diff --git a/core/SConscript.prodtest b/core/SConscript.prodtest
index ec71b3cc7..7e66eb938 100644
--- a/core/SConscript.prodtest
+++ b/core/SConscript.prodtest
@@ -57,8 +57,10 @@ SOURCE_MOD += [
'vendor/trezor-crypto/aes/aeskey.c',
'vendor/trezor-crypto/aes/aestab.c',
'vendor/trezor-crypto/bignum.c',
+ 'vendor/trezor-crypto/buffer.c',
'vendor/trezor-crypto/chacha_drbg.c',
'vendor/trezor-crypto/chacha20poly1305/chacha_merged.c',
+ 'vendor/trezor-crypto/der.c',
'vendor/trezor-crypto/ecdsa.c',
'vendor/trezor-crypto/hmac.c',
'vendor/trezor-crypto/hmac_drbg.c',
diff --git a/core/embed/prodtest/optiga_prodtest.c b/core/embed/prodtest/optiga_prodtest.c
index c59a0553a..927fc5b1a 100644
--- a/core/embed/prodtest/optiga_prodtest.c
+++ b/core/embed/prodtest/optiga_prodtest.c
@@ -17,12 +17,16 @@
* along with this program. If not, see .
*/
-#include "optiga_prodtest.h"
+#include
+
#include "aes/aes.h"
+#include "buffer.h"
+#include "der.h"
#include "ecdsa.h"
#include "memzero.h"
#include "nist256p1.h"
#include "optiga_commands.h"
+#include "optiga_prodtest.h"
#include "optiga_transport.h"
#include "prodtest_common.h"
#include "rand.h"
@@ -295,7 +299,7 @@ void optigaid_read(void) {
void cert_read(uint16_t oid) {
if (!optiga_paired()) return;
- static uint8_t cert[2048] = {0};
+ static uint8_t cert[OPTIGA_MAX_CERT_SIZE] = {0};
size_t cert_size = 0;
optiga_result ret =
optiga_get_data_object(oid, false, cert, sizeof(cert), &cert_size);
@@ -337,7 +341,7 @@ void cert_write(uint16_t oid, char *data) {
metadata.change = OPTIGA_META_ACCESS_ALWAYS;
set_metadata(oid, &metadata); // Ignore result.
- uint8_t data_bytes[1024];
+ uint8_t data_bytes[OPTIGA_MAX_CERT_SIZE];
int len = get_from_hex(data_bytes, sizeof(data_bytes), data);
if (len < 0) {
@@ -351,6 +355,21 @@ void cert_write(uint16_t oid, char *data) {
return;
}
+ // Verify that the certificate was written correctly.
+ static uint8_t cert[OPTIGA_MAX_CERT_SIZE] = {0};
+ size_t cert_size = 0;
+ ret = optiga_get_data_object(oid, false, cert, sizeof(cert), &cert_size);
+ if (OPTIGA_SUCCESS != ret || cert_size != len ||
+ memcmp(data_bytes, cert, len) != 0) {
+ vcp_println("ERROR optiga_get_data_object error %d for 0x%04x.", ret, oid);
+ return;
+ }
+
+ if (oid == OID_CERT_DEV && !check_device_cert_chain(cert, cert_size)) {
+ // Error returned by check_device_cert_chain().
+ return;
+ }
+
vcp_println("OK");
}
@@ -512,3 +531,165 @@ void sec_read(void) {
vcp_print("OK ");
vcp_println_hex(&sec, sizeof(sec));
}
+
+// clang-format off
+static const uint8_t ECDSA_WITH_SHA256[] = {
+ 0x30, 0x0a, // a sequence of 10 bytes
+ 0x06, 0x08, // an OID of 8 bytes
+ 0x2a, 0x86, 0x48, 0xce, 0x3d, 0x04, 0x03, 0x02,
+};
+// clang-format on
+
+static const uint8_t ROOT_PUBLIC_KEYS[][65] = {
+ {
+ // Production root public key.
+ 0x04, 0xca, 0x97, 0x48, 0x0a, 0xc0, 0xd7, 0xb1, 0xe6, 0xef, 0xaf,
+ 0xe5, 0x18, 0xcd, 0x43, 0x3c, 0xec, 0x2b, 0xf8, 0xab, 0x98, 0x22,
+ 0xd7, 0x6e, 0xaf, 0xd3, 0x43, 0x63, 0xb5, 0x5d, 0x63, 0xe6, 0x03,
+ 0x80, 0xbf, 0xf2, 0x0a, 0xcc, 0x75, 0xcd, 0xe0, 0x3c, 0xff, 0xcb,
+ 0x50, 0xab, 0x6f, 0x8c, 0xe7, 0x0c, 0x87, 0x8e, 0x37, 0xeb, 0xc5,
+ 0x8f, 0xf7, 0xcc, 0xa0, 0xa8, 0x3b, 0x16, 0xb1, 0x5f, 0xa5,
+ },
+ {
+ // Development root public key.
+ 0x04, 0x7f, 0x77, 0x36, 0x8d, 0xea, 0x2d, 0x4d, 0x61, 0xe9, 0x89,
+ 0xf4, 0x74, 0xa5, 0x67, 0x23, 0xc3, 0x21, 0x2d, 0xac, 0xf8, 0xa8,
+ 0x08, 0xd8, 0x79, 0x55, 0x95, 0xef, 0x38, 0x44, 0x14, 0x27, 0xc4,
+ 0x38, 0x9b, 0xc4, 0x54, 0xf0, 0x20, 0x89, 0xd7, 0xf0, 0x8b, 0x87,
+ 0x30, 0x05, 0xe4, 0xc2, 0x8d, 0x43, 0x24, 0x68, 0x99, 0x78, 0x71,
+ 0xc0, 0xbf, 0x28, 0x6f, 0xd3, 0x86, 0x1e, 0x21, 0xe9, 0x6a,
+ },
+};
+
+bool check_device_cert_chain(const uint8_t *chain, size_t chain_size) {
+ // Checks the integrity of the device certificate chain to ensure that the
+ // certificate data was not corrupted in transport and that the device
+ // certificate belongs to this device. THIS IS NOT A FULL VERIFICATION OF THE
+ // CERTIFICATE CHAIN.
+
+ // Generate a P-256 signature using the device private key.
+ uint8_t digest[SHA256_DIGEST_LENGTH] = {1};
+ uint8_t der_sig[72] = {DER_SEQUENCE};
+ size_t der_sig_size = 0;
+ if (optiga_calc_sign(OID_KEY_DEV, digest, sizeof(digest), &der_sig[2],
+ sizeof(der_sig) - 2, &der_sig_size) != OPTIGA_SUCCESS) {
+ vcp_println("ERROR check_device_cert_chain, optiga_calc_sign.");
+ return false;
+ }
+ der_sig[1] = der_sig_size;
+
+ uint8_t sig[64] = {0};
+ if (ecdsa_sig_from_der(der_sig, der_sig_size + 2, sig) != 0) {
+ vcp_println("ERROR check_device_cert_chain, ecdsa_sig_from_der.");
+ return false;
+ }
+
+ BUFFER_READER chain_reader = {0};
+ buffer_reader_init(&chain_reader, chain, chain_size);
+ int cert_count = 0;
+ while (buffer_remaining(&chain_reader) > 0) {
+ // Read the next certificate in the chain.
+ cert_count += 1;
+ DER_ITEM cert = {0};
+ if (!der_read_item(&chain_reader, &cert) || cert.id != DER_SEQUENCE) {
+ vcp_println("ERROR check_device_cert_chain, der_read_item 1, cert %d.",
+ cert_count);
+ return false;
+ }
+
+ // Read the tbsCertificate.
+ DER_ITEM tbs_cert = {0};
+ if (!der_read_item(&cert.buf, &tbs_cert)) {
+ vcp_println("ERROR check_device_cert_chain, der_read_item 2, cert %d.",
+ cert_count);
+ return false;
+ }
+
+ // Read the Subject Public Key Info.
+ DER_ITEM pub_key_info = {0};
+ for (int i = 0; i < 7; ++i) {
+ if (!der_read_item(&tbs_cert.buf, &pub_key_info)) {
+ vcp_println("ERROR check_device_cert_chain, der_read_item 3, cert %d.",
+ cert_count);
+ return false;
+ }
+ }
+
+ // Read the public key.
+ DER_ITEM pub_key = {0};
+ uint8_t unused_bits = 0;
+ const uint8_t *pub_key_bytes = NULL;
+ for (int i = 0; i < 2; ++i) {
+ if (!der_read_item(&pub_key_info.buf, &pub_key)) {
+ vcp_println("ERROR check_device_cert_chain, der_read_item 4, cert %d.",
+ cert_count);
+ return false;
+ }
+ }
+
+ if (!buffer_get(&pub_key.buf, &unused_bits) ||
+ buffer_remaining(&pub_key.buf) != 65 ||
+ !buffer_ptr(&pub_key.buf, &pub_key_bytes)) {
+ vcp_println("ERROR check_device_cert_chain, reading public key, cert %d.",
+ cert_count);
+ return false;
+ }
+
+ // Verify the previous signature.
+ if (ecdsa_verify_digest(&nist256p1, pub_key_bytes, sig, digest) != 0) {
+ vcp_println(
+ "ERROR check_device_cert_chain, ecdsa_verify_digest, cert %d.",
+ cert_count);
+ return false;
+ }
+
+ // Prepare the hash of tbsCertificate for the next signature verification.
+ sha256_Raw(tbs_cert.buf.data, tbs_cert.buf.size, digest);
+
+ // Read the signatureAlgorithm and ensure it matches ECDSA_WITH_SHA256.
+ DER_ITEM sig_alg = {0};
+ if (!der_read_item(&cert.buf, &sig_alg) ||
+ sig_alg.buf.size != sizeof(ECDSA_WITH_SHA256) ||
+ memcmp(ECDSA_WITH_SHA256, sig_alg.buf.data,
+ sizeof(ECDSA_WITH_SHA256)) != 0) {
+ vcp_println(
+ "ERROR check_device_cert_chain, checking signatureAlgorithm, cert "
+ "%d.",
+ cert_count);
+ return false;
+ }
+
+ // Read the signatureValue.
+ DER_ITEM sig_val = {0};
+ if (!der_read_item(&cert.buf, &sig_val) || sig_val.id != DER_BIT_STRING ||
+ !buffer_get(&sig_val.buf, &unused_bits) || unused_bits != 0) {
+ vcp_println(
+ "ERROR check_device_cert_chain, reading signatureValue, cert %d.",
+ cert_count);
+ return false;
+ }
+
+ // Extract the signature for the next signature verification.
+ const uint8_t *sig_bytes = NULL;
+ if (!buffer_ptr(&sig_val.buf, &sig_bytes) ||
+ ecdsa_sig_from_der(sig_bytes, buffer_remaining(&sig_val.buf), sig) !=
+ 0) {
+ vcp_println("ERROR check_device_cert_chain, ecdsa_sig_from_der, cert %d.",
+ cert_count);
+ return false;
+ }
+ }
+
+ // Verify that the last certificate in the chain is valid for one of the known
+ // root public keys.
+ for (int i = 0; i < sizeof(ROOT_PUBLIC_KEYS) / sizeof(ROOT_PUBLIC_KEYS[0]);
+ ++i) {
+ if (ecdsa_verify_digest(&nist256p1, ROOT_PUBLIC_KEYS[i], sig, digest) ==
+ 0) {
+ return true;
+ }
+ }
+
+ vcp_println("ERROR check_device_cert_chain, ecdsa_verify_digest root.");
+ return false;
+}
diff --git a/core/embed/prodtest/optiga_prodtest.h b/core/embed/prodtest/optiga_prodtest.h
index 6c4f34e80..313349f37 100644
--- a/core/embed/prodtest/optiga_prodtest.h
+++ b/core/embed/prodtest/optiga_prodtest.h
@@ -48,5 +48,6 @@ void optiga_lock(void);
optiga_locked_status get_optiga_locked_status(void);
void check_locked(void);
void sec_read(void);
+bool check_device_cert_chain(const uint8_t *chain, size_t chain_size);
#endif
diff --git a/core/embed/trezorhal/optiga_commands.h b/core/embed/trezorhal/optiga_commands.h
index 5b0fda968..cf5b6fc81 100644
--- a/core/embed/trezorhal/optiga_commands.h
+++ b/core/embed/trezorhal/optiga_commands.h
@@ -130,6 +130,7 @@ typedef struct {
#define OPTIGA_MAX_METADATA_SIZE 44
#define OPTIGA_RANDOM_MIN_SIZE 8
#define OPTIGA_RANDOM_MAX_SIZE 256
+#define OPTIGA_MAX_CERT_SIZE 1728
#define OPTIGA_ACCESS_CONDITION(ac_id, oid) \
{ (const uint8_t[]){ac_id, oid >> 8, oid & 0xff}, 3 }
diff --git a/crypto/buffer.c b/crypto/buffer.c
index 9b6d34eac..1306224aa 100644
--- a/crypto/buffer.c
+++ b/crypto/buffer.c
@@ -46,6 +46,16 @@ size_t buffer_remaining(BUFFER_READER *buf) {
return buf->size - buf->pos;
}
+bool buffer_ptr(BUFFER_READER *buf, const uint8_t **ptr) {
+ if ((buf->data == NULL) || (buf->pos > buf->size)) {
+ return false;
+ }
+
+ *ptr = &buf->data[buf->pos];
+
+ return true;
+}
+
bool buffer_peek(const BUFFER_READER *buf, uint8_t *byte) {
if ((buf->data == NULL) || (buf->pos >= buf->size)) {
return false;
diff --git a/crypto/buffer.h b/crypto/buffer.h
index 6be46dcf2..cfc9cd3da 100644
--- a/crypto/buffer.h
+++ b/crypto/buffer.h
@@ -46,6 +46,7 @@ typedef struct {
void buffer_reader_init(BUFFER_READER *buf, const uint8_t *data, size_t size);
void buffer_writer_init(BUFFER_WRITER *buf, uint8_t *data, size_t size);
size_t __wur buffer_remaining(BUFFER_READER *buf);
+bool __wur buffer_ptr(BUFFER_READER *buf, const uint8_t **ptr);
bool __wur buffer_peek(const BUFFER_READER *buf, uint8_t *byte);
bool __wur buffer_get(BUFFER_READER *buf, uint8_t *byte);
bool __wur buffer_seek(BUFFER_READER *buf, size_t pos);
diff --git a/crypto/der.h b/crypto/der.h
index b6c84033c..ed3bc1afe 100644
--- a/crypto/der.h
+++ b/crypto/der.h
@@ -32,6 +32,7 @@
#define DER_SEQUENCE 0x30
#define DER_INTEGER 0x02
+#define DER_BIT_STRING 0x03
// Struct representing a DER-encoded ASN.1 data value.
typedef struct {