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Merge pull request #5117 from gilles-peskine-arm/psa-rsa-pss_any_salt-2.x

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Backport 2.x: PSA: fix salt length for PSS verification
This commit is contained in:
Manuel Pégourié-Gonnard
2021-10-29 16:36:46 +02:00
committed by GitHub
parent 6295dcb600 f8362ca847
commit 1f1bc2df7c
11 changed files with 486 additions and 53 deletions
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40
library/psa_crypto_rsa.c
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@ -447,6 +447,27 @@ exit:
return( status );
}
#if defined(BUILTIN_ALG_RSA_PSS)
static int rsa_pss_expected_salt_len( psa_algorithm_t alg,
const mbedtls_rsa_context *rsa,
size_t hash_length )
{
if( PSA_ALG_IS_RSA_PSS_ANY_SALT( alg ) )
return( MBEDTLS_RSA_SALT_LEN_ANY );
/* Otherwise: standard salt length, i.e. largest possible salt length
* up to the hash length. */
int klen = (int) mbedtls_rsa_get_len( rsa ); // known to fit
int hlen = (int) hash_length; // known to fit
int room = klen - 2 - hlen;
if( room < 0 )
return( 0 ); // there is no valid signature in this case anyway
else if( room > hlen )
return( hlen );
else
return( room );
}
#endif
static psa_status_t rsa_verify_hash(
const psa_key_attributes_t *attributes,
const uint8_t *key_buffer, size_t key_buffer_size,
@ -494,15 +515,18 @@ static psa_status_t rsa_verify_hash(
#if defined(BUILTIN_ALG_RSA_PSS)
if( PSA_ALG_IS_RSA_PSS( alg ) )
{
int slen = rsa_pss_expected_salt_len( alg, rsa, hash_length );
mbedtls_rsa_set_padding( rsa, MBEDTLS_RSA_PKCS_V21, md_alg );
ret = mbedtls_rsa_rsassa_pss_verify( rsa,
mbedtls_psa_get_random,
MBEDTLS_PSA_RANDOM_STATE,
MBEDTLS_RSA_PUBLIC,
md_alg,
(unsigned int) hash_length,
hash,
signature );
ret = mbedtls_rsa_rsassa_pss_verify_ext( rsa,
mbedtls_psa_get_random,
MBEDTLS_PSA_RANDOM_STATE,
MBEDTLS_RSA_PUBLIC,
md_alg,
(unsigned int) hash_length,
hash,
md_alg,
slen,
signature );
}
else
#endif /* BUILTIN_ALG_RSA_PSS */