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trezor-firmware
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fix(legacy): Improve compile-time checks of message sizes.

Browse Source 
Distinguish between the maximum size of a protobuf-encoded message
and the maximum size of a C struct containing a decoded message.
pull/1531/head
Andrew Kozlik 3 years ago committed by Andrew Kozlik
parent 54fec3742f
commit a36439a57f
4 changed files with 74 additions and 37 deletions
Show Stats Download Patch File Download Diff File

2
legacy/firmware/fsm.c
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@ -67,7 +67,7 @@
// message methods
static uint8_t msg_resp[MSG_OUT_SIZE] __attribute__((aligned));
static uint8_t msg_resp[MSG_OUT_DECODED_SIZE] __attribute__((aligned));
#define RESP_INIT(TYPE) \
TYPE *resp = (TYPE *)(void *)msg_resp; \

55
legacy/firmware/messages.c
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@ -25,16 +25,12 @@
#include "memzero.h"
#include "messages.h"
#include "trezor.h"
#include "usb.h"
#include "util.h"
#include "messages.pb.h"
#include "pb_decode.h"
#include "pb_encode.h"
// The size of the message header "?##<2 bytes msg_id><4 bytes msg_size>".
#define MSG_HEADER_SIZE 9
struct MessagesMap_t {
char type; // n = normal, d = debug
char dir; // i = in, o = out
@ -72,17 +68,22 @@ void MessageProcessFunc(char type, char dir, uint16_t msg_id, void *ptr) {
}
}
// Buffer for outgoing USB packets.
static uint32_t msg_out_start = 0;
static uint32_t msg_out_end = 0;
static uint32_t msg_out_cur = 0;
static uint8_t msg_out[MSG_OUT_SIZE];
static uint8_t msg_out[MSG_OUT_BUFFER_SIZE];
_Static_assert(MSG_OUT_BUFFER_SIZE % USB_PACKET_SIZE == 0,
"MSG_OUT_BUFFER_SIZE");
#if DEBUG_LINK
static uint32_t msg_debug_out_start = 0;
static uint32_t msg_debug_out_end = 0;
static uint32_t msg_debug_out_cur = 0;
static uint8_t msg_debug_out[MSG_DEBUG_OUT_SIZE];
static uint8_t msg_debug_out[MSG_DEBUG_OUT_BUFFER_SIZE];
_Static_assert(MSG_DEBUG_OUT_BUFFER_SIZE % USB_PACKET_SIZE == 0,
"MSG_DEBUG_OUT_BUFFER_SIZE");
#endif
@ -95,7 +96,7 @@ static inline void msg_out_append(uint8_t c) {
msg_out_cur++;
if (msg_out_cur == USB_PACKET_SIZE) {
msg_out_cur = 0;
msg_out_end = (msg_out_end + 1) % (MSG_OUT_SIZE / USB_PACKET_SIZE);
msg_out_end = (msg_out_end + 1) % (MSG_OUT_BUFFER_SIZE / USB_PACKET_SIZE);
}
}
@ -111,7 +112,7 @@ static inline void msg_debug_out_append(uint8_t c) {
if (msg_debug_out_cur == USB_PACKET_SIZE) {
msg_debug_out_cur = 0;
msg_debug_out_end =
(msg_debug_out_end + 1) % (MSG_DEBUG_OUT_SIZE / USB_PACKET_SIZE);
(msg_debug_out_end + 1) % (MSG_DEBUG_OUT_BUFFER_SIZE / USB_PACKET_SIZE);
}
}
@ -124,7 +125,7 @@ static inline void msg_out_pad(void) {
msg_out_cur++;
}
msg_out_cur = 0;
msg_out_end = (msg_out_end + 1) % (MSG_OUT_SIZE / USB_PACKET_SIZE);
msg_out_end = (msg_out_end + 1) % (MSG_OUT_BUFFER_SIZE / USB_PACKET_SIZE);
}
#if DEBUG_LINK
@ -137,7 +138,7 @@ static inline void msg_debug_out_pad(void) {
}
msg_debug_out_cur = 0;
msg_debug_out_end =
(msg_debug_out_end + 1) % (MSG_DEBUG_OUT_SIZE / USB_PACKET_SIZE);
(msg_debug_out_end + 1) % (MSG_DEBUG_OUT_BUFFER_SIZE / USB_PACKET_SIZE);
}
#endif
@ -219,13 +220,13 @@ enum {
};
void msg_process(char type, uint16_t msg_id, const pb_msgdesc_t *fields,
uint8_t *msg_raw, uint32_t msg_size) {
static uint8_t msg_data[MSG_IN_SIZE];
memzero(msg_data, sizeof(msg_data));
pb_istream_t stream = pb_istream_from_buffer(msg_raw, msg_size);
bool status = pb_decode(&stream, fields, msg_data);
uint8_t *msg_encoded, uint32_t msg_encoded_size) {
static uint8_t msg_decoded[MSG_IN_DECODED_SIZE];
memzero(msg_decoded, sizeof(msg_decoded));
pb_istream_t stream = pb_istream_from_buffer(msg_encoded, msg_encoded_size);
bool status = pb_decode(&stream, fields, msg_decoded);
if (status) {
MessageProcessFunc(type, 'i', msg_id, msg_data);
MessageProcessFunc(type, 'i', msg_id, msg_decoded);
} else {
fsm_sendFailure(FailureType_Failure_DataError, stream.errmsg);
}
@ -233,9 +234,9 @@ void msg_process(char type, uint16_t msg_id, const pb_msgdesc_t *fields,
void msg_read_common(char type, const uint8_t *buf, uint32_t len) {
static char read_state = READSTATE_IDLE;
static uint8_t msg_in[MSG_IN_SIZE];
static uint8_t msg_encoded[MSG_IN_ENCODED_SIZE];
static uint16_t msg_id = 0xFFFF;
static uint32_t msg_size = 0;
static uint32_t msg_encoded_size = 0;
static uint32_t msg_pos = 0;
static const pb_msgdesc_t *fields = 0;
@ -247,7 +248,7 @@ void msg_read_common(char type, const uint8_t *buf, uint32_t len) {
return;
}
msg_id = (buf[3] << 8) + buf[4];
msg_size =
msg_encoded_size =
((uint32_t)buf[5] << 24) + (buf[6] << 16) + (buf[7] << 8) + buf[8];
fields = MessageFields(type, 'i', msg_id);
@ -256,14 +257,14 @@ void msg_read_common(char type, const uint8_t *buf, uint32_t len) {
_("Unknown message"));
return;
}
if (msg_size > MSG_IN_SIZE) { // message is too big :(
if (msg_encoded_size > MSG_IN_ENCODED_SIZE) { // message is too big :(
fsm_sendFailure(FailureType_Failure_DataError, _("Message too big"));
return;
}
read_state = READSTATE_READING;
memcpy(msg_in, buf + MSG_HEADER_SIZE, len - MSG_HEADER_SIZE);
memcpy(msg_encoded, buf + MSG_HEADER_SIZE, len - MSG_HEADER_SIZE);
msg_pos = len - MSG_HEADER_SIZE;
} else if (read_state == READSTATE_READING) {
if (buf[0] != '?') { // invalid contents
@ -272,14 +273,14 @@ void msg_read_common(char type, const uint8_t *buf, uint32_t len) {
}
/* raw data starts at buf + 1 with len - 1 bytes */
buf++;
len = MIN(len - 1, MSG_IN_SIZE - msg_pos);
len = MIN(len - 1, MSG_IN_ENCODED_SIZE - msg_pos);
memcpy(msg_in + msg_pos, buf, len);
memcpy(msg_encoded + msg_pos, buf, len);
msg_pos += len;
}
if (msg_pos >= msg_size) {
msg_process(type, msg_id, fields, msg_in, msg_size);
if (msg_pos >= msg_encoded_size) {
msg_process(type, msg_id, fields, msg_encoded, msg_encoded_size);
msg_pos = 0;
read_state = READSTATE_IDLE;
}
@ -288,7 +289,7 @@ void msg_read_common(char type, const uint8_t *buf, uint32_t len) {
const uint8_t *msg_out_data(void) {
if (msg_out_start == msg_out_end) return 0;
uint8_t *data = msg_out + (msg_out_start * USB_PACKET_SIZE);
msg_out_start = (msg_out_start + 1) % (MSG_OUT_SIZE / USB_PACKET_SIZE);
msg_out_start = (msg_out_start + 1) % (MSG_OUT_BUFFER_SIZE / USB_PACKET_SIZE);
debugLog(0, "", "msg_out_data");
return data;
}
@ -299,7 +300,7 @@ const uint8_t *msg_debug_out_data(void) {
if (msg_debug_out_start == msg_debug_out_end) return 0;
uint8_t *data = msg_debug_out + (msg_debug_out_start * USB_PACKET_SIZE);
msg_debug_out_start =
(msg_debug_out_start + 1) % (MSG_DEBUG_OUT_SIZE / USB_PACKET_SIZE);
(msg_debug_out_start + 1) % (MSG_DEBUG_OUT_BUFFER_SIZE / USB_PACKET_SIZE);
debugLog(0, "", "msg_debug_out_data");
return data;
}

31
legacy/firmware/messages.h
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@ -23,10 +23,28 @@
#include <stdbool.h>
#include <stdint.h>
#include "trezor.h"
#include "usb.h"
#define MSG_IN_SIZE (15 * 1024)
// The size of the message header "?##<2 bytes msg_id><4 bytes msg_size>".
#define MSG_HEADER_SIZE 9
#define MSG_OUT_SIZE (3 * 1024)
// Maximum size of an incoming protobuf-encoded message without headers.
#define MSG_IN_ENCODED_SIZE (15 * 1024)
// Maximum size of a C struct containing a decoded incoming message.
#define MSG_IN_DECODED_SIZE (15 * 1024)
// Buffer size for outgoing USB packets with headers.
#define MSG_OUT_BUFFER_SIZE (3 * 1024)
// Maximum size of an outgoing protobuf-encoded message without headers.
// (Continuation packets have a one byte "?" header.)
#define MSG_OUT_ENCODED_SIZE \
(MSG_OUT_BUFFER_SIZE - MSG_HEADER_SIZE - \
((MSG_OUT_BUFFER_SIZE / USB_PACKET_SIZE) - 1))
// Maximum size of a C struct containing a decoded outgoing message.
#define MSG_OUT_DECODED_SIZE (3 * 1024)
#define msg_read(buf, len) msg_read_common('n', (buf), (len))
#define msg_write(id, ptr) msg_write_common('n', (id), (ptr))
@ -34,7 +52,14 @@ const uint8_t *msg_out_data(void);
#if DEBUG_LINK
#define MSG_DEBUG_OUT_SIZE (2 * 1024)
// Buffer size for outgoing debuglink USB packets with headers.
#define MSG_DEBUG_OUT_BUFFER_SIZE (2 * 1024)
// Maximum size of an outgoing protobuf-encoded debug message without headers.
// (Continuation packets have a one byte "?" header.)
#define MSG_DEBUG_OUT_ENCODED_SIZE \
(MSG_DEBUG_OUT_BUFFER_SIZE - MSG_HEADER_SIZE - \
((MSG_DEBUG_OUT_BUFFER_SIZE / USB_PACKET_SIZE) - 1))
#define msg_debug_read(buf, len) msg_read_common('d', (buf), (len))
#define msg_debug_write(id, ptr) msg_write_common('d', (id), (ptr))

23
legacy/firmware/protob/messages_map.py
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@ -82,18 +82,29 @@ def handle_message(fh, fl, skipped, message):
)
)
bufsize = None
encoded_size = None
decoded_size = None
t = interface + direction
if t == "ni":
bufsize = "MSG_IN_SIZE"
encoded_size = "MSG_IN_ENCODED_SIZE"
decoded_size = "MSG_IN_DECODED_SIZE"
elif t == "no":
bufsize = "MSG_OUT_SIZE"
encoded_size = "MSG_OUT_ENCODED_SIZE"
decoded_size = "MSG_OUT_DECODED_SIZE"
elif t == "do":
bufsize = "MSG_DEBUG_OUT_SIZE"
if bufsize:
encoded_size = "MSG_DEBUG_OUT_ENCODED_SIZE"
decoded_size = "MSG_OUT_DECODED_SIZE"
if encoded_size:
fl.write(
'_Static_assert(%s >= sizeof(%s_size), "msg buffer too small");\n'
% (encoded_size, short_name)
)
if decoded_size:
fl.write(
'_Static_assert(%s >= sizeof(%s), "msg buffer too small");\n'
% (bufsize, short_name)
% (decoded_size, short_name)
)

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