDTLS_SHA512_C
derive_output:PSA_ALG_TLS12_PSK_TO_MS(PSA_ALG_SHA_384):"01020304":"5bed47716a11a49a6268a8350b085929116ad9ccc8181f09a05b07a7741576d65bed47718dfd82f2d3f57544afe52decae6819b970dc716ada72ae0dd3072e9a":"6d617374657220736563726574":48:"f5a61fbdd2ec415762abb8042a6c16645a53d2edb6dec8c8":"5ca71689301f9f4d875128c87608b75250b20a9550e4fe18"
PSA key derivation: HKDF SHA-256, request maximum capacity
depends_on:MBEDTLS_MD_C:MBEDTLS_SHA256_C
derive_output:PSA_ALG_HKDF(PSA_ALG_SHA_256):"0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b":"000102030405060708090a0b0c":"f0f1f2f3f4f5f6f7f8f9":255 * 32:"3cb25f25faacd57a90434f64d0362f2a2d2d0a90cf1a5a4c5db02d56ecc4c5bf34007208d5b887185865":""
@ -1553,6 +1580,10 @@ PSA key derivation: HKDF SHA-1, request too much capacity
depends_on:MBEDTLS_MD_C:MBEDTLS_SHA1_C
derive_setup:PSA_KEY_TYPE_DERIVE:"0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c":PSA_ALG_HKDF(PSA_ALG_SHA_1):"":"":255 * 20 + 1:PSA_ERROR_INVALID_ARGUMENT
PSA key derivation: TLS 1.2 PSK-to-MS, SHA-256, PSK too long (160 Bytes)
depends_on:MBEDTLS_MD_C:MBEDTLS_SHA256_C
derive_setup:PSA_KEY_TYPE_DERIVE:"01020304050607080102030405060708010203040506070801020304050607080102030405060708010203040506070801020304050607080102030405060708010203040506070801020304050607080102030405060708010203040506070801020304050607080102030405060708010203040506070801020304050607080102030405060708010203040506070801020304050607080102030405060708":PSA_ALG_TLS12_PSK_TO_MS(PSA_ALG_SHA_256):"":"":100:PSA_ERROR_INVALID_ARGUMENT
PSA key derivation: over capacity 42: output 42+1
depends_on:MBEDTLS_MD_C:MBEDTLS_SHA256_C
derive_output:PSA_ALG_HKDF(PSA_ALG_SHA_256):"0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b":"000102030405060708090a0b0c":"f0f1f2f3f4f5f6f7f8f9":42:"3cb25f25faacd57a90434f64d0362f2a2d2d0a90cf1a5a4c5db02d56ecc4c5bf34007208d5b887185865":"ff"