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Merge pull request #3080 from aaronjamt/patch-synth-iv-improv

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[hf seos] Fix Synthesized IV validation
This commit is contained in:
Iceman
2026-01-24 08:32:44 +01:00
committed by GitHub
parent 7522652ad2 f399b8d3a6
commit dda3093e6e
1 changed files with 25 additions and 10 deletions
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client/src/cmdhfseos.c
+25 -10
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@@ -803,6 +803,30 @@ static int select_ADF_decrypt(const char *selectADFOID, uint8_t *CRYPTOGRAM_encr
// 4.1 Selected ADF
// 4.2 Diversifier
// 4.3 Nonce
// Synthesized IV works on half-blocks:
// Half of a block of random data, followed
// by half a block of the CMAC of that data
uint8_t iv_size;
if (encryption_algorithm == 0x02) {
iv_size = 4;
} else if (encryption_algorithm == 0x09) {
iv_size = 8;
} else {
PrintAndLogEx(ERR, _RED_("Unknown Encryption Algorithm"));
return PM3_ESOFT;
}
uint8_t mac[iv_size];
uint8_t MAC_key[24] = {0x00};
memcpy(MAC_key, keys[key_index].privMacKey, 16);
create_cmac(MAC_key, CRYPTOGRAM_encrypted_data_raw, mac, iv_size, sizeof(mac), encryption_algorithm);
if (memcmp(CRYPTOGRAM_encrypted_data_raw+iv_size, mac, iv_size) != 0) {
PrintAndLogEx(ERR, "Synthesized IV Verification Failed");
PrintAndLogEx(ERR, _YELLOW_("Likely wrong Priv Mac Key"));
return PM3_ESOFT;
}
uint8_t privEncKey[16] = {};
memcpy(privEncKey, keys[key_index].privEncKey, 16);
uint8_t CRYPTOGRAM_decrypted_data[64];
@@ -823,7 +847,7 @@ static int select_ADF_decrypt(const char *selectADFOID, uint8_t *CRYPTOGRAM_encr
int CRYPTOGRAM_decrypted_data_length = sizeof(CRYPTOGRAM_decrypted_data);
// Skip synthesized IV
for (int i = 16; i < CRYPTOGRAM_decrypted_data_length; i++) {
for (int i = iv_size * 2; i < CRYPTOGRAM_decrypted_data_length; i++) {
// ADF OID tag
if (CRYPTOGRAM_decrypted_data[i] == 0x06 && CRYPTOGRAM_decrypted_data[i + 1] < 20) {
adf_length = ((CRYPTOGRAM_decrypted_data[i + 1]));
@@ -851,15 +875,6 @@ static int select_ADF_decrypt(const char *selectADFOID, uint8_t *CRYPTOGRAM_encr
selectADFOID_UPPER[x] = toupper(selectADFOID_UPPER[x]);
}
uint8_t mac[8];
uint8_t iv_size = i/2;
create_cmac(keys[key_index].privMacKey, CRYPTOGRAM_encrypted_data_raw, mac, iv_size, sizeof(mac), encryption_algorithm);
if (memcmp(CRYPTOGRAM_encrypted_data_raw+iv_size, mac, iv_size) != 0) {
PrintAndLogEx(ERR, "Synthesized IV Verification Failed");
PrintAndLogEx(ERR, _YELLOW_("Likely wrong Priv Mac Key"));
return PM3_ESOFT;
}
// Compare the 2 ADF responses, if they don't match then the decryption is wrong
// We do the + 4 to remove the first 4 bytes of the ADF OID ASN.1 Tag (0611)
if (strcmp(CRYPTOGRAM_ADF_UPPER + 4, selectADFOID_UPPER + 4) != 0) {