Add a simple (raw) PKCS#1 padding mode

* src/cipher.h (PUBKEY_ENC_PKCS1_RAW): New.
* cipher/pubkey-util.c (_gcry_pk_util_parse_flaglist): Handle pkcs1-raw
  flag.
* cipher/pubkey-util.c (_gcry_pk_util_data_to_mpi):
  Handle s-exp like (data (flags pkcs1-raw) (value xxxxx))
* cipher/rsa-common.c (_gcry_rsa_pkcs1_encode_raw_for_sig):
  PKCS#1-encode data with embedded hash OID for signature verification.
* tests/basic.c (check_pubkey_sign): Add tests for s-exps with pkcs1-raw
  flag.

--
Allow user to specify (flags pkcs1-raw) to enable pkcs1 padding of raw
value (no hash algorithm is specified). It is up to the user to verify
that the passed value is properly formatted and includes DER-encoded
ASN OID of the used hash function.

Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/cipher/pubkey-internal.h b/cipher/pubkey-internal.h
index 193248c3..b8167c77 100644
--- a/cipher/pubkey-internal.h
+++ b/cipher/pubkey-internal.h
@@ -56,6 +56,10 @@ gpg_err_code_t
 _gcry_rsa_pkcs1_decode_for_enc (unsigned char **r_result, size_t *r_resultlen,
                                 unsigned int nbits, gcry_mpi_t value);
 gpg_err_code_t
+_gcry_rsa_pkcs1_encode_raw_for_sig (gcry_mpi_t *r_result, unsigned int nbits,
+                                const unsigned char *value, size_t valuelen);
+
+gpg_err_code_t
 _gcry_rsa_pkcs1_encode_for_sig (gcry_mpi_t *r_result, unsigned int nbits,
                                 const unsigned char *value, size_t valuelen,
                                 int algo);