scripts/sign-file.c: Add support for signing with a raw signature
authorJuerg Haefliger <juerg.haefliger@hpe.com>
Thu, 4 Feb 2016 11:09:25 +0000 (12:09 +0100)
committerDavid Howells <dhowells@redhat.com>
Thu, 18 Feb 2016 17:20:48 +0000 (17:20 +0000)
This patch adds support for signing a kernel module with a raw
detached PKCS#7 signature/message.

The signature is not converted and is simply appended to the module so
it needs to be in the right format. Using openssl, a valid signature can
be generated like this:
  $ openssl smime -sign -nocerts -noattr -binary -in <module> -inkey \
    <key> -signer <x509> -outform der -out <raw sig>

The resulting raw signature from the above command is (more or less)
identical to the raw signature that sign-file itself can produce like
this:
  $ scripts/sign-file -d <hash algo> <key> <x509> <module>

Signed-off-by: Juerg Haefliger <juerg.haefliger@hpe.com>
Signed-off-by: David Howells <dhowells@redhat.com>
scripts/sign-file.c

index a0b806d2b31df41c4f4c60a1284087080d73b8e8..80b7f7f933d600ef318607f36272d595b294ab6b 100755 (executable)
@@ -2,9 +2,11 @@
  *
  * Copyright © 2014-2015 Red Hat, Inc. All Rights Reserved.
  * Copyright © 2015      Intel Corporation.
+ * Copyright © 2016      Hewlett Packard Enterprise Development LP
  *
  * Authors: David Howells <dhowells@redhat.com>
  *          David Woodhouse <dwmw2@infradead.org>
+ *          Juerg Haefliger <juerg.haefliger@hpe.com>
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public License
@@ -67,6 +69,8 @@ void format(void)
 {
        fprintf(stderr,
                "Usage: scripts/sign-file [-dp] <hash algo> <key> <x509> <module> [<dest>]\n");
+       fprintf(stderr,
+               "       scripts/sign-file -s <raw sig> <hash algo> <x509> <module> [<dest>]\n");
        exit(2);
 }
 
@@ -126,26 +130,84 @@ static int pem_pw_cb(char *buf, int len, int w, void *v)
        return pwlen;
 }
 
+static EVP_PKEY *read_private_key(const char *private_key_name)
+{
+       EVP_PKEY *private_key;
+
+       if (!strncmp(private_key_name, "pkcs11:", 7)) {
+               ENGINE *e;
+
+               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");
+               private_key = ENGINE_load_private_key(e, private_key_name,
+                                                     NULL, NULL);
+               ERR(!private_key, "%s", private_key_name);
+       } else {
+               BIO *b;
+
+               b = BIO_new_file(private_key_name, "rb");
+               ERR(!b, "%s", private_key_name);
+               private_key = PEM_read_bio_PrivateKey(b, NULL, pem_pw_cb,
+                                                     NULL);
+               ERR(!private_key, "%s", private_key_name);
+               BIO_free(b);
+       }
+
+       return private_key;
+}
+
+static X509 *read_x509(const char *x509_name)
+{
+       X509 *x509;
+       BIO *b;
+
+       b = BIO_new_file(x509_name, "rb");
+       ERR(!b, "%s", x509_name);
+       x509 = d2i_X509_bio(b, NULL); /* Binary encoded X.509 */
+       if (!x509) {
+               ERR(BIO_reset(b) != 1, "%s", x509_name);
+               x509 = PEM_read_bio_X509(b, NULL, NULL,
+                                        NULL); /* PEM encoded X.509 */
+               if (x509)
+                       drain_openssl_errors();
+       }
+       BIO_free(b);
+       ERR(!x509, "%s", x509_name);
+
+       return x509;
+}
+
 int main(int argc, char **argv)
 {
        struct module_signature sig_info = { .id_type = PKEY_ID_PKCS7 };
        char *hash_algo = NULL;
-       char *private_key_name, *x509_name, *module_name, *dest_name;
+       char *private_key_name = NULL, *raw_sig_name = NULL;
+       char *x509_name, *module_name, *dest_name;
        bool save_sig = false, replace_orig;
        bool sign_only = false;
+       bool raw_sig = false;
        unsigned char buf[4096];
        unsigned long module_size, sig_size;
        unsigned int use_signed_attrs;
        const EVP_MD *digest_algo;
        EVP_PKEY *private_key;
 #ifndef USE_PKCS7
-       CMS_ContentInfo *cms;
+       CMS_ContentInfo *cms = NULL;
        unsigned int use_keyid = 0;
 #else
-       PKCS7 *pkcs7;
+       PKCS7 *pkcs7 = NULL;
 #endif
        X509 *x509;
-       BIO *b, *bd = NULL, *bm;
+       BIO *bd, *bm;
        int opt, n;
        OpenSSL_add_all_algorithms();
        ERR_load_crypto_strings();
@@ -160,8 +222,9 @@ int main(int argc, char **argv)
 #endif
 
        do {
-               opt = getopt(argc, argv, "dpk");
+               opt = getopt(argc, argv, "sdpk");
                switch (opt) {
+               case 's': raw_sig = true; break;
                case 'p': save_sig = true; break;
                case 'd': sign_only = true; save_sig = true; break;
 #ifndef USE_PKCS7
@@ -177,8 +240,13 @@ int main(int argc, char **argv)
        if (argc < 4 || argc > 5)
                format();
 
-       hash_algo = argv[0];
-       private_key_name = argv[1];
+       if (raw_sig) {
+               raw_sig_name = argv[0];
+               hash_algo = argv[1];
+       } else {
+               hash_algo = argv[0];
+               private_key_name = argv[1];
+       }
        x509_name = argv[2];
        module_name = argv[3];
        if (argc == 5) {
@@ -198,101 +266,74 @@ int main(int argc, char **argv)
        }
 #endif
 
-       /* Read the private key and the X.509 cert the PKCS#7 message
-        * will point to.
-        */
-       if (!strncmp(private_key_name, "pkcs11:", 7)) {
-               ENGINE *e;
-
-               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");
-               private_key = ENGINE_load_private_key(e, private_key_name, NULL,
-                                                     NULL);
-               ERR(!private_key, "%s", private_key_name);
-       } else {
-               b = BIO_new_file(private_key_name, "rb");
-               ERR(!b, "%s", private_key_name);
-               private_key = PEM_read_bio_PrivateKey(b, NULL, pem_pw_cb, NULL);
-               ERR(!private_key, "%s", private_key_name);
-               BIO_free(b);
-       }
-
-       b = BIO_new_file(x509_name, "rb");
-       ERR(!b, "%s", x509_name);
-       x509 = d2i_X509_bio(b, NULL); /* Binary encoded X.509 */
-       if (!x509) {
-               ERR(BIO_reset(b) != 1, "%s", x509_name);
-               x509 = PEM_read_bio_X509(b, NULL, NULL, NULL); /* PEM encoded X.509 */
-               if (x509)
-                       drain_openssl_errors();
-       }
-       BIO_free(b);
-       ERR(!x509, "%s", x509_name);
-
-       /* Open the destination file now so that we can shovel the module data
-        * across as we read it.
-        */
-       if (!sign_only) {
-               bd = BIO_new_file(dest_name, "wb");
-               ERR(!bd, "%s", dest_name);
-       }
-
-       /* Digest the module data. */
-       OpenSSL_add_all_digests();
-       display_openssl_errors(__LINE__);
-       digest_algo = EVP_get_digestbyname(hash_algo);
-       ERR(!digest_algo, "EVP_get_digestbyname");
-
+       /* Open the module file */
        bm = BIO_new_file(module_name, "rb");
        ERR(!bm, "%s", module_name);
 
+       if (!raw_sig) {
+               /* Read the private key and the X.509 cert the PKCS#7 message
+                * will point to.
+                */
+               private_key = read_private_key(private_key_name);
+               x509 = read_x509(x509_name);
+
+               /* Digest the module data. */
+               OpenSSL_add_all_digests();
+               display_openssl_errors(__LINE__);
+               digest_algo = EVP_get_digestbyname(hash_algo);
+               ERR(!digest_algo, "EVP_get_digestbyname");
+
 #ifndef USE_PKCS7
-       /* Load the signature message from the digest buffer. */
-       cms = CMS_sign(NULL, NULL, NULL, NULL,
-                      CMS_NOCERTS | CMS_PARTIAL | CMS_BINARY | CMS_DETACHED | CMS_STREAM);
-       ERR(!cms, "CMS_sign");
-
-       ERR(!CMS_add1_signer(cms, x509, private_key, digest_algo,
-                            CMS_NOCERTS | CMS_BINARY | CMS_NOSMIMECAP |
-                            use_keyid | use_signed_attrs),
-           "CMS_add1_signer");
-       ERR(CMS_final(cms, bm, NULL, CMS_NOCERTS | CMS_BINARY) < 0,
-           "CMS_final");
+               /* Load the signature message from the digest buffer. */
+               cms = CMS_sign(NULL, NULL, NULL, NULL,
+                              CMS_NOCERTS | CMS_PARTIAL | CMS_BINARY |
+                              CMS_DETACHED | CMS_STREAM);
+               ERR(!cms, "CMS_sign");
+
+               ERR(!CMS_add1_signer(cms, x509, private_key, digest_algo,
+                                    CMS_NOCERTS | CMS_BINARY |
+                                    CMS_NOSMIMECAP | use_keyid |
+                                    use_signed_attrs),
+                   "CMS_add1_signer");
+               ERR(CMS_final(cms, bm, NULL, CMS_NOCERTS | CMS_BINARY) < 0,
+                   "CMS_final");
 
 #else
-       pkcs7 = PKCS7_sign(x509, private_key, NULL, bm,
-                          PKCS7_NOCERTS | PKCS7_BINARY |
-                          PKCS7_DETACHED | use_signed_attrs);
-       ERR(!pkcs7, "PKCS7_sign");
+               pkcs7 = PKCS7_sign(x509, private_key, NULL, bm,
+                                  PKCS7_NOCERTS | PKCS7_BINARY |
+                                  PKCS7_DETACHED | use_signed_attrs);
+               ERR(!pkcs7, "PKCS7_sign");
 #endif
 
-       if (save_sig) {
-               char *sig_file_name;
+               if (save_sig) {
+                       char *sig_file_name;
+                       BIO *b;
 
-               ERR(asprintf(&sig_file_name, "%s.p7s", module_name) < 0,
-                   "asprintf");
-               b = BIO_new_file(sig_file_name, "wb");
-               ERR(!b, "%s", sig_file_name);
+                       ERR(asprintf(&sig_file_name, "%s.p7s", module_name) < 0,
+                           "asprintf");
+                       b = BIO_new_file(sig_file_name, "wb");
+                       ERR(!b, "%s", sig_file_name);
 #ifndef USE_PKCS7
-               ERR(i2d_CMS_bio_stream(b, cms, NULL, 0) < 0,
-                   "%s", sig_file_name);
+                       ERR(i2d_CMS_bio_stream(b, cms, NULL, 0) < 0,
+                           "%s", sig_file_name);
 #else
-               ERR(i2d_PKCS7_bio(b, pkcs7) < 0,
-                       "%s", sig_file_name);
+                       ERR(i2d_PKCS7_bio(b, pkcs7) < 0,
+                           "%s", sig_file_name);
 #endif
-               BIO_free(b);
+                       BIO_free(b);
+               }
+
+               if (sign_only) {
+                       BIO_free(bm);
+                       return 0;
+               }
        }
 
-       if (sign_only)
-               return 0;
+       /* Open the destination file now so that we can shovel the module data
+        * across as we read it.
+        */
+       bd = BIO_new_file(dest_name, "wb");
+       ERR(!bd, "%s", dest_name);
 
        /* Append the marker and the PKCS#7 message to the destination file */
        ERR(BIO_reset(bm) < 0, "%s", module_name);
@@ -300,14 +341,29 @@ int main(int argc, char **argv)
               n > 0) {
                ERR(BIO_write(bd, buf, n) < 0, "%s", dest_name);
        }
+       BIO_free(bm);
        ERR(n < 0, "%s", module_name);
        module_size = BIO_number_written(bd);
 
+       if (!raw_sig) {
 #ifndef USE_PKCS7
-       ERR(i2d_CMS_bio_stream(bd, cms, NULL, 0) < 0, "%s", dest_name);
+               ERR(i2d_CMS_bio_stream(bd, cms, NULL, 0) < 0, "%s", dest_name);
 #else
-       ERR(i2d_PKCS7_bio(bd, pkcs7) < 0, "%s", dest_name);
+               ERR(i2d_PKCS7_bio(bd, pkcs7) < 0, "%s", dest_name);
 #endif
+       } else {
+               BIO *b;
+
+               /* Read the raw signature file and write the data to the
+                * destination file
+                */
+               b = BIO_new_file(raw_sig_name, "rb");
+               ERR(!b, "%s", raw_sig_name);
+               while ((n = BIO_read(b, buf, sizeof(buf))), n > 0)
+                       ERR(BIO_write(bd, buf, n) < 0, "%s", dest_name);
+               BIO_free(b);
+       }
+
        sig_size = BIO_number_written(bd) - module_size;
        sig_info.sig_len = htonl(sig_size);
        ERR(BIO_write(bd, &sig_info, sizeof(sig_info)) < 0, "%s", dest_name);