HPRE can only deal with src_data smaller than 'p' in 'CURVE25519'
algorithm, but 'rfc7748' says:
'Implementations MUST accept non-canonical values and process them as
if they had been reduced modulo the field prime'
So we get its modulus to p, and then deal it with HPRE.
Signed-off-by: Meng Yu <yumeng18@xxxxxxxxxx>
---
drivers/crypto/hisilicon/hpre/hpre_crypto.c | 22 ++++++++++++++++++----
1 file changed, 18 insertions(+), 4 deletions(-)
diff --git a/drivers/crypto/hisilicon/hpre/hpre_crypto.c b/drivers/crypto/hisilicon/hpre/hpre_crypto.c
index d743c54..f363653 100644
--- a/drivers/crypto/hisilicon/hpre/hpre_crypto.c
+++ b/drivers/crypto/hisilicon/hpre/hpre_crypto.c
@@ -1729,6 +1729,17 @@ static int hpre_curve25519_msg_request_set(struct hpre_ctx *ctx,
return 0;
}
+static void hpre_curve25519_src_modulo_p(u8 *ptr)
+{
+ int i;
+
+ for (i = 0; i < CURVE25519_KEY_SIZE - 1; i++)
+ ptr[i] = 0;
+
+ /* The modulus is ptr's last byte minus '0xed'(last byte of p) */
+ ptr[i] -= 0xed;
+}
+
static int hpre_curve25519_src_init(struct hpre_asym_request *hpre_req,
struct scatterlist *data, unsigned int len)
{
@@ -1767,10 +1778,13 @@ static int hpre_curve25519_src_init(struct hpre_asym_request *hpre_req,
curve = ecc_get_curve25519();
fill_curve_param(p, curve->p, CURVE25519_KEY_SIZE, curve->g.ndigits);
- if (memcmp(ptr, p, ctx->key_sz) >= 0) {
- dev_err(dev, "gx is out of p!\n");
- goto err;
- }
+
+ /*
+ * When src_data equals (2^255 - 19) ~ (2^255 - 1), it is out of p,
+ * we get its modulus to p, and then use it.
+ */
+ if (memcmp(ptr, p, ctx->key_sz) >= 0)
+ hpre_curve25519_src_modulo_p(ptr);
hpre_req->src = ptr;
msg->in = cpu_to_le64(dma);
--
2.8.1
