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MRTD TLV parsing (and select)

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This commit is contained in:
Chris van Marle
2022-10-11 22:13:32 +02:00
parent b5e420c11b
commit 69ff30e86a
3 changed files with 130 additions and 30 deletions
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lib/nfc/helpers/iso7816.c
+33 -1
View File
@@ -13,15 +13,22 @@ TlvInfo iso7816_tlv_parse(const uint8_t* data) {
// 11111 10000001 00000001 - 11111 11111111 01111111 => 128 - 16383 (3 byte)
tlv.tag = *(data++);
tlv.ber.constructed = ((tlv.tag & 0x20) != 0);
tlv.ber.class = (tlv.tag >> 6) & 0x03;
if ((tlv.tag & 0x1f) == 0x1f) {
// BER-TLV, multi byte tag
tlv.tag = *(data++);
tlv.tag <<= 8;
tlv.tag |= *(data++);
tlv.ber.tag = tlv.tag & 0x7f;
if(tlv.tag & 0x80) {
// BER-TLV, 3 byte tag
tlv.tag &= ~0x80;
tlv.tag <<= 7;
tlv.tag |= *(data++) & 0x7f;
tlv.ber.tag = tlv.tag & 0x3fff;
}
} else {
tlv.ber.tag = tlv.tag & 0x1f;
}
//TODO: check for invalid 'indefinite length'
@@ -49,3 +56,28 @@ TlvInfo iso7816_tlv_parse(const uint8_t* data) {
return tlv;
}
TlvInfo iso7816_tlv_select(const uint8_t* data, size_t length, const uint16_t tags[], size_t num_tags) {
TlvInfo tlv;
size_t offset = 0;
if(num_tags == 0) {
return (TlvInfo){.tag = 0x0000};
}
while(offset < length) {
tlv = iso7816_tlv_parse(data + offset);
if(tlv.tag == tags[0]) {
if(num_tags == 1) {
return tlv;
} else {
return iso7816_tlv_select(tlv.value, tlv.length, tags+1, num_tags - 1);
}
}
offset = tlv.next - data; // TODO: use some length value of TlvInfo instead of this monstrosity
}
return (TlvInfo){.tag = 0x0000};
}
lib/nfc/helpers/iso7816.h
+7 -10
View File
@@ -11,17 +11,12 @@
#define BER_CLASS_PRIVATE 0x3
typedef struct {
union {
uint16_t tag; // TODO: use define/typedef for this data format?
struct {
uint16_t tag;
struct {
// LSB
uint8_t tag : 5;
uint8_t constructed : 1;
uint8_t class : 2;
// MSB
} ber;
//TODO: currently only works for 1-byte tags
};
uint8_t constructed : 1;
uint8_t class : 2;
} ber;
size_t length;
const uint8_t* value;
@@ -31,3 +26,5 @@ typedef struct {
// ISO7816-5 §5.2
// Simple-TLV and BER-TLV parsing
TlvInfo iso7816_tlv_parse(const uint8_t* data);
TlvInfo iso7816_tlv_select(const uint8_t* data, size_t length, const uint16_t tags[], size_t num_tags);
test_iso7816_helpers.c
+90 -19
View File
@@ -6,19 +6,31 @@
#define COLOR_GREEN "\033[0;32m"
#define COLOR_RESET "\033[0;0m"
//TODO: do something with ISO7816-4 Table 9 — Interindustry data objects for tag allocation authority
//0x06 Object identifier (encoding specified in ISO/IEC 8825-1, see examples in annex A)
//0x41 Country code (encoding specified in ISO 3166-1 [1] ) and optional national data
//0x42 Issuer identification number (encoding and registration specified in ISO/IEC 7812-1 [3] ) and optional issuer data
//0x4F Application identifier (AID, encoding specified in 8.2.1.2)
void print_hex(const uint8_t* data, size_t length) {
for(size_t i=0; i<length; ++i) {
printf("%02X", data[i]);
}
}
void print_tlv(char* fmt, TlvInfo tlv) {
printf("%s Tag: %x, Length: %ld, Value: ", fmt, tlv.tag, tlv.length);
print_hex(tlv.value, tlv.length);
printf("\n");
}
void test_iso7816_tlv_parse(const uint8_t* input, size_t input_size, uint16_t exp_tag, size_t exp_length) {
TlvInfo tlv = iso7816_tlv_parse(input);
if(tlv.tag != exp_tag) {
printf(COLOR_RED "FAILED - iso7816_tlv_parse Tag for ");
print_hex(input, input_size);
printf(" is not %d, but %d\n" COLOR_RESET,
printf(" is not %1$d (%1$x), but %2$d (%2$x)\n" COLOR_RESET,
exp_tag, tlv.tag);
return;
}
@@ -58,7 +70,7 @@ void test_iso7816_tlv_parse_ber(const uint8_t* input, size_t input_size, uint8_t
if(tlv.ber.tag != exp_tag) {
printf(COLOR_RED "FAILED - iso7816_tlv_parse ber.tag for ");
print_hex(input, input_size);
printf(" is not %d, but %d\n" COLOR_RESET,
printf(" is not %1$d (%1$x), but %2$d (%2$x)\n" COLOR_RESET,
exp_tag, tlv.ber.tag);
return;
}
@@ -76,31 +88,75 @@ void test_iso7816_tlv_parse_ber(const uint8_t* input, size_t input_size, uint8_t
printf(" is class:%d, constructed:%d, tag:%d, length:%ld\n" COLOR_RESET, tlv.ber.class, tlv.ber.constructed, tlv.ber.tag, tlv.length);
}
void describe_tlv(const uint8_t* data, size_t length, size_t indent) {
TlvInfo tlv = iso7816_tlv_parse(data);
//TODO: memcmp values above?
char prefix[indent+1];
memset(prefix, ' ', indent);
prefix[indent] = '\x00';
void test_iso7816_tlv_select(const uint8_t* input, size_t input_size, const uint16_t tags[], size_t num_tags, uint16_t exp_tag, uint8_t* exp_data, size_t exp_data_length) {
TlvInfo tlv = iso7816_tlv_select(input, input_size, tags, num_tags);
printf("%sTag: %d (BER - class: %d, constr: %d, tag: %d)\n", prefix, tlv.tag, tlv.ber.class, tlv.ber.constructed, tlv.ber.tag);
printf("%sLength: %ld\n", prefix, tlv.length);
printf("%sValue: ", prefix);
print_hex(tlv.value, tlv.length);
printf("\n");
if(tlv.tag != exp_tag) {
printf(COLOR_RED "FAILED - iso7816_tlv_select tag for ");
print_hex(input, input_size);
printf(" is not %d, but %d\n" COLOR_RESET,
exp_tag, tlv.tag);
return;
}
if(tlv.ber.constructed) {
describe_tlv(tlv.value, tlv.length, indent+2);
if(tlv.length != exp_data_length) {
printf(COLOR_RED "FAILED - iso7816_tlv_select length for ");
print_hex(input, input_size);
printf(" is not %ld, but %ld\n" COLOR_RESET,
exp_data_length, tlv.length);
return;
}
if(memcmp(tlv.value, exp_data, tlv.length)) {
printf(COLOR_RED "FAILED - iso7816_tlv_select value for ");
print_hex(input, input_size);
printf(" is not\n");
print_hex(exp_data, exp_data_length);
printf(", but\n");
print_hex(tlv.value, tlv.length);
printf(COLOR_RESET "\n");
return;
}
printf(COLOR_GREEN "SUCCESS - iso7816_tlv_select for ");
print_hex(input, input_size);
printf(" is tag:%d, length:%ld\n" COLOR_RESET, tlv.tag, tlv.length);
}
void describe_tlv(const uint8_t* data, size_t length, size_t level) {
size_t offset = 0;
char prefix[level+1];
memset(prefix, ' ', level);
prefix[level] = '\x00';
printf("%sDescribe TLV (lvl: %ld), size: %ld\n", prefix, level, length);
while(offset < length) {
TlvInfo tlv = iso7816_tlv_parse(data + offset);
printf("%sTag: %x (%d) (BER - class: %d, constr: %d, tag: %d)\n", prefix, tlv.tag, tlv.tag, tlv.ber.class, tlv.ber.constructed, tlv.ber.tag);
printf("%sLength: %ld\n", prefix, tlv.length);
printf("%sValue: ", prefix);
print_hex(tlv.value, tlv.length);
printf("\n");
if(tlv.ber.constructed) {
describe_tlv(tlv.value, tlv.length, level+1);
}
offset = tlv.next - data;
}
}
int main(int argc, char** argv) {
test_iso7816_tlv_parse("\x0F\x05\x48\x65\x6C\x6C\x6F", 7, 15, 5);
test_iso7816_tlv_parse("\x5F\x0F\x05\x48\x65\x6C\x6C\x6F", 8, 15, 5);
test_iso7816_tlv_parse("\x5F\x1F\x05\x48\x65\x6C\x6C\x6F", 8, 31, 5);
test_iso7816_tlv_parse("\x5F\x7F\x05\x48\x65\x6C\x6C\x6F", 8, 127, 5);
test_iso7816_tlv_parse("\x5F\x81\x00\x05\x48\x65\x6C\x6C\x6F", 9, 128, 5);
test_iso7816_tlv_parse("\x5F\xFF\x7F\x05\x48\x65\x6C\x6C\x6F", 9, 16383, 5);
test_iso7816_tlv_parse_ber("\x5F\x0F\x05\x48\x65\x6C\x6C\x6F", 8, BER_CLASS_APPLICATION, 0, 15, 5);
test_iso7816_tlv_parse_ber("\x5F\x1F\x05\x48\x65\x6C\x6C\x6F", 8, BER_CLASS_APPLICATION, 0, 31, 5);
test_iso7816_tlv_parse_ber("\x5F\x7F\x05\x48\x65\x6C\x6C\x6F", 8, BER_CLASS_APPLICATION, 0, 127, 5);
test_iso7816_tlv_parse_ber("\x5F\x81\x00\x05\x48\x65\x6C\x6C\x6F", 9, BER_CLASS_APPLICATION, 0, 128, 5);
test_iso7816_tlv_parse_ber("\x5F\xFF\x7F\x05\x48\x65\x6C\x6C\x6F", 9, BER_CLASS_APPLICATION, 0, 16383, 5);
test_iso7816_tlv_parse("\x0F\xff\x00\x05\x48\x65\x6C\x6C\x6F", 9, 15, 5);
test_iso7816_tlv_parse("\x04\xff\x01\x00\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65\x65", 260, 4, 256);
test_iso7816_tlv_parse("\x4F\x81\x05\x48\x65\x6C\x6C\x6F", 8, 0x4f, 5);
@@ -112,14 +168,29 @@ int main(int argc, char** argv) {
test_iso7816_tlv_parse_ber("\x8A\x02Hi", 4, BER_CLASS_CONTEXT, 0, 10, 2);
test_iso7816_tlv_parse_ber("\x6A\x04\x8A\x02Hi", 6, BER_CLASS_APPLICATION, 1, 10, 4);
test_iso7816_tlv_parse_ber("\xDF\x8A\x7F\x02Hi", 4, BER_CLASS_PRIVATE, 0, 0x57f, 2);
printf("=====\nEF.DIR\n");
const uint8_t *ef_dir_data = "\x61\x09\x4F\x07\xA0\x00\x00\x02\x47\x10\x01\x61\x09\x4F\x07\xA0\x00\x00\x02\x47\x20\x01";
size_t ef_dir_data_len = 22;
describe_tlv(ef_dir_data, ef_dir_data_len, 0);
printf("=====\nEF.CardAccess\n");
const uint8_t *ef_cardaccess_data = "\x31\x14\x30\x12\x06\x0A\x04\x00\x7F\x00\x07\x02\x02\x04\x02\x04\x02\x01\x02\x02\x01\x0E\x90\x00";
size_t ef_cardaccess_data_len = 24;
describe_tlv(ef_cardaccess_data, ef_cardaccess_data_len, 0);
printf("=====\nEF.Com\n");
const uint8_t *ef_com_data = "\x60\x16\x5F\x01\x04\x30\x31\x30\x37\x5F\x36\x06\x30\x34\x30\x30\x30\x30\x5C\x04\x61\x75\x6F\x6E";
size_t ef_com_data_len = 24;
describe_tlv(ef_com_data, ef_com_data_len, 0);
printf("====\n");
TlvInfo tlv = iso7816_tlv_select(ef_com_data, ef_com_data_len, (uint16_t[]){0x60, 0x5f36}, 2);
print_tlv("0x60, 0x5f36:", tlv);
test_iso7816_tlv_select(ef_com_data, ef_com_data_len, (uint16_t[]){0x60, 0x5f36}, 2, 0x5f36, "\x30\x34\x30\x30\x30\x30", 6);
return 0;
}