From a99a52f5a64c2676e3d0fa70caa2e76e51742c9d Mon Sep 17 00:00:00 2001
From: merlokk <807634+merlokk@users.noreply.github.com>
Date: Thu, 8 Apr 2021 17:58:25 +0300
Subject: [PATCH 1/2] check CDA SDAD present

---
 client/src/emv/cmdemv.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/client/src/emv/cmdemv.c b/client/src/emv/cmdemv.c
index 08f9435fd..83f268f57 100644
--- a/client/src/emv/cmdemv.c
+++ b/client/src/emv/cmdemv.c
@@ -1143,9 +1143,13 @@ static int CmdEMVExec(const char *Cmd) {
             // CDA
             PrintAndLogEx(NORMAL, "\n* CDA:");
             struct tlvdb *ac_tlv = tlvdb_parse_multi(buf, len);
-            res = trCDA(tlvRoot, ac_tlv, pdol_data_tlv, cdol_data_tlv);
-            if (res) {
-                PrintAndLogEx(NORMAL, "CDA error (%d)", res);
+            if (tlvdb_get(ac_tlv, 0x9f4b, NULL)) {
+                res = trCDA(tlvRoot, ac_tlv, pdol_data_tlv, cdol_data_tlv);
+                if (res) {
+                    PrintAndLogEx(NORMAL, "CDA error (%d)", res);
+                }
+            } else {
+                PrintAndLogEx(NORMAL, "\n* Signed Dynamic Application Data (0x9f4b) not present");
             }
 
             free(ac_tlv);

From 2f634923bb584765e0cd2d39318943f03caab50a Mon Sep 17 00:00:00 2001
From: merlokk <807634+merlokk@users.noreply.github.com>
Date: Thu, 8 Apr 2021 17:59:47 +0300
Subject: [PATCH 2/2] if SSAD present before check it (A@Pay)

---
 client/src/emv/emv_pki.c |  2 +-
 client/src/emv/emvcore.c | 26 +++++++++++++++-----------
 2 files changed, 16 insertions(+), 12 deletions(-)

diff --git a/client/src/emv/emv_pki.c b/client/src/emv/emv_pki.c
index f06a5ea69..456e2960a 100644
--- a/client/src/emv/emv_pki.c
+++ b/client/src/emv/emv_pki.c
@@ -349,7 +349,7 @@ unsigned char *emv_pki_sdatl_fill(const struct tlvdb *db, size_t *sdatl_len) {
 }
 
 struct tlvdb *emv_pki_recover_dac_ex(const struct emv_pk *enc_pk, const struct tlvdb *db, const struct tlv *sda_tlv, bool showData) {
-    size_t data_len;
+    size_t data_len = 0;
 
     // Static Data Authentication Tag List
     size_t sdatl_len;
diff --git a/client/src/emv/emvcore.c b/client/src/emv/emvcore.c
index 5a8236595..6e3767546 100644
--- a/client/src/emv/emvcore.c
+++ b/client/src/emv/emvcore.c
@@ -970,17 +970,21 @@ int trCDA(struct tlvdb *tlv, struct tlvdb *ac_tlv, struct tlv *pdol_data_tlv, st
                   sprint_hex(icc_pk->serial, 3)
                  );
 
-    struct tlvdb *dac_db = emv_pki_recover_dac(issuer_pk, tlv, sda_tlv);
-    if (dac_db) {
-        const struct tlv *dac_tlv = tlvdb_get(dac_db, 0x9f45, NULL);
-        PrintAndLogEx(SUCCESS, "SSAD verified (%s) (%02hhx:%02hhx)", _GREEN_("ok"), dac_tlv->value[0], dac_tlv->value[1]);
-        tlvdb_add(tlv, dac_db);
-    } else {
-        PrintAndLogEx(ERR, "Error: SSAD verify error");
-        emv_pk_free(pk);
-        emv_pk_free(issuer_pk);
-        emv_pk_free(icc_pk);
-        return 4;
+    // Signed Static Application Data (SSAD) check
+    const struct tlv *ssad_tlv = tlvdb_get(tlv, 0x93, NULL);
+    if (ssad_tlv && ssad_tlv->len > 1) {
+        struct tlvdb *dac_db = emv_pki_recover_dac(issuer_pk, tlv, sda_tlv);
+        if (dac_db) {
+            const struct tlv *dac_tlv = tlvdb_get(dac_db, 0x9f45, NULL);
+            PrintAndLogEx(SUCCESS, "Signed Static Application Data (SSAD) verified (%s) (%02hhx:%02hhx)", _GREEN_("ok"), dac_tlv->value[0], dac_tlv->value[1]);
+            tlvdb_add(tlv, dac_db);
+        } else {
+            PrintAndLogEx(ERR, "Error: Signed Static Application Data (SSAD) verify error");
+            emv_pk_free(pk);
+            emv_pk_free(issuer_pk);
+            emv_pk_free(icc_pk);
+            return 4;
+        }
     }
 
     PrintAndLogEx(INFO, "* * Check Signed Dynamic Application Data (SDAD)");