Implement Octet String to Integer conversion [RFC3447 sec 4.2] in rsa.c. It's
the second step of signature generation operation.
This patch is temporary set non-RSASP1 message to pks->S for debugging.
Reviewed-by: Jiri Kosina <jkosina@xxxxxxx>
Signed-off-by: Lee, Chun-Yi <jlee@xxxxxxxx>
---
crypto/asymmetric_keys/rsa.c | 29 ++++++++++++++++++++++++-----
1 files changed, 24 insertions(+), 5 deletions(-)
diff --git a/crypto/asymmetric_keys/rsa.c b/crypto/asymmetric_keys/rsa.c
index c26ae77..0862018 100644
--- a/crypto/asymmetric_keys/rsa.c
+++ b/crypto/asymmetric_keys/rsa.c
@@ -168,6 +168,20 @@ static int RSA_I2OSP(MPI x, size_t xLen, u8 **_X)
}
/*
+ * Octet String to Integer conversion [RFC3447 sec 4.2]
+ */
+static int RSA_OS2IP(u8 *X, size_t XLen, MPI *_x)
+{
+ MPI x;
+
+ x = mpi_alloc((XLen + BYTES_PER_MPI_LIMB - 1) / BYTES_PER_MPI_LIMB);
+ mpi_set_buffer(x, X, XLen, 0);
+
+ *_x = x;
+ return 0;
+}
+
+/*
* EMSA_PKCS1-v1_5-ENCODE [RFC3447 sec 9.2]
* @M: message to be signed, and octet string
* @emLen: intended length in octets of the encoded message
@@ -412,6 +426,9 @@ static struct public_key_signature *RSA_generate_signature(
{
struct public_key_signature *pks;
u8 *EM = NULL;
+ MPI m = NULL;
+ MPI s = NULL;
+ unsigned X_size;
size_t emLen;
int ret;
@@ -431,14 +448,16 @@ static struct public_key_signature *RSA_generate_signature(
if (ret < 0)
goto error_v1_5_encode;
- /* TODO 2): m = OS2IP (EM) */
+ /* 2): m = OS2IP (EM) */
+ ret = RSA_OS2IP(EM, emLen, &m);
+ if (ret < 0)
+ goto error_v1_5_encode;
/* TODO 3): s = RSASP1 (K, m) */
+ s = m;
- /* TODO 4): S = I2OSP (s, k) */
-
- /* TODO: signature S to a u8* S or set to sig->rsa.s? */
- pks->S = EM; /* TODO: temporary set S to EM */
+ /* 4): S = I2OSP (s, k) */
+ _RSA_I2OSP(s, &X_size, &pks->S);
return pks;
--
1.6.4.2
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