Implement RSASP1 and fill-in the following data to public key signature
structure: signature length (pkcs->k), signature octet
strings (pks->S) and MPI of signature (pks->rsa.s).
Reviewed-by: Jiri Kosina <jkosina@xxxxxxx>
Signed-off-by: Lee, Chun-Yi <jlee@xxxxxxxx>
---
crypto/asymmetric_keys/rsa.c | 47 +++++++++++++++++++++++++++++++++++++++--
1 files changed, 44 insertions(+), 3 deletions(-)
diff --git a/crypto/asymmetric_keys/rsa.c b/crypto/asymmetric_keys/rsa.c
index 0862018..e60defe 100644
--- a/crypto/asymmetric_keys/rsa.c
+++ b/crypto/asymmetric_keys/rsa.c
@@ -86,6 +86,39 @@ static const struct {
};
/*
+ * RSASP1() function [RFC3447 sec 5.2.1]
+ */
+static int RSASP1(const struct private_key *key, MPI m, MPI *_s)
+{
+ MPI s;
+ int ret;
+
+ /* (1) Validate 0 <= m < n */
+ if (mpi_cmp_ui(m, 0) < 0) {
+ kleave(" = -EBADMSG [m < 0]");
+ return -EBADMSG;
+ }
+ if (mpi_cmp(m, key->rsa.n) >= 0) {
+ kleave(" = -EBADMSG [m >= n]");
+ return -EBADMSG;
+ }
+
+ s = mpi_alloc(0);
+ if (!s)
+ return -ENOMEM;
+
+ /* (2) s = m^d mod n */
+ ret = mpi_powm(s, m, key->rsa.d, key->rsa.n);
+ if (ret < 0) {
+ mpi_free(s);
+ return ret;
+ }
+
+ *_s = s;
+ return 0;
+}
+
+/*
* RSAVP1() function [RFC3447 sec 5.2.2]
*/
static int RSAVP1(const struct public_key *key, MPI s, MPI *_m)
@@ -173,9 +206,12 @@ static int RSA_I2OSP(MPI x, size_t xLen, u8 **_X)
static int RSA_OS2IP(u8 *X, size_t XLen, MPI *_x)
{
MPI x;
+ int ret;
x = mpi_alloc((XLen + BYTES_PER_MPI_LIMB - 1) / BYTES_PER_MPI_LIMB);
- mpi_set_buffer(x, X, XLen, 0);
+ ret = mpi_set_buffer(x, X, XLen, 0);
+ if (ret < 0)
+ return ret;
*_x = x;
return 0;
@@ -453,8 +489,13 @@ static struct public_key_signature *RSA_generate_signature(
if (ret < 0)
goto error_v1_5_encode;
- /* TODO 3): s = RSASP1 (K, m) */
- s = m;
+ /* 3): s = RSASP1 (K, m) */
+ RSASP1(key, m, &s);
+
+ pks->rsa.s = s;
+ pks->nr_mpi = 1;
+ pks->k = mpi_get_nbits(s);
+ pks->k = (pks->k + 7) / 8;
/* 4): S = I2OSP (s, k) */
_RSA_I2OSP(s, &X_size, &pks->S);
--
1.6.4.2
--
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