* [PATCH 1/2] ima-evm-utils: Allow manual setting keyid for signing
2021-05-03 23:34 [PATCH 0/2] ima-evm-utils: Add --keyid option Vitaly Chikunov
@ 2021-05-03 23:34 ` Vitaly Chikunov
2021-05-03 23:34 ` [PATCH 2/2] ima-evm-utils: Allow manual setting keyid from a cert file Vitaly Chikunov
1 sibling, 0 replies; 3+ messages in thread
From: Vitaly Chikunov @ 2021-05-03 23:34 UTC (permalink / raw)
To: Mimi Zohar, Dmitry Kasatkin, linux-integrity
Allow user to set signature's keyid using `--keyid' option. Keyid should
correspond to SKID in certificate, when keyid is calculated using SHA-1
in libimaevm it may mismatch keyid extracted by the kernel from SKID of
certificate (the way public key is presented to the kernel), thus making
signatures not verifiable. This may happen when certificate is using non
SHA-1 SKID (see rfc7093) or just 'unique number' (see rfc5280 4.2.1.2).
As a last resort user may specify arbitrary keyid using the new option.
This commit creates backward compatible ABI change for libimaevm,
because of adding additional parameter to imaevm_params - older
libimaevm can work with newer client.
Signed-off-by: Vitaly Chikunov <vt@altlinux.org>
---
README | 1 +
src/evmctl.c | 14 ++++++++++++++
src/imaevm.h | 1 +
src/libimaevm.c | 8 +++++---
tests/sign_verify.test | 1 +
5 files changed, 22 insertions(+), 3 deletions(-)
diff --git a/README b/README
index 321045d..8cd66e0 100644
--- a/README
+++ b/README
@@ -48,6 +48,7 @@ OPTIONS
--xattr-user store xattrs in user namespace (for testing purposes)
--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)
-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 1815f55..7983299 100644
--- a/src/evmctl.c
+++ b/src/evmctl.c
@@ -2446,6 +2446,7 @@ static void usage(void)
" --xattr-user store xattrs in user namespace (for testing purposes)\n"
" --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"
" -o, --portable generate portable EVM signatures\n"
" -p, --pass password for encrypted signing key\n"
" -r, --recursive recurse into directories (sign)\n"
@@ -2525,6 +2526,7 @@ static struct option opts[] = {
{"xattr-user", 0, 0, 140},
{"ignore-violations", 0, 0, 141},
{"pcrs", 1, 0, 142},
+ {"keyid", 1, 0, 143},
{}
};
@@ -2569,6 +2571,8 @@ 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(
@@ -2713,6 +2717,16 @@ 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) {
+ log_err("Invalid keyid value.\n");
+ exit(1);
+ }
+ imaevm_params.keyid = keyid;
+ break;
case '?':
exit(1);
break;
diff --git a/src/imaevm.h b/src/imaevm.h
index 4503919..9f38059 100644
--- a/src/imaevm.h
+++ b/src/imaevm.h
@@ -196,6 +196,7 @@ struct libimaevm_params {
const char *hash_algo;
const char *keyfile;
const char *keypass;
+ uint32_t keyid; /* keyid overriding value, unless 0. */
};
struct RSA_ASN1_template {
diff --git a/src/libimaevm.c b/src/libimaevm.c
index fa6c278..481d29d 100644
--- a/src/libimaevm.c
+++ b/src/libimaevm.c
@@ -45,6 +45,7 @@
#include <sys/param.h>
#include <sys/stat.h>
#include <asm/byteorder.h>
+#include <arpa/inet.h>
#include <unistd.h>
#include <dirent.h>
#include <string.h>
@@ -894,7 +895,6 @@ static int sign_hash_v2(const char *algo, const unsigned char *hash,
const EVP_MD *md;
size_t sigsize;
const char *st;
- uint32_t keyid;
if (!hash) {
log_err("sign_hash_v2: hash is null\n");
@@ -932,8 +932,10 @@ static int sign_hash_v2(const char *algo, const unsigned char *hash,
return -1;
}
- calc_keyid_v2(&keyid, name, pkey);
- hdr->keyid = keyid;
+ if (imaevm_params.keyid)
+ hdr->keyid = htonl(imaevm_params.keyid);
+ else
+ calc_keyid_v2(&hdr->keyid, name, pkey);
st = "EVP_PKEY_CTX_new";
if (!(ctx = EVP_PKEY_CTX_new(pkey, NULL)))
diff --git a/tests/sign_verify.test b/tests/sign_verify.test
index 288e133..2c21812 100755
--- a/tests/sign_verify.test
+++ b/tests/sign_verify.test
@@ -359,6 +359,7 @@ sign_verify rsa1024 sha256 0x0301 --rsa
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
sign_verify rsa1024 sha256 0x030204:K:0080
try_different_keys
try_different_sigs
--
2.11.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* [PATCH 2/2] ima-evm-utils: Allow manual setting keyid from a cert file
2021-05-03 23:34 [PATCH 0/2] ima-evm-utils: Add --keyid option Vitaly Chikunov
2021-05-03 23:34 ` [PATCH 1/2] ima-evm-utils: Allow manual setting keyid for signing Vitaly Chikunov
@ 2021-05-03 23:34 ` Vitaly Chikunov
1 sibling, 0 replies; 3+ messages in thread
From: Vitaly Chikunov @ 2021-05-03 23:34 UTC (permalink / raw)
To: Mimi Zohar, Dmitry Kasatkin, linux-integrity
User can specify `--keyid @/path/to/cert.pem' to extract keyid from
SKID of the certificate file. PEM or DER format is auto-detected.
I decided to reuse `--keyid' option instead of adding a new option (like
`--cert') to signify to the user it's just keyid extraction and nothing
more.
Signed-off-by: Vitaly Chikunov <vt@altlinux.org>
---
README | 1 +
src/evmctl.c | 81 ++++++++++++++++++++++++++++++++++++++++++++++----
tests/sign_verify.test | 1 +
3 files changed, 78 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..434e1b6 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 +2571,70 @@ 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 < 4) {
+ 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 - 4, 4);
+ 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 +2780,19 @@ 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
^ permalink raw reply related [flat|nested] 3+ messages in thread