Merge tag 'v1.20' into dgit/experimental

1 files changed, 26 insertions, 0 deletions

diff --git a/slowequals.c b/slowequals.c
new file mode 100644
index 0000000..48e488e
--- /dev/null
+++ b/slowequals.c
@@ -0,0 +1,26 @@
+#include <string.h>
+
+/* Implements a constant time version of strcmp()
+ * Will return 1 if a and b are equal, 0 if they are not */
+int slow_equals(const char* a, const char* b)
+{
+    size_t lena, lenb, diff, i;
+    lena = strlen(a);
+    lenb = strlen(b);
+    diff = strlen(a) ^ strlen(b);
+
+    for(i=0; i<lena && i<lenb; i++)
+    {
+        diff |= a[i] ^ b[i];
+    }
+    if (diff == 0)
+    {
+        return 1;
+    }
+    else
+    {
+        return 0;
+    }
+}
+
+