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Fix incorrect CAD was written when removing credentials

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This commit is contained in:
Matt Moran 2022-01-07 00:30:25 +13:00
commit 6f510db9fb
1 changed files with 20 additions and 26 deletions
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46
client/src/cmdhfgallagher.c
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@ -386,7 +386,7 @@ static int hfgal_create_creds_file(DesfireContext_t *ctx, uint8_t *site_key, uin
* @param num_entries Will be set to the number of entries in the Card Application Directory.
*/
static int hfgal_read_cad(DesfireContext_t *ctx, uint8_t *dest_buf,
uint8_t dest_buf_len, uint8_t *num_entries, bool verbose) {
uint8_t dest_buf_len, uint8_t *num_entries_out, bool verbose) {
if (dest_buf_len < 3 * 36) {
PrintAndLogEx(ERR, "hfgal_read_cad destination buffer is incorrectly sized. "
"Received length %d, must be at least %d", dest_buf_len, 3 * 36);
@ -409,16 +409,19 @@ static int hfgal_read_cad(DesfireContext_t *ctx, uint8_t *dest_buf,
}
// Count number of entries (i.e. count until we hit a NULL entry)
*num_entries = 0;
uint8_t num_entries = 0;
for (uint8_t i = 0; i < dest_buf_len; i += 6) {
if (memcmp(&dest_buf[i], "\0\0\0\0\0\0", 6) == 0) break;
*num_entries += 1;
num_entries++;
}
*num_entries_out = num_entries;
if (verbose) {
if (num_entries == 0) {
PrintAndLogEx(WARNING, "Card Application Directory is empty");
} else if (verbose) {
// Print what we found
PrintAndLogEx(SUCCESS, "Card Application Directory contains:" NOLF);
for (int i = 0; i < *num_entries; i++)
for (int i = 0; i < num_entries; i++)
PrintAndLogEx(NORMAL, "%s %06X" NOLF, (i == 0) ? "" : ",",
cad_aid_byte_to_uint(&dest_buf[i * 6 + 3]));
PrintAndLogEx(NORMAL, "");
@ -594,19 +597,19 @@ static int hfgal_remove_aid_from_cad(DesfireContext_t *ctx, uint8_t *site_key,
HFGAL_RET_IF_ERR(res);
// Check if facility already exists in CAD
uint8_t entry_num = 0;
for (; entry_num < num_entries; entry_num++) {
if (aid > 0 && aid == cad_aid_byte_to_uint(&cad[entry_num * 6 + 3]))
uint8_t entry_idx;
for (entry_idx = 0; entry_idx < num_entries; entry_idx++) {
if (aid > 0 && aid == cad_aid_byte_to_uint(&cad[entry_idx * 6 + 3]))
break;
}
if (entry_num >= num_entries)
if (entry_idx >= num_entries)
HFGAL_RET_ERR(PM3_EINVARG, "Specified facility or AID does not exist in the Card Application Directory");
// Remove entry (shift all entries left, then clear the last entry)
memmove(
&cad[entry_num * 6],
&cad[(entry_num + 1) * 6],
ARRAYLEN(cad) - (entry_num + 1) * 6
&cad[entry_idx * 6],
&cad[(entry_idx + 1) * 6],
ARRAYLEN(cad) - (entry_idx + 1) * 6
);
memset(&cad[ARRAYLEN(cad) - 6], 0, 6);
@ -617,10 +620,11 @@ static int hfgal_remove_aid_from_cad(DesfireContext_t *ctx, uint8_t *site_key,
HFGAL_RET_IF_ERR(res);
// Determine what files we need to update
uint8_t file_id_start = (entry_num - 1) / 6;
uint8_t file_id_start = entry_idx / 6;
uint8_t file_id_stop = (num_entries - 1) / 6;
bool delete_last_file = (num_entries - 1) % 6 == 0;
for (uint8_t file_id = file_id_start; file_id <= file_id_stop; file_id++) {
for (uint8_t file_id = file_id_start; file_id <= file_id_stop - delete_last_file; file_id++) {
// Write file
res = DesfireWriteFile(ctx, file_id, 0, 36, &cad[file_id * 36]);
HFGAL_RET_IF_ERR_WITH_MSG(res, "Failed writing data to file %d in CAD (AID %06X)", file_id, CAD_AID);
@ -629,8 +633,8 @@ static int hfgal_remove_aid_from_cad(DesfireContext_t *ctx, uint8_t *site_key,
PrintAndLogEx(INFO, "Updated file %d in CAD", file_id);
}
// Delete empty files if necessary
if (file_id_start != file_id_stop) {
// Delete empty file if necessary
if (delete_last_file) {
uint8_t file_id = file_id_stop;
DesfireSetCommMode(ctx, DCMMACed);
@ -639,16 +643,6 @@ static int hfgal_remove_aid_from_cad(DesfireContext_t *ctx, uint8_t *site_key,
if (verbose)
PrintAndLogEx(INFO, "Deleted unnecessary file %d from CAD (AID %06X)", file_id, CAD_AID);
// Delete the Card Application Directory if necessary
// (if we just deleted the last file in it)
if (file_id == 0) {
res = hfgal_delete_app(ctx, site_key, CAD_AID, verbose);
HFGAL_RET_IF_ERR_WITH_MSG(res, "Failed deleting file %d from CAD (AID %06X)", file_id, CAD_AID);
if (verbose)
PrintAndLogEx(INFO, "Removed CAD because it was empty");
}
}
PrintAndLogEx(INFO, "Successfully removed %06X from the Card Application Directory", aid);