From: Vitaly Chikunov <vt@altlinux.org>
To: Mimi Zohar <zohar@linux.vnet.ibm.com>,
Dmitry Kasatkin <dmitry.kasatkin@gmail.com>,
linux-integrity@vger.kernel.org
Cc: Elvira Khabirova <lineprinter0@gmail.com>
Subject: [PATCH v2 2/3] ima-evm-utils: Allow manual setting keyid from a cert file
Date: Tue, 4 May 2021 07:33:56 +0300 [thread overview]
Message-ID: <20210504043357.4093409-3-vt@altlinux.org> (raw)
In-Reply-To: <20210504043357.4093409-1-vt@altlinux.org>
Allow user to specify `--keyid @/path/to/cert.pem' to extract keyid from
SKID of the certificate file. PEM or DER format is auto-detected.
`--keyid' option is reused instead of adding a new option (like possible
`--cert') to signify to the user it's only keyid extraction and nothing
more.
Signed-off-by: Vitaly Chikunov <vt@altlinux.org>
---
README | 1 +
src/evmctl.c | 82 +++++++++++++++++++++++++++++++++++++++++++++++---
tests/sign_verify.test | 1 +
3 files changed, 79 insertions(+), 5 deletions(-)
diff --git a/README b/README
index 8cd66e0..0e1f6ba 100644
--- a/README
+++ b/README
@@ -49,6 +49,7 @@ OPTIONS
--rsa use RSA key type and signing scheme v1
-k, --key path to signing key (default: /etc/keys/{privkey,pubkey}_evm.pem)
--keyid val overwrite signature keyid with a value (for signing)
+ val is a x509 cert file if prefixed with '@'
-o, --portable generate portable EVM signatures
-p, --pass password for encrypted signing key
-r, --recursive recurse into directories (sign)
diff --git a/src/evmctl.c b/src/evmctl.c
index 7983299..fdb0fb3 100644
--- a/src/evmctl.c
+++ b/src/evmctl.c
@@ -42,6 +42,7 @@
#include <sys/param.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
+#include <arpa/inet.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>
@@ -57,12 +58,14 @@
#include <termios.h>
#include <assert.h>
+#include <openssl/asn1.h>
#include <openssl/sha.h>
#include <openssl/pem.h>
#include <openssl/hmac.h>
#include <openssl/err.h>
#include <openssl/rsa.h>
#include <openssl/engine.h>
+#include <openssl/x509v3.h>
#include "hash_info.h"
#include "pcr.h"
#include "utils.h"
@@ -2447,6 +2450,7 @@ static void usage(void)
" --rsa use RSA key type and signing scheme v1\n"
" -k, --key path to signing key (default: /etc/keys/{privkey,pubkey}_evm.pem)\n"
" --keyid val overwrite signature keyid with a value (for signing)\n"
+ " val is a x509 cert file if prefixed with '@'\n"
" -o, --portable generate portable EVM signatures\n"
" -p, --pass password for encrypted signing key\n"
" -r, --recursive recurse into directories (sign)\n"
@@ -2567,12 +2571,71 @@ static char *get_password(void)
return pwd;
}
+/* Return true if FILE is possibly PEM encoded (otherwise DER). */
+static int is_encoding_pem(FILE *in)
+{
+ char buf[6]; /* Room for the 5 minus signs and '\0'. */
+ int pem = 0;
+
+ if (fgets(buf, sizeof(buf), in) &&
+ strspn(buf, "-") == sizeof(buf) - 1)
+ pem = 1;
+ rewind(in);
+ return pem;
+}
+
+/* Extract keyid from SKID of the cert. No return on error. */
+static unsigned long int extract_keyid(const char *certfile)
+{
+ uint32_t keyid_raw;
+ const ASN1_OCTET_STRING *skid;
+ int skid_len;
+ X509 *x = NULL;
+ int pem;
+ FILE *in;
+
+ if (!(in = fopen(certfile, "r"))) {
+ log_err("Cannot open cert file %s: %s\n", certfile,
+ strerror(errno));
+ exit(1);
+ }
+ if ((pem = is_encoding_pem(in)))
+ x = PEM_read_X509(in, &x, NULL, NULL);
+ else
+ x = d2i_X509_fp(in, &x);
+ if (!x) {
+ ERR_print_errors_fp(stderr);
+ log_err("Cannot read x509 cert from %s file %s\n",
+ pem? "PEM" : "DER", certfile);
+ fclose(in);
+ exit(1);
+ }
+ fclose(in);
+
+ if (!(skid = X509_get0_subject_key_id(x))) {
+ log_err("%s: SKID not found\n", certfile);
+ goto err_free;
+ }
+ skid_len = ASN1_STRING_length(skid);
+ if (skid_len < sizeof(keyid_raw)) {
+ log_err("%s: SKID too short (len %d)\n", certfile, skid_len);
+ goto err_free;
+ }
+ memcpy(&keyid_raw, ASN1_STRING_get0_data(skid) + skid_len
+ - sizeof(keyid_raw), sizeof(keyid_raw));
+ log_info("keyid %04x (from %s)\n", ntohl(keyid_raw), certfile);
+ return ntohl(keyid_raw);
+
+err_free:
+ X509_free(x);
+ exit(1);
+}
+
int main(int argc, char *argv[])
{
int err = 0, c, lind;
ENGINE *eng = NULL;
unsigned long int keyid;
- char *eptr;
#if !(OPENSSL_VERSION_NUMBER < 0x10100000)
OPENSSL_init_crypto(
@@ -2718,10 +2781,19 @@ int main(int argc, char *argv[])
pcrfile[npcrfile++] = optarg;
break;
case 143:
- errno = 0;
- keyid = strtoul(optarg, &eptr, 16);
- if (errno || eptr - optarg != strlen(optarg) ||
- keyid > UINT_MAX || keyid == 0) {
+ if (optarg[0] == '@') {
+ keyid = extract_keyid(optarg + 1);
+ } else {
+ char *eptr;
+
+ errno = 0;
+ keyid = strtoul(optarg, &eptr, 16);
+ if (eptr - optarg != strlen(optarg) || errno) {
+ log_err("Invalid keyid value.\n");
+ exit(1);
+ }
+ }
+ if (keyid > UINT_MAX || keyid == 0) {
log_err("Invalid keyid value.\n");
exit(1);
}
diff --git a/tests/sign_verify.test b/tests/sign_verify.test
index 2c21812..52ea33a 100755
--- a/tests/sign_verify.test
+++ b/tests/sign_verify.test
@@ -360,6 +360,7 @@ sign_verify rsa1024 md5 0x030201:K:0080
sign_verify rsa1024 sha1 0x030202:K:0080
sign_verify rsa1024 sha224 0x030207:K:0080
expect_pass check_sign TYPE=ima KEY=rsa1024 ALG=sha256 PREFIX=0x030204aabbccdd0080 OPTS=--keyid=aabbccdd
+expect_pass check_sign TYPE=ima KEY=rsa1024 ALG=sha256 PREFIX=0x030204:K:0080 OPTS=--keyid=@test-rsa1024.cer
sign_verify rsa1024 sha256 0x030204:K:0080
try_different_keys
try_different_sigs
--
2.11.0
next prev parent reply other threads:[~2021-05-04 4:35 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-04 4:33 [PATCH v2 0/3] ima-evm-utils: Add --keyid option Vitaly Chikunov
2021-05-04 4:33 ` [PATCH v2 1/3] ima-evm-utils: Allow manual setting keyid for signing Vitaly Chikunov
2021-05-04 12:51 ` Stefan Berger
2021-05-04 23:18 ` Vitaly Chikunov
2021-05-04 23:43 ` Dmitry V. Levin
2021-05-06 1:15 ` Vitaly Chikunov
2021-05-04 4:33 ` Vitaly Chikunov [this message]
2021-05-04 13:04 ` [PATCH v2 2/3] ima-evm-utils: Allow manual setting keyid from a cert file Stefan Berger
2021-05-04 23:21 ` Vitaly Chikunov
2021-05-04 13:28 ` Stefan Berger
2021-05-04 4:33 ` [PATCH v2 3/3] ima-evm-utils: Read keyid from the cert appended to the key file Vitaly Chikunov
2021-05-04 13:38 ` Stefan Berger
2021-05-04 22:27 ` Vitaly Chikunov
2021-05-05 1:04 ` Stefan Berger
2021-05-05 1:15 ` Vitaly Chikunov
2021-05-05 5:15 ` Vitaly Chikunov
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