modsign: Extract signing cert from CONFIG_MODULE_SIG_KEY if needed
Where an external PEM file or PKCS#11 URI is given, we can get the cert
from it for ourselves instead of making the user drop signing_key.x509
in place for us.
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: David Howells <dhowells@redhat.com>
diff --git a/scripts/extract-cert.c b/scripts/extract-cert.c
new file mode 100644
index 0000000..4fd5b2f
--- /dev/null
+++ b/scripts/extract-cert.c
@@ -0,0 +1,132 @@
+/* Extract X.509 certificate in DER form from PKCS#11 or PEM.
+ *
+ * Copyright © 2014 Red Hat, Inc. All Rights Reserved.
+ * Copyright © 2015 Intel Corporation.
+ *
+ * Authors: David Howells <dhowells@redhat.com>
+ * David Woodhouse <dwmw2@infradead.org>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <string.h>
+#include <getopt.h>
+#include <err.h>
+#include <arpa/inet.h>
+#include <openssl/bio.h>
+#include <openssl/evp.h>
+#include <openssl/pem.h>
+#include <openssl/pkcs7.h>
+#include <openssl/err.h>
+#include <openssl/engine.h>
+
+#define PKEY_ID_PKCS7 2
+
+static __attribute__((noreturn))
+void format(void)
+{
+ fprintf(stderr,
+ "Usage: scripts/extract-cert <source> <dest>\n");
+ exit(2);
+}
+
+static void display_openssl_errors(int l)
+{
+ const char *file;
+ char buf[120];
+ int e, line;
+
+ if (ERR_peek_error() == 0)
+ return;
+ fprintf(stderr, "At main.c:%d:\n", l);
+
+ while ((e = ERR_get_error_line(&file, &line))) {
+ ERR_error_string(e, buf);
+ fprintf(stderr, "- SSL %s: %s:%d\n", buf, file, line);
+ }
+}
+
+static void drain_openssl_errors(void)
+{
+ const char *file;
+ int line;
+
+ if (ERR_peek_error() == 0)
+ return;
+ while (ERR_get_error_line(&file, &line)) {}
+}
+
+#define ERR(cond, fmt, ...) \
+ do { \
+ bool __cond = (cond); \
+ display_openssl_errors(__LINE__); \
+ if (__cond) { \
+ err(1, fmt, ## __VA_ARGS__); \
+ } \
+ } while(0)
+
+static const char *key_pass;
+
+int main(int argc, char **argv)
+{
+ char *cert_src, *cert_dst;
+ X509 *x509;
+ BIO *b;
+
+ OpenSSL_add_all_algorithms();
+ ERR_load_crypto_strings();
+ ERR_clear_error();
+
+ key_pass = getenv("KBUILD_SIGN_PIN");
+
+ if (argc != 3)
+ format();
+
+ cert_src = argv[1];
+ cert_dst = argv[2];
+
+ if (!strncmp(cert_src, "pkcs11:", 7)) {
+ ENGINE *e;
+ struct {
+ const char *cert_id;
+ X509 *cert;
+ } parms;
+
+ parms.cert_id = cert_src;
+ parms.cert = NULL;
+
+ ENGINE_load_builtin_engines();
+ drain_openssl_errors();
+ e = ENGINE_by_id("pkcs11");
+ ERR(!e, "Load PKCS#11 ENGINE");
+ if (ENGINE_init(e))
+ drain_openssl_errors();
+ else
+ ERR(1, "ENGINE_init");
+ if (key_pass)
+ ERR(!ENGINE_ctrl_cmd_string(e, "PIN", key_pass, 0), "Set PKCS#11 PIN");
+ ENGINE_ctrl_cmd(e, "LOAD_CERT_CTRL", 0, &parms, NULL, 1);
+ ERR(!parms.cert, "Get X.509 from PKCS#11");
+ x509 = parms.cert;
+ } else {
+ b = BIO_new_file(cert_src, "rb");
+ ERR(!b, "%s", cert_src);
+ x509 = PEM_read_bio_X509(b, NULL, NULL, NULL);
+ ERR(!x509, "%s", cert_src);
+ BIO_free(b);
+ }
+
+ b = BIO_new_file(cert_dst, "wb");
+ ERR(!b, "%s", cert_dst);
+ ERR(!i2d_X509_bio(b, x509), cert_dst);
+ BIO_free(b);
+
+ return 0;
+}