2023-10-29 01:10:15

by Dimitri John Ledkov

[permalink] [raw]
Subject: [PATCH kmod] libkmod: remove pkcs7 obj_to_hash_algo()

Switch to using OBJ_obj2txt() to calculate and print the pkcs7
signature hash name. This eliminates the need to duplicate libcrypto
NID to name mapping, detect SM3 openssl compile-time support, and
enables using any hashes that openssl and kernel know about. For
example SHA3 are being added for v6.7 and with this patch are
automatically supported.

Signed-off-by: Dimitri John Ledkov <[email protected]>
---
configure.ac | 7 -----
libkmod/libkmod-signature.c | 59 +++++++++++++------------------------
2 files changed, 20 insertions(+), 46 deletions(-)

diff --git a/configure.ac b/configure.ac
index 7bf8d78ca7..a6b8fa0308 100644
--- a/configure.ac
+++ b/configure.ac
@@ -133,13 +133,6 @@ AC_ARG_WITH([openssl],
AS_IF([test "x$with_openssl" != "xno"], [
PKG_CHECK_MODULES([libcrypto], [libcrypto >= 1.1.0], [LIBS="$LIBS $libcrypto_LIBS"])
AC_DEFINE([ENABLE_OPENSSL], [1], [Enable openssl for modinfo.])
- AC_COMPILE_IFELSE([AC_LANG_SOURCE([[#include <openssl/ssl.h>
- int nid = NID_sm3;]])], [
- AC_MSG_NOTICE([openssl supports sm3])
- ], [
- AC_MSG_NOTICE([openssl sm3 support not detected])
- CPPFLAGS="$CPPFLAGS -DOPENSSL_NO_SM3"
- ])
module_signatures="PKCS7 $module_signatures"
], [
AC_MSG_NOTICE([openssl support not requested])
diff --git a/libkmod/libkmod-signature.c b/libkmod/libkmod-signature.c
index b749a818f9..80f6447bce 100644
--- a/libkmod/libkmod-signature.c
+++ b/libkmod/libkmod-signature.c
@@ -127,6 +127,7 @@ struct pkcs7_private {
PKCS7 *pkcs7;
unsigned char *key_id;
BIGNUM *sno;
+ char *hash_algo;
};

static void pkcs7_free(void *s)
@@ -137,42 +138,11 @@ static void pkcs7_free(void *s)
PKCS7_free(pvt->pkcs7);
BN_free(pvt->sno);
free(pvt->key_id);
+ free(pvt->hash_algo);
free(pvt);
si->private = NULL;
}

-static int obj_to_hash_algo(const ASN1_OBJECT *o)
-{
- int nid;
-
- nid = OBJ_obj2nid(o);
- switch (nid) {
- case NID_md4:
- return PKEY_HASH_MD4;
- case NID_md5:
- return PKEY_HASH_MD5;
- case NID_sha1:
- return PKEY_HASH_SHA1;
- case NID_ripemd160:
- return PKEY_HASH_RIPE_MD_160;
- case NID_sha256:
- return PKEY_HASH_SHA256;
- case NID_sha384:
- return PKEY_HASH_SHA384;
- case NID_sha512:
- return PKEY_HASH_SHA512;
- case NID_sha224:
- return PKEY_HASH_SHA224;
-# ifndef OPENSSL_NO_SM3
- case NID_sm3:
- return PKEY_HASH_SM3;
-# endif
- default:
- return -1;
- }
- return -1;
-}
-
static const char *x509_name_to_str(X509_NAME *name)
{
int i;
@@ -219,7 +189,8 @@ static bool fill_pkcs7(const char *mem, off_t size,
unsigned char *key_id_str;
struct pkcs7_private *pvt;
const char *issuer_str;
- int hash_algo;
+ char *hash_algo;
+ int hash_algo_len;

size -= sig_len;
pkcs7_raw = mem + size;
@@ -278,27 +249,37 @@ static bool fill_pkcs7(const char *mem, off_t size,

X509_ALGOR_get0(&o, NULL, NULL, dig_alg);

- hash_algo = obj_to_hash_algo(o);
- if (hash_algo < 0)
+ // Use OBJ_obj2txt to calculate string length
+ hash_algo_len = OBJ_obj2txt(NULL, 0, o, 0);
+ if (hash_algo_len < 0)
goto err3;
- sig_info->hash_algo = pkey_hash_algo[hash_algo];
- // hash algo has not been recognized
- if (sig_info->hash_algo == NULL)
+ hash_algo = malloc(hash_algo_len + 1);
+ if (hash_algo == NULL)
goto err3;
+ hash_algo_len = OBJ_obj2txt(hash_algo, hash_algo_len + 1, o, 0);
+ if (hash_algo_len < 0)
+ goto err4;
+
+ // Assign libcrypto hash algo string or number
+ sig_info->hash_algo = hash_algo;
+
sig_info->id_type = pkey_id_type[modsig->id_type];

pvt = malloc(sizeof(*pvt));
if (pvt == NULL)
- goto err3;
+ goto err4;

pvt->pkcs7 = pkcs7;
pvt->key_id = key_id_str;
pvt->sno = sno_bn;
+ pvt->hash_algo = hash_algo;
sig_info->private = pvt;

sig_info->free = pkcs7_free;

return true;
+err4:
+ free(hash_algo);
err3:
free(key_id_str);
err2:
--
2.34.1