From 283e8ba2dfde54f8f27d7d0f459a07de79a39d55 Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 25 Sep 2015 16:31:46 +0100 Subject: [PATCH] MODSIGN: Change from CMS to PKCS#7 signing if the openssl is too old The sign-file.c program actually uses CMS rather than PKCS#7 to sign a file since that allows the target X.509 certificate to be specified by subjectKeyId rather than by issuer + serialNumber. However, older versions of the OpenSSL crypto library (such as may be found in CentOS 5.11) don't support CMS. Assume everything prior to OpenSSL-1.0.0 doesn't support CMS and switch to using PKCS#7 in that case. Further, the pre-1.0.0 OpenSSL only supports PKCS#7 signing with SHA1, so give an error from the sign-file script if the caller requests anything other than SHA1. The compiler gives the following error with an OpenSSL crypto library that's too old: HOSTCC scripts/sign-file scripts/sign-file.c:23:25: fatal error: openssl/cms.h: No such file or directory #include Reported-by: Vinson Lee Signed-off-by: David Howells Acked-by: David Woodhouse --- Documentation/Changes | 2 +- scripts/sign-file.c | 94 +++++++++++++++++++++++++++++++++++-------- 2 files changed, 78 insertions(+), 18 deletions(-) diff --git a/Documentation/Changes b/Documentation/Changes index 6d8863004858..f447f0516f07 100644 --- a/Documentation/Changes +++ b/Documentation/Changes @@ -43,7 +43,7 @@ o udev 081 # udevd --version o grub 0.93 # grub --version || grub-install --version o mcelog 0.6 # mcelog --version o iptables 1.4.2 # iptables -V -o openssl & libcrypto 1.0.1k # openssl version +o openssl & libcrypto 1.0.0 # openssl version Kernel compilation diff --git a/scripts/sign-file.c b/scripts/sign-file.c index c3899ca4811c..250a7a645033 100755 --- a/scripts/sign-file.c +++ b/scripts/sign-file.c @@ -20,13 +20,34 @@ #include #include #include +#include #include #include #include -#include #include #include +/* + * Use CMS if we have openssl-1.0.0 or newer available - otherwise we have to + * assume that it's not available and its header file is missing and that we + * should use PKCS#7 instead. Switching to the older PKCS#7 format restricts + * the options we have on specifying the X.509 certificate we want. + * + * Further, older versions of OpenSSL don't support manually adding signers to + * the PKCS#7 message so have to accept that we get a certificate included in + * the signature message. Nor do such older versions of OpenSSL support + * signing with anything other than SHA1 - so we're stuck with that if such is + * the case. + */ +#if OPENSSL_VERSION_NUMBER < 0x10000000L +#define USE_PKCS7 +#endif +#ifndef USE_PKCS7 +#include +#else +#include +#endif + struct module_signature { uint8_t algo; /* Public-key crypto algorithm [0] */ uint8_t hash; /* Digest algorithm [0] */ @@ -110,30 +131,42 @@ 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_cms = false, replace_orig; + bool save_sig = false, replace_orig; bool sign_only = false; unsigned char buf[4096]; - unsigned long module_size, cms_size; - unsigned int use_keyid = 0, use_signed_attrs = CMS_NOATTR; + 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; + unsigned int use_keyid = 0; +#else + PKCS7 *pkcs7; +#endif X509 *x509; BIO *b, *bd = NULL, *bm; int opt, n; - OpenSSL_add_all_algorithms(); ERR_load_crypto_strings(); ERR_clear_error(); key_pass = getenv("KBUILD_SIGN_PIN"); +#ifndef USE_PKCS7 + use_signed_attrs = CMS_NOATTR; +#else + use_signed_attrs = PKCS7_NOATTR; +#endif + do { opt = getopt(argc, argv, "dpk"); switch (opt) { - case 'p': save_cms = true; break; - case 'd': sign_only = true; save_cms = true; break; + case 'p': save_sig = true; break; + case 'd': sign_only = true; save_sig = true; break; +#ifndef USE_PKCS7 case 'k': use_keyid = CMS_USE_KEYID; break; +#endif case -1: break; default: format(); } @@ -157,6 +190,14 @@ int main(int argc, char **argv) replace_orig = true; } +#ifdef USE_PKCS7 + if (strcmp(hash_algo, "sha1") != 0) { + fprintf(stderr, "sign-file: %s only supports SHA1 signing\n", + OPENSSL_VERSION_TEXT); + exit(3); + } +#endif + /* Read the private key and the X.509 cert the PKCS#7 message * will point to. */ @@ -213,7 +254,8 @@ int main(int argc, char **argv) bm = BIO_new_file(module_name, "rb"); ERR(!bm, "%s", module_name); - /* Load the CMS message from the digest buffer. */ +#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"); @@ -221,17 +263,31 @@ int main(int argc, char **argv) ERR(!CMS_add1_signer(cms, x509, private_key, digest_algo, CMS_NOCERTS | CMS_BINARY | CMS_NOSMIMECAP | use_keyid | use_signed_attrs), - "CMS_sign_add_signer"); + "CMS_add1_signer"); ERR(CMS_final(cms, bm, NULL, CMS_NOCERTS | CMS_BINARY) < 0, "CMS_final"); - if (save_cms) { - char *cms_name; +#else + pkcs7 = PKCS7_sign(x509, private_key, NULL, bm, + PKCS7_NOCERTS | PKCS7_BINARY | + PKCS7_DETACHED | use_signed_attrs); + ERR(!pkcs7, "PKCS7_sign"); +#endif - 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); + if (save_sig) { + char *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); +#else + ERR(i2d_PKCS7_bio(b, pkcs7) < 0, + "%s", sig_file_name); +#endif BIO_free(b); } @@ -247,9 +303,13 @@ int main(int argc, char **argv) ERR(n < 0, "%s", module_name); module_size = BIO_number_written(bd); +#ifndef USE_PKCS7 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); +#else + ERR(i2d_PKCS7_bio(bd, pkcs7) < 0, "%s", dest_name); +#endif + 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); ERR(BIO_write(bd, magic_number, sizeof(magic_number) - 1) < 0, "%s", dest_name); -- 2.30.2