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Minor improvements to pk_ecc_read_compressed()

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- new name starting with pk_ecc for consistency
- re-order params to match the PSA convention: buf, len, &size
- add comment about input consumption

Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
This commit is contained in:
Manuel Pégourié-Gonnard 2023-07-26 11:06:46 +02:00
parent e82fcd9c9e
commit df151bbc37
1 changed files with 17 additions and 12 deletions
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29
library/pkparse.c
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@ -679,11 +679,14 @@ static int pk_parse_key_rfc8410_der(mbedtls_pk_context *pk,
/*
* Create a temporary ecp_keypair for converting an EC point in compressed
* format to an uncompressed one
*
* Consumes everything or fails - inherited from
* mbedtls_ecp_point_read_binary().
*/
static int pk_convert_compressed_ec(mbedtls_pk_context *pk,
const unsigned char *in_start, size_t in_len,
size_t *out_buf_len, unsigned char *out_buf,
size_t out_buf_size)
static int pk_ecc_read_compressed(mbedtls_pk_context *pk,
const unsigned char *in_start, size_t in_len,
unsigned char *out_buf, size_t out_buf_size,
size_t *out_buf_len)
{
#if defined(MBEDTLS_PK_PARSE_EC_COMPRESSED)
mbedtls_ecp_keypair ecp_key;
@ -730,7 +733,7 @@ static int pk_get_ecpubkey(unsigned char **p, const unsigned char *end,
#if defined(MBEDTLS_PK_USE_PSA_EC_DATA)
mbedtls_svc_key_id_t key;
psa_key_attributes_t key_attrs = PSA_KEY_ATTRIBUTES_INIT;
size_t len = (end - *p);
size_t len = (size_t) (end - *p);
if (len > PSA_EXPORT_PUBLIC_KEY_MAX_SIZE) {
return MBEDTLS_ERR_PK_BAD_INPUT_DATA;
@ -739,19 +742,20 @@ static int pk_get_ecpubkey(unsigned char **p, const unsigned char *end,
if ((**p == 0x02) || (**p == 0x03)) {
/* Compressed format, not supported by PSA Crypto.
* Try converting using functions from ECP_LIGHT. */
ret = pk_convert_compressed_ec(pk, *p, len,
&(pk->pub_raw_len), pk->pub_raw,
PSA_EXPORT_PUBLIC_KEY_MAX_SIZE);
ret = pk_ecc_read_compressed(pk, *p, len,
pk->pub_raw,
PSA_EXPORT_PUBLIC_KEY_MAX_SIZE,
&pk->pub_raw_len);
if (ret != 0) {
return ret;
}
} else {
/* Uncompressed format */
if ((size_t) (end - *p) > MBEDTLS_PK_MAX_EC_PUBKEY_RAW_LEN) {
if (len > MBEDTLS_PK_MAX_EC_PUBKEY_RAW_LEN) {
return MBEDTLS_ERR_PK_BUFFER_TOO_SMALL;
}
memcpy(pk->pub_raw, *p, (end - *p));
pk->pub_raw_len = end - *p;
memcpy(pk->pub_raw, *p, len);
pk->pub_raw_len = len;
}
/* Validate the key by trying to importing it */
@ -778,7 +782,8 @@ static int pk_get_ecpubkey(unsigned char **p, const unsigned char *end,
#endif /* MBEDTLS_PK_USE_PSA_EC_DATA */
/*
* We know mbedtls_ecp_point_read_binary consumed all bytes or failed
* We know mbedtls_ecp_point_read_binary and pk_ecc_read_compressed either
* consumed all bytes or failed, and memcpy consumed all bytes too.
*/
*p = (unsigned char *) end;