added APDU input chaining

Update udev docs

docs/solo/udev.md

@@ -1,20 +1,21 @@
 # Summary
 
-On Linux, by default USB dongles can't be accessed by users, for security reasons. To allow user access, so-called "udev rules" must be installed. (Under Fedora, your key may work without such a rule.)
+On Linux, by default USB dongles can't be accessed by users, for security reasons. To allow user access, so-called "udev rules" must be installed.
 
-Create a file like [`70-solokeys-access.rules`](https://github.com/solokeys/solo/blob/master/udev/70-solokeys-access.rules) in your `/etc/udev/rules.d` directory, for instance the following rule should cover normal access (it has to be on one line):
+For some users, things will work automatically:
 
-```
-SUBSYSTEM=="hidraw", ATTRS{idVendor}=="0483", ATTRS{idProduct}=="a2ca", TAG+="uaccess", MODE="0660", GROUP="plugdev"
-```
+  - Fedora seems to use a ["universal" udev rule for FIDO devices](https://github.com/amluto/u2f-hidraw-policy)
+  - Our udev rule made it into [libu2f-host](https://github.com/Yubico/libu2f-host/) v1.1.10
+  - Arch Linux [has this package](https://www.archlinux.org/packages/community/x86_64/libu2f-host/)
+  - [Debian sid](https://packages.debian.org/sid/libu2f-udev) and [Ubuntu Eon](https://packages.ubuntu.com/eoan/libu2f-udev) can use the `libu2f-udev` package
+  - Debian Buster and Ubuntu Disco still distribute v1.1.10, so need the manual rule
+  - FreeBSD has support in [u2f-devd](https://github.com/solokeys/solo/issues/144#issuecomment-500216020)
 
-Additionally, run the following command after you create this file (it is not necessary to do this again in the future):
+There is hope that `udev` itself will adopt the Fedora approach (which is to check for HID usage page `F1D0`, and avoids manually whitelisting each U2F/FIDO2 key): <https://github.com/systemd/systemd/issues/11996>.
 
-```
-sudo udevadm control --reload-rules && sudo udevadm trigger
-```
+Further progress is tracked in: <https://github.com/solokeys/solo/issues/144>.
 
-A simple way to setup both the udev rule and the udevadm reload is:
+If you still need to setup a rule, a simple way to do it is:
 
 ```
 git clone git@github.com:solokeys/solo.git
@@ -22,9 +23,11 @@ cd solo/udev
 make setup
 ```
 
-We are working on getting user access to Solo keys enabled automatically in common Linux distributions: <https://github.com/solokeys/solo/issues/144>.
-
-
+Or, manually, create a file like [`70-solokeys-access.rules`](https://github.com/solokeys/solo/blob/master/udev/70-solokeys-access.rules) in your `/etc/udev/rules.d` directory.
+Additionally, run the following command after you create this file (it is not necessary to do this again in the future):
+```
+sudo udevadm control --reload-rules && sudo udevadm trigger
+```
 
 # How do udev rules work and why are they needed
 

fido2/apdu.c

@@ -13,7 +13,7 @@ int apdu_decode(uint8_t *data, size_t len, APDU_STRUCT *apdu)
 {
     EXT_APDU_HEADER *hapdu = (EXT_APDU_HEADER *)data;
     
-    apdu->cla = hapdu->cla;
+    apdu->cla = hapdu->cla & 0xef; // mask chaining bit if any
     apdu->ins = hapdu->ins;
     apdu->p1 = hapdu->p1;
     apdu->p2 = hapdu->p2;

fido2/apdu.h

@@ -44,12 +44,14 @@ extern int apdu_decode(uint8_t *data, size_t len, APDU_STRUCT *apdu);
 #define APDU_FIDO_NFCCTAP_MSG         0x10
 #define APDU_INS_SELECT               0xA4
 #define APDU_INS_READ_BINARY          0xB0
+#define APDU_GET_RESPONSE             0xC0
 
 #define SW_SUCCESS                    0x9000
 #define SW_GET_RESPONSE               0x6100  // Command successfully executed; 'XX' bytes of data are available and can be requested using GET RESPONSE.
 #define SW_WRONG_LENGTH               0x6700
 #define SW_COND_USE_NOT_SATISFIED     0x6985
 #define SW_FILE_NOT_FOUND             0x6a82
+#define SW_INCORRECT_P1P2             0x6a86
 #define SW_INS_INVALID                0x6d00  // Instruction code not supported or invalid
 #define SW_CLA_INVALID                0x6e00  
 #define SW_INTERNAL_EXCEPTION         0x6f00

fido2/crypto.c

@@ -262,6 +262,11 @@ void crypto_ecc256_derive_public_key(uint8_t * data, int len, uint8_t * x, uint8
     memmove(y,pubkey+32,32);
 }
 
+void crypto_ecc256_compute_public_key(uint8_t * privkey, uint8_t * pubkey)
+{
+    uECC_compute_public_key(privkey, pubkey, _es256_curve);
+}
+
 void crypto_load_external_key(uint8_t * key, int len)
 {
     _signing_key = key;

fido2/crypto.h

@@ -26,6 +26,7 @@ void crypto_sha512_final(uint8_t * hash);
 
 void crypto_ecc256_init();
 void crypto_ecc256_derive_public_key(uint8_t * data, int len, uint8_t * x, uint8_t * y);
+void crypto_ecc256_compute_public_key(uint8_t * privkey, uint8_t * pubkey);
 
 void crypto_ecc256_load_key(uint8_t * data, int len, uint8_t * data2, int len2);
 void crypto_ecc256_load_attestation_key();

fido2/ctap.c

@@ -256,7 +256,9 @@ static int ctap_generate_cose_key(CborEncoder * cose_key, uint8_t * hmac_input,
     switch(algtype)
     {
         case COSE_ALG_ES256:
+            if (device_is_nfc() == NFC_IS_ACTIVE) device_set_clock_rate(DEVICE_LOW_POWER_FAST);
             crypto_ecc256_derive_public_key(hmac_input, len, x, y);
+            if (device_is_nfc() == NFC_IS_ACTIVE) device_set_clock_rate(DEVICE_LOW_POWER_IDLE);
             break;
         default:
             printf2(TAG_ERR,"Error, COSE alg %d not supported\n", algtype);
@@ -1479,6 +1481,11 @@ uint8_t ctap_client_pin(CborEncoder * encoder, uint8_t * request, int length)
 
             ret = cbor_encode_int(&map, RESP_keyAgreement);
             check_ret(ret);
+
+            if (device_is_nfc() == NFC_IS_ACTIVE) device_set_clock_rate(DEVICE_LOW_POWER_FAST);
+            crypto_ecc256_compute_public_key(KEY_AGREEMENT_PRIV, KEY_AGREEMENT_PUB);
+            if (device_is_nfc() == NFC_IS_ACTIVE) device_set_clock_rate(DEVICE_LOW_POWER_IDLE);
+
             ret = ctap_add_cose_key(&map, KEY_AGREEMENT_PUB, KEY_AGREEMENT_PUB+32, PUB_KEY_CRED_PUB_KEY, COSE_ALG_ECDH_ES_HKDF_256);
             check_retr(ret);
 
@@ -1678,7 +1685,7 @@ uint8_t ctap_request(uint8_t * pkt_raw, int length, CTAP_RESPONSE * resp)
             break;
         default:
             status = CTAP1_ERR_INVALID_COMMAND;
-            printf2(TAG_ERR,"error, invalid cmd\n");
+            printf2(TAG_ERR,"error, invalid cmd: 0x%02x\n", cmd);
     }
 
 done:
@@ -1767,10 +1774,7 @@ void ctap_init()
         exit(1);
     }
 
-    if (device_is_nfc() != NFC_IS_ACTIVE)
-    {
     ctap_reset_key_agreement();
-    }
 
 #ifdef BRIDGE_TO_WALLET
     wallet_init();
@@ -1969,7 +1973,7 @@ int8_t ctap_load_key(uint8_t index, uint8_t * key)
 
 static void ctap_reset_key_agreement()
 {
-    crypto_ecc256_make_key_pair(KEY_AGREEMENT_PUB, KEY_AGREEMENT_PRIV);
+    ctap_generate_rng(KEY_AGREEMENT_PRIV, sizeof(KEY_AGREEMENT_PRIV));
 }
 
 void ctap_reset()

pc/device.c

@@ -628,3 +628,8 @@ int device_is_nfc()
 {
     return 0;
 }
+
+void device_set_clock_rate(DEVICE_CLOCK_RATE param)
+{
+
+}

targets/stm32l432/src/crypto.c

@@ -282,6 +282,11 @@ void crypto_ecc256_derive_public_key(uint8_t * data, int len, uint8_t * x, uint8
     memmove(x,pubkey,32);
     memmove(y,pubkey+32,32);
 }
+void crypto_ecc256_compute_public_key(uint8_t * privkey, uint8_t * pubkey)
+{
+    uECC_compute_public_key(privkey, pubkey, _es256_curve);
+}
+
 
 void crypto_load_external_key(uint8_t * key, int len)
 {

targets/stm32l432/src/nfc.c

@@ -14,6 +14,11 @@
 
 #define IS_IRQ_ACTIVE()         (1  == (LL_GPIO_ReadInputPort(SOLO_AMS_IRQ_PORT) & SOLO_AMS_IRQ_PIN))
 
+// chain buffer for 61XX responses
+static uint8_t chain_buffer[2048] = {0};
+static size_t chain_buffer_len = 0;
+static bool chain_buffer_tx = false;
+
 uint8_t p14443_block_offset(uint8_t pcb) {
     uint8_t offset = 1;
     // NAD following
@@ -213,7 +218,7 @@ bool nfc_write_response(uint8_t req0, uint16_t resp)
 	return nfc_write_response_ex(req0, NULL, 0, resp);
 }
 
-void nfc_write_response_chaining(uint8_t req0, uint8_t * data, int len)
+void nfc_write_response_chaining_plain(uint8_t req0, uint8_t * data, int len)
 {
     uint8_t res[32 + 2];
 	uint8_t iBlock = NFC_CMD_IBLOCK | (req0 & 0x0f);
@@ -284,6 +289,38 @@ void nfc_write_response_chaining(uint8_t req0, uint8_t * data, int len)
 	}
 }
 
+void append_get_response(uint8_t *data, size_t rest_len)
+{
+    data[0] = 0x61;
+    data[1] = 0x00;
+    if (rest_len <= 0xff)
+        data[1] = rest_len & 0xff;
+}
+
+void nfc_write_response_chaining(uint8_t req0, uint8_t * data, int len, bool extapdu)
+{
+    chain_buffer_len = 0;
+    chain_buffer_tx = true;
+    
+    // if we dont need to break data to parts that need to exchange via GET RESPONSE command (ISO 7816-4 7.1.3)
+	if (len <= 255 || extapdu)
+    {
+        nfc_write_response_chaining_plain(req0, data, len);
+    } else {
+        size_t pcklen = MIN(253, len);
+        chain_buffer_len = len - pcklen;
+        printf1(TAG_NFC, "61XX chaining %d/%d.\r\n", pcklen, chain_buffer_len);
+        
+        memmove(chain_buffer, data, pcklen);
+        append_get_response(&chain_buffer[pcklen], chain_buffer_len);
+       
+        nfc_write_response_chaining_plain(req0, chain_buffer, pcklen + 2); // 2 for 61XX 
+    
+        // put the rest data into chain buffer
+        memmove(chain_buffer, &data[pcklen], chain_buffer_len);        
+    }    
+}
+
 // WTX on/off:
 // sends/receives WTX frame to reader every `WTX_time` time in ms
 // works via timer interrupts
@@ -490,11 +527,14 @@ void nfc_process_iblock(uint8_t * buf, int len)
     int status;
     uint16_t reslen;
 
-    printf1(TAG_NFC,"Iblock: ");
-	dump_hex1(TAG_NFC, buf, len);
-
     uint8_t block_offset = p14443_block_offset(buf[0]);
     
+    // clear tx chain buffer if we have some other command than GET RESPONSE
+    if (chain_buffer_tx && buf[block_offset + 1] != APDU_GET_RESPONSE) {
+        chain_buffer_len = 0;
+        chain_buffer_tx = false;
+    }
+    
     APDU_STRUCT apdu;
     if (apdu_decode(buf + block_offset, len - block_offset, &apdu)) {
         printf1(TAG_NFC,"apdu decode error\r\n");
@@ -504,6 +544,31 @@ void nfc_process_iblock(uint8_t * buf, int len)
     printf1(TAG_NFC,"apdu ok. %scase=%02x cla=%02x ins=%02x p1=%02x p2=%02x lc=%d le=%d\r\n", 
         apdu.extended_apdu ? "[e]":"", apdu.case_type, apdu.cla, apdu.ins, apdu.p1, apdu.p2, apdu.lc, apdu.le);
 
+    // APDU level chaining. ISO7816-4, 5.1.1. class byte
+    if (!chain_buffer_tx && buf[block_offset] & 0x10) {
+        
+        if (chain_buffer_len + len > sizeof(chain_buffer)) {
+            nfc_write_response(buf[0], SW_WRONG_LENGTH);
+            return;
+        }
+        
+        memmove(&chain_buffer[chain_buffer_len], apdu.data, apdu.lc);
+        chain_buffer_len += apdu.lc;
+        delay(1);
+        nfc_write_response(buf[0], SW_SUCCESS);
+        printf1(TAG_NFC, "APDU chaining ok. %d/%d\r\n", apdu.lc, chain_buffer_len);
+        return;
+    }
+    
+    // if we have ISO 7816 APDU chain - move there all the data
+    if (!chain_buffer_tx && chain_buffer_len > 0) {
+        delay(1);
+        memmove(&apdu.data[chain_buffer_len], apdu.data, apdu.lc);
+        memmove(apdu.data, chain_buffer, chain_buffer_len);
+        apdu.lc += chain_buffer_len; // here apdu struct does not match with memory!
+        printf1(TAG_NFC, "APDU chaining merge. %d/%d\r\n", chain_buffer_len, apdu.lc);
+    }
+
     // check CLA
     if (apdu.cla != 0x00 && apdu.cla != 0x80) {
         printf1(TAG_NFC, "Unknown CLA %02x\r\n", apdu.cla);
@@ -514,6 +579,53 @@ void nfc_process_iblock(uint8_t * buf, int len)
     // TODO this needs to be organized better
     switch(apdu.ins)
     {
+        // ISO 7816. 7.1 GET RESPONSE command
+        case APDU_GET_RESPONSE:
+            if (apdu.p1 != 0x00 || apdu.p2 != 0x00)
+            {
+                nfc_write_response(buf[0], SW_INCORRECT_P1P2);
+                printf1(TAG_NFC, "P1 or P2 error\r\n");
+                return;
+            }
+            
+            // too many bytes needs. 0x00 and 0x100 - any length
+            if (apdu.le != 0 && apdu.le != 0x100 && apdu.le > chain_buffer_len)
+            {
+                uint16_t wlresp = SW_WRONG_LENGTH;  // here can be 6700, 6C00, 6FXX. but the most standard way - 67XX or 6700
+                if (chain_buffer_len <= 0xff)
+                    wlresp += chain_buffer_len & 0xff;
+                nfc_write_response(buf[0], wlresp);
+                printf1(TAG_NFC, "buffer length less than requesteds\r\n");
+                return;
+            }
+            
+            // create temporary packet
+            uint8_t pck[255] = {0};
+            size_t pcklen = 253;
+            if (apdu.le)
+                pcklen = apdu.le;
+            if (pcklen > chain_buffer_len)
+                pcklen = chain_buffer_len;
+
+            printf1(TAG_NFC, "GET RESPONSE. pck len: %d buffer len: %d\r\n", pcklen, chain_buffer_len); 
+            
+            // create packet and add 61XX there if we have another portion(s) of data
+            memmove(pck, chain_buffer, pcklen);
+            size_t dlen = 0;
+            if (chain_buffer_len - pcklen)
+            {
+                append_get_response(&pck[pcklen], chain_buffer_len - pcklen);
+                dlen = 2;
+            }
+
+            // send
+            nfc_write_response_chaining_plain(buf[0], pck, pcklen + dlen); // dlen for 61XX
+            
+            // shift the buffer
+            chain_buffer_len -= pcklen;
+            memmove(chain_buffer, &chain_buffer[pcklen], chain_buffer_len);
+        break;
+        
         case APDU_INS_SELECT:
             // if (apdu->p1 == 0 && apdu->p2 == 0x0c)
             // {
@@ -557,7 +669,7 @@ void nfc_process_iblock(uint8_t * buf, int len)
 			printf1(TAG_NFC, "U2F GetVersion command.\r\n");
 
 			u2f_request_nfc(&buf[block_offset], apdu.data, apdu.lc, &ctap_resp);
-            nfc_write_response_chaining(buf[0], ctap_resp.data, ctap_resp.length);
+            nfc_write_response_chaining(buf[0], ctap_resp.data, ctap_resp.length, apdu.extended_apdu);
         break;
 
         case APDU_FIDO_U2F_REGISTER:
@@ -589,7 +701,7 @@ void nfc_process_iblock(uint8_t * buf, int len)
 
 			printf1(TAG_NFC, "U2F resp len: %d\r\n", ctap_resp.length);
             printf1(TAG_NFC,"U2F Register P2 took %d\r\n", timestamp());
-            nfc_write_response_chaining(buf[0], ctap_resp.data, ctap_resp.length);
+            nfc_write_response_chaining(buf[0], ctap_resp.data, ctap_resp.length, apdu.extended_apdu);
 
             printf1(TAG_NFC,"U2F Register answered %d (took %d)\r\n", millis(), timestamp());
        break;
@@ -618,7 +730,7 @@ void nfc_process_iblock(uint8_t * buf, int len)
 
 			printf1(TAG_NFC, "U2F resp len: %d\r\n", ctap_resp.length);
             printf1(TAG_NFC,"U2F Authenticate processing %d (took %d)\r\n", millis(), timestamp());
-			nfc_write_response_chaining(buf[0], ctap_resp.data, ctap_resp.length);
+			nfc_write_response_chaining(buf[0], ctap_resp.data, ctap_resp.length, apdu.extended_apdu);
             printf1(TAG_NFC,"U2F Authenticate answered %d (took %d)\r\n", millis(), timestamp);
         break;
 
@@ -630,13 +742,16 @@ void nfc_process_iblock(uint8_t * buf, int len)
 
 			printf1(TAG_NFC, "FIDO2 CTAP message. %d\r\n", timestamp());
 
-			WTX_on(WTX_TIME_DEFAULT);
+			// WTX_on(WTX_TIME_DEFAULT);
             request_from_nfc(true);
             ctap_response_init(&ctap_resp);
+            delay(1);
+            printf1(TAG_NFC,"[%d] ", apdu.lc);
+            dump_hex1(TAG_NFC,apdu.data, apdu.lc);
             status = ctap_request(apdu.data, apdu.lc, &ctap_resp);
             request_from_nfc(false);
-			if (!WTX_off())
-				return;
+			// if (!WTX_off())
+			// 	return;
 
 			printf1(TAG_NFC, "CTAP resp: 0x%02x  len: %d\r\n", status, ctap_resp.length);
 
@@ -652,7 +767,7 @@ void nfc_process_iblock(uint8_t * buf, int len)
 			ctap_resp.data[ctap_resp.length - 1] = SW_SUCCESS & 0xff;
 
             printf1(TAG_NFC,"CTAP processing %d (took %d)\r\n", millis(), timestamp());
-			nfc_write_response_chaining(buf[0], ctap_resp.data, ctap_resp.length);
+			nfc_write_response_chaining(buf[0], ctap_resp.data, ctap_resp.length, apdu.extended_apdu);
             printf1(TAG_NFC,"CTAP answered %d (took %d)\r\n", millis(), timestamp());
         break;
 
@@ -688,6 +803,9 @@ void nfc_process_iblock(uint8_t * buf, int len)
 			nfc_write_response(buf[0], SW_INS_INVALID);
         break;
     }
+    
+    printf1(TAG_NFC,"prev.Iblock: ");
+	dump_hex1(TAG_NFC, buf, len);
 }
 
 static uint8_t ibuf[1024];
@@ -721,7 +839,7 @@ void nfc_process_block(uint8_t * buf, unsigned int len)
         uint8_t block_offset = p14443_block_offset(buf[0]);
 		if (buf[0] & 0x10)
 		{
-			printf1(TAG_NFC_APDU, "NFC_CMD_IBLOCK chaining blen=%d len=%d\r\n", ibuflen, len);
+			printf1(TAG_NFC_APDU, "NFC_CMD_IBLOCK chaining blen=%d len=%d offs=%d\r\n", ibuflen, len, block_offset);
 			if (ibuflen + len > sizeof(ibuf))
 			{
 				printf1(TAG_NFC, "I block memory error! must have %d but have only %d\r\n", ibuflen + len, sizeof(ibuf));
@@ -754,14 +872,15 @@ void nfc_process_block(uint8_t * buf, unsigned int len)
 				memmove(ibuf, buf, block_offset);
 				ibuflen += block_offset;
 
-				printf1(TAG_NFC_APDU, "NFC_CMD_IBLOCK chaining last block. blen=%d len=%d\r\n", ibuflen, len);
+				printf1(TAG_NFC_APDU, "NFC_CMD_IBLOCK chaining last block. blen=%d len=%d offset=%d\r\n", ibuflen, len, block_offset);
 
 				printf1(TAG_NFC_APDU,"i> ");
 				dump_hex1(TAG_NFC_APDU, buf, len);
 
 				nfc_process_iblock(ibuf, ibuflen);
 			} else {
-				nfc_process_iblock(buf, len);
+                memcpy(ibuf, buf, len); // because buf only 32b
+				nfc_process_iblock(ibuf, len);
 			}
 			clear_ibuf();
 		}