Squashed 'src/univalue/' changes from 5a58a46671..98261b1e7b

98261b1e7b Merge #22: Clamp JSON object depth to PHP limit
54c4015415 Clamp JSON object depth to PHP limit

git-subtree-dir: src/univalue
git-subtree-split: 98261b1e7be4ce9820e25c8ce37d40cdef19ab20

lib/univalue_read.cpp

@@ -8,6 +8,14 @@
 #include "univalue.h"
 #include "univalue_utffilter.h"
 
+/*
+ * According to stackexchange, the original json test suite wanted
+ * to limit depth to 22.  Widely-deployed PHP bails at depth 512,
+ * so we will follow PHP's lead, which should be more than sufficient
+ * (further stackexchange comments indicate depth > 32 rarely occurs).
+ */
+static const size_t MAX_JSON_DEPTH = 512;
+
 static bool json_isdigit(int ch)
 {
     return ((ch >= '0') && (ch <= '9'));
@@ -323,6 +331,9 @@ bool UniValue::read(const char *raw, size_t size)
                 stack.push_back(newTop);
             }
 
+            if (stack.size() > MAX_JSON_DEPTH)
+                return false;
+
             if (utyp == VOBJ)
                 setExpect(OBJ_NAME);
             else