From 80a4698a7fe544806401a5efa253de1abd256c94 Mon Sep 17 00:00:00 2001
From: Jean-Michel Picod <jmichel@google.com>
Date: Fri, 6 Jan 2023 13:03:10 +0100
Subject: [PATCH] Initial rework on TLV to avoid mem leaks

---
 client/src/emv/tlv.c | 73 ++++++++++++++++++++++++++++++++++++--------
 client/src/emv/tlv.h | 19 +++++++++++-
 2 files changed, 78 insertions(+), 14 deletions(-)

diff --git a/client/src/emv/tlv.c b/client/src/emv/tlv.c
index f22bfea4c..67fa51b58 100644
--- a/client/src/emv/tlv.c
+++ b/client/src/emv/tlv.c
@@ -44,19 +44,6 @@
 //  const typeof( ((type *)0)->member ) *__mptr = (ptr);
 //        (type *)( (char *)__mptr - offsetof(type,member) );})
 
-struct tlvdb {
-    struct tlv tag;
-    struct tlvdb *next;
-    struct tlvdb *parent;
-    struct tlvdb *children;
-};
-
-struct tlvdb_root {
-    struct tlvdb db;
-    size_t len;
-    unsigned char buf[0];
-};
-
 static tlv_tag_t tlv_parse_tag(const unsigned char **buf, size_t *len) {
     tlv_tag_t tag;
 
@@ -212,6 +199,7 @@ struct tlvdb *tlvdb_parse(const unsigned char *buf, size_t len) {
 err:
     tlvdb_free(&root->db);
 
+    free(root);
     return NULL;
 }
 
@@ -248,9 +236,53 @@ struct tlvdb *tlvdb_parse_multi(const unsigned char *buf, size_t len) {
 err:
     tlvdb_free(&root->db);
 
+    free(root);
     return NULL;
 }
 
+bool tlvdb_parse_root(struct tlvdb_root *root) {
+    if (root == NULL || root->len == 0) {
+        return false;
+    }
+
+    const uint8_t *tmp;
+    size_t left;
+
+    tmp = root->buf;
+    left = root->len;
+    if (tlvdb_parse_one(&root->db, NULL, &tmp, &left) == true) {
+        if (left == 0) {
+            return true;
+        }
+    }
+    return false;
+}
+
+bool tlvdb_parse_root_multi(struct tlvdb_root *root) {
+    if (root == NULL || root->len == 0) {
+        return false;
+    }
+
+    const uint8_t *tmp;
+    size_t left;
+
+    tmp = root->buf;
+    left = root->len;
+    if (tlvdb_parse_one(&root->db, NULL, &tmp, &left) == true) {
+        while (left > 0) {
+            struct tlvdb *db = calloc(1, sizeof(*db));
+            if (tlvdb_parse_one(db, NULL, &tmp, &left) == true) {
+                tlvdb_add(&root->db, db);
+            } else {
+                free(db);
+                return false;
+            }
+        }
+        return true;
+    }
+    return false;
+}
+
 struct tlvdb *tlvdb_fixed(tlv_tag_t tag, size_t len, const unsigned char *value) {
     struct tlvdb_root *root = calloc(1, sizeof(*root) + len);
 
@@ -291,6 +323,21 @@ void tlvdb_free(struct tlvdb *tlvdb) {
     }
 }
 
+void tlvdb_root_free(struct tlvdb_root *root) {
+    if (root == NULL) {
+        return;
+    }
+    if (root->db.children) {
+        tlvdb_free(root->db.children);
+        root->db.children = NULL;
+    }
+    if (root->db.next) {
+        tlvdb_free(root->db.next);
+        root->db.next = NULL;
+    }
+    free(root);
+}
+
 struct tlvdb *tlvdb_find_next(struct tlvdb *tlvdb, tlv_tag_t tag) {
     if (!tlvdb)
         return NULL;
diff --git a/client/src/emv/tlv.h b/client/src/emv/tlv.h
index 50d046659..39f1bcacd 100644
--- a/client/src/emv/tlv.h
+++ b/client/src/emv/tlv.h
@@ -31,14 +31,31 @@ struct tlv {
     const unsigned char *value;
 };
 
-struct tlvdb;
+struct tlvdb {
+    struct tlv tag;
+    struct tlvdb *next;
+    struct tlvdb *parent;
+    struct tlvdb *children;
+};
+
+struct tlvdb_root {
+    struct tlvdb db;
+    size_t len;
+    unsigned char buf[0];
+};
+
 typedef void (*tlv_cb)(void *data, const struct tlv *tlv, int level, bool is_leaf);
 
 struct tlvdb *tlvdb_fixed(tlv_tag_t tag, size_t len, const unsigned char *value);
 struct tlvdb *tlvdb_external(tlv_tag_t tag, size_t len, const unsigned char *value);
 struct tlvdb *tlvdb_parse(const unsigned char *buf, size_t len);
 struct tlvdb *tlvdb_parse_multi(const unsigned char *buf, size_t len);
+
+bool tlvdb_parse_root(struct tlvdb_root *root);
+bool tlvdb_parse_root_multi(struct tlvdb_root *root);
+
 void tlvdb_free(struct tlvdb *tlvdb);
+void tlvdb_root_free(struct tlvdb_root *root);
 
 struct tlvdb *tlvdb_elm_get_next(struct tlvdb *tlvdb);
 struct tlvdb *tlvdb_elm_get_children(struct tlvdb *tlvdb);