Use timingsafe_memcmp() where available.

See ticket 17944; patch from "logan".

diff --git a/changes/17944 b/changes/17944
new file mode 100644 (file)
index 0000000..b279506
--- /dev/null
+++ b/changes/17944
@@ -0,0 +1,3 @@
+  o Minor features (portability):
+    - Use timingsafe_memcmp() where available. Closes ticket 17944;
+      patch from "logan".

diff --git a/configure.ac b/configure.ac
index ad86f764de5c4a01a19b3cc8c70d391f050f49cf..a47cee6058eb30c1263ab75eb212839c8e4e610e 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -381,6 +381,7 @@ AC_CHECK_FUNCS(
         backtrace_symbols_fd \
         clock_gettime \
        eventfd \
+       timingsafe_memcmp \
         flock \
         ftime \
         getaddrinfo \

diff --git a/src/common/di_ops.c b/src/common/di_ops.c
index c9d1350880a72eb2e36281da1f0d41a7ac11bba3..70f2da737711671bc1e0ffe9f25d2e948e9f51c3 100644 (file)
--- a/src/common/di_ops.c
+++ b/src/common/di_ops.c
@@ -25,6 +25,9 @@
 int
 tor_memcmp(const void *a, const void *b, size_t len)
 {
+#ifdef HAVE_TIMINGSAFE_MEMCMP
+  return timingsafe_memcmp(a, b, len);
+#else
   const uint8_t *x = a;
   const uint8_t *y = b;
   size_t i = len;
@@ -83,6 +86,7 @@ tor_memcmp(const void *a, const void *b, size_t len)
   }
 
   return retval;
+#endif /* timingsafe_memcmp */
 }
 
 /**