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@fbeutin-ledger
fbeutin-ledger committed Aug 1, 2023
1 parent b22def4 commit eed7f31
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Showing 7 changed files with 171 additions and 116 deletions.
25 changes: 2 additions & 23 deletions src/command_dispatcher.c
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Original file line number Diff line number Diff line change
Expand Up @@ -16,31 +16,10 @@

#include "io.h"


int dispatch_command(command_t *cmd) {
PRINTF("command: %d, subcommand: %d, state: %d\n", cmd->ins, cmd->subcommand, G_swap_ctx.state);

if (cmd->rate != FIXED && cmd->rate != FLOATING) {
PRINTF("Unexpected P1 %d\n", cmd->rate);
return reply_error(WRONG_P1);
}

if (cmd->subcommand != SWAP && cmd->subcommand != SELL && cmd->subcommand != FUND) {
PRINTF("Attempting to recognize NG subcommand\n");
uint8_t subcommand = 0x0F & cmd->subcommand;
uint8_t extension = 0xF0 & cmd->subcommand;
PRINTF("subcommand = %d\n", subcommand);
PRINTF("extension = %d\n", extension);
if (subcommand != SWAP_NG && subcommand != SELL_NG && subcommand != FUND_NG) {
PRINTF("Unexpected subcommand %d\n", subcommand);
return reply_error(WRONG_P2);
}
if (extension != P2_NONE && extension != P2_MORE && extension != P2_EXTEND && (extension != (P2_MORE | P2_EXTEND))) {
PRINTF("Unexpected extension %d\n", extension);
return reply_error(WRONG_P2);
}
cmd->subcommand = subcommand;
}

int ret = -1;
bool valid_command_received = false;

Expand Down Expand Up @@ -72,7 +51,7 @@ int dispatch_command(command_t *cmd) {
}
break;
case PROCESS_TRANSACTION_RESPONSE_COMMAND:
if (G_swap_ctx.state == TRANSACTION_RECEIVE_IN_PROGRESS && cmd->subcommand == G_swap_ctx.subcommand) {
if (G_swap_ctx.state == PROVIDER_CHECKED && cmd->subcommand == G_swap_ctx.subcommand) {
ret = process_transaction(cmd);
valid_command_received = true;
}
Expand Down
17 changes: 11 additions & 6 deletions src/commands.h
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Original file line number Diff line number Diff line change
@@ -1,7 +1,7 @@
#ifndef _COMMANDS_H_
#define _COMMANDS_H_
#pragma once

#include "buffer.h"

// commands
typedef enum {
GET_VERSION_COMMAND = 0x02,
Expand All @@ -15,12 +15,19 @@ typedef enum {
START_SIGNING_TRANSACTION = 0x0A,
} command_e;

// subcommands
typedef enum { SWAP = 0x00, SELL = 0x01, FUND = 0x02, SWAP_NG = 0x03, SELL_NG = 0x04, FUND_NG = 0x05 } subcommand_e;

// Different rates possible
typedef enum { FIXED = 0x00, FLOATING = 0x01 } rate_e;

// subcommands
typedef enum { SWAP = 0x00, SELL = 0x01, FUND = 0x02, SWAP_NG = 0x03, SELL_NG = 0x04, FUND_NG = 0x05 } subcommand_e;
#define SUBCOMMAND_PART 0x0F

#define P2_NONE (0x00 << 4)
#define P2_EXTEND (0x01 << 4)
#define P2_MORE (0x02 << 4)
#define EXTENSION_PART 0xF0

/**
* Structure with fields of APDU command.
*/
Expand All @@ -30,5 +37,3 @@ typedef struct {
subcommand_e subcommand; /// P2
buf_t data; /// Command data
} command_t;

#endif //_COMMANDS_H_
17 changes: 5 additions & 12 deletions src/globals.h
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Original file line number Diff line number Diff line change
Expand Up @@ -8,13 +8,6 @@
#include "buffer.h"
#include "swap_lib_calls.h"

#define P1_CONFIRM 0x01
#define P1_NON_CONFIRM 0x00

#define P2_NONE (0x00 << 4)
#define P2_EXTEND (0x01 << 4)
#define P2_MORE (0x02 << 4)

#define CURVE_SIZE_BYTES 32U
#define UNCOMPRESSED_KEY_LENGTH 65U
#define MIN_DER_SIGNATURE_LENGTH 67U
Expand All @@ -34,7 +27,7 @@ extern uint8_t G_io_seproxyhal_spi_buffer[IO_SEPROXYHAL_BUFFER_SIZE_B];

#pragma pack(push, 1)
typedef struct partner_data_s {
unsigned char name_length;
uint8_t name_length;
union {
// SELL and SWAP flows display nothing
// FUND flow displays "To xyz"
Expand All @@ -50,12 +43,12 @@ typedef struct partner_data_s {

typedef struct swap_app_context_s {
union {
unsigned char sell_fund[32]; // device_transaction_id (SELL && FUND && NG)
uint8_t sell_fund[32]; // device_transaction_id (SELL && FUND && NG)
char swap[10]; // device_transaction_id (SWAP)
} device_transaction_id;

unsigned char transaction_fee[16];
unsigned char transaction_fee_length;
uint8_t transaction_fee[16];
uint8_t transaction_fee_length;

partner_data_t partner;
state_e state;
Expand All @@ -77,7 +70,7 @@ typedef struct swap_app_context_s {
};
};

unsigned char sha256_digest[32];
uint8_t sha256_digest[32];

cx_ecfp_256_public_key_t ledger_public_key;

Expand Down
114 changes: 91 additions & 23 deletions src/main.c
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Original file line number Diff line number Diff line change
Expand Up @@ -37,15 +37,16 @@ uint8_t G_io_seproxyhal_spi_buffer[IO_SEPROXYHAL_BUFFER_SIZE_B];

typedef struct apdu_s {
uint8_t ins;
uint8_t p1;
uint8_t p2;
uint8_t rate;
uint8_t subcommand;
uint16_t data_length;
uint8_t data[510];
} apdu_t;
apdu_t G_received_apdu;

swap_app_context_t G_swap_ctx;


void app_main(void) {
int input_length = 0;

Expand All @@ -54,43 +55,109 @@ void app_main(void) {
for (;;) {
input_length = recv_apdu();
PRINTF("New APDU received:\n%.*H\n", input_length, G_io_apdu_buffer);
if (input_length == -1) // there were an error, lets start from the beginning
// there were a fatal error during APDU reception, restart from the beginning
// Don't bother trying to send a status code, IOs are probably out
if (input_length == -1) {
return;
if (input_length < OFFSET_CDATA || G_io_apdu_buffer[OFFSET_CLA] != CLA) {
PRINTF("Error: bad APDU\n");
reply_error(INVALID_INSTRUCTION);
}

if (input_length < OFFSET_CDATA) {
PRINTF("Error: malformed APDU\n");
reply_error(MALFORMED_APDU);
return;
}
if (G_io_apdu_buffer[OFFSET_CLA] != CLA) {
PRINTF("Error: malformed APDU\n");
reply_error(CLASS_NOT_SUPPORTED);
return;
}

// P2_EXTEND is set to signal that this APDU buffer extends, rather
// than replaces, the current message buffer
bool first_data_chunk = !(G_io_apdu_buffer[OFFSET_P2] & P2_EXTEND);
if (!first_data_chunk && G_swap_ctx.state != TRANSACTION_RECEIVE_IN_PROGRESS) {
PRINTF("Error: Unexpected !first_data_chunk\n");
uint8_t ins = G_io_apdu_buffer[OFFSET_INS];
if (ins != GET_VERSION_COMMAND
&& ins != START_NEW_TRANSACTION_COMMAND
&& ins != SET_PARTNER_KEY_COMMAND
&& ins != CHECK_PARTNER_COMMAND
&& ins != PROCESS_TRANSACTION_RESPONSE_COMMAND
&& ins != CHECK_TRANSACTION_SIGNATURE_COMMAND
&& ins != CHECK_PAYOUT_ADDRESS
&& ins != CHECK_REFUND_ADDRESS
&& ins != START_SIGNING_TRANSACTION) {
PRINTF("Incorrect instruction %d\n", ins);
reply_error(INVALID_INSTRUCTION);
return;
}

bool last_data_chunk = !(G_io_apdu_buffer[OFFSET_P2] & P2_MORE);
if (!last_data_chunk && G_swap_ctx.state != PROVIDER_CHECKED) {
PRINTF("Error: Unexpected !first_data_chunk\n");
reply_error(INVALID_INSTRUCTION);
uint8_t rate = G_io_apdu_buffer[OFFSET_P1];
if (rate != FIXED && rate != FLOATING) {
PRINTF("Incorrect P1 %d\n", rate);
reply_error(WRONG_P1);
return;
}

uint8_t subcommand = G_io_apdu_buffer[OFFSET_P2] & SUBCOMMAND_PART;
if (subcommand != SWAP
&& subcommand != SELL
&& subcommand != FUND
&& subcommand != SWAP_NG
&& subcommand != SELL_NG
&& subcommand != FUND_NG) {
PRINTF("Incorrect subcommand %d\n", subcommand);
reply_error(WRONG_P2_SUBCOMMAND);
return;
}

uint8_t extension = G_io_apdu_buffer[OFFSET_P2] & EXTENSION_PART;
if ((extension & ~(P2_NONE|P2_MORE|P2_EXTEND)) != 0) {
PRINTF("Incorrect extension %d\n", extension);
reply_error(WRONG_P2_EXTENSION);
return;
}

uint8_t data_length = G_io_apdu_buffer[OFFSET_LC];
if (data_length != input_length - OFFSET_CDATA) {
PRINTF("Incorrect advertized length %d\n", data_length);
reply_error(INVALID_DATA_LENGTH);
return;
}

// P2_MORE is set to signal that this APDU buffer is not complete
// P2_EXTEND is set to signal that this APDU buffer extends a previous one
bool first_data_chunk = !(extension & P2_EXTEND);
bool last_data_chunk = !(extension & P2_MORE);

// if (!first_data_chunk && G_swap_ctx.state != PROVIDER_CHECKED) {
// PRINTF("Error: Unexpected !first_data_chunk\n");
// reply_error(INVALID_INSTRUCTION);
// return;
// }

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// if (!last_data_chunk && G_swap_ctx.state != PROVIDER_CHECKED) {
// PRINTF("Error: Unexpected !first_data_chunk\n");
// reply_error(INVALID_INSTRUCTION);
// return;
// }

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if (first_data_chunk) {
G_received_apdu.ins = G_io_apdu_buffer[OFFSET_INS];
G_received_apdu.p1 = G_io_apdu_buffer[OFFSET_P1];
G_received_apdu.p2 = G_io_apdu_buffer[OFFSET_P2];
G_received_apdu.data_length = input_length - OFFSET_CDATA;
PRINTF("Receiving the first part of an apdu\n");
G_received_apdu.ins = ins;
G_received_apdu.rate = rate;
G_received_apdu.subcommand = subcommand;
G_received_apdu.data_length = data_length;
memcpy(G_received_apdu.data, G_io_apdu_buffer + OFFSET_CDATA, G_received_apdu.data_length);
PRINTF("P1 G_received_apdu.data_length = %d\n", G_received_apdu.data_length);
for (int i = 0; i < G_received_apdu.data_length; ++i) {
PRINTF("%02x", G_received_apdu.data[i]);
}
PRINTF("\n");
} else {
PRINTF("Followup data chunk\n");
PRINTF("Extending an already received partial of an apdu\n");
if (G_received_apdu.ins != ins
|| G_received_apdu.rate != rate
|| G_received_apdu.subcommand != subcommand) {
PRINTF("Refusing to extend a different apdu\n");
reply_error(INVALID_PZ_EXTENSION);
return;
}
memcpy(G_received_apdu.data + G_received_apdu.data_length, G_io_apdu_buffer + OFFSET_CDATA, input_length - OFFSET_CDATA);
G_received_apdu.data_length += input_length - OFFSET_CDATA;

Expand All @@ -102,15 +169,16 @@ void app_main(void) {
}

if (!last_data_chunk) {
G_swap_ctx.state = TRANSACTION_RECEIVE_IN_PROGRESS;
// Reply a blank success to indicate that we await the followup part
// Do NOT update any kind of internal state machine, we have not validated what we have received
reply_success();
continue;
}

command_t cmd = {
.ins = (command_e) G_received_apdu.ins,
.rate = G_received_apdu.p1,
.subcommand = G_received_apdu.p2,
.rate = G_received_apdu.rate,
.subcommand = G_received_apdu.subcommand,
.data =
{
.bytes = G_received_apdu.data,
Expand Down
13 changes: 6 additions & 7 deletions src/states.h
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Original file line number Diff line number Diff line change
Expand Up @@ -5,12 +5,11 @@ typedef enum {
WAITING_TRANSACTION = 1,
PROVIDER_SET = 2,
PROVIDER_CHECKED = 3,
TRANSACTION_RECEIVE_IN_PROGRESS = 4,
TRANSACTION_RECEIVED = 5,
SIGNATURE_CHECKED = 6,
TO_ADDR_CHECKED = 7,
WAITING_USER_VALIDATION = 8,
WAITING_SIGNING = 9,
SIGN_FINISHED = 10,
TRANSACTION_RECEIVED = 4,
SIGNATURE_CHECKED = 5,
TO_ADDR_CHECKED = 6,
WAITING_USER_VALIDATION = 7,
WAITING_SIGNING = 8,
SIGN_FINISHED = 9,
STATE_UPPER_BOUND,
} state_e;
11 changes: 6 additions & 5 deletions src/swap_errors.h
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Original file line number Diff line number Diff line change
@@ -1,5 +1,4 @@
#ifndef _SWAP_ERRORS_H_
#define _SWAP_ERRORS_H_
#pragma once

// This value is the part of the host <-> device protocol
// they will be reported to host in APDU
Expand All @@ -15,10 +14,12 @@ typedef enum {
USER_REFUSED = 0x6A84,
INTERNAL_ERROR = 0x6A85,
WRONG_P1 = 0x6A86,
WRONG_P2 = 0x6A87,
WRONG_P2_SUBCOMMAND = 0x6A87,
WRONG_P2_EXTENSION = 0x6A88,
INVALID_PZ_EXTENSION = 0x6A89,
CLASS_NOT_SUPPORTED = 0x6E00,
MALFORMED_APDU = 0x6E01,
INVALID_DATA_LENGTH = 0x6E02,
INVALID_INSTRUCTION = 0x6D00,
SIGN_VERIFICATION_FAIL = 0x9D1A
} swap_error_e;

#endif //_SWAP_ERRORS_H_
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