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PSA interruptible sign/verify: detect unsupported mechanism in start

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In particular, if interruptible ECDSA is supported but not the deterministic
variant, detect this in psa_sign_hash_start(), whereas before start() would
succeed and psa_sign_hash_complete() would fail. This avoids an
inconsistency between psa_sign_hash() and psa_sign_hash_start() that would
be annoying to handle in test_suite_psa_crypto_op_fail.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
This commit is contained in:
Gilles Peskine
2024-11-20 16:13:10 +01:00
parent 6bf0b2e678
commit 8a8aa59f52
2 changed files with 32 additions and 4 deletions
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32
library/psa_crypto.c
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@ -3932,6 +3932,34 @@ uint32_t mbedtls_psa_verify_hash_get_num_ops(
* defined( MBEDTLS_ECP_RESTARTABLE ) */
}
/* Detect supported interruptible sign/verify mechanisms precisely.
* This is not strictly needed: we could accept everything, and let the
* code fail later during complete() if the mechanism is unsupported
* (e.g. attempting deterministic ECDSA when only the randomized variant
* is available). But it's easier for applications and especially for our
* test code to detect all not-supported errors during start().
*
* Note that this function ignores the hash component. The core code
* is supposed to check the hash part by calling is_hash_supported().
*/
static inline int can_do_interruptible_sign_verify(psa_algorithm_t alg)
{
#if defined(MBEDTLS_ECP_RESTARTABLE)
#if defined(MBEDTLS_PSA_BUILTIN_ALG_DETERMINISTIC_ECDSA)
if (PSA_ALG_IS_DETERMINISTIC_ECDSA(alg)) {
return 1;
}
#endif
#if defined(MBEDTLS_PSA_BUILTIN_ALG_ECDSA)
if (PSA_ALG_IS_RANDOMIZED_ECDSA(alg)) {
return 1;
}
#endif
#endif /* defined(MBEDTLS_ECP_RESTARTABLE) */
(void) alg;
return 0;
}
psa_status_t mbedtls_psa_sign_hash_start(
mbedtls_psa_sign_hash_interruptible_operation_t *operation,
const psa_key_attributes_t *attributes, const uint8_t *key_buffer,
@ -3945,7 +3973,7 @@ psa_status_t mbedtls_psa_sign_hash_start(
return PSA_ERROR_NOT_SUPPORTED;
}
if (!PSA_ALG_IS_ECDSA(alg)) {
if (!can_do_interruptible_sign_verify(alg)) {
return PSA_ERROR_NOT_SUPPORTED;
}
@ -4161,7 +4189,7 @@ psa_status_t mbedtls_psa_verify_hash_start(
return PSA_ERROR_NOT_SUPPORTED;
}
if (!PSA_ALG_IS_ECDSA(alg)) {
if (!can_do_interruptible_sign_verify(alg)) {
return PSA_ERROR_NOT_SUPPORTED;
}