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Fix heap out-of-bounds reads on short iCLASS dump files #3433

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Fix heap out-of-bounds reads on short iCLASS dump files #3433

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28 changes: 24 additions & 4 deletions client/src/cmdhficlass.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1937,8 +1937,12 @@ static int CmdHFiClassELoad(const char *Cmd) {
}

if (verbose) {
print_picopass_header((picopass_hdr_t *) dump);
print_picopass_info((picopass_hdr_t *) dump);
if (bytes_read < sizeof(picopass_hdr_t)) {
PrintAndLogEx(FAILED, "Error, dump file is too small to be a valid iCLASS dump - bytes: %zu, expected at least: %zu", bytes_read, sizeof(picopass_hdr_t));
} else {
print_picopass_header((picopass_hdr_t *) dump);
print_picopass_info((picopass_hdr_t *) dump);
}
}

PrintAndLogEx(NORMAL, "");
Expand Down Expand Up @@ -2059,8 +2063,12 @@ static int CmdHFiClassEView(const char *Cmd) {
}

if (verbose) {
print_picopass_header((picopass_hdr_t *) dump);
print_picopass_info((picopass_hdr_t *) dump);
if (bytes < sizeof(picopass_hdr_t)) {
PrintAndLogEx(FAILED, "Error, only %u bytes downloaded, too small to be a valid iCLASS dump - expected at least: %zu", bytes, sizeof(picopass_hdr_t));
} else {
print_picopass_header((picopass_hdr_t *) dump);
print_picopass_info((picopass_hdr_t *) dump);
}
}

PrintAndLogEx(NORMAL, "");
Expand Down Expand Up @@ -2326,6 +2334,18 @@ static int CmdHFiClassDecrypt(const char *Cmd) {
return res;
}

// Below (and in iclass_decode_credentials()) we unconditionally probe
// fixed offsets up through block 9 -- app_issuer_area (block 5), the
// aa1_encryption flag and block 7 in iclass_decode_credentials(), and
// the block 9 PACS/PIN check here -- regardless of what applimit or
// decryptedlen/8 say the "real" block count is. All 10 blocks (0-9)
// must actually be present in the loaded file before any of that runs.
if (decryptedlen < 10 * PICOPASS_BLOCK_SIZE) {
PrintAndLogEx(FAILED, "Error, dump file is too small - bytes: %zu, expected at least: %d", decryptedlen, 10 * PICOPASS_BLOCK_SIZE);
free(decrypted);
return PM3_EFILE;
}

have_file = true;
}

Expand Down
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