From ed8c20762a314124cbdd62e9d3e8aa7aa2a16020 Mon Sep 17 00:00:00 2001 From: David Howells Date: Mon, 20 Jul 2015 21:16:33 +0100 Subject: [PATCH] sign-file: Generate CMS message as signature instead of PKCS#7 Make sign-file use the OpenSSL CMS routines to generate a message to be used as the signature blob instead of the PKCS#7 routines. This allows us to change how the matching X.509 certificate is selected. With PKCS#7 the only option is to match on the serial number and issuer fields of an X.509 certificate; with CMS, we also have the option of matching by subjectKeyId extension. The new behaviour is selected with the "-k" flag. Without the -k flag specified, the output is pretty much identical to the PKCS#7 output. Whilst we're at it, don't include the S/MIME capability list in the message as it's irrelevant to us. Signed-off-by: David Howells Reviewed-By: David Woodhouse #include #include -#include +#include #include #include @@ -107,13 +107,14 @@ 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; - bool save_pkcs7 = false, replace_orig; + bool save_cms = false, replace_orig; bool sign_only = false; unsigned char buf[4096]; - unsigned long module_size, pkcs7_size; + unsigned long module_size, cms_size; + unsigned int use_keyid = 0; const EVP_MD *digest_algo; EVP_PKEY *private_key; - PKCS7 *pkcs7; + CMS_ContentInfo *cms; X509 *x509; BIO *b, *bd = NULL, *bm; int opt, n; @@ -125,10 +126,11 @@ int main(int argc, char **argv) key_pass = getenv("KBUILD_SIGN_PIN"); do { - opt = getopt(argc, argv, "dp"); + opt = getopt(argc, argv, "dpk"); switch (opt) { - case 'p': save_pkcs7 = true; break; - case 'd': sign_only = true; save_pkcs7 = true; break; + case 'p': save_cms = true; break; + case 'd': sign_only = true; save_cms = true; break; + case 'k': use_keyid = CMS_USE_KEYID; break; case -1: break; default: format(); } @@ -208,23 +210,24 @@ int main(int argc, char **argv) bm = BIO_new_file(module_name, "rb"); ERR(!bm, "%s", module_name); - /* Load the PKCS#7 message from the digest buffer. */ - pkcs7 = PKCS7_sign(NULL, NULL, NULL, NULL, - PKCS7_NOCERTS | PKCS7_PARTIAL | PKCS7_BINARY | PKCS7_DETACHED | PKCS7_STREAM); - ERR(!pkcs7, "PKCS7_sign"); + /* Load the CMS 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(!PKCS7_sign_add_signer(pkcs7, x509, private_key, digest_algo, PKCS7_NOCERTS | PKCS7_BINARY), - "PKCS7_sign_add_signer"); - ERR(PKCS7_final(pkcs7, bm, PKCS7_NOCERTS | PKCS7_BINARY) < 0, - "PKCS7_final"); + ERR(!CMS_add1_signer(cms, x509, private_key, digest_algo, + CMS_NOCERTS | CMS_BINARY | CMS_NOSMIMECAP | use_keyid), + "CMS_sign_add_signer"); + ERR(CMS_final(cms, bm, NULL, CMS_NOCERTS | CMS_BINARY) < 0, + "CMS_final"); - if (save_pkcs7) { - char *pkcs7_name; + if (save_cms) { + char *cms_name; - ERR(asprintf(&pkcs7_name, "%s.pkcs7", module_name) < 0, "asprintf"); - b = BIO_new_file(pkcs7_name, "wb"); - ERR(!b, "%s", pkcs7_name); - ERR(i2d_PKCS7_bio_stream(b, pkcs7, NULL, 0) < 0, "%s", pkcs7_name); + ERR(asprintf(&cms_name, "%s.p7s", module_name) < 0, "asprintf"); + b = BIO_new_file(cms_name, "wb"); + ERR(!b, "%s", cms_name); + ERR(i2d_CMS_bio_stream(b, cms, NULL, 0) < 0, "%s", cms_name); BIO_free(b); } @@ -240,9 +243,9 @@ int main(int argc, char **argv) ERR(n < 0, "%s", module_name); module_size = BIO_number_written(bd); - ERR(i2d_PKCS7_bio_stream(bd, pkcs7, NULL, 0) < 0, "%s", dest_name); - pkcs7_size = BIO_number_written(bd) - module_size; - sig_info.sig_len = htonl(pkcs7_size); + ERR(i2d_CMS_bio_stream(bd, cms, NULL, 0) < 0, "%s", dest_name); + cms_size = BIO_number_written(bd) - module_size; + sig_info.sig_len = htonl(cms_size); ERR(BIO_write(bd, &sig_info, sizeof(sig_info)) < 0, "%s", dest_name); ERR(BIO_write(bd, magic_number, sizeof(magic_number) - 1) < 0, "%s", dest_name); -- 2.20.1