[PATCH] crypto/virtio: fix DER encoding for positive RSA param

[Gowrishankar Muthukrishnan]

As per RFC 8017, RSA parameter needs to be positive integer.
This patch fixes TLV encoding function appropriately.

Fixes: 6fe6a7f7bcf ("crypto/virtio: add asymmetric RSA support")

Signed-off-by: Gowrishankar Muthukrishnan <gmuthukri...@marvell.com>
---
 drivers/crypto/virtio/virtio_cryptodev.c | 30 ++++++++++++++++--------
 1 file changed, 20 insertions(+), 10 deletions(-)

diff --git a/drivers/crypto/virtio/virtio_cryptodev.c 
b/drivers/crypto/virtio/virtio_cryptodev.c
index b01e97c988..4440e02dc9 100644
--- a/drivers/crypto/virtio/virtio_cryptodev.c
+++ b/drivers/crypto/virtio/virtio_cryptodev.c
@@ -1459,27 +1459,37 @@ tlv_encode(uint8_t *tlv, uint8_t type, uint8_t *data, 
size_t len)
 {
        uint8_t *lenval = tlv;
        size_t lenval_n = 0;
+       size_t dlen = len;
+       uint8_t off = 0;
+
+       if (data != NULL && data[0] & 0x80) {
+               dlen += 1;
+               off = 1;
+       }
 
        if (len > 65535) {
                goto _exit;
        } else if (len > 255) {
-               lenval_n = 4 + len;
+               lenval_n = 4 + dlen;
                lenval[0] = type;
                lenval[1] = 0x82;
-               lenval[2] = (len & 0xFF00) >> 8;
-               lenval[3] = (len & 0xFF);
-               rte_memcpy(&lenval[4], data, len);
+               lenval[2] = (dlen & 0xFF00) >> 8;
+               lenval[3] = (dlen & 0xFF);
+               lenval += (4 + off);
+               rte_memcpy(lenval, data, len);
        } else if (len > 127) {
-               lenval_n = 3 + len;
+               lenval_n = 3 + dlen;
                lenval[0] = type;
                lenval[1] = 0x81;
-               lenval[2] = len;
-               rte_memcpy(&lenval[3], data, len);
+               lenval[2] = dlen;
+               lenval += (3 + off);
+               rte_memcpy(lenval, data, len);
        } else {
-               lenval_n = 2 + len;
+               lenval_n = 2 + dlen;
                lenval[0] = type;
-               lenval[1] = len;
-               rte_memcpy(&lenval[2], data, len);
+               lenval[1] = dlen;
+               lenval += (2 + off);
+               rte_memcpy(lenval, data, len);
        }
 
 _exit:
-- 
2.25.1