Implemented vendor header.

Header is generated with

    ./tools/build_vendorheader 'key1,key2,key3' 2 1.1 SatoshiLabs assets/satoshilabs.png micropython/firmware/vendorheader.bin

where

- keyN is a 64 character hex string encoding the public key
- 2 encodes 2/3 key scheme
- 1.1 is the version number (major, minor)
- SatoshiLabs is the vendor name
- satoshilabs.png is the vendor image

Updated the firmware compilation that it adds vendor header and updated loader
that it handles vendor header to be present.

Makefile.firmware

@@ -311,6 +311,7 @@ OBJ_HAL += $(addprefix $(BUILD_MP)/,\
 
 # OBJ micropython/
 OBJ_FW += $(addprefix $(BUILD_FW)/, \
+	firmware/vendorheader.o \
 	firmware/header.o \
 	firmware/main.o \
 	firmware/mphalport.o \
@@ -399,6 +400,11 @@ QSTR_GEN_EXTRA_CFLAGS += -DNO_QSTR -DN_X64 -DN_X86 -DN_THUMB -DN_ARM -DN_XTENSA
 
 all: $(BUILD)/$(TARGET).bin
 
+$(BUILD_FW)/firmware/vendorheader.o: $(SRCDIR_FW)/firmware/vendorheader.bin
+	$(Q)$(OBJCOPY) -I binary -O elf32-littlearm -B arm \
+	  --rename-section .data=.vendorheader,alloc,load,readonly,contents \
+	  $< $@
+
 $(BUILD)/$(TARGET).elf: $(OBJ)
 	$(ECHO) "LINK $@"
 	$(Q)$(LD) $(LDFLAGS) -o $@ $^ $(LIBS)

docs/bootloader.md

@@ -61,12 +61,12 @@ TREZOR Core firmware consists of 3 parts:
 
 ### Vendor Header
 
-Total length of vendor header is 84 + 32 * (number of pubkeys) + (length of vendor string) + (length of vendor image) bytes rounded up to the closest multiply of 512 bytes.
+Total length of vendor header is 84 + 32 * (number of pubkeys) + (length of vendor string rounded up to multiple of 4) + (length of vendor image) bytes rounded up to the closest multiple of 512 bytes.
 
 | offset | length | name | description |
 |-------:|-------:|------|-------------|
 | 0x0000 | 4      | magic | firmware magic `TRZV` |
-| 0x0004 | 4      | hdrlen | length of the vendor header |
+| 0x0004 | 4      | hdrlen | length of the vendor header (multiple of 512) |
 | 0x0008 | 4      | expiry | valid until timestamp (0=infinity) |
 | 0x000C | 1      | vmajor | version (major) |
 | 0x000D | 1      | vminor | version (minor) |
@@ -77,8 +77,9 @@ Total length of vendor header is 84 + 32 * (number of pubkeys) + (length of vend
 | ?      | 32     | vpubn | vendor pubkey n |
 | ?      | 1      | vstr_len | vendor string length |
 | ?      | ?      | vstr | vendor string |
-| ?      | 2      | vimg_len | vendor image length |
+| ?      | ?      | vstrpad | padding to a multiple of 4 bytes |
 | ?      | ?      | vimg | vendor image (in [TOIf format](toif.md)) |
+| ?      | ?      | reserved | padding to an address that is -65 modulo 512 |
 | ?      | 1      | sigmask | SatoshiLabs signature indexes (bitmap) |
 | ?      | 64     | sig | SatoshiLabs aggregated signature |
 

micropython/bootloader/image_options.h

@@ -1,2 +1,2 @@
 #define IMAGE_MAGIC   0x4C5A5254 // TRZL
-#define IMAGE_MAXSIZE (1 * 64 * 1024 + 7 * 128 + 1024)
+#define IMAGE_MAXSIZE (1 * 64 * 1024 + 7 * 128 * 1024)

micropython/firmware/main.c

@@ -24,7 +24,6 @@
 
 int main(void) {
 
-    SCB->VTOR = FIRMWARE_START + HEADER_SIZE;
     periph_init();
 
     pendsv_init();

micropython/firmware/memory.ld

@@ -28,6 +28,7 @@ SECTIONS
     /* Firmware Header */
     .header :
     {
+        KEEP(*(.vendorheader))
         KEEP(*(.header))
     } > FLASH
 

micropython/loader/image_options.h

@@ -1,2 +1,2 @@
 #define IMAGE_MAGIC   0x465A5254 // TRZF
-#define IMAGE_MAXSIZE (7 * 128 + 1024)
+#define IMAGE_MAXSIZE (7 * 128 * 1024)

micropython/loader/main.c

@@ -17,14 +17,16 @@ void pendsv_isr_handler(void) {
 void check_and_jump(void)
 {
     LOADER_PRINTLN("checking firmware");
-    if (image_check_signature((const uint8_t *)FIRMWARE_START)) {
+	// TODO: check vendor header and its signature
+	uint32_t vhdrlen = *((const uint32_t *) (FIRMWARE_START + 4));
+    if (image_check_signature((const uint8_t *) (FIRMWARE_START + vhdrlen))) {
         LOADER_PRINTLN("valid firmware image");
         // TODO: remove debug wait
         LOADER_PRINTLN("waiting 1 second");
         HAL_Delay(1000);
         // end
         LOADER_PRINTLN("JUMP!");
-        jump_to(FIRMWARE_START + HEADER_SIZE);
+        jump_to(FIRMWARE_START + vhdrlen + HEADER_SIZE);
     } else {
         LOADER_PRINTLN("invalid firmware image");
     }

tools/binctl

@@ -85,9 +85,15 @@ class BinImage:
 
 class FirmwareImage(BinImage):
 
-    def __init__(self, data):
-        super().__init__(data, magic=b'TRZF', max_size=7*128*1024)
+    def __init__(self, data, vhdrlen):
+        super().__init__(data[vhdrlen:], magic=b'TRZF', max_size=7*128*1024)
+        self.vheader = data[0:vhdrlen]
 
+    def write(self, filename):
+        with open(filename, 'wb') as f:
+            f.write(self.vheader)
+            f.write(self.serialize_header())
+            f.write(self.code)
 
 class LoaderImage(BinImage):
 
@@ -95,7 +101,6 @@ class LoaderImage(BinImage):
         super().__init__(data, magic=b'TRZL', max_size=64*1024 + 7*128*1024)
 
 
-"""
 class VendorHeader:
 
     def __init__(self, data):
@@ -107,7 +112,7 @@ class VendorHeader:
         self.vminor, \
         self.vsig_m, \
         self.vsig_n = header
-        assert self.magic == b'TRZF'
+        assert self.magic == b'TRZV'
         assert self.vsig_m > 0 and self.vsig_m <= self.vsig_n
         assert self.vsig_n > 0 and self.vsig_n <= 8
         p = 16
@@ -119,8 +124,9 @@ class VendorHeader:
         p += 1
         self.vstr = data[p:p + self.vstr_len]
         p += self.vstr_len
-        self.vimg_len, _ = struct.unpack('<H', data[p: p + 2])
-        p += 2
+        vstr_pad = -p & 3
+        p += vstr_pad
+        self.vimg_len = len(data) - 65 - p
         self.vimg = data[p:p + self.vimg_len]
         p += self.vimg_len
         self.sigmask = data[p]
@@ -128,8 +134,8 @@ class VendorHeader:
         self.sig = data[p:p+64]
         assert len(data) == 4 + 4 + 4 + 1 + 1 + 1 + 1 + \
                             32 * len(self.vpub) + \
-                            1 + self.vstr_len + \
-                            2 + self.vimg_len + \
+                            1 + self.vstr_len + vstr_pad + \
+                            self.vimg_len + \
                             1 + 64
 
     def print(self):
@@ -169,7 +175,6 @@ class VendorHeader:
     def write(self, filename):
         with open(filename, 'wb') as f:
             f.write(self.serialize_header())
-"""
 
 
 def binopen(filename):
@@ -180,13 +185,17 @@ def binopen(filename):
     magic = data[:4]
     if magic == b'TRZL':
         return LoaderImage(data)
+    if magic == b'TRZV':
+        vheader = VendorHeader(data)
+        if len(data) == vheader.hdrlen:
+            return vheader
+        subdata = data[vheader.hdrlen:]
+        if subdata[:4] == b'TRZF':
+            return FirmwareImage(data, vheader.hdrlen)
     if magic == b'TRZF':
-        return FirmwareImage(data)
-    # if magic == b'TRZV':
-    #     return VendorHeader(data)
+        return FirmwareImage(data, 0)
     raise Exception('Unknown file format')
 
-
 def main():
     if len(sys.argv) < 2:
         print('Usage: binctl file.bin [-s]')

tools/build_vendorheader

@@ -0,0 +1,109 @@
+#!/usr/bin/env python3
+from PIL import Image
+import sys
+import re
+import struct
+import zlib
+import binascii
+
+def process_rgb(w, h, pix):
+    data = bytes()
+    for j in range(h):
+        for i in range(w):
+            r, g, b = pix[i, j]
+            c = ((r & 0xF8) << 8) | ((g & 0xFC) << 3) | ((b & 0xF8) >> 3)
+            data += struct.pack('>H', c)
+    return data
+
+
+def process_grayscale(w, h, pix):
+    data = bytes()
+    for j in range(h):
+        for i in range(w // 2):
+            l1, l2 = pix[i * 2, j], pix[i * 2 + 1, j]
+            c = (l1 & 0xF0) | (l2 >> 4)
+            data += struct.pack('>B', c)
+    return data
+
+
+def process_image(ifn):
+    im = Image.open(ifn)
+    w, h = im.size
+    print('Opened %s ... %d x %d @ %s' % (ifn, w, h, im.mode))
+
+    if im.mode == 'RGB':
+        print('Detected RGB mode')
+    elif im.mode == 'L':
+        if w % 2 > 0:
+            print('PNG file must have width divisible by 2')
+            return 3
+        print('Detected GRAYSCALE mode')
+    else:
+        print('Unknown mode:', im.mode)
+        return 4
+
+    pix = im.load()
+
+    if im.mode == 'RGB':
+        ofn = '%s.toif' % ifn[:-4]
+        pixeldata = process_rgb(w, h, pix)
+    else:
+        ofn = '%s.toig' % ifn[:-4]
+        pixeldata = process_grayscale(w, h, pix)
+    z = zlib.compressobj(level=9, wbits=10)
+    zdata = z.compress(pixeldata) + z.flush()
+    zdata = zdata[2:-4] # strip header and checksum
+
+    toif = b''
+    if im.mode == 'RGB':
+        toif += b'TOIf'
+    else:
+        toif += b'TOIg'
+    toif += struct.pack('<HH', w, h)
+    toif += struct.pack('<I', len(zdata))
+    toif += zdata
+    return toif
+
+# encode vendor name, add length byte and padding to multiple of 4
+def vendorencode(vname):
+    vbin = vname.encode('utf-8')
+    vbin = struct.pack('<B',len(vbin)) + vbin
+    vbin += b'\0' * (-len(vbin) & 3)
+    return vbin
+
+def encodekey(key):
+    if len(key) != 64:
+        raise Exception("Wrong key length")
+    return binascii.unhexlify(key)
+
+def main():
+    if len(sys.argv) < 7:
+        print('Usage build_vendorheader key1hex,... m version vendorname vendorimage.png vendorimage.bin')
+        return 1
+
+    keys = list(map(encodekey, sys.argv[1].split(',')))
+    m = int(sys.argv[2])
+    (major,minor) = map(lambda x: int(x),
+                        re.search('^(\d+)\.(\d+)$', sys.argv[3]).groups())
+    vname = sys.argv[4]
+    ifn = sys.argv[5]
+    ofn = sys.argv[6]
+    if not ifn.endswith('.png'):
+        print('Must provide PNG file')
+        return 2
+
+    timeout = 0
+    vheader = b'TRZV' + struct.pack('<IIBBBB', 0, timeout, major, minor, m, len(keys))
+    for k in keys:
+        vheader += k
+    vheader += vendorencode(vname) + process_image(ifn)
+    padding = 65 + (-len(vheader) - 65) & 511
+    vheader += b'\0' * padding
+
+    # put in length
+    vheader = vheader[0:4] + struct.pack('<I', len(vheader)) + vheader[8:]
+
+    with open(ofn, 'wb') as f:
+        f.write(vheader)
+
+main()