From 997cd7577ff9b0f38a8ad05ce68d9cbd48310bc5 Mon Sep 17 00:00:00 2001
From: iceman1001 <iceman@iuse.se>
Date: Tue, 4 May 2021 15:59:21 +0200
Subject: [PATCH] added 'data asn1' - decodes asn1 byte arrays

---
 client/src/cmddata.c          | 29 +++++++++++++++++++++++++++++
 client/src/crypto/asn1utils.c |  4 ++--
 client/src/emv/emvcore.c      |  6 +++---
 3 files changed, 34 insertions(+), 5 deletions(-)

diff --git a/client/src/cmddata.c b/client/src/cmddata.c
index 1e96e92d6..1f10ceb18 100644
--- a/client/src/cmddata.c
+++ b/client/src/cmddata.c
@@ -28,6 +28,7 @@
 #include "mifare/ndef.h"
 #include "cliparser.h"
 #include "cmdlft55xx.h"          // print...
+#include "crypto/asn1utils.h"     // ASN1 decode / print
 
 uint8_t DemodBuffer[MAX_DEMOD_BUF_LEN];
 size_t DemodBufferLen = 0;
@@ -2882,6 +2883,33 @@ static int CmdDataModulationSearch(const char *Cmd) {
     return try_detect_modulation();
 }
 
+static int CmdAsn1Decoder(const char* Cmd) {
+
+    CLIParserContext *ctx;
+    CLIParserInit(&ctx, "data asn1",
+                  "Decode ASN1 bytearray\n"
+                  "",
+                  "data asn1 -d 303381050186922305a5020500a6088101010403030008a7188516eeee4facacf4fbde5e5c49d95e55bfbca74267b02407a9020500\n"
+                 );
+
+    void *argtable[] = {
+        arg_param_begin,
+        arg_str1("d", NULL, "<hex>", "ASN1 encoded byte array"),
+        arg_param_end
+    };
+    CLIExecWithReturn(ctx, Cmd, argtable, false);
+    int dlen = 256;
+    uint8_t data[256];
+    CLIGetHexWithReturn(ctx, 1, data, &dlen);
+    CLIParserFree(ctx);
+
+    // print ASN1 decoded array in TLV view
+    PrintAndLogEx(INFO, "---------------- " _CYAN_("ASN1 TLV") " -----------------");
+    asn1_print(data, dlen, "  ");
+    PrintAndLogEx(NORMAL, "");
+    return PM3_SUCCESS;
+}
+
 static command_t CommandTable[] = {
     {"help",            CmdHelp,                 AlwaysAvailable,  "This help"},
 
@@ -2916,6 +2944,7 @@ static command_t CommandTable[] = {
     {"getbitstream",    CmdGetBitStream,         AlwaysAvailable,  "Convert GraphBuffer's >=1 values to 1 and <1 to 0"},
 
     {"-----------",     CmdHelp,                 AlwaysAvailable, "------------------------- " _CYAN_("General") "-------------------------"},
+    {"asn1",            CmdAsn1Decoder,         AlwaysAvailable,  "asn1 decoder"},
     {"bin2hex",         Cmdbin2hex,              AlwaysAvailable,  "Converts binary to hexadecimal"},
     {"bitsamples",      CmdBitsamples,           IfPm3Present,     "Get raw samples as bitstring"},
     {"clear",           CmdBuffClear,            AlwaysAvailable,  "Clears bigbuf on deviceside and graph window"},
diff --git a/client/src/crypto/asn1utils.c b/client/src/crypto/asn1utils.c
index a076f207d..9f2dfd5b9 100644
--- a/client/src/crypto/asn1utils.c
+++ b/client/src/crypto/asn1utils.c
@@ -61,7 +61,7 @@ exit:
     return res;
 }
 
-static void print_cb(void *data, const struct tlv *tlv, int level, bool is_leaf) {
+static void asn1_print_cb(void *data, const struct tlv *tlv, int level, bool is_leaf) {
     bool candump = true;
     asn1_tag_dump(tlv, level, &candump);
     if (is_leaf && candump) {
@@ -73,7 +73,7 @@ int asn1_print(uint8_t *asn1buf, size_t asn1buflen, const char *indent) {
 
     struct tlvdb *t = tlvdb_parse_multi(asn1buf, asn1buflen);
     if (t) {
-        tlvdb_visit(t, print_cb, NULL, 0);
+        tlvdb_visit(t, asn1_print_cb, NULL, 0);
         tlvdb_free(t);
     } else {
         PrintAndLogEx(ERR, "Can't parse data as TLV tree");
diff --git a/client/src/emv/emvcore.c b/client/src/emv/emvcore.c
index 4ab081fff..9073d086a 100644
--- a/client/src/emv/emvcore.c
+++ b/client/src/emv/emvcore.c
@@ -157,7 +157,7 @@ enum CardPSVendor GetCardPSVendor(uint8_t *AID, size_t AIDlen) {
     return CV_NA;
 }
 
-static void print_cb(void *data, const struct tlv *tlv, int level, bool is_leaf) {
+static void emv_print_cb(void *data, const struct tlv *tlv, int level, bool is_leaf) {
     emv_tag_dump(tlv, level);
     if (is_leaf) {
         print_buffer(tlv->value, tlv->len, level);
@@ -169,7 +169,7 @@ bool TLVPrintFromBuffer(uint8_t *data, int datalen) {
     if (t) {
         PrintAndLogEx(INFO, "-------------------- " _CYAN_("TLV decoded") " --------------------");
 
-        tlvdb_visit(t, print_cb, NULL, 0);
+        tlvdb_visit(t, emv_print_cb, NULL, 0);
         tlvdb_free(t);
         return true;
     } else {
@@ -182,7 +182,7 @@ void TLVPrintFromTLVLev(struct tlvdb *tlv, int level) {
     if (!tlv)
         return;
 
-    tlvdb_visit(tlv, print_cb, NULL, level);
+    tlvdb_visit(tlv, emv_print_cb, NULL, level);
 }
 
 void TLVPrintFromTLV(struct tlvdb *tlv) {