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Move pk_ecdsa_sig_asn1_from_psa() before ecdsa_sign_wrap()

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Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
This commit is contained in:
Neil Armstrong 2022-03-01 10:14:17 +01:00
parent 5874aa38f7
commit 15021659d1
1 changed files with 80 additions and 87 deletions
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167
library/pk_wrap.c
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@ -741,8 +741,87 @@ static int ecdsa_verify_wrap( void *ctx, mbedtls_md_type_t md_alg,
#endif /* MBEDTLS_USE_PSA_CRYPTO */
#if defined(MBEDTLS_USE_PSA_CRYPTO)
/*
* Simultaneously convert and move raw MPI from the beginning of a buffer
* to an ASN.1 MPI at the end of the buffer.
* See also mbedtls_asn1_write_mpi().
*
* p: pointer to the end of the output buffer
* start: start of the output buffer, and also of the mpi to write at the end
* n_len: length of the mpi to read from start
*/
static int asn1_write_mpibuf( unsigned char **p, unsigned char *start,
size_t n_len )
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
size_t len = 0;
if( (size_t)( *p - start ) < n_len )
return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
len = n_len;
*p -= len;
memmove( *p, start, len );
/* ASN.1 DER encoding requires minimal length, so skip leading 0s.
* Neither r nor s should be 0, but as a failsafe measure, still detect
* that rather than overflowing the buffer in case of a PSA error. */
while( len > 0 && **p == 0x00 )
{
++(*p);
--len;
}
/* this is only reached if the signature was invalid */
if( len == 0 )
return( MBEDTLS_ERR_PLATFORM_HW_ACCEL_FAILED );
/* if the msb is 1, ASN.1 requires that we prepend a 0.
* Neither r nor s can be 0, so we can assume len > 0 at all times. */
if( **p & 0x80 )
{
if( *p - start < 1 )
return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
*--(*p) = 0x00;
len += 1;
}
MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );
MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start,
MBEDTLS_ASN1_INTEGER ) );
return( (int) len );
}
/* Transcode signature from PSA format to ASN.1 sequence.
* See ecdsa_signature_to_asn1 in ecdsa.c, but with byte buffers instead of
* MPIs, and in-place.
*
* [in/out] sig: the signature pre- and post-transcoding
* [in/out] sig_len: signature length pre- and post-transcoding
* [int] buf_len: the available size the in/out buffer
*/
static int pk_ecdsa_sig_asn1_from_psa( unsigned char *sig, size_t *sig_len,
size_t buf_len );
size_t buf_len )
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
size_t len = 0;
const size_t rs_len = *sig_len / 2;
unsigned char *p = sig + buf_len;
MBEDTLS_ASN1_CHK_ADD( len, asn1_write_mpibuf( &p, sig + rs_len, rs_len ) );
MBEDTLS_ASN1_CHK_ADD( len, asn1_write_mpibuf( &p, sig, rs_len ) );
MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &p, sig, len ) );
MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &p, sig,
MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) );
memmove( sig, p, len );
*sig_len = len;
return( 0 );
}
static int find_ecdsa_private_key( unsigned char **buf, unsigned char *end, size_t *key_len )
{
@ -1118,92 +1197,6 @@ static int pk_opaque_can_do( mbedtls_pk_type_t type )
type == MBEDTLS_PK_ECDSA );
}
#if defined(MBEDTLS_ECDSA_C)
/*
* Simultaneously convert and move raw MPI from the beginning of a buffer
* to an ASN.1 MPI at the end of the buffer.
* See also mbedtls_asn1_write_mpi().
*
* p: pointer to the end of the output buffer
* start: start of the output buffer, and also of the mpi to write at the end
* n_len: length of the mpi to read from start
*/
static int asn1_write_mpibuf( unsigned char **p, unsigned char *start,
size_t n_len )
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
size_t len = 0;
if( (size_t)( *p - start ) < n_len )
return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
len = n_len;
*p -= len;
memmove( *p, start, len );
/* ASN.1 DER encoding requires minimal length, so skip leading 0s.
* Neither r nor s should be 0, but as a failsafe measure, still detect
* that rather than overflowing the buffer in case of a PSA error. */
while( len > 0 && **p == 0x00 )
{
++(*p);
--len;
}
/* this is only reached if the signature was invalid */
if( len == 0 )
return( MBEDTLS_ERR_PLATFORM_HW_ACCEL_FAILED );
/* if the msb is 1, ASN.1 requires that we prepend a 0.
* Neither r nor s can be 0, so we can assume len > 0 at all times. */
if( **p & 0x80 )
{
if( *p - start < 1 )
return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
*--(*p) = 0x00;
len += 1;
}
MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );
MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start,
MBEDTLS_ASN1_INTEGER ) );
return( (int) len );
}
/* Transcode signature from PSA format to ASN.1 sequence.
* See ecdsa_signature_to_asn1 in ecdsa.c, but with byte buffers instead of
* MPIs, and in-place.
*
* [in/out] sig: the signature pre- and post-transcoding
* [in/out] sig_len: signature length pre- and post-transcoding
* [int] buf_len: the available size the in/out buffer
*/
static int pk_ecdsa_sig_asn1_from_psa( unsigned char *sig, size_t *sig_len,
size_t buf_len )
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
size_t len = 0;
const size_t rs_len = *sig_len / 2;
unsigned char *p = sig + buf_len;
MBEDTLS_ASN1_CHK_ADD( len, asn1_write_mpibuf( &p, sig + rs_len, rs_len ) );
MBEDTLS_ASN1_CHK_ADD( len, asn1_write_mpibuf( &p, sig, rs_len ) );
MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &p, sig, len ) );
MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &p, sig,
MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) );
memmove( sig, p, len );
*sig_len = len;
return( 0 );
}
#endif /* MBEDTLS_ECDSA_C */
static int pk_opaque_sign_wrap( void *ctx, mbedtls_md_type_t md_alg,
const unsigned char *hash, size_t hash_len,
unsigned char *sig, size_t sig_size, size_t *sig_len,