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Merge pull request #7143 from paul-elliott-arm/interruptible_sign_hash_codestyle_wipeout

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Update psa_wipe_output_buffer() and change name to psa_wipe_tag_output_buffer()
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Paul Elliott 2023-02-28 15:34:06 +00:00 committed by GitHub
commit 6a459f5de5
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1 changed files with 48 additions and 49 deletions
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97
library/psa_crypto.c
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@ -322,6 +322,44 @@ psa_status_t mbedtls_to_psa_error(int ret)
}
}
/**
* \brief For output buffers which contain "tags"
* (outputs that may be checked for validity like
* hashes, MACs and signatures), fill the unused
* part of the output buffer (the whole buffer on
* error, the trailing part on success) with
* something that isn't a valid tag (barring an
* attack on the tag and deliberately-crafted
* input), in case the caller doesn't check the
* return status properly.
*
* \param output_buffer Pointer to buffer to wipe. May not be NULL
* unless \p output_buffer_size is zero.
* \param status Status of function called to generate
* output_buffer originally
* \param output_buffer_size Size of output buffer. If zero, \p output_buffer
* could be NULL.
* \param output_buffer_length Length of data written to output_buffer, must be
* less than \p output_buffer_size
*/
static void psa_wipe_tag_output_buffer(uint8_t *output_buffer, psa_status_t status,
size_t output_buffer_size, size_t output_buffer_length)
{
size_t offset = 0;
if (output_buffer_size == 0) {
/* If output_buffer_size is 0 then we have nothing to do. We must not
call memset because output_buffer may be NULL in this case */
return;
}
if (status == PSA_SUCCESS) {
offset = output_buffer_length;
}
memset(output_buffer + offset, '!', output_buffer_size - offset);
}
@ -2504,10 +2542,7 @@ exit:
operation->mac_size = 0;
}
if (mac_size > operation->mac_size) {
memset(&mac[operation->mac_size], '!',
mac_size - operation->mac_size);
}
psa_wipe_tag_output_buffer(mac, status, mac_size, *mac_length);
abort_status = psa_mac_abort(operation);
@ -2601,9 +2636,8 @@ exit:
*mac_length = mac_size;
operation_mac_size = 0;
}
if (mac_size > operation_mac_size) {
memset(&mac[operation_mac_size], '!', mac_size - operation_mac_size);
}
psa_wipe_tag_output_buffer(mac, status, mac_size, *mac_length);
unlock_status = psa_unlock_key_slot(slot);
@ -2683,37 +2717,6 @@ static psa_status_t psa_sign_verify_check_alg(int input_is_message,
return PSA_SUCCESS;
}
/**
* \brief Fill the unused part of the output buffer (the
* whole buffer on error, the trailing part on
* success) with something that isn't a valid
* signature (barring an attack on the signature
* and deliberately-crafted input), in case the
* caller doesn't check the return status properly.
*
* \param output_buffer pointer to buffer to wipe. May not be NULL
* unless \p output_buffer_size is zero.
* \param status status of function called to generate
* output_buffer originally
* \param output_buffer_size Size of output buffer. If zero, \p output_buffer
* could be NULL
* \param output_buffer_length Length of data written to output_buffer, must be
* less than \p output_buffer_size
*/
static void psa_wipe_output_buffer(uint8_t *output_buffer, psa_status_t status,
size_t output_buffer_size, size_t output_buffer_length)
{
if (status == PSA_SUCCESS) {
memset(output_buffer + output_buffer_length, '!',
output_buffer_size - output_buffer_length);
} else if (output_buffer_size > 0) {
memset(output_buffer, '!', output_buffer_size);
}
/* If output_buffer_size is 0 then we have nothing to do. We must
* not call memset because output_buffer may be NULL in this
* case.*/
}
static psa_status_t psa_sign_internal(mbedtls_svc_key_id_t key,
int input_is_message,
psa_algorithm_t alg,
@ -2776,8 +2779,8 @@ static psa_status_t psa_sign_internal(mbedtls_svc_key_id_t key,
exit:
psa_wipe_output_buffer(signature, status, signature_size,
*signature_length);
psa_wipe_tag_output_buffer(signature, status, signature_size,
*signature_length);
unlock_status = psa_unlock_key_slot(slot);
@ -3293,8 +3296,8 @@ psa_status_t psa_sign_hash_complete(
exit:
psa_wipe_output_buffer(signature, status, signature_size,
*signature_length);
psa_wipe_tag_output_buffer(signature, status, signature_size,
*signature_length);
if (status != PSA_OPERATION_INCOMPLETE) {
if (status != PSA_SUCCESS) {
@ -4910,18 +4913,14 @@ psa_status_t psa_aead_finish(psa_aead_operation_t *operation,
tag, tag_size, tag_length);
exit:
/* In case the operation fails and the user fails to check for failure or
* the zero tag size, make sure the tag is set to something implausible.
* Even if the operation succeeds, make sure we clear the rest of the
* buffer to prevent potential leakage of anything previously placed in
* the same buffer.*/
if (tag != NULL) {
if (status != PSA_SUCCESS) {
memset(tag, '!', tag_size);
} else if (*tag_length < tag_size) {
memset(tag + *tag_length, '!', (tag_size - *tag_length));
}
}
psa_wipe_tag_output_buffer(tag, status, tag_size, *tag_length);
psa_aead_abort(operation);