Skip to content

[hf seos] Correct command padding size #3027

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
iceman1001 merged 1 commit into from
Nov 27, 2025
+22 −18
Merged

[hf seos] Correct command padding size #3027

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
40 changes: 22 additions & 18 deletions client/src/cmdhfseos.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -163,11 +163,12 @@ static void increment_command_wrapper(uint8_t *input, int input_len) {
input[input_len - 1]++; // Increment the last element of the header by 1
}

static void padToBlockSize(const uint8_t *input, int inputSize, int blockSize, uint8_t *output) {
int paddingSize = blockSize - (inputSize % blockSize);
memcpy(output, input, inputSize);
memset(output + inputSize, 0x80, 1);
memset(output + inputSize + 1, 0x00, paddingSize - 1);
static void padToBlockSize(const uint8_t *input, int *inputSize, int blockSize, uint8_t *output) {
int paddingSize = blockSize - (*inputSize % blockSize);
memcpy(output, input, *inputSize);
memset(output + *inputSize, 0x80, 1);
memset(output + *inputSize + 1, 0x00, paddingSize - 1);
*inputSize += paddingSize;
}

static void generate_command_wrapping(uint8_t *command_Header, int command_header_len, uint8_t *unencrypted_Command, int unencrypted_command_len, uint8_t *rndICC, uint8_t *rndIFD, uint8_t *diversified_enc_key, uint8_t *diversified_mac_key, int encryption_algorithm, uint8_t *command, int *command_len) {
Expand All @@ -188,29 +189,32 @@ static void generate_command_wrapping(uint8_t *command_Header, int command_heade
increment_command_wrapper(rndCounter, block_size);

// Command Header is for the APDU Command to be sent
uint8_t padded_Command_Header[block_size];
padToBlockSize(command_Header, command_header_len, block_size, padded_Command_Header);
int padded_Command_Header_len = command_header_len;
uint8_t padded_Command_Header[padded_Command_Header_len+block_size];
padToBlockSize(command_Header, &padded_Command_Header_len, block_size, padded_Command_Header);

// Unencrypted Command is our actual command data
uint8_t padded_unencrypted_Command[block_size];
padToBlockSize(unencrypted_Command, unencrypted_command_len, block_size, padded_unencrypted_Command);
int padded_unencrypted_Command_len = unencrypted_command_len;
uint8_t padded_unencrypted_Command[padded_unencrypted_Command_len+block_size];
padToBlockSize(unencrypted_Command, &padded_unencrypted_Command_len, block_size, padded_unencrypted_Command);

uint8_t padded_encrypted_Command[block_size];
create_cryptogram(diversified_enc_key, padded_unencrypted_Command, padded_encrypted_Command, sizeof(padded_unencrypted_Command), encryption_algorithm);
uint8_t padded_encrypted_Command[padded_unencrypted_Command_len];
create_cryptogram(diversified_enc_key, padded_unencrypted_Command, padded_encrypted_Command, padded_unencrypted_Command_len, encryption_algorithm);

uint8_t asn1_tag_cryptograph[2] = {0x85, ARRAYLEN(padded_encrypted_Command)};
uint8_t asn1_tag_mac[2] = {0x8e, 0x08};
uint8_t command_trailer[2] = {0x97, 0x00};
uint8_t padded_command_trailer[block_size - ARRAYLEN(command_trailer)];
padToBlockSize(command_trailer, sizeof(command_trailer), sizeof(padded_command_trailer), padded_command_trailer);
int padded_command_trailer_len = ARRAYLEN(command_trailer);
uint8_t padded_command_trailer[padded_command_trailer_len+block_size];
padToBlockSize(command_trailer, &padded_command_trailer_len, block_size, padded_command_trailer);

uint8_t toEncrypt[ARRAYLEN(rndCounter) + ARRAYLEN(padded_Command_Header) + ARRAYLEN(asn1_tag_cryptograph) + ARRAYLEN(padded_encrypted_Command) + ARRAYLEN(padded_command_trailer)];
uint8_t toEncrypt[ARRAYLEN(rndCounter) + padded_Command_Header_len + ARRAYLEN(asn1_tag_cryptograph) + ARRAYLEN(padded_encrypted_Command) + padded_command_trailer_len];

memcpy(toEncrypt, rndCounter, ARRAYLEN(rndCounter));
memcpy(toEncrypt + ARRAYLEN(rndCounter), padded_Command_Header, ARRAYLEN(padded_Command_Header));
memcpy(toEncrypt + ARRAYLEN(rndCounter) + ARRAYLEN(padded_Command_Header), asn1_tag_cryptograph, ARRAYLEN(asn1_tag_cryptograph));
memcpy(toEncrypt + ARRAYLEN(rndCounter) + ARRAYLEN(padded_Command_Header) + ARRAYLEN(asn1_tag_cryptograph), padded_encrypted_Command, ARRAYLEN(padded_encrypted_Command));
memcpy(toEncrypt + ARRAYLEN(rndCounter) + ARRAYLEN(padded_Command_Header) + ARRAYLEN(asn1_tag_cryptograph) + ARRAYLEN(padded_encrypted_Command), padded_command_trailer, ARRAYLEN(padded_command_trailer));
memcpy(toEncrypt + ARRAYLEN(rndCounter), padded_Command_Header, padded_Command_Header_len);
memcpy(toEncrypt + ARRAYLEN(rndCounter) + padded_Command_Header_len, asn1_tag_cryptograph, ARRAYLEN(asn1_tag_cryptograph));
memcpy(toEncrypt + ARRAYLEN(rndCounter) + padded_Command_Header_len + ARRAYLEN(asn1_tag_cryptograph), padded_encrypted_Command, ARRAYLEN(padded_encrypted_Command));
memcpy(toEncrypt + ARRAYLEN(rndCounter) + padded_Command_Header_len + ARRAYLEN(asn1_tag_cryptograph) + ARRAYLEN(padded_encrypted_Command), padded_command_trailer, padded_command_trailer_len);

// Breakdown
// 0181e43801010201 + 0000000000000001 + 0CCB3FFF800000000000000000000000 + 8510EB54DA90CB43AEE7FBFE816ECA25A10D + 9700 + 800000000000000000000000
Expand Down
Loading