selftests/sgx: Use a statically generated 3072-bit RSA key

Use a statically generated key for signing the enclave, because
generating keys on the fly can eat the kernel entropy pool. Another
good reason for doing this is predictable builds. The RSA has been
arbitrarily selected. It's contents do not matter.

This also makes the selftest execute a lot quicker instead of the delay
that it had before (because of slow key generation).

 [ bp: Disambiguate "static key" which means something else in the
   kernel, fix typos. ]

Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: linux-kselftest@vger.kernel.org
Link: https://lkml.kernel.org/r/20201118170640.39629-1-jarkko@kernel.org

tools/testing/selftests/sgx/Makefile

@@ -25,7 +25,8 @@ endif
 $(OUTPUT)/test_sgx: $(OUTPUT)/main.o \
 		    $(OUTPUT)/load.o \
 		    $(OUTPUT)/sigstruct.o \
-		    $(OUTPUT)/call.o
+		    $(OUTPUT)/call.o \
+		    $(OUTPUT)/sign_key.o
 	$(CC) $(HOST_CFLAGS) -o $@ $^ -lcrypto
 
 $(OUTPUT)/main.o: main.c
@@ -40,6 +41,9 @@ $(OUTPUT)/sigstruct.o: sigstruct.c
 $(OUTPUT)/call.o: call.S
 	$(CC) $(HOST_CFLAGS) -c $< -o $@
 
+$(OUTPUT)/sign_key.o: sign_key.S
+	$(CC) $(HOST_CFLAGS) -c $< -o $@
+
 $(OUTPUT)/test_encl.elf: test_encl.lds test_encl.c test_encl_bootstrap.S
 	$(CC) $(ENCL_CFLAGS) -T $^ -o $@
 

tools/testing/selftests/sgx/main.h

@@ -27,6 +27,9 @@ struct encl {
 	struct sgx_sigstruct sigstruct;
 };
 
+extern unsigned char sign_key[];
+extern unsigned char sign_key_end[];
+
 void encl_delete(struct encl *ctx);
 bool encl_load(const char *path, struct encl *encl);
 bool encl_measure(struct encl *encl);

tools/testing/selftests/sgx/sign_key.S

@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/**
+* Copyright(c) 2016-20 Intel Corporation.
+*/
+
+    .section ".rodata", "a"
+
+sign_key:
+    .globl sign_key
+    .incbin "sign_key.pem"
+sign_key_end:
+    .globl sign_key_end

tools/testing/selftests/sgx/sign_key.pem

@@ -0,0 +1,39 @@
+-----BEGIN RSA PRIVATE KEY-----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+-----END RSA PRIVATE KEY-----

tools/testing/selftests/sgx/sigstruct.c

@@ -135,33 +135,21 @@ static inline const BIGNUM *get_modulus(RSA *key)
 
 static RSA *gen_sign_key(void)
 {
-	BIGNUM *e;
+	unsigned long sign_key_length;
+	BIO *bio;
 	RSA *key;
-	int ret;
 
-	e = BN_new();
-	key = RSA_new();
+	sign_key_length = (unsigned long)&sign_key_end -
+			  (unsigned long)&sign_key;
 
-	if (!e || !key)
-		goto err;
+	bio = BIO_new_mem_buf(&sign_key, sign_key_length);
+	if (!bio)
+		return NULL;
 
-	ret = BN_set_word(e, RSA_3);
-	if (ret != 1)
-		goto err;
-
-	ret = RSA_generate_key_ex(key, 3072, e, NULL);
-	if (ret != 1)
-		goto err;
-
-	BN_free(e);
+	key = PEM_read_bio_RSAPrivateKey(bio, NULL, NULL, NULL);
+	BIO_free(bio);
 
 	return key;
-
-err:
-	RSA_free(key);
-	BN_free(e);
-
-	return NULL;
 }
 
 static void reverse_bytes(void *data, int length)
@@ -339,8 +327,10 @@ bool encl_measure(struct encl *encl)
 		goto err;
 
 	key = gen_sign_key();
-	if (!key)
+	if (!key) {
+		ERR_print_errors_fp(stdout);
 		goto err;
+	}
 
 	BN_bn2bin(get_modulus(key), sigstruct->modulus);