bug fixes for indefinite containers

include/nanocbor/nanocbor.h

@@ -89,6 +89,17 @@ extern "C" {
 #define NANOCBOR_SIZE_WORD          26U /**< Value contained in a word */
 #define NANOCBOR_SIZE_LONG          27U /**< Value contained in a long */
 #define NANOCBOR_SIZE_INDEFINITE    31U /**< Indefinite sized container */
+#define NANOCBOR_END_MARKER         (0xFFU) /**< Indefinite end */
+/** @} */
+
+/**
+ * @name CBOR tag types
+ * @{
+ */
+#define NANOCBOR_TAG_TSTR           0U /**< Standard date/time string */
+#define NANOCBOR_TAG_EPOCH          1U /**< Epoch-based date/time */
+#define NANOCBOR_TAG_UBIGNUM        2U /**< Unsigned bignum */
+#define NANOCBOR_TAG_NBIGNUM        3U /**< Negative bignum */
 /** @} */
 
 /**
@@ -187,6 +198,16 @@ void nanocbor_decoder_init(nanocbor_value_t *value,
  */
 int nanocbor_get_type(const nanocbor_value_t *value);
 
+/**
+ * @brief Retrieve the CBOR value at the current position
+ *
+ * @param[in]   value   decoder value context
+ *
+ * @return              value
+ * @return              NANOCBOR_ERR_OVERFLOW if the buffer is exhausted
+ */
+int nanocbor_get_value(const nanocbor_value_t *value);
+
 /**
  * @brief Check if the current buffer or container is exhausted
  *

src/decoder.c

@@ -75,8 +75,7 @@ bool nanocbor_at_end(const nanocbor_value_t *it)
     /* The container is at the end when */
     if (_over_end(it) || /* Number of items exhausted */
         /* Indefinite container and the current item is the end marker */
-        ((nanocbor_container_indefinite(it) &&
-         *it->cur == (NANOCBOR_TYPE_FLOAT | NANOCBOR_SIZE_INDEFINITE))) ||
+        ((nanocbor_container_indefinite(it) && *it->cur == (NANOCBOR_END_MARKER))) ||
         /* Or the remaining number of items is zero */
         (nanocbor_in_container(it) && it->remaining == 0)
             ) {
@@ -93,6 +92,14 @@ int nanocbor_get_type(const nanocbor_value_t *value)
     return (_get_type(value) >> NANOCBOR_TYPE_OFFSET);
 }
 
+int nanocbor_get_value(const nanocbor_value_t *value)
+{
+    if (nanocbor_at_end(value)) {
+        return NANOCBOR_ERR_END;
+    }
+    return (*value->cur & NANOCBOR_VALUE_MASK);
+}
+
 static int _get_uint64(nanocbor_value_t *cvalue, uint32_t *value, uint8_t max, int type)
 {
     int ctype = nanocbor_get_type(cvalue);
@@ -279,7 +286,7 @@ int _enter_container(nanocbor_value_t *it, nanocbor_value_t *container,
     container->end = it->end;
     container->remaining = 0;
 
-    if (_value_match_exact(it, type | NANOCBOR_VALUE_MASK) == 1) {
+    if (_value_match_exact(it, (type << NANOCBOR_TYPE_OFFSET) | NANOCBOR_VALUE_MASK) == 1) {
         container->flags = NANOCBOR_DECODER_FLAG_INDEFINITE |
                            NANOCBOR_DECODER_FLAG_CONTAINER;
         container->cur = it->cur;

tests/fuzz/inputs/tagged_date.cbor

@@ -0,0 +1 @@
+�t2013-03-21T20:04:00Z

tests/fuzz/main.c

@@ -53,6 +53,35 @@ void _parse_map(nanocbor_value_t *it, unsigned indent)
     }
 }
 
+static int _parse_tag(nanocbor_value_t *value, unsigned indent)
+{
+    if (indent > 10) {
+        return -2;
+    }
+    switch (nanocbor_get_value(value)) {
+        case NANOCBOR_TAG_TSTR:
+            {
+                const uint8_t *buf;
+                size_t len;
+                if (nanocbor_skip_simple(value) <= 0) {
+                    return -1;
+                }
+                if (nanocbor_get_tstr(value, &buf, &len) >= 0) {
+                    printf("\"%.*s\"", (int)len, buf);
+                }
+                else {
+                    return -1;
+                }
+            }
+            break;
+        default:
+            printf("Unsupported type\n");
+            return -1;
+
+    }
+    return 1;
+}
+
 static int _parse_type(nanocbor_value_t *value, unsigned indent)
 {
     uint8_t type = nanocbor_get_type(value);
@@ -159,6 +188,11 @@ static int _parse_type(nanocbor_value_t *value, unsigned indent)
                 }
                 break;
             }
+        case NANOCBOR_TYPE_TAG:
+            {
+                _parse_tag(value, indent);
+            }
+                break;
         default:
             printf("Unsupported type\n");
             return -1;