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 ABI change for libimaevm, because of adding
additional parameter to imaevm_params - newer libimaevm cannot work
with older clients.
Signed-off-by: Vitaly Chikunov <vt@xxxxxxxxxxxx>
Reported-by: Elvira Khabirova <lineprinter0@xxxxxxxxx>
Reviewed-by: Stefan Berger <stefanb@xxxxxxxxxxxxx>
---
README | 1 +
src/evmctl.c | 15 +++++++++++++++
src/imaevm.h | 1 +
src/libimaevm.c | 8 +++++---
tests/sign_verify.test | 1 +
5 files changed, 23 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 7a6f202..d853d34 100644
--- a/src/evmctl.c
+++ b/src/evmctl.c
@@ -2514,6 +2514,7 @@ 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"
@@ -2594,6 +2595,7 @@ static struct option opts[] = {
{"ignore-violations", 0, 0, 141},
{"pcrs", 1, 0, 142},
{"verify-bank", 2, 0, 143},
+ {"keyid", 1, 0, 144},
{}
};
@@ -2638,6 +2640,8 @@ 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(
@@ -2785,6 +2789,17 @@ int main(int argc, char *argv[])
case 143:
verify_bank = optarg;
break;
+ case 144:
+ errno = 0;
+ keyid = strtoul(optarg, &eptr, 16);
+ if (errno || eptr - optarg != strlen(optarg) ||
+ keyid == ULONG_MAX || 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 3d7aa51..eccf5fa 100755
--- a/tests/sign_verify.test
+++ b/tests/sign_verify.test
@@ -365,6 +365,7 @@ 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
