On 5/5/21 2:48 AM, Vitaly Chikunov wrote:
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.
This commit creates ABI change for libimaevm, due to adding new function
ima_read_keyid(). Newer clients cannot work with older libimaevm.
Together with previous commit it creates backward-incompatible ABI
change, thus soname should be incremented on release.
Signed-off-by: Vitaly Chikunov <vt@xxxxxxxxxxxx>
---
README | 1 +
src/evmctl.c | 22 ++++++++++---
src/imaevm.h | 1 +
src/libimaevm.c | 85 ++++++++++++++++++++++++++++++++++++++++++++++++++
tests/sign_verify.test | 1 +
5 files changed, 105 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 8ae5488..6a60599 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"
@@ -2572,7 +2576,6 @@ int main(int argc, char *argv[])
int err = 0, c, lind;
ENGINE *eng = NULL;
unsigned long keyid;
- char *eptr;
#if !(OPENSSL_VERSION_NUMBER < 0x10100000)
OPENSSL_init_crypto(
@@ -2718,10 +2721,19 @@ 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 == ULONG_MAX || keyid > UINT_MAX ||
+ if (optarg[0] == '@') {
+ keyid = ima_read_keyid(optarg + 1, NULL);
+ } 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 == ULONG_MAX || keyid > UINT_MAX ||
keyid == 0) {
log_err("Invalid keyid value.\n");
exit(1);
diff --git a/src/imaevm.h b/src/imaevm.h
index 9f38059..eab7f32 100644
--- a/src/imaevm.h
+++ b/src/imaevm.h
@@ -219,6 +219,7 @@ EVP_PKEY *read_pub_pkey(const char *keyfile, int x509);
void calc_keyid_v1(uint8_t *keyid, char *str, const unsigned char *pkey, int len);
void calc_keyid_v2(uint32_t *keyid, char *str, EVP_PKEY *pkey);
int key2bin(RSA *key, unsigned char *pub);
+unsigned long ima_read_keyid(const char *certfile, uint32_t *keyid);
int sign_hash(const char *algo, const unsigned char *hash, int size, const char *keyfile, const char *keypass, unsigned char *sig);
int verify_hash(const char *file, const unsigned char *hash, int size, unsigned char *sig, int siglen);
diff --git a/src/libimaevm.c b/src/libimaevm.c
index 481d29d..a22d9bb 100644
--- a/src/libimaevm.c
+++ b/src/libimaevm.c
@@ -57,6 +57,7 @@
#include <openssl/pem.h>
#include <openssl/evp.h>
#include <openssl/x509.h>
+#include <openssl/x509v3.h>
#include <openssl/err.h>
#include "imaevm.h"
@@ -748,6 +749,90 @@ void calc_keyid_v2(uint32_t *keyid, char *str, EVP_PKEY *pkey)
X509_PUBKEY_free(pk);
}
+enum keyid_file_type {
+ KEYID_FILE_PEM_KEY = 0,
+ KEYID_FILE_UNK_CERT,
+};
+
+/*
+ * @is_cert: 1 - this is a x509 cert file (maybe PEM, maybe DER encoded);
This probably change since you wrote it. Is this file_type now?
+ * 0 - this is a PEM encoded private key file with possible appended
+ * x509 cert.
+ */
+static unsigned long _ima_read_keyid(const char *certfile, uint32_t *keyid,
+ enum keyid_file_type file_type)
+{
+ uint32_t keyid_raw;
+ const ASN1_OCTET_STRING *skid;
+ int skid_len;
+ X509 *x = NULL;
+ FILE *fp;
+
+ if (!(fp = fopen(certfile, "r"))) {
+ log_err("read keyid: %s: Cannot open: %s\n", certfile,
+ strerror(errno));
+ return -1;
+ }
+ if (!PEM_read_X509(fp, &x, NULL, NULL)) {
+ if (ERR_GET_REASON(ERR_peek_last_error()) == PEM_R_NO_START_LINE) {
+ ERR_clear_error();
+ if (file_type == KEYID_FILE_PEM_KEY) {
+ log_debug("%s: x509 certificate not found\n",
+ certfile);
+ fclose(fp);
+ return -1;
+ }
+ rewind(fp);
+ d2i_X509_fp(fp, &x);
+ }
+ if (!x) {
+ ERR_print_errors_fp(stderr);
+ log_err("read keyid: %s: Error reading x509 certificate\n",
+ certfile);
+ fclose(fp);
+ return -1;
+ }
+ }
+ fclose(fp);
+
+ if (!(skid = X509_get0_subject_key_id(x))) {
+ log_err("read keyid: %s: SKID not found\n", certfile);
+ goto err_free;
+ }
+ skid_len = ASN1_STRING_length(skid);
+ if (skid_len < sizeof(keyid_raw)) {
+ log_err("read keyid: %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));
+ if (keyid)
+ memcpy(keyid, &keyid_raw, sizeof(*keyid));
If keyid is supposed to be in native format then you have to apply
ntohl() to it..
+ log_info("keyid %04x (from %s)\n", ntohl(keyid_raw), certfile);
+ return ntohl(keyid_raw);
I thought this should return 0 ?
+
+err_free:
+ X509_free(x);
+ return -1;
+}
+
+/**
+ * ima_read_keyid() - Read 32-bit keyid from the cert file.
+ * @certfile: File possibly containing certificate in DER/PEM format.
+ * @keyid: Output keyid in network order.
+ *
+ * Try to read keyid from Subject Key Identifier (SKID) of certificate.
+ * Autodetect if cert is in PEM or DER encoding.
+ *
+ * Return: -1 (ULONG_MAX) on error;
+ * 32-bit keyid as unsigned integer in host order.
That's confusing, two times the same result, one time in host order, on
time in network order. Why not just one return value in host order?
+ */
+unsigned long ima_read_keyid(const char *certfile, uint32_t *keyid)
+{
+ return _ima_read_keyid(certfile, keyid, KEYID_FILE_UNK_CERT);
+}
+
static EVP_PKEY *read_priv_pkey(const char *keyfile, const char *keypass)
{
FILE *fp;
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
