The PKCS#7 code in sign-file allows for signing only with SHA-1. Since
SHA-1 support for module signing has been removed, drop PKCS#7 support in
favor of using only CMS.
The use of the PKCS#7 code is selected by the following:
#if defined(LIBRESSL_VERSION_NUMBER) || \
OPENSSL_VERSION_NUMBER < 0x10000000L || \
defined(OPENSSL_NO_CMS)
#define USE_PKCS7
#endif
Looking at the individual ifdefs:
* LIBRESSL_VERSION_NUMBER: LibreSSL added the CMS implementation from
OpenSSL in 3.1.0, making the ifdef no longer relevant. This version was
released on April 8, 2020.
* OPENSSL_VERSION_NUMBER < 0x10000000L: OpenSSL 1.0.0 was released on March
29, 2010. Supporting earlier versions should no longer be necessary. The
file Documentation/process/changes.rst already states that at least
version 1.0.0 is required to build the kernel.
* OPENSSL_NO_CMS: OpenSSL can be configured with "no-cms" to disable the
CMS support. In this case, sign-file will no longer be usable. The CMS
support is now required.
In practice, since distributions now typically sign modules with SHA-2, for
which sign-file already required CMS support, removing PKCS#7 shouldn't
cause any issues.
Signed-off-by: Petr Pavlu <[email protected]>
---
scripts/sign-file.c | 66 +++------------------------------------------
1 file changed, 3 insertions(+), 63 deletions(-)
diff --git a/scripts/sign-file.c b/scripts/sign-file.c
index 7070245edfc1..16f2bf2e1e3c 100644
--- a/scripts/sign-file.c
+++ b/scripts/sign-file.c
@@ -24,6 +24,7 @@
#include <arpa/inet.h>
#include <openssl/opensslv.h>
#include <openssl/bio.h>
+#include <openssl/cms.h>
#include <openssl/evp.h>
#include <openssl/pem.h>
#include <openssl/err.h>
@@ -39,29 +40,6 @@
#endif
#include "ssl-common.h"
-/*
- * 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 defined(LIBRESSL_VERSION_NUMBER) || \
- OPENSSL_VERSION_NUMBER < 0x10000000L || \
- defined(OPENSSL_NO_CMS)
-#define USE_PKCS7
-#endif
-#ifndef USE_PKCS7
-#include <openssl/cms.h>
-#else
-#include <openssl/pkcs7.h>
-#endif
-
struct module_signature {
uint8_t algo; /* Public-key crypto algorithm [0] */
uint8_t hash; /* Digest algorithm [0] */
@@ -228,15 +206,10 @@ int main(int argc, char **argv)
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 = NULL;
unsigned int use_keyid = 0;
-#else
- PKCS7 *pkcs7 = NULL;
-#endif
X509 *x509;
BIO *bd, *bm;
int opt, n;
@@ -246,21 +219,13 @@ int main(int argc, char **argv)
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, "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
case 'k': use_keyid = CMS_USE_KEYID; break;
-#endif
case -1: break;
default: format();
}
@@ -289,14 +254,6 @@ 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
-
/* Open the module file */
bm = BIO_new_file(module_name, "rb");
ERR(!bm, "%s", module_name);
@@ -314,7 +271,6 @@ int main(int argc, char **argv)
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 |
@@ -323,19 +279,12 @@ 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_NOSMIMECAP | CMS_NOATTR |
+ use_keyid),
"CMS_add1_signer");
ERR(CMS_final(cms, bm, NULL, CMS_NOCERTS | CMS_BINARY) != 1,
"CMS_final");
-#else
- 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;
BIO *b;
@@ -344,13 +293,8 @@ int main(int argc, char **argv)
"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) != 1,
"%s", sig_file_name);
-#else
- ERR(i2d_PKCS7_bio(b, pkcs7) != 1,
- "%s", sig_file_name);
-#endif
BIO_free(b);
}
@@ -377,11 +321,7 @@ int main(int argc, char **argv)
module_size = BIO_number_written(bd);
if (!raw_sig) {
-#ifndef USE_PKCS7
ERR(i2d_CMS_bio_stream(bd, cms, NULL, 0) != 1, "%s", dest_name);
-#else
- ERR(i2d_PKCS7_bio(bd, pkcs7) != 1, "%s", dest_name);
-#endif
} else {
BIO *b;
--
2.51.1
