crypto: ecdh - make ecdh_shared_secret unique

There is another ecdh_shared_secret in net/bluetooth/ecc.c

Fixes: 3c4b2390 ("crypto: ecdh - Add ECDH software support")
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

CVE-2018-5383

(cherry picked from commit 8f44df15)
Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Connor Kuehl <connor.kuehl@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

crypto/ecc.c

@@ -966,7 +966,7 @@ int ecdh_make_pub_key(unsigned int curve_id, unsigned int ndigits,
 	return ret;
 }
 
-int ecdh_shared_secret(unsigned int curve_id, unsigned int ndigits,
+int crypto_ecdh_shared_secret(unsigned int curve_id, unsigned int ndigits,
 		       const u8 *private_key, unsigned int private_key_len,
 		       const u8 *public_key, unsigned int public_key_len,
 		       u8 *secret, unsigned int secret_len)

crypto/ecc.h

@@ -60,7 +60,7 @@ int ecdh_make_pub_key(const unsigned int curve_id, unsigned int ndigits,
 		      u8 *public_key, unsigned int public_key_len);
 
 /**
- * ecdh_shared_secret() - Compute a shared secret
+ * crypto_ecdh_shared_secret() - Compute a shared secret
  *
  * @curve_id:		id representing the curve to use
  * @private_key:	private key of part A
@@ -70,13 +70,13 @@ int ecdh_make_pub_key(const unsigned int curve_id, unsigned int ndigits,
  * @secret:		buffer for storing the calculated shared secret
  * @secret_len:		length of the secret buffer
  *
- * Note: It is recommended that you hash the result of ecdh_shared_secret
+ * Note: It is recommended that you hash the result of crypto_ecdh_shared_secret
  * before using it for symmetric encryption or HMAC.
  *
  * Returns 0 if the shared secret was generated successfully, a negative value
  * if an error occurred.
  */
-int ecdh_shared_secret(unsigned int curve_id, unsigned int ndigits,
+int crypto_ecdh_shared_secret(unsigned int curve_id, unsigned int ndigits,
 		       const u8 *private_key, unsigned int private_key_len,
 		       const u8 *public_key, unsigned int public_key_len,
 		       u8 *secret, unsigned int secret_len);

crypto/ecdh.c

@@ -79,7 +79,7 @@ static int ecdh_compute_value(struct kpp_request *req)
 		if (copied != 2 * nbytes)
 			return -EINVAL;
 
-		ret = ecdh_shared_secret(ctx->curve_id, ctx->ndigits,
+		ret = crypto_ecdh_shared_secret(ctx->curve_id, ctx->ndigits,
 					 (const u8 *)ctx->private_key, nbytes,
 					 (const u8 *)ctx->public_key, 2 * nbytes,
 					 (u8 *)ctx->shared_secret, nbytes);