Check for leading zeros in tor_inet_aton()

2 files changed, 23 insertions, 1 deletions

diff --git a/src/lib/net/.may_include b/src/lib/net/.may_include
index e4368f799b..6e9af9737a 100644
--- a/src/lib/net/.may_include
+++ b/src/lib/net/.may_include
@@ -14,4 +14,5 @@ lib/net/*.h
 lib/string/*.h
 lib/subsys/*.h
 lib/testsupport/*.h
-lib/malloc/*.h
\ No newline at end of file
+lib/malloc/*.h
+lib/smartlist_core/*.h
diff --git a/src/lib/net/inaddr.c b/src/lib/net/inaddr.c
index a655ca6ad8..7ae376b119 100644
--- a/src/lib/net/inaddr.c
+++ b/src/lib/net/inaddr.c
@@ -11,7 +11,9 @@
 #include "lib/net/inaddr.h"
 
 #include "lib/cc/torint.h"
+#include "lib/container/smartlist.h"
 #include "lib/log/util_bug.h"
+#include "lib/malloc/malloc.h"
 #include "lib/net/inaddr_st.h"
 #include "lib/string/compat_ctype.h"
 #include "lib/string/compat_string.h"
@@ -39,8 +41,27 @@ tor_inet_aton(const char *str, struct in_addr *addr)
 {
   unsigned a,b,c,d;
   char more;
+  bool is_octal = false;
+  smartlist_t *sl = NULL;
+
   if (tor_sscanf(str, "%3u.%3u.%3u.%3u%c", &a, &b, &c, &d, &more) != 4)
     return 0;
+
+  /* Parse the octets and check them for leading zeros. */
+  sl = smartlist_new();
+  smartlist_split_string(sl, str, ".", 0, 0);
+  SMARTLIST_FOREACH(sl, const char *, octet, {
+    is_octal = (strlen(octet) > 1 && octet[0] == '0');
+    if (is_octal) {
+        break;
+    }
+  });
+  SMARTLIST_FOREACH(sl, char *, octet, tor_free(octet));
+  smartlist_free(sl);
+
+  if (is_octal)
+    return 0;
+
   if (a > 255) return 0;
   if (b > 255) return 0;
   if (c > 255) return 0;