diff --git a/changes/bug8037 b/changes/bug8037
new file mode 100644
index 0000000000..989745fc39
--- /dev/null
+++ b/changes/bug8037
@@ -0,0 +1,8 @@
+  o Minor bugfixes:
+    - Correctly store microdescriptors and extrainfo descriptors with
+      an internal NUL byte. Fixes bug 8037; bugfix on 0.2.0.1-alpha.
+      Bug reported by "cypherpunks".
+
+  o Minor features:
+    - Reject as invalid most directory objects containing a
+      NUL. Belt-and-suspender fix for bug 8037.
diff --git a/src/common/util.c b/src/common/util.c
index 2f1bc6171b..db160fdf0a 100644
--- a/src/common/util.c
+++ b/src/common/util.c
@@ -281,6 +281,20 @@ tor_memdup_(const void *mem, size_t len DMALLOC_PARAMS)
   return dup;
 }
 
+/** As tor_memdup(), but add an extra 0 byte at the end of the resulting
+ * memory. */
+void *
+tor_memdup_nulterm(const void *mem, size_t len DMALLOC_PARAMS)
+{
+  char *dup;
+  tor_assert(len < SIZE_T_CEILING+1);
+  tor_assert(mem);
+  dup = tor_malloc_(len+1 DMALLOC_FN_ARGS);
+  memcpy(dup, mem, len);
+  dup[len] = '\0';
+  return dup;
+}
+
 /** Helper for places that need to take a function pointer to the right
  * spelling of "free()". */
 void
diff --git a/src/common/util.h b/src/common/util.h
index 712352b032..96a02dd775 100644
--- a/src/common/util.h
+++ b/src/common/util.h
@@ -83,6 +83,8 @@ char *tor_strndup_(const char *s, size_t n DMALLOC_PARAMS)
   ATTR_MALLOC ATTR_NONNULL((1));
 void *tor_memdup_(const void *mem, size_t len DMALLOC_PARAMS)
   ATTR_MALLOC ATTR_NONNULL((1));
+void *tor_memdup_nulterm_(const void *mem, size_t len DMALLOC_PARAMS)
+  ATTR_MALLOC ATTR_NONNULL((1));
 void tor_free_(void *mem);
 #ifdef USE_DMALLOC
 extern int dmalloc_free(const char *file, const int line, void *pnt,
@@ -116,6 +118,7 @@ extern int dmalloc_free(const char *file, const int line, void *pnt,
 #define tor_strdup(s)          tor_strdup_(s DMALLOC_ARGS)
 #define tor_strndup(s, n)      tor_strndup_(s, n DMALLOC_ARGS)
 #define tor_memdup(s, n)       tor_memdup_(s, n DMALLOC_ARGS)
+#define tor_memdup_nulterm(s, n)       tor_memdup_nulterm_(s, n DMALLOC_ARGS)
 
 void tor_log_mallinfo(int severity);
 
diff --git a/src/or/routerparse.c b/src/or/routerparse.c
index 0eadcc90f7..370cf2682e 100644
--- a/src/or/routerparse.c
+++ b/src/or/routerparse.c
@@ -1494,7 +1494,7 @@ extrainfo_parse_entry_from_string(const char *s, const char *end,
   extrainfo = tor_malloc_zero(sizeof(extrainfo_t));
   extrainfo->cache_info.is_extrainfo = 1;
   if (cache_copy)
-    extrainfo->cache_info.signed_descriptor_body = tor_strndup(s, end-s);
+    extrainfo->cache_info.signed_descriptor_body = tor_memdup_nulterm(s, end-s);
   extrainfo->cache_info.signed_descriptor_len = end-s;
   memcpy(extrainfo->cache_info.signed_descriptor_digest, digest, DIGEST_LEN);
 
@@ -3921,8 +3921,15 @@ tokenize_string(memarea_t *area,
   tor_assert(area);
 
   s = &start;
-  if (!end)
+  if (!end) {
     end = start+strlen(start);
+  } else {
+    /* it's only meaningful to check for nuls if we got an end-of-string ptr */
+    if (memchr(start, '\0', end-start)) {
+      log_warn(LD_DIR, "parse error: internal NUL character.");
+      return -1;
+    }
+  }
   for (i = 0; i < NIL_; ++i)
     counts[i] = 0;
 
@@ -4256,7 +4263,7 @@ microdescs_parse_from_string(const char *s, const char *eos,
 
       md->bodylen = start_of_next_microdesc - cp;
       if (copy_body)
-        md->body = tor_strndup(cp, md->bodylen);
+        md->body = tor_memdup_nulterm(cp, md->bodylen);
       else
         md->body = (char*)cp;
       md->off = cp - start;