/* Get the "nbits" parameter from an s-expression of the format:
*
* (algo
* (parameter_name_1 ....)
* ....
* (parameter_name_n ....))
*
* Example:
*
* (rsa
* (nbits 4:2048))
*
* On success the value for nbits is stored at R_NBITS. If no nbits
* parameter is found, the function returns success and stores 0 at
* R_NBITS. For parsing errors the function returns an error code and
* stores 0 at R_NBITS.
*/
gpg_err_code_t
_gcry_pk_util_get_nbits (gcry_sexp_t list, unsigned int *r_nbits)
{
char buf[50];
const char *s;
size_t n;
*r_nbits = 0;
list = sexp_find_token (list, "nbits", 0);
if (!list)
return 0; /* No NBITS found. */
s = sexp_nth_data (list, 1, &n);
if (!s || n >= DIM (buf) - 1 )
{
/* NBITS given without a cdr. */
sexp_release (list);
return GPG_ERR_INV_OBJ;
}
memcpy (buf, s, n);
buf[n] = 0;
*r_nbits = (unsigned int)strtoul (buf, NULL, 0);
sexp_release (list);
return 0;
}
/* Get the optional "rsa-use-e" parameter from an s-expression of the
* format:
*
* (algo
* (parameter_name_1 ....)
* ....
* (parameter_name_n ....))
*
* Example:
*
* (rsa
* (nbits 4:2048)
* (rsa-use-e 2:41))
*
* On success the value for nbits is stored at R_E. If no rsa-use-e
* parameter is found, the function returns success and stores 65537 at
* R_E. For parsing errors the function returns an error code and
* stores 0 at R_E.
*/
gpg_err_code_t
_gcry_pk_util_get_rsa_use_e (gcry_sexp_t list, unsigned long *r_e)
{
char buf[50];
const char *s;
size_t n;
*r_e = 0;
list = sexp_find_token (list, "rsa-use-e", 0);
if (!list)
{
*r_e = 65537; /* Not given, use the value generated by old versions. */
return 0;
}
s = sexp_nth_data (list, 1, &n);
if (!s || n >= DIM (buf) - 1 )
{
/* No value or value too large. */
sexp_release (list);
return GPG_ERR_INV_OBJ;
}
memcpy (buf, s, n);
buf[n] = 0;
*r_e = strtoul (buf, NULL, 0);
sexp_release (list);
return 0;
}
/* Given the s-expression SEXP with the first element be either
* "private-key" or "public-key" return the spec structure for it. We
* look through the list to find a list beginning with "private-key"
* or "public-key" - the first one found is used. If WANT_PRIVATE is
* set the function will only succeed if a private key has been given.
* On success the spec is stored at R_SPEC. On error NULL is stored
* at R_SPEC and an error code returned. If R_PARMS is not NULL and
* the fucntion returns success, the parameter list below
* "private-key" or "public-key" is stored there and the caller must
* call gcry_sexp_release on it.
*/
static gcry_err_code_t
spec_from_sexp (gcry_sexp_t sexp, int want_private,
gcry_pk_spec_t **r_spec, gcry_sexp_t *r_parms)
{
gcry_sexp_t list, l2;
char *name;
gcry_pk_spec_t *spec;
*r_spec = NULL;
if (r_parms)
*r_parms = NULL;
/* Check that the first element is valid. If we are looking for a
public key but a private key was supplied, we allow the use of
the private key anyway. The rationale for this is that the
private key is a superset of the public key. */
list = sexp_find_token (sexp, want_private? "private-key":"public-key", 0);
if (!list && !want_private)
list = sexp_find_token (sexp, "private-key", 0);
if (!list)
return GPG_ERR_INV_OBJ; /* Does not contain a key object. */
l2 = sexp_cadr (list);
sexp_release (list);
list = l2;
name = sexp_nth_string (list, 0);
if (!name)
{
sexp_release ( list );
return GPG_ERR_INV_OBJ; /* Invalid structure of object. */
}
spec = spec_from_name (name);
xfree (name);
if (!spec)
{
sexp_release (list);
return GPG_ERR_PUBKEY_ALGO; /* Unknown algorithm. */
}
*r_spec = spec;
if (r_parms)
*r_parms = list;
else
sexp_release (list);
return 0;
}
/*
Create a public key pair and return it in r_key.
How the key is created depends on s_parms:
(genkey
(algo
(parameter_name_1 ....)
....
(parameter_name_n ....)
))
The key is returned in a format depending on the
algorithm. Both, private and secret keys are returned
and optionally some additional informatin.
For elgamal we return this structure:
(key-data
(public-key
(elg
(p <mpi>)
(g <mpi>)
(y <mpi>)
)
)
(private-key
(elg
(p <mpi>)
(g <mpi>)
(y <mpi>)
(x <mpi>)
)
)
(misc-key-info
(pm1-factors n1 n2 ... nn)
))
*/
gcry_err_code_t
_gcry_pk_genkey (gcry_sexp_t *r_key, gcry_sexp_t s_parms)
{
gcry_pk_spec_t *spec = NULL;
gcry_sexp_t list = NULL;
gcry_sexp_t l2 = NULL;
char *name = NULL;
gcry_err_code_t rc;
*r_key = NULL;
list = sexp_find_token (s_parms, "genkey", 0);
if (!list)
{
rc = GPG_ERR_INV_OBJ; /* Does not contain genkey data. */
goto leave;
}
l2 = sexp_cadr (list);
sexp_release (list);
list = l2;
l2 = NULL;
if (! list)
{
rc = GPG_ERR_NO_OBJ; /* No cdr for the genkey. */
goto leave;
}
name = _gcry_sexp_nth_string (list, 0);
if (!name)
{
rc = GPG_ERR_INV_OBJ; /* Algo string missing. */
goto leave;
}
spec = spec_from_name (name);
xfree (name);
name = NULL;
if (!spec)
{
rc = GPG_ERR_PUBKEY_ALGO; /* Unknown algorithm. */
goto leave;
}
if (spec->generate)
rc = spec->generate (list, r_key);
else
rc = GPG_ERR_NOT_IMPLEMENTED;
leave:
sexp_release (list);
xfree (name);
sexp_release (l2);
return rc;
}
/* Helper to extract an MPI from key parameters. */
static gpg_err_code_t
mpi_from_keyparam (gcry_mpi_t *r_a, gcry_sexp_t keyparam, const char *name)
{
gcry_err_code_t ec = 0;
gcry_sexp_t l1;
l1 = sexp_find_token (keyparam, name, 0);
if (l1)
{
*r_a = sexp_nth_mpi (l1, 1, GCRYMPI_FMT_USG);
sexp_release (l1);
if (!*r_a)
ec = GPG_ERR_INV_OBJ;
}
return ec;
}
/* Take the hash value and convert into an MPI, suitable for
passing to the low level functions. We currently support the
old style way of passing just a MPI and the modern interface which
allows to pass flags so that we can choose between raw and pkcs1
padding - may be more padding options later.
(<mpi>)
or
(data
[(flags [raw, direct, pkcs1, oaep, pss, no-blinding, rfc6979, eddsa])]
[(hash <algo> <value>)]
[(value <text>)]
[(hash-algo <algo>)]
[(label <label>)]
[(salt-length <length>)]
[(random-override <data>)]
)
Either the VALUE or the HASH element must be present for use
with signatures. VALUE is used for encryption.
HASH-ALGO is specific to OAEP and EDDSA.
LABEL is specific to OAEP.
SALT-LENGTH is for PSS.
RANDOM-OVERRIDE is used to replace random nonces for regression
testing. */
gcry_err_code_t
_gcry_pk_util_data_to_mpi (gcry_sexp_t input, gcry_mpi_t *ret_mpi,
struct pk_encoding_ctx *ctx)
{
gcry_err_code_t rc = 0;
gcry_sexp_t ldata, lhash, lvalue;
size_t n;
const char *s;
int unknown_flag = 0;
int parsed_flags = 0;
*ret_mpi = NULL;
ldata = sexp_find_token (input, "data", 0);
if (!ldata)
{ /* assume old style */
*ret_mpi = sexp_nth_mpi (input, 0, 0);
return *ret_mpi ? GPG_ERR_NO_ERROR : GPG_ERR_INV_OBJ;
}
/* See whether there is a flags list. */
{
gcry_sexp_t lflags = sexp_find_token (ldata, "flags", 0);
if (lflags)
{
if (_gcry_pk_util_parse_flaglist (lflags,
&parsed_flags, &ctx->encoding))
unknown_flag = 1;
sexp_release (lflags);
}
}
if (ctx->encoding == PUBKEY_ENC_UNKNOWN)
ctx->encoding = PUBKEY_ENC_RAW; /* default to raw */
/* Get HASH or MPI */
lhash = sexp_find_token (ldata, "hash", 0);
lvalue = lhash? NULL : sexp_find_token (ldata, "value", 0);
if (!(!lhash ^ !lvalue))
rc = GPG_ERR_INV_OBJ; /* none or both given */
else if (unknown_flag)
rc = GPG_ERR_INV_FLAG;
else if (ctx->encoding == PUBKEY_ENC_RAW
&& (parsed_flags & PUBKEY_FLAG_EDDSA))
{
/* Prepare for EdDSA. */
gcry_sexp_t list;
void *value;
size_t valuelen;
if (!lvalue)
{
rc = GPG_ERR_INV_OBJ;
goto leave;
}
/* Get HASH-ALGO. */
list = sexp_find_token (ldata, "hash-algo", 0);
if (list)
{
s = sexp_nth_data (list, 1, &n);
if (!s)
rc = GPG_ERR_NO_OBJ;
else
{
ctx->hash_algo = get_hash_algo (s, n);
if (!ctx->hash_algo)
rc = GPG_ERR_DIGEST_ALGO;
}
sexp_release (list);
}
else
rc = GPG_ERR_INV_OBJ;
if (rc)
goto leave;
/* Get VALUE. */
value = sexp_nth_buffer (lvalue, 1, &valuelen);
if (!value)
{
/* We assume that a zero length message is meant by
"(value)". This is commonly used by test vectors. Note
that S-expression do not allow zero length items. */
valuelen = 0;
value = xtrymalloc (1);
if (!value)
rc = gpg_err_code_from_syserror ();
}
else if ((valuelen * 8) < valuelen)
{
xfree (value);
rc = GPG_ERR_TOO_LARGE;
}
if (rc)
goto leave;
/* Note that mpi_set_opaque takes ownership of VALUE. */
*ret_mpi = mpi_set_opaque (NULL, value, valuelen*8);
}
else if (ctx->encoding == PUBKEY_ENC_RAW && lhash
&& ((parsed_flags & PUBKEY_FLAG_RAW_FLAG)
|| (parsed_flags & PUBKEY_FLAG_RFC6979)))
{
/* Raw encoding along with a hash element. This is commonly
used for DSA. For better backward error compatibility we
allow this only if either the rfc6979 flag has been given or
the raw flags was explicitly given. */
if (sexp_length (lhash) != 3)
rc = GPG_ERR_INV_OBJ;
else if ( !(s=sexp_nth_data (lhash, 1, &n)) || !n )
rc = GPG_ERR_INV_OBJ;
else
{
void *value;
size_t valuelen;
ctx->hash_algo = get_hash_algo (s, n);
if (!ctx->hash_algo)
rc = GPG_ERR_DIGEST_ALGO;
else if (!(value=sexp_nth_buffer (lhash, 2, &valuelen)))
rc = GPG_ERR_INV_OBJ;
else if ((valuelen * 8) < valuelen)
{
xfree (value);
rc = GPG_ERR_TOO_LARGE;
}
else
*ret_mpi = mpi_set_opaque (NULL, value, valuelen*8);
}
}
else if (ctx->encoding == PUBKEY_ENC_RAW && lvalue)
{
/* RFC6969 may only be used with the a hash value and not the
MPI based value. */
if (parsed_flags & PUBKEY_FLAG_RFC6979)
{
rc = GPG_ERR_CONFLICT;
goto leave;
}
/* Get the value */
*ret_mpi = sexp_nth_mpi (lvalue, 1, GCRYMPI_FMT_USG);
if (!*ret_mpi)
rc = GPG_ERR_INV_OBJ;
}
else if (ctx->encoding == PUBKEY_ENC_PKCS1 && lvalue
&& ctx->op == PUBKEY_OP_ENCRYPT)
{
const void * value;
size_t valuelen;
gcry_sexp_t list;
void *random_override = NULL;
size_t random_override_len = 0;
if ( !(value=sexp_nth_data (lvalue, 1, &valuelen)) || !valuelen )
rc = GPG_ERR_INV_OBJ;
else
{
/* Get optional RANDOM-OVERRIDE. */
list = sexp_find_token (ldata, "random-override", 0);
if (list)
{
s = sexp_nth_data (list, 1, &n);
if (!s)
rc = GPG_ERR_NO_OBJ;
else if (n > 0)
{
random_override = xtrymalloc (n);
if (!random_override)
rc = gpg_err_code_from_syserror ();
else
{
memcpy (random_override, s, n);
random_override_len = n;
}
}
sexp_release (list);
if (rc)
goto leave;
}
rc = _gcry_rsa_pkcs1_encode_for_enc (ret_mpi, ctx->nbits,
value, valuelen,
random_override,
random_override_len);
xfree (random_override);
}
}
else if (ctx->encoding == PUBKEY_ENC_PKCS1 && lhash
&& (ctx->op == PUBKEY_OP_SIGN || ctx->op == PUBKEY_OP_VERIFY))
{
if (sexp_length (lhash) != 3)
rc = GPG_ERR_INV_OBJ;
else if ( !(s=sexp_nth_data (lhash, 1, &n)) || !n )
rc = GPG_ERR_INV_OBJ;
else
{
const void * value;
size_t valuelen;
ctx->hash_algo = get_hash_algo (s, n);
if (!ctx->hash_algo)
rc = GPG_ERR_DIGEST_ALGO;
else if ( !(value=sexp_nth_data (lhash, 2, &valuelen))
|| !valuelen )
rc = GPG_ERR_INV_OBJ;
else
rc = _gcry_rsa_pkcs1_encode_for_sig (ret_mpi, ctx->nbits,
value, valuelen,
ctx->hash_algo);
}
}
else if (ctx->encoding == PUBKEY_ENC_OAEP && lvalue
&& ctx->op == PUBKEY_OP_ENCRYPT)
{
const void * value;
size_t valuelen;
if ( !(value=sexp_nth_data (lvalue, 1, &valuelen)) || !valuelen )
rc = GPG_ERR_INV_OBJ;
else
{
gcry_sexp_t list;
void *random_override = NULL;
size_t random_override_len = 0;
/* Get HASH-ALGO. */
list = sexp_find_token (ldata, "hash-algo", 0);
if (list)
{
s = sexp_nth_data (list, 1, &n);
if (!s)
rc = GPG_ERR_NO_OBJ;
else
{
ctx->hash_algo = get_hash_algo (s, n);
if (!ctx->hash_algo)
rc = GPG_ERR_DIGEST_ALGO;
}
sexp_release (list);
if (rc)
goto leave;
}
/* Get LABEL. */
list = sexp_find_token (ldata, "label", 0);
if (list)
{
s = sexp_nth_data (list, 1, &n);
if (!s)
rc = GPG_ERR_NO_OBJ;
else if (n > 0)
{
ctx->label = xtrymalloc (n);
if (!ctx->label)
rc = gpg_err_code_from_syserror ();
else
{
memcpy (ctx->label, s, n);
ctx->labellen = n;
}
}
sexp_release (list);
if (rc)
goto leave;
}
/* Get optional RANDOM-OVERRIDE. */
list = sexp_find_token (ldata, "random-override", 0);
if (list)
{
s = sexp_nth_data (list, 1, &n);
if (!s)
rc = GPG_ERR_NO_OBJ;
else if (n > 0)
{
random_override = xtrymalloc (n);
if (!random_override)
rc = gpg_err_code_from_syserror ();
else
{
memcpy (random_override, s, n);
random_override_len = n;
}
}
sexp_release (list);
if (rc)
goto leave;
}
rc = _gcry_rsa_oaep_encode (ret_mpi, ctx->nbits, ctx->hash_algo,
value, valuelen,
ctx->label, ctx->labellen,
random_override, random_override_len);
xfree (random_override);
}
}
else if (ctx->encoding == PUBKEY_ENC_PSS && lhash
&& ctx->op == PUBKEY_OP_SIGN)
{
if (sexp_length (lhash) != 3)
rc = GPG_ERR_INV_OBJ;
else if ( !(s=sexp_nth_data (lhash, 1, &n)) || !n )
rc = GPG_ERR_INV_OBJ;
else
{
const void * value;
size_t valuelen;
void *random_override = NULL;
size_t random_override_len = 0;
ctx->hash_algo = get_hash_algo (s, n);
if (!ctx->hash_algo)
rc = GPG_ERR_DIGEST_ALGO;
else if ( !(value=sexp_nth_data (lhash, 2, &valuelen))
|| !valuelen )
rc = GPG_ERR_INV_OBJ;
else
{
gcry_sexp_t list;
/* Get SALT-LENGTH. */
list = sexp_find_token (ldata, "salt-length", 0);
if (list)
{
s = sexp_nth_data (list, 1, &n);
if (!s)
{
rc = GPG_ERR_NO_OBJ;
goto leave;
}
ctx->saltlen = (unsigned int)strtoul (s, NULL, 10);
sexp_release (list);
}
/* Get optional RANDOM-OVERRIDE. */
list = sexp_find_token (ldata, "random-override", 0);
if (list)
{
s = sexp_nth_data (list, 1, &n);
if (!s)
rc = GPG_ERR_NO_OBJ;
else if (n > 0)
{
random_override = xtrymalloc (n);
if (!random_override)
rc = gpg_err_code_from_syserror ();
else
{
memcpy (random_override, s, n);
random_override_len = n;
}
}
sexp_release (list);
if (rc)
goto leave;
}
/* Encode the data. (NBITS-1 is due to 8.1.1, step 1.) */
rc = _gcry_rsa_pss_encode (ret_mpi, ctx->nbits - 1,
ctx->hash_algo,
value, valuelen, ctx->saltlen,
random_override, random_override_len);
xfree (random_override);
}
}
}
else if (ctx->encoding == PUBKEY_ENC_PSS && lhash
&& ctx->op == PUBKEY_OP_VERIFY)
{
if (sexp_length (lhash) != 3)
rc = GPG_ERR_INV_OBJ;
else if ( !(s=sexp_nth_data (lhash, 1, &n)) || !n )
rc = GPG_ERR_INV_OBJ;
else
{
ctx->hash_algo = get_hash_algo (s, n);
if (!ctx->hash_algo)
rc = GPG_ERR_DIGEST_ALGO;
else
{
*ret_mpi = sexp_nth_mpi (lhash, 2, GCRYMPI_FMT_USG);
if (!*ret_mpi)
rc = GPG_ERR_INV_OBJ;
ctx->verify_cmp = pss_verify_cmp;
ctx->verify_arg = *ret_mpi;
}
}
}
else
rc = GPG_ERR_CONFLICT;
leave:
sexp_release (ldata);
sexp_release (lhash);
sexp_release (lvalue);
if (!rc)
ctx->flags = parsed_flags;
else
{
xfree (ctx->label);
ctx->label = NULL;
}
return rc;
}
/* Parse a "enc-val" s-expression and store the inner parameter list
at R_PARMS. ALGO_NAMES is used to verify that the algorithm in
"enc-val" is valid. Returns 0 on success and stores a new list at
R_PARMS which must be freed by the caller. On error R_PARMS is set
to NULL and an error code returned. If R_ECCFLAGS is not NULL flag
values are set into it; as of now they are only used with ecc
algorithms.
(enc-val
[(flags [raw, pkcs1, oaep, no-blinding])]
[(hash-algo <algo>)]
[(label <label>)]
(<algo>
(<param_name1> <mpi>)
...
(<param_namen> <mpi>)))
HASH-ALGO and LABEL are specific to OAEP. CTX will be updated with
encoding information. */
gpg_err_code_t
_gcry_pk_util_preparse_encval (gcry_sexp_t sexp, const char **algo_names,
gcry_sexp_t *r_parms,
struct pk_encoding_ctx *ctx)
{
gcry_err_code_t rc = 0;
gcry_sexp_t l1 = NULL;
gcry_sexp_t l2 = NULL;
char *name = NULL;
size_t n;
int parsed_flags = 0;
int i;
*r_parms = NULL;
/* Check that the first element is valid. */
l1 = sexp_find_token (sexp, "enc-val" , 0);
if (!l1)
{
rc = GPG_ERR_INV_OBJ; /* Does not contain an encrypted value object. */
goto leave;
}
l2 = sexp_nth (l1, 1);
if (!l2)
{
rc = GPG_ERR_NO_OBJ; /* No cadr for the data object. */
goto leave;
}
/* Extract identifier of sublist. */
name = sexp_nth_string (l2, 0);
if (!name)
{
rc = GPG_ERR_INV_OBJ; /* Invalid structure of object. */
goto leave;
}
if (!strcmp (name, "flags"))
{
const char *s;
/* There is a flags element - process it. */
rc = _gcry_pk_util_parse_flaglist (l2, &parsed_flags, &ctx->encoding);
if (rc)
goto leave;
if (ctx->encoding == PUBKEY_ENC_PSS)
{
rc = GPG_ERR_CONFLICT;
goto leave;
}
/* Get the OAEP parameters HASH-ALGO and LABEL, if any. */
if (ctx->encoding == PUBKEY_ENC_OAEP)
{
/* Get HASH-ALGO. */
sexp_release (l2);
l2 = sexp_find_token (l1, "hash-algo", 0);
if (l2)
{
s = sexp_nth_data (l2, 1, &n);
if (!s)
rc = GPG_ERR_NO_OBJ;
else
{
ctx->hash_algo = get_hash_algo (s, n);
if (!ctx->hash_algo)
rc = GPG_ERR_DIGEST_ALGO;
}
if (rc)
goto leave;
}
/* Get LABEL. */
sexp_release (l2);
l2 = sexp_find_token (l1, "label", 0);
if (l2)
{
s = sexp_nth_data (l2, 1, &n);
if (!s)
rc = GPG_ERR_NO_OBJ;
else if (n > 0)
{
ctx->label = xtrymalloc (n);
if (!ctx->label)
rc = gpg_err_code_from_syserror ();
else
{
memcpy (ctx->label, s, n);
ctx->labellen = n;
}
}
if (rc)
goto leave;
}
}
/* Get the next which has the actual data - skip HASH-ALGO and LABEL. */
for (i = 2; (sexp_release (l2), l2 = sexp_nth (l1, i)); i++)
{
s = sexp_nth_data (l2, 0, &n);
if (!(n == 9 && !memcmp (s, "hash-algo", 9))
&& !(n == 5 && !memcmp (s, "label", 5))
&& !(n == 15 && !memcmp (s, "random-override", 15)))
break;
}
if (!l2)
{
rc = GPG_ERR_NO_OBJ; /* No cadr for the data object. */
goto leave;
}
/* Extract sublist identifier. */
xfree (name);
name = sexp_nth_string (l2, 0);
if (!name)
{
rc = GPG_ERR_INV_OBJ; /* Invalid structure of object. */
goto leave;
}
}
else /* No flags - flag as legacy structure. */
parsed_flags |= PUBKEY_FLAG_LEGACYRESULT;
for (i=0; algo_names[i]; i++)
if (!stricmp (name, algo_names[i]))
break;
if (!algo_names[i])
{
rc = GPG_ERR_CONFLICT; /* "enc-val" uses an unexpected algo. */
goto leave;
}
*r_parms = l2;
l2 = NULL;
ctx->flags |= parsed_flags;
rc = 0;
leave:
xfree (name);
sexp_release (l2);
sexp_release (l1);
return rc;
}
/* Parse a "sig-val" s-expression and store the inner parameter list at
R_PARMS. ALGO_NAMES is used to verify that the algorithm in
"sig-val" is valid. Returns 0 on success and stores a new list at
R_PARMS which must be freed by the caller. On error R_PARMS is set
to NULL and an error code returned. If R_ECCFLAGS is not NULL flag
values are set into it; as of now they are only used with ecc
algorithms. */
gpg_err_code_t
_gcry_pk_util_preparse_sigval (gcry_sexp_t s_sig, const char **algo_names,
gcry_sexp_t *r_parms, int *r_eccflags)
{
gpg_err_code_t rc;
gcry_sexp_t l1 = NULL;
gcry_sexp_t l2 = NULL;
char *name = NULL;
int i;
*r_parms = NULL;
if (r_eccflags)
*r_eccflags = 0;
/* Extract the signature value. */
l1 = sexp_find_token (s_sig, "sig-val", 0);
if (!l1)
{
rc = GPG_ERR_INV_OBJ; /* Does not contain a signature value object. */
goto leave;
}
l2 = sexp_nth (l1, 1);
if (!l2)
{
rc = GPG_ERR_NO_OBJ; /* No cadr for the sig object. */
goto leave;
}
name = sexp_nth_string (l2, 0);
if (!name)
{
rc = GPG_ERR_INV_OBJ; /* Invalid structure of object. */
goto leave;
}
else if (!strcmp (name, "flags"))
{
/* Skip a "flags" parameter and look again for the algorithm
name. This is not used but here just for the sake of
consistent S-expressions we need to handle it. */
sexp_release (l2);
l2 = sexp_nth (l1, 2);
if (!l2)
{
rc = GPG_ERR_INV_OBJ;
goto leave;
}
xfree (name);
name = sexp_nth_string (l2, 0);
if (!name)
{
rc = GPG_ERR_INV_OBJ; /* Invalid structure of object. */
goto leave;
}
}
for (i=0; algo_names[i]; i++)
if (!stricmp (name, algo_names[i]))
break;
if (!algo_names[i])
{
rc = GPG_ERR_CONFLICT; /* "sig-val" uses an unexpected algo. */
goto leave;
}
if (r_eccflags)
{
if (!strcmp (name, "eddsa"))
*r_eccflags = PUBKEY_FLAG_EDDSA;
if (!strcmp (name, "gost"))
*r_eccflags = PUBKEY_FLAG_GOST;
}
*r_parms = l2;
l2 = NULL;
rc = 0;
leave:
xfree (name);
sexp_release (l2);
sexp_release (l1);
return rc;
}
/* Return the so called KEYGRIP which is the SHA-1 hash of the public
key parameters expressed in a way depending on the algorithm.
ARRAY must either be 20 bytes long or NULL; in the latter case a
newly allocated array of that size is returned, otherwise ARRAY or
NULL is returned to indicate an error which is most likely an
unknown algorithm. The function accepts public or secret keys. */
unsigned char *
_gcry_pk_get_keygrip (gcry_sexp_t key, unsigned char *array)
{
gcry_sexp_t list = NULL;
gcry_sexp_t l2 = NULL;
gcry_pk_spec_t *spec = NULL;
const char *s;
char *name = NULL;
int idx;
const char *elems;
gcry_md_hd_t md = NULL;
int okay = 0;
/* Check that the first element is valid. */
list = sexp_find_token (key, "public-key", 0);
if (! list)
list = sexp_find_token (key, "private-key", 0);
if (! list)
list = sexp_find_token (key, "protected-private-key", 0);
if (! list)
list = sexp_find_token (key, "shadowed-private-key", 0);
if (! list)
return NULL; /* No public- or private-key object. */
l2 = sexp_cadr (list);
sexp_release (list);
list = l2;
l2 = NULL;
name = _gcry_sexp_nth_string (list, 0);
if (!name)
goto fail; /* Invalid structure of object. */
spec = spec_from_name (name);
if (!spec)
goto fail; /* Unknown algorithm. */
elems = spec->elements_grip;
if (!elems)
goto fail; /* No grip parameter. */
if (_gcry_md_open (&md, GCRY_MD_SHA1, 0))
goto fail;
if (spec->comp_keygrip)
{
/* Module specific method to compute a keygrip. */
if (spec->comp_keygrip (md, list))
goto fail;
}
else
{
/* Generic method to compute a keygrip. */
for (idx = 0, s = elems; *s; s++, idx++)
{
const char *data;
size_t datalen;
char buf[30];
l2 = sexp_find_token (list, s, 1);
if (! l2)
goto fail;
data = sexp_nth_data (l2, 1, &datalen);
if (! data)
goto fail;
_snprintf (buf, sizeof buf, "(1:%c%u:", *s, (unsigned int)datalen);
_gcry_md_write (md, buf, strlen (buf));
_gcry_md_write (md, data, datalen);
sexp_release (l2);
l2 = NULL;
_gcry_md_write (md, ")", 1);
}
}
if (!array)
{
array = xtrymalloc (20);
if (! array)
goto fail;
}
memcpy (array, _gcry_md_read (md, GCRY_MD_SHA1), 20);
okay = 1;
fail:
xfree (name);
sexp_release (l2);
_gcry_md_close (md);
sexp_release (list);
return okay? array : NULL;
}
/* This function creates a new context for elliptic curve operations.
Either KEYPARAM or CURVENAME must be given. If both are given and
KEYPARAM has no curve parameter, CURVENAME is used to add missing
parameters. On success 0 is returned and the new context stored at
R_CTX. On error NULL is stored at R_CTX and an error code is
returned. The context needs to be released using
gcry_ctx_release. */
gpg_err_code_t
_gcry_mpi_ec_new (gcry_ctx_t *r_ctx,
gcry_sexp_t keyparam, const char *curvename)
{
gpg_err_code_t errc;
gcry_ctx_t ctx = NULL;
enum gcry_mpi_ec_models model = MPI_EC_WEIERSTRASS;
enum ecc_dialects dialect = ECC_DIALECT_STANDARD;
gcry_mpi_t p = NULL;
gcry_mpi_t a = NULL;
gcry_mpi_t b = NULL;
gcry_mpi_point_t G = NULL;
gcry_mpi_t n = NULL;
gcry_mpi_point_t Q = NULL;
gcry_mpi_t d = NULL;
int flags = 0;
gcry_sexp_t l1;
*r_ctx = NULL;
if (keyparam)
{
/* Parse an optional flags list. */
l1 = sexp_find_token (keyparam, "flags", 0);
if (l1)
{
errc = _gcry_pk_util_parse_flaglist (l1, &flags, NULL);
sexp_release (l1);
l1 = NULL;
if (errc)
goto leave;
}
/* Check whether a curve name was given. */
l1 = sexp_find_token (keyparam, "curve", 5);
/* If we don't have a curve name or if override parameters have
explicitly been requested, parse them. */
if (!l1 || (flags & PUBKEY_FLAG_PARAM))
{
errc = mpi_from_keyparam (&p, keyparam, "p");
if (errc)
goto leave;
errc = mpi_from_keyparam (&a, keyparam, "a");
if (errc)
goto leave;
errc = mpi_from_keyparam (&b, keyparam, "b");
if (errc)
goto leave;
errc = point_from_keyparam (&G, keyparam, "g", NULL);
if (errc)
goto leave;
errc = mpi_from_keyparam (&n, keyparam, "n");
if (errc)
goto leave;
}
}
else
l1 = NULL; /* No curvename. */
/* Check whether a curve parameter is available and use that to fill
in missing values. If no curve parameter is available try an
optional provided curvename. If only the curvename has been
given use that one. */
if (l1 || curvename)
{
char *name;
elliptic_curve_t *E;
if (l1)
{
name = sexp_nth_string (l1, 1);
sexp_release (l1);
if (!name)
{
errc = GPG_ERR_INV_OBJ; /* Name missing or out of core. */
goto leave;
}
}
else
name = NULL;
E = xtrycalloc (1, sizeof *E);
if (!E)
{
errc = gpg_err_code_from_syserror ();
xfree (name);
goto leave;
}
errc = _gcry_ecc_fill_in_curve (0, name? name : curvename, E, NULL);
xfree (name);
if (errc)
{
xfree (E);
goto leave;
}
model = E->model;
dialect = E->dialect;
if (!p)
{
p = E->p;
E->p = NULL;
}
if (!a)
{
a = E->a;
E->a = NULL;
}
if (!b)
{
b = E->b;
E->b = NULL;
}
if (!G)
{
G = mpi_point_snatch_set (NULL, E->G.x, E->G.y, E->G.z);
E->G.x = NULL;
E->G.y = NULL;
E->G.z = NULL;
}
if (!n)
{
n = E->n;
E->n = NULL;
}
_gcry_ecc_curve_free (E);
xfree (E);
}
errc = _gcry_mpi_ec_p_new (&ctx, model, dialect, flags, p, a, b);
if (!errc)
{
mpi_ec_t ec = _gcry_ctx_get_pointer (ctx, CONTEXT_TYPE_EC);
if (b)
{
mpi_free (ec->b);
ec->b = b;
b = NULL;
}
if (G)
{
ec->G = G;
G = NULL;
}
if (n)
{
ec->n = n;
n = NULL;
}
/* Now that we know the curve name we can look for the public key
Q. point_from_keyparam needs to know the curve parameters so
that it is able to use the correct decompression. Parsing
the private key D could have been done earlier but it is less
surprising if we do it here as well. */
if (keyparam)
{
errc = point_from_keyparam (&Q, keyparam, "q", ec);
if (errc)
goto leave;
errc = mpi_from_keyparam (&d, keyparam, "d");
if (errc)
goto leave;
}
if (Q)
{
ec->Q = Q;
Q = NULL;
}
if (d)
{
ec->d = d;
d = NULL;
}
*r_ctx = ctx;
ctx = NULL;
}
leave:
_gcry_ctx_release (ctx);
mpi_free (p);
mpi_free (a);
mpi_free (b);
_gcry_mpi_point_release (G);
mpi_free (n);
_gcry_mpi_point_release (Q);
mpi_free (d);
return errc;
}
/* Helper to extract a point from key parameters. If no parameter
with NAME is found, the functions tries to find a non-encoded point
by appending ".x", ".y" and ".z" to NAME. ".z" is in this case
optional and defaults to 1. EC is the context which at this point
may not be fully initialized. */
static gpg_err_code_t
point_from_keyparam (gcry_mpi_point_t *r_a,
gcry_sexp_t keyparam, const char *name, mpi_ec_t ec)
{
gcry_err_code_t rc;
gcry_sexp_t l1;
gcry_mpi_point_t point;
l1 = sexp_find_token (keyparam, name, 0);
if (l1)
{
gcry_mpi_t a;
a = sexp_nth_mpi (l1, 1, GCRYMPI_FMT_OPAQUE);
sexp_release (l1);
if (!a)
return GPG_ERR_INV_OBJ;
point = mpi_point_new (0);
if (ec && ec->dialect == ECC_DIALECT_ED25519)
rc = _gcry_ecc_eddsa_decodepoint (a, ec, point, NULL, NULL);
else
rc = _gcry_ecc_os2ec (point, a);
mpi_free (a);
if (rc)
{
mpi_point_release (point);
return rc;
}
}
else
{
char *tmpname;
gcry_mpi_t x = NULL;
gcry_mpi_t y = NULL;
gcry_mpi_t z = NULL;
tmpname = xtrymalloc (strlen (name) + 2 + 1);
if (!tmpname)
return gpg_err_code_from_syserror ();
strcpy (stpcpy (tmpname, name), ".x");
rc = mpi_from_keyparam (&x, keyparam, tmpname);
if (rc)
{
xfree (tmpname);
return rc;
}
strcpy (stpcpy (tmpname, name), ".y");
rc = mpi_from_keyparam (&y, keyparam, tmpname);
if (rc)
{
mpi_free (x);
xfree (tmpname);
return rc;
}
strcpy (stpcpy (tmpname, name), ".z");
rc = mpi_from_keyparam (&z, keyparam, tmpname);
if (rc)
{
mpi_free (y);
mpi_free (x);
xfree (tmpname);
return rc;
}
if (!z)
z = mpi_set_ui (NULL, 1);
if (x && y)
point = mpi_point_snatch_set (NULL, x, y, z);
else
{
mpi_free (x);
mpi_free (y);
mpi_free (z);
point = NULL;
}
xfree (tmpname);
}
if (point)
*r_a = point;
return 0;
}
/* Return the name matching the parameters in PKEY. This works only
with curves described by the Weierstrass equation. */
const char *
_gcry_ecc_get_curve (gcry_sexp_t keyparms, int iterator, unsigned int *r_nbits)
{
gpg_err_code_t rc;
const char *result = NULL;
elliptic_curve_t E;
gcry_mpi_t mpi_g = NULL;
gcry_mpi_t tmp = NULL;
int idx;
memset (&E, 0, sizeof E);
if (r_nbits)
*r_nbits = 0;
if (!keyparms)
{
idx = iterator;
if (idx >= 0 && idx < DIM (domain_parms))
{
result = domain_parms[idx].desc;
if (r_nbits)
*r_nbits = domain_parms[idx].nbits;
}
return result;
}
/*
* Extract the curve parameters..
*/
rc = gpg_err_code (sexp_extract_param (keyparms, NULL, "-pabgn",
&E.p, &E.a, &E.b, &mpi_g, &E.n,
NULL));
if (rc == GPG_ERR_NO_OBJ)
{
/* This might be the second use case of checking whether a
specific curve given by name is supported. */
gcry_sexp_t l1;
char *name;
l1 = sexp_find_token (keyparms, "curve", 5);
if (!l1)
goto leave; /* No curve name parameter. */
name = sexp_nth_string (l1, 1);
sexp_release (l1);
if (!name)
goto leave; /* Name missing or out of core. */
idx = find_domain_parms_idx (name);
xfree (name);
if (idx >= 0) /* Curve found. */
{
result = domain_parms[idx].desc;
if (r_nbits)
*r_nbits = domain_parms[idx].nbits;
}
return result;
}
if (rc)
goto leave;
if (mpi_g)
{
_gcry_mpi_point_init (&E.G);
if (_gcry_ecc_os2ec (&E.G, mpi_g))
goto leave;
}
for (idx = 0; domain_parms[idx].desc; idx++)
{
mpi_free (tmp);
tmp = scanval (domain_parms[idx].p);
if (!mpi_cmp (tmp, E.p))
{
mpi_free (tmp);
tmp = scanval (domain_parms[idx].a);
if (!mpi_cmp (tmp, E.a))
{
mpi_free (tmp);
tmp = scanval (domain_parms[idx].b);
if (!mpi_cmp (tmp, E.b))
{
mpi_free (tmp);
tmp = scanval (domain_parms[idx].n);
if (!mpi_cmp (tmp, E.n))
{
mpi_free (tmp);
tmp = scanval (domain_parms[idx].g_x);
if (!mpi_cmp (tmp, E.G.x))
{
mpi_free (tmp);
tmp = scanval (domain_parms[idx].g_y);
if (!mpi_cmp (tmp, E.G.y))
{
result = domain_parms[idx].desc;
if (r_nbits)
*r_nbits = domain_parms[idx].nbits;
goto leave;
}
}
}
}
}
}
}
leave:
_gcry_mpi_release (tmp);
_gcry_mpi_release (E.p);
_gcry_mpi_release (E.a);
_gcry_mpi_release (E.b);
_gcry_mpi_release (mpi_g);
_gcry_mpi_point_free_parts (&E.G);
_gcry_mpi_release (E.n);
return result;
}
