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CLI: Fix getting selfsigning cert for ED25519 key
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@aveenismail
aveenismail committed Apr 29, 2024
1 parent 0662ad6 commit 496d26d
Showing 1 changed file with 152 additions and 22 deletions.
174 changes: 152 additions & 22 deletions tool/yubico-piv-tool.c
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Original file line number Diff line number Diff line change
Expand Up @@ -55,6 +55,8 @@
#include <openssl/rsa.h>
#include <openssl/x509v3.h>
#include <openssl/err.h>
#include <openssl/evp.h>
#include <openssl/crypto.h>
#include <zlib.h>

#include "cmdline.h"
Expand Down Expand Up @@ -252,12 +254,6 @@ static EVP_PKEY* wrap_public_key(ykpiv_state *state, int algorithm, EVP_PKEY *pu
fprintf(stderr, "Failed to wrap public EC key\n");
}
EVP_PKEY_assign_EC_KEY(pkey, sk);
#if (OPENSSL_VERSION_NUMBER >= 0x10100000L)
} else if (algorithm == YKPIV_ALGO_ED25519) {
EVP_PKEY_assign(pkey, EVP_PKEY_ED25519, public_key);
} else if (algorithm == YKPIV_ALGO_X25519) {
EVP_PKEY_assign(pkey, EVP_PKEY_X25519, public_key);
#endif
}
return pkey;
}
Expand Down Expand Up @@ -1031,17 +1027,84 @@ static bool request_certificate(ykpiv_state *state, enum enum_key_format key_for
req->signature->flags = ASN1_STRING_FLAG_BITS_LEFT;
}
#else
/* With opaque structures we can not touch whatever we want, but we need
* to embed the sign_data function in the RSA/EC key structures */
EVP_PKEY *sk = wrap_public_key(state, algorithm, public_key, key, oid, oid_len);

if(X509_REQ_sign(req, sk, md) == 0) {
fprintf(stderr, "Failed signing request.\n");
ERR_print_errors_fp(stderr);
#if (OPENSSL_VERSION_NUMBER >= 0x10100000L)
if (algorithm == YKPIV_ALGO_ED25519) {

// Generate a dummy ED25519 to sign with OpenSSL
EVP_PKEY *ed_key = NULL;
EVP_PKEY_CTX *ed_ctx = EVP_PKEY_CTX_new_id(EVP_PKEY_ED25519, NULL);
EVP_PKEY_keygen_init(ed_ctx);
EVP_PKEY_keygen(ed_ctx, &ed_key);
EVP_PKEY_CTX_free(ed_ctx);
PEM_write_PrivateKey(stdout, ed_key, NULL, NULL, 0, NULL, NULL);

// Sign the request object using the dummy key
if (X509_REQ_sign(req, ed_key, md) == 0) {
fprintf(stderr, "Failed signing certificate.\n");
ERR_print_errors_fp(stderr);
EVP_PKEY_free(ed_key);
goto request_out;
}
EVP_PKEY_free(ed_key);

// encode the signed certificate request
unsigned char *all_req_data = NULL;
int all_req_len = i2d_X509_REQ(req, &all_req_data);

// Extract the request data without the signature
unsigned char *req_data = NULL;
int req_len = i2d_re_X509_REQ_tbs(req, &req_data);

// Extract the signature from the certificate and encode it
ASN1_BIT_STRING *psig;
const X509_ALGOR *palg;
X509_REQ_get0_signature(req, (const ASN1_BIT_STRING **) &psig, &palg);
unsigned char *ossl_sig_data = NULL;
int ossl_sig_len = i2d_ASN1_BIT_STRING(psig, &ossl_sig_data);

// Sign the request data using the YubiKey
unsigned char yk_sig[1024] = {0};
size_t yk_siglen = sizeof(yk_sig);
if (!sign_data(state, req_data, req_len, yk_sig, &yk_siglen, algorithm, key)) {
fprintf(stderr, "Failed signing tbs request portion.\n");
EVP_PKEY_free(ed_key);
goto request_out;
}

// replace the signature from OpenSSL with the signature from the YubiKey
ASN1_BIT_STRING_set(psig, yk_sig, yk_siglen);
unsigned char *sig_data = NULL;
int sig_len = i2d_ASN1_BIT_STRING(psig, &sig_data);

// Find the signature on the req from OpenSSL and replace it with the signature from the YubiKey
unsigned char *p = all_req_data;
while((memcmp(p, ossl_sig_data, ossl_sig_len) != 0) && (p < all_req_data+all_req_len)) {
p++;
}
if(p >= all_req_data+all_req_len) {
fprintf(stderr, "Failed to find dummy signature.\n");
goto request_out;
}
memcpy(p, sig_data, sig_len);

} else {
#endif
/* With opaque structures we can not touch whatever we want, but we need
* to embed the sign_data function in the RSA/EC key structures */
EVP_PKEY *sk = wrap_public_key(state, algorithm, public_key, key, oid, oid_len);

if(X509_REQ_sign(req, sk, md) == 0) {
fprintf(stderr, "Failed signing request.\n");
ERR_print_errors_fp(stderr);
EVP_PKEY_free(sk);
goto request_out;
}
EVP_PKEY_free(sk);
goto request_out;
#if (OPENSSL_VERSION_NUMBER >= 0x10100000L)
}
EVP_PKEY_free(sk);
#endif

#endif

if(key_format == key_format_arg_PEM) {
Expand Down Expand Up @@ -1341,18 +1404,85 @@ static bool selfsign_certificate(ykpiv_state *state, enum enum_key_format key_fo
x509->signature->flags = ASN1_STRING_FLAG_BITS_LEFT;
}
#else
/* With opaque structures we can not touch whatever we want, but we need
* to embed the sign_data function in the RSA/EC key structures */
EVP_PKEY *sk = wrap_public_key(state, algorithm, public_key, key, oid, oid_len);

if(X509_sign(x509, sk, md) == 0) {
fprintf(stderr, "Failed signing certificate.\n");
ERR_print_errors_fp(stderr);
#if (OPENSSL_VERSION_NUMBER >= 0x10100000L)
if (algorithm == YKPIV_ALGO_ED25519) {

// Generate a dummy ED25519 to sign with OpenSSL
EVP_PKEY *ed_key = NULL;
EVP_PKEY_CTX *ed_ctx = EVP_PKEY_CTX_new_id(EVP_PKEY_ED25519, NULL);
EVP_PKEY_keygen_init(ed_ctx);
EVP_PKEY_keygen(ed_ctx, &ed_key);
EVP_PKEY_CTX_free(ed_ctx);
PEM_write_PrivateKey(stdout, ed_key, NULL, NULL, 0, NULL, NULL);

// Sign the X509 object using the dummy key
if (X509_sign(x509, ed_key, md) == 0) {
fprintf(stderr, "Failed signing certificate.\n");
ERR_print_errors_fp(stderr);
EVP_PKEY_free(ed_key);
goto selfsign_out;
}
EVP_PKEY_free(ed_key);

// encode the signed certificate
unsigned char *all_cert_data = NULL;
int all_cert_len = i2d_X509(x509, &all_cert_data);

// Extract the certificate data without the signature
unsigned char *cert_data = NULL;
int cert_len = i2d_re_X509_tbs(x509, &cert_data);

// Extract the signature from the certificate and encode it
ASN1_BIT_STRING *psig;
const X509_ALGOR *palg;
X509_get0_signature((const ASN1_BIT_STRING **) &psig, &palg, x509);
unsigned char *ossl_sig_data = NULL;
int ossl_sig_len = i2d_ASN1_BIT_STRING(psig, &ossl_sig_data);

// Sign the certificate data using the YubiKey
unsigned char yk_sig[1024] = {0};
size_t yk_siglen = sizeof(yk_sig);
if (!sign_data(state, cert_data, cert_len, yk_sig, &yk_siglen, algorithm, key)) {
fprintf(stderr, "Failed signing tbs certificate portion.\n");
EVP_PKEY_free(ed_key);
goto selfsign_out;
}

// replace the signature from OpenSSL with the signature from the YubiKey
ASN1_BIT_STRING_set(psig, yk_sig, yk_siglen);
unsigned char *sig_data = NULL;
int sig_len = i2d_ASN1_BIT_STRING(psig, &sig_data);


// Find the signature on the cert from OpenSSL and replace it with the signature from the YubiKey
unsigned char *p = all_cert_data;
while((memcmp(p, ossl_sig_data, ossl_sig_len) != 0) && (p < all_cert_data+all_cert_len)) {
p++;
}
if(p >= all_cert_data+all_cert_len) {
fprintf(stderr, "Failed to find dummy signature.\n");
goto selfsign_out;
}
memcpy(p, sig_data, sig_len);

} else {
#endif
/* With opaque structures we can not touch whatever we want, but we need
* to embed the sign_data function in the RSA/EC key structures */
EVP_PKEY *sk = wrap_public_key(state, algorithm, public_key, key, oid, oid_len);

if(X509_sign(x509, sk, md) == 0) {
fprintf(stderr, "Failed signing certificate.\n");
ERR_print_errors_fp(stderr);
EVP_PKEY_free(sk);
goto selfsign_out;
}
EVP_PKEY_free(sk);
goto selfsign_out;
#if (OPENSSL_VERSION_NUMBER >= 0x10100000L)
}
#endif

EVP_PKEY_free(sk);
#endif

if(key_format == key_format_arg_PEM) {
Expand Down

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