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PSA: Reject curves that are not enabled in the PSA configuration

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If an elliptic curve was enabled in the Mbed TLS classic API (#define
MBEDTLS_ECP_DP_xxx), but not enabled in the PSA configuration (#define
PSA_WANT_ECC_xxx), it would still work if you tried to use it through
PSA.

This is generally benign, but could be a security issue if you want to
disable a curve in PSA for some security reason (such as a known bug
in its implementation, which may not matter in the classic API if Mbed
TLS is running in a secure enclave and is only reachable from
untrusted callers through the PSA API). More urgently, this broke
test_suite_psa_crypto_not_supported.generated.

So if a curve is not enabled in the PSA configuration, ensure that
it's treated as unsupported through the PSA software implementation.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
This commit is contained in:
Gilles Peskine 2021-03-23 13:12:34 +01:00
parent 398413024d
commit a1684f42d3
1 changed files with 26 additions and 0 deletions
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26
library/psa_crypto.c
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@ -423,58 +423,84 @@ mbedtls_ecp_group_id mbedtls_ecc_group_of_psa( psa_ecc_family_t curve,
case PSA_ECC_FAMILY_SECP_R1:
switch( bits )
{
#if defined(PSA_WANT_ECC_SECP_R1_192)
case 192:
return( MBEDTLS_ECP_DP_SECP192R1 );
#endif
#if defined(PSA_WANT_ECC_SECP_R1_224)
case 224:
return( MBEDTLS_ECP_DP_SECP224R1 );
#endif
#if defined(PSA_WANT_ECC_SECP_R1_256)
case 256:
return( MBEDTLS_ECP_DP_SECP256R1 );
#endif
#if defined(PSA_WANT_ECC_SECP_R1_384)
case 384:
return( MBEDTLS_ECP_DP_SECP384R1 );
#endif
#if defined(PSA_WANT_ECC_SECP_R1_521)
case 521:
return( MBEDTLS_ECP_DP_SECP521R1 );
case 528:
if( bits_is_sloppy )
return( MBEDTLS_ECP_DP_SECP521R1 );
break;
#endif
}
break;
case PSA_ECC_FAMILY_BRAINPOOL_P_R1:
switch( bits )
{
#if defined(PSA_WANT_ECC_BRAINPOOL_P_R1_256)
case 256:
return( MBEDTLS_ECP_DP_BP256R1 );
#endif
#if defined(PSA_WANT_ECC_BRAINPOOL_P_R1_384)
case 384:
return( MBEDTLS_ECP_DP_BP384R1 );
#endif
#if defined(PSA_WANT_ECC_BRAINPOOL_P_R1_512)
case 512:
return( MBEDTLS_ECP_DP_BP512R1 );
#endif
}
break;
case PSA_ECC_FAMILY_MONTGOMERY:
switch( bits )
{
#if defined(PSA_WANT_ECC_MONTGOMERY_255)
case 255:
return( MBEDTLS_ECP_DP_CURVE25519 );
case 256:
if( bits_is_sloppy )
return( MBEDTLS_ECP_DP_CURVE25519 );
break;
#endif
#if defined(PSA_WANT_ECC_MONTGOMERY_448)
case 448:
return( MBEDTLS_ECP_DP_CURVE448 );
#endif
}
break;
case PSA_ECC_FAMILY_SECP_K1:
switch( bits )
{
#if defined(PSA_WANT_ECC_SECP_K1_192)
case 192:
return( MBEDTLS_ECP_DP_SECP192K1 );
#endif
#if defined(PSA_WANT_ECC_SECP_K1_224)
case 224:
return( MBEDTLS_ECP_DP_SECP224K1 );
#endif
#if defined(PSA_WANT_ECC_SECP_K1_256)
case 256:
return( MBEDTLS_ECP_DP_SECP256K1 );
#endif
}
break;
}