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[PATCH] sign-file: Add -D "digest mode"

Fam Zheng posted 1 patch 1 month, 3 weeks ago
There is a newer version of this series
scripts/sign-file.c | 41 ++++++++++++++++++++++++++++++++++++-----
1 file changed, 36 insertions(+), 5 deletions(-)
[PATCH] sign-file: Add -D "digest mode"
Posted by Fam Zheng 1 month, 3 weeks ago 
This allows the command to sign by a binary digest file, instead of the
original ko file.

Combined with the -p (save_sig), we can now split module building (e.g.
dkms) and module signing into different steps and environments, while
_not_ requiring copying the whole module file back and forth.

Example usage:

1. On host side:
    mod=ip6_gre.ko
    openssl dgst -binary -sha256 $mod > $mod.digest

2. Send $mod.digest over to a signing service

3. On the server side, sign the digest using new mode:

    ./sign-file -dpD sha256 private_key.pem cert.pem $mod.digest

4. Server returns the signature (it will be named $mod.digest.p7s) in
binary

5. Client uses the returned signature to sign the ko locally:

    ./sign-file -s signature sha256 cert.pem $mod

Signed-off-by: Fam Zheng <fam.zheng@bytedance.com>
---
 scripts/sign-file.c | 41 ++++++++++++++++++++++++++++++++++++-----
 1 file changed, 36 insertions(+), 5 deletions(-)

diff --git a/scripts/sign-file.c b/scripts/sign-file.c
index 7070245edfc1..29e1aa798f54 100644
--- a/scripts/sign-file.c
+++ b/scripts/sign-file.c
@@ -56,6 +56,9 @@
 	defined(OPENSSL_NO_CMS)
 #define USE_PKCS7
 #endif
+#if OPENSSL_VERSION_NUMBER > 0x30200000L
+#define HAS_CMS_final_digest 1
+#endif
 #ifndef USE_PKCS7
 #include <openssl/cms.h>
 #else
@@ -80,9 +83,9 @@ static __attribute__((noreturn))
 void format(void)
 {
 	fprintf(stderr,
-		"Usage: scripts/sign-file [-dp] <hash algo> <key> <x509> <module> [<dest>]\n");
+		"Usage: scripts/sign-file [-dpD] <hash algo> <key> <x509> <file> [<dest>]\n");
 	fprintf(stderr,
-		"       scripts/sign-file -s <raw sig> <hash algo> <x509> <module> [<dest>]\n");
+		"       scripts/sign-file -s <raw sig> <hash algo> <x509> <file> [<dest>]\n");
 	exit(2);
 }
 
@@ -229,6 +232,9 @@ int main(int argc, char **argv)
 	unsigned char buf[4096];
 	unsigned long module_size, sig_size;
 	unsigned int use_signed_attrs;
+	bool digest_mode = false;
+	unsigned char digest_bin[4096];
+	long digest_len;
 	const EVP_MD *digest_algo;
 	EVP_PKEY *private_key;
 #ifndef USE_PKCS7
@@ -253,11 +259,20 @@ int main(int argc, char **argv)
 #endif
 
 	do {
-		opt = getopt(argc, argv, "sdpk");
+		opt = getopt(argc, argv, "sdpkD");
 		switch (opt) {
 		case 's': raw_sig = true; break;
 		case 'p': save_sig = true; break;
 		case 'd': sign_only = true; save_sig = true; break;
+		case 'D':
+#ifdef HAS_CMS_final_digest
+			digest_mode = true;
+			break;
+#else
+			fprintf(stderr, "digest signing is not supported by the openssl version in use\n");
+			exit(3);
+			break;
+#endif
 #ifndef USE_PKCS7
 		case 'k': use_keyid = CMS_USE_KEYID; break;
 #endif
@@ -301,6 +316,17 @@ int main(int argc, char **argv)
 	bm = BIO_new_file(module_name, "rb");
 	ERR(!bm, "%s", module_name);
 
+#ifdef HAS_CMS_final_digest
+	if (digest_mode) {
+		digest_len = BIO_read(bm, digest_bin, sizeof(digest_bin));
+		if (digest_len >= sizeof(digest_bin)) {
+			fprintf(stderr, "sign-file: Digest file too large (max %ld)\n", sizeof(digest_bin));
+			exit(3);
+		}
+		ERR(BIO_reset(bm) < 0, "%s", module_name);
+	}
+#endif
+
 	if (!raw_sig) {
 		/* Read the private key and the X.509 cert the PKCS#7 message
 		 * will point to.
@@ -324,10 +350,15 @@ int main(int argc, char **argv)
 		ERR(!CMS_add1_signer(cms, x509, private_key, digest_algo,
 				     CMS_NOCERTS | CMS_BINARY |
 				     CMS_NOSMIMECAP | use_keyid |
+				     (digest_mode ? CMS_KEY_PARAM : 0) |
 				     use_signed_attrs),
 		    "CMS_add1_signer");
-		ERR(CMS_final(cms, bm, NULL, CMS_NOCERTS | CMS_BINARY) != 1,
-		    "CMS_final");
+		if (digest_mode)
+			ERR(CMS_final_digest(cms, digest_bin, digest_len, NULL, CMS_NOCERTS | CMS_BINARY) != 1,
+			    "CMS_final_digest");
+		else
+			ERR(CMS_final(cms, bm, NULL, CMS_NOCERTS | CMS_BINARY) != 1,
+			    "CMS_final");
 
 #else
 		pkcs7 = PKCS7_sign(x509, private_key, NULL, bm,
-- 
2.20.1
Re: [PATCH] sign-file: Add -D "digest mode"
Posted by kernel test robot 1 month, 3 weeks ago 
Hi Fam,

kernel test robot noticed the following build warnings:

[auto build test WARNING on linus/master]
[also build test WARNING on v6.12-rc1 next-20241004]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Fam-Zheng/sign-file-Add-D-digest-mode/20241002-215025
base:   linus/master
patch link:    https://lore.kernel.org/r/20241002133837.1030094-1-fam.zheng%40bytedance.com
patch subject: [PATCH] sign-file: Add -D "digest mode"
config: alpha-allyesconfig (https://download.01.org/0day-ci/archive/20241004/202410042115.WT7VlS8U-lkp@intel.com/config)
compiler: alpha-linux-gcc (GCC) 13.3.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241004/202410042115.WT7VlS8U-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202410042115.WT7VlS8U-lkp@intel.com/

All warnings (new ones prefixed by >>):

   In file included from scripts/sign-file.c:40:
   scripts/sign-file.c: In function 'main':
>> scripts/sign-file.c:357:29: warning: implicit declaration of function 'CMS_final_digest' [-Wimplicit-function-declaration]
     357 |                         ERR(CMS_final_digest(cms, digest_bin, digest_len, NULL, CMS_NOCERTS | CMS_BINARY) != 1,
         |                             ^~~~~~~~~~~~~~~~
   scripts/ssl-common.h:27:32: note: in definition of macro 'ERR'
      27 |                 bool __cond = (cond);                   \
         |                                ^~~~
--
   In file included from scripts/sign-file.c:40:
   scripts/sign-file.c: In function 'main':
>> scripts/sign-file.c:357:29: warning: implicit declaration of function 'CMS_final_digest' [-Wimplicit-function-declaration]
     357 |                         ERR(CMS_final_digest(cms, digest_bin, digest_len, NULL, CMS_NOCERTS | CMS_BINARY) != 1,
         |                             ^~~~~~~~~~~~~~~~
   scripts/ssl-common.h:27:32: note: in definition of macro 'ERR'
      27 |                 bool __cond = (cond);                   \
         |                                ^~~~


vim +/CMS_final_digest +357 scripts/sign-file.c

   329	
   330		if (!raw_sig) {
   331			/* Read the private key and the X.509 cert the PKCS#7 message
   332			 * will point to.
   333			 */
   334			private_key = read_private_key(private_key_name);
   335			x509 = read_x509(x509_name);
   336	
   337			/* Digest the module data. */
   338			OpenSSL_add_all_digests();
   339			drain_openssl_errors(__LINE__, 0);
   340			digest_algo = EVP_get_digestbyname(hash_algo);
   341			ERR(!digest_algo, "EVP_get_digestbyname");
   342	
   343	#ifndef USE_PKCS7
   344			/* Load the signature message from the digest buffer. */
   345			cms = CMS_sign(NULL, NULL, NULL, NULL,
   346				       CMS_NOCERTS | CMS_PARTIAL | CMS_BINARY |
   347				       CMS_DETACHED | CMS_STREAM);
   348			ERR(!cms, "CMS_sign");
   349	
   350			ERR(!CMS_add1_signer(cms, x509, private_key, digest_algo,
   351					     CMS_NOCERTS | CMS_BINARY |
   352					     CMS_NOSMIMECAP | use_keyid |
   353					     (digest_mode ? CMS_KEY_PARAM : 0) |
   354					     use_signed_attrs),
   355			    "CMS_add1_signer");
   356			if (digest_mode)
 > 357				ERR(CMS_final_digest(cms, digest_bin, digest_len, NULL, CMS_NOCERTS | CMS_BINARY) != 1,
   358				    "CMS_final_digest");
   359			else
   360				ERR(CMS_final(cms, bm, NULL, CMS_NOCERTS | CMS_BINARY) != 1,
   361				    "CMS_final");
   362	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
Re: [PATCH] sign-file: Add -D "digest mode"
Posted by kernel test robot 1 month, 3 weeks ago 
Hi Fam,

kernel test robot noticed the following build errors:

[auto build test ERROR on linus/master]
[also build test ERROR on v6.12-rc1 next-20241003]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Fam-Zheng/sign-file-Add-D-digest-mode/20241002-215025
base:   linus/master
patch link:    https://lore.kernel.org/r/20241002133837.1030094-1-fam.zheng%40bytedance.com
patch subject: [PATCH] sign-file: Add -D "digest mode"
config: hexagon-allmodconfig (https://download.01.org/0day-ci/archive/20241004/202410041509.PbZBKm0L-lkp@intel.com/config)
compiler: clang version 20.0.0git (https://github.com/llvm/llvm-project fef3566a25ff0e34fb87339ba5e13eca17cec00f)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241004/202410041509.PbZBKm0L-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202410041509.PbZBKm0L-lkp@intel.com/

All errors (new ones prefixed by >>):

   WARNING: unmet direct dependencies detected for GET_FREE_REGION
   Depends on [n]: SPARSEMEM [=n]
   Selected by [m]:
   - RESOURCE_KUNIT_TEST [=m] && RUNTIME_TESTING_MENU [=y] && KUNIT [=m]
>> scripts/sign-file.c:357:8: error: call to undeclared function 'CMS_final_digest'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
   357 |                         ERR(CMS_final_digest(cms, digest_bin, digest_len, NULL, CMS_NOCERTS | CMS_BINARY) != 1,
   |                             ^
   1 error generated.
   make[3]: *** [scripts/Makefile.host:116: scripts/sign-file] Error 1
   make[3]: Target 'scripts/' not remade because of errors.
   make[2]: *** [Makefile:1187: scripts] Error 2
   make[2]: Target 'prepare' not remade because of errors.
   make[1]: *** [Makefile:224: __sub-make] Error 2
   make[1]: Target 'prepare' not remade because of errors.
   make: *** [Makefile:224: __sub-make] Error 2
   make: Target 'prepare' not remade because of errors.

Kconfig warnings: (for reference only)
   WARNING: unmet direct dependencies detected for MODVERSIONS
   Depends on [n]: MODULES [=y] && !COMPILE_TEST [=y]
   Selected by [y]:
   - RANDSTRUCT_FULL [=y] && (CC_HAS_RANDSTRUCT [=y] || GCC_PLUGINS [=n]) && MODULES [=y]
   WARNING: unmet direct dependencies detected for GET_FREE_REGION
   Depends on [n]: SPARSEMEM [=n]
   Selected by [m]:
   - RESOURCE_KUNIT_TEST [=m] && RUNTIME_TESTING_MENU [=y] && KUNIT [=m]


vim +/CMS_final_digest +357 scripts/sign-file.c

   329	
   330		if (!raw_sig) {
   331			/* Read the private key and the X.509 cert the PKCS#7 message
   332			 * will point to.
   333			 */
   334			private_key = read_private_key(private_key_name);
   335			x509 = read_x509(x509_name);
   336	
   337			/* Digest the module data. */
   338			OpenSSL_add_all_digests();
   339			drain_openssl_errors(__LINE__, 0);
   340			digest_algo = EVP_get_digestbyname(hash_algo);
   341			ERR(!digest_algo, "EVP_get_digestbyname");
   342	
   343	#ifndef USE_PKCS7
   344			/* Load the signature message from the digest buffer. */
   345			cms = CMS_sign(NULL, NULL, NULL, NULL,
   346				       CMS_NOCERTS | CMS_PARTIAL | CMS_BINARY |
   347				       CMS_DETACHED | CMS_STREAM);
   348			ERR(!cms, "CMS_sign");
   349	
   350			ERR(!CMS_add1_signer(cms, x509, private_key, digest_algo,
   351					     CMS_NOCERTS | CMS_BINARY |
   352					     CMS_NOSMIMECAP | use_keyid |
   353					     (digest_mode ? CMS_KEY_PARAM : 0) |
   354					     use_signed_attrs),
   355			    "CMS_add1_signer");
   356			if (digest_mode)
 > 357				ERR(CMS_final_digest(cms, digest_bin, digest_len, NULL, CMS_NOCERTS | CMS_BINARY) != 1,
   358				    "CMS_final_digest");
   359			else
   360				ERR(CMS_final(cms, bm, NULL, CMS_NOCERTS | CMS_BINARY) != 1,
   361				    "CMS_final");
   362	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

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