>>>>> On Fri, 16 Nov 2018 20:32:28 +0200, Yauheni Kaliuta wrote:
> The patch adds data fetching from the PKCS#7 certificate using
> openssl library (which is used by scripts/sign-file.c in the linux
> kernel to sign modules).
> In general the certificate can contain many signatures, but since
> kmod (modinfo) supports only one signature at the moment,
Did not finish the paragraph:
In general the certificate can contain many signatures, but since
kmod (modinfo) supports only one signature at the moment, only first
one is taken.
> With the current sign-file.c certificate doesn't contain signer
> key's fingerprint, so "serial number" is used for the key id.
> Signed-off-by: Yauheni Kaliuta <yauheni.kaliuta@xxxxxxxxxx>
> ---
> Makefile.am | 4 +-
> configure.ac | 11 ++
> libkmod/libkmod-internal.h | 3 +
> libkmod/libkmod-module.c | 3 +
> libkmod/libkmod-signature.c | 195 +++++++++++++++++++++++++++++++++++-
> 5 files changed, 211 insertions(+), 5 deletions(-)
> diff --git a/Makefile.am b/Makefile.am
> index 194e1115ae70..5ab7fc0b4750 100644
> --- a/Makefile.am
> +++ b/Makefile.am
> @@ -35,6 +35,8 @@ SED_PROCESS = \
> -e 's,@liblzma_LIBS\@,${liblzma_LIBS},g' \
> -e 's,@zlib_CFLAGS\@,${zlib_CFLAGS},g' \
> -e 's,@zlib_LIBS\@,${zlib_LIBS},g' \
> + -e 's,@openssl_CFLAGS\@,${openssl_CFLAGS},g' \
> + -e 's,@openssl_LIBS\@,${openssl_LIBS},g' \
> < $< > $@ || rm $@
> %.pc: %.pc.in Makefile
> @@ -87,7 +89,7 @@ libkmod_libkmod_la_DEPENDENCIES = \
> ${top_srcdir}/libkmod/libkmod.sym
> libkmod_libkmod_la_LIBADD = \
> shared/libshared.la \
> - ${liblzma_LIBS} ${zlib_LIBS}
> + ${liblzma_LIBS} ${zlib_LIBS} ${openssl_LIBS}
> noinst_LTLIBRARIES += libkmod/libkmod-internal.la
> libkmod_libkmod_internal_la_SOURCES = $(libkmod_libkmod_la_SOURCES)
> diff --git a/configure.ac b/configure.ac
> index fbc7391b2d1b..2e33380a0cc2 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -106,6 +106,17 @@ AS_IF([test "x$with_zlib" != "xno"], [
> ])
> CC_FEATURE_APPEND([with_features], [with_zlib], [ZLIB])
> +AC_ARG_WITH([openssl],
> + AS_HELP_STRING([--with-openssl], [handle PKCS7 signatures @<:@default=disabled@:>@]),
> + [], [with_openssl=no])
> +AS_IF([test "x$with_openssl" != "xno"], [
> + PKG_CHECK_MODULES([openssl], [openssl])
> + AC_DEFINE([ENABLE_OPENSSL], [1], [Enable openssl for modinfo.])
> +], [
> + AC_MSG_NOTICE([openssl support not requested])
> +])
> +CC_FEATURE_APPEND([with_features], [with_openssl], [OPENSSL])
> +
> AC_ARG_WITH([bashcompletiondir],
> AS_HELP_STRING([--with-bashcompletiondir=DIR], [Bash completions directory]),
> [],
> diff --git a/libkmod/libkmod-internal.h b/libkmod/libkmod-internal.h
> index 346579c71aab..a65ddd156f18 100644
> --- a/libkmod/libkmod-internal.h
> +++ b/libkmod/libkmod-internal.h
> @@ -188,5 +188,8 @@ struct kmod_signature_info {
> const char *algo, *hash_algo, *id_type;
> const char *sig;
> size_t sig_len;
> + void (*free)(void *);
> + void *private;
> };
> bool kmod_module_signature_info(const struct kmod_file *file, struct kmod_signature_info *sig_info) _must_check_ __attribute__((nonnull(1, 2)));
> +void kmod_module_signature_info_free(struct kmod_signature_info *sig_info) __attribute__((nonnull));
> diff --git a/libkmod/libkmod-module.c b/libkmod/libkmod-module.c
> index 889f26479a98..bffe715cdef4 100644
> --- a/libkmod/libkmod-module.c
> +++ b/libkmod/libkmod-module.c
> @@ -2357,6 +2357,9 @@ KMOD_EXPORT int kmod_module_get_info(const struct kmod_module *mod, struct kmod_
> ret = count;
> list_error:
> + /* aux structures freed in normal case also */
> + kmod_module_signature_info_free(&sig_info);
> +
> if (ret < 0) {
> kmod_module_info_free_list(*list);
> *list = NULL;
> diff --git a/libkmod/libkmod-signature.c b/libkmod/libkmod-signature.c
> index 429ffbd8a957..4b44c3701d28 100644
> --- a/libkmod/libkmod-signature.c
> +++ b/libkmod/libkmod-signature.c
> @@ -19,6 +19,10 @@
> #include <endian.h>
> #include <inttypes.h>
> +#ifdef ENABLE_OPENSSL
> +#include <openssl/cms.h>
> +#include <openssl/ssl.h>
> +#endif
> #include <stdio.h>
> #include <stdlib.h>
> #include <string.h>
> @@ -115,15 +119,192 @@ static bool fill_default(const char *mem, off_t size,
> return true;
> }
> -static bool fill_unknown(const char *mem, off_t size,
> - const struct module_signature *modsig, size_t sig_len,
> - struct kmod_signature_info *sig_info)
> +#ifdef ENABLE_OPENSSL
> +
> +struct pkcs7_private {
> + CMS_ContentInfo *cms;
> + unsigned char *key_id;
> + BIGNUM *sno;
> +};
> +
> +static void pkcs7_free(void *s)
> +{
> + struct kmod_signature_info *si = s;
> + struct pkcs7_private *pvt = si->private;
> +
> + CMS_ContentInfo_free(pvt->cms);
> + BN_free(pvt->sno);
> + free(pvt->key_id);
> + 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;
> + default:
> + return -1;
> + }
> + return -1;
> +}
> +
> +static const char *x509_name_to_str(X509_NAME *name)
> +{
> + int i;
> + X509_NAME_ENTRY *e;
> + ASN1_STRING *d;
> + ASN1_OBJECT *o;
> + int nid = -1;
> + const char *str;
> +
> + for (i = 0; i < X509_NAME_entry_count(name); i++) {
> + e = X509_NAME_get_entry(name, i);
> + o = X509_NAME_ENTRY_get_object(e);
> + nid = OBJ_obj2nid(o);
> + if (nid == NID_commonName)
> + break;
> + }
> + if (nid == -1)
> + return NULL;
> +
> + d = X509_NAME_ENTRY_get_data(e);
> + str = (const char *)ASN1_STRING_get0_data(d);
> +
> + return str;
> +}
> +
> +static bool fill_pkcs7(const char *mem, off_t size,
> + const struct module_signature *modsig, size_t sig_len,
> + struct kmod_signature_info *sig_info)
> +{
> + const char *pkcs7_raw;
> + CMS_ContentInfo *cms;
> + STACK_OF(CMS_SignerInfo) *sis;
> + CMS_SignerInfo *si;
> + int rc;
> + ASN1_OCTET_STRING *key_id;
> + X509_NAME *issuer;
> + ASN1_INTEGER *sno;
> + ASN1_OCTET_STRING *sig;
> + BIGNUM *sno_bn;
> + X509_ALGOR *dig_alg;
> + X509_ALGOR *sig_alg;
> + const ASN1_OBJECT *o;
> + BIO *in;
> + int len;
> + unsigned char *key_id_str;
> + struct pkcs7_private *pvt;
> + const char *issuer_str;
> +
> + size -= sig_len;
> + pkcs7_raw = mem + size;
> +
> + in = BIO_new_mem_buf(pkcs7_raw, sig_len);
> +
> + cms = d2i_CMS_bio(in, NULL);
> + if (cms == NULL) {
> + BIO_free(in);
> + return false;
> + }
> +
> + BIO_free(in);
> +
> + sis = CMS_get0_SignerInfos(cms);
> + if (sis == NULL)
> + goto err;
> +
> + si = sk_CMS_SignerInfo_value(sis, 0);
> + if (si == NULL)
> + goto err;
> +
> + rc = CMS_SignerInfo_get0_signer_id(si, &key_id, &issuer, &sno);
> + if (rc == 0)
> + goto err;
> +
> + sig = CMS_SignerInfo_get0_signature(si);
> + if (sig == NULL)
> + goto err;
> +
> + CMS_SignerInfo_get0_algs(si, NULL, NULL, &dig_alg, &sig_alg);
> +
> + sig_info->sig = (const char *)ASN1_STRING_get0_data(sig);
> + sig_info->sig_len = ASN1_STRING_length(sig);
> +
> +
> + sno_bn = ASN1_INTEGER_to_BN(sno, NULL);
> + if (sno_bn == NULL)
> + goto err;
> +
> + len = BN_num_bytes(sno_bn);
> + key_id_str = malloc(len);
> + BN_bn2bin(sno_bn, key_id_str);
> +
> + sig_info->key_id = (const char *)key_id_str;
> + sig_info->key_id_len = len;
> +
> + issuer_str = x509_name_to_str(issuer);
> + if (issuer_str != NULL) {
> + sig_info->signer = issuer_str;
> + sig_info->signer_len = strlen(issuer_str);
> + }
> +
> + sig_info->algo = NULL;
> +
> + X509_ALGOR_get0(&o, NULL, NULL, dig_alg);
> +
> + sig_info->hash_algo = pkey_hash_algo[obj_to_hash_algo(o)];
> + sig_info->id_type = pkey_id_type[modsig->id_type];
> +
> + pvt = malloc(sizeof(*pvt));
> + if (pvt == NULL)
> + goto err;
> +
> + pvt->cms = cms;
> + pvt->key_id = key_id_str;
> + pvt->sno = sno_bn;
> + sig_info->private = pvt;
> +
> + sig_info->free = pkcs7_free;
> +
> + return true;
> +
> +err:
> + CMS_ContentInfo_free(cms);
> + return false;
> +}
> +
> +#else /* ENABLE OPENSSL */
> +
> +static bool fill_pkcs7(const char *mem, off_t size,
> + const struct module_signature *modsig, size_t sig_len,
> + struct kmod_signature_info *sig_info)
> {
sig_info-> hash_algo = "unknown";
sig_info-> id_type = pkey_id_type[modsig->id_type];
> return true;
> }
> +#endif /* ENABLE OPENSSL */
> +
> #define SIG_MAGIC "~Module signature appended~\n"
> /*
> @@ -167,8 +348,14 @@ bool kmod_module_signature_info(const struct kmod_file *file, struct kmod_signat
> switch (modsig->id_type) {
> case PKEY_ID_PKCS7:
> - return fill_unknown(mem, size, modsig, sig_len, sig_info);
> + return fill_pkcs7(mem, size, modsig, sig_len, sig_info);
> default:
> return fill_default(mem, size, modsig, sig_len, sig_info);
> }
> }
> +
> +void kmod_module_signature_info_free(struct kmod_signature_info *sig_info)
> +{
> + if (sig_info->free)
> + sig_info->free(sig_info);
> +}
> --
> 2.19.1
--
WBR,
Yauheni Kaliuta
