Merge remote-tracking branch 'origin/master' into ecdh-merge

Makefile.in

@@ -65,6 +65,13 @@ LDFLAGS:=@LIBS@
 ARFLAGS:=cru
 doc:=doc
 
+# files that should be ignored by git
+GITIGNOREDS:= core \*~ \*.[oa] \*.gz \*.cap \*.pcap Makefile \
+ autom4te.cache/ config.h config.log config.status configure \
+ doc/Doxyfile doc/doxygen.out doc/html/ $(LIB) tests/ccm-test \
+ tests/dtls-client tests/dtls-server tests/prf-test $(package) \
+ $(DISTDIR)/ TAGS \*.patch .gitignore
+
 .PHONY: all dirs clean install dist distclean .gitignore doc TAGS
 
 .SUFFIXES:
@@ -122,4 +129,5 @@ TAGS:
 	mv $@.new $@
 
 .gitignore:
-	echo "core\n*~\n*.[oa]\n*.gz\n*.cap\n$(PROGRAM)\n$(DISTDIR)\n.gitignore" >$@
+	echo $(GITIGNOREDS) | sed 's/ /\n/g' > $@
+

ccm.c

@@ -1,6 +1,6 @@
 /* dtls -- a very basic DTLS implementation
  *
- * Copyright (C) 2011--2012 Olaf Bergmann <[email protected]>
+ * Copyright (C) 2011--2013 Olaf Bergmann <[email protected]>
  *
  * Permission is hereby granted, free of charge, to any person
  * obtaining a copy of this software and associated documentation
@@ -298,7 +298,7 @@ dtls_ccm_decrypt_message(rijndael_ctx *ctx, size_t M, size_t L,
   memxor(msg, S, M);
 
   /* return length if MAC is valid, otherwise continue with error handling */
-  if (memcmp(X, msg, M) == 0) 
+  if (equals(X, msg, M))
     return len - M;
 
  error:

configure.in

@@ -1,7 +1,7 @@
 #                                               -*- Autoconf -*-
 # Process this file with autoconf to produce a configure script.
 #
-# Copyright (C) 2011--2012 Olaf Bergmann <[email protected]>
+# Copyright (C) 2011--2013 Olaf Bergmann <[email protected]>
 #
 # Permission is hereby granted, free of charge, to any person
 # obtaining a copy of this software and associated documentation
@@ -24,7 +24,7 @@
 # SOFTWARE.
 
 AC_PREREQ([2.65])
-AC_INIT([tinydtls], [0.4.0])
+AC_INIT([tinydtls], [0.5.0])
 AC_CONFIG_SRCDIR([dtls.c])
 dnl AC_CONFIG_HEADERS([config.h])
 

global.h

@@ -1,6 +1,6 @@
 /* dtls -- a very basic DTLS implementation
  *
- * Copyright (C) 2011--2012 Olaf Bergmann <[email protected]>
+ * Copyright (C) 2011--2013 Olaf Bergmann <[email protected]>
  *
  * Permission is hereby granted, free of charge, to any person
  * obtaining a copy of this software and associated documentation
@@ -188,6 +188,25 @@ memxor(unsigned char *x, const unsigned char *y, size_t n) {
   }
 }
 
+/**
+ * Compares \p len bytes from @p a with @p b in constant time. This
+ * functions always traverses the entire length to prevent timing
+ * attacks.
+ *
+ * \param a Byte sequence to compare
+ * \param b Byte sequence to compare
+ * \param len Number of bytes to compare.
+ * \return \c 1 if \p a and \p b are equal, \c 0 otherwise.
+ */
+static inline int
+equals(unsigned char *a, unsigned char *b, size_t len) {
+  int result = 1;
+  while (len--) {
+    result &= (*a++ == *b++);
+  }
+  return result;
+}
+
 #ifdef HAVE_FLS
 #define dtls_fls(i) fls(i)
 #else

tests/ccm-test.c

@@ -48,7 +48,6 @@ PROCESS_THREAD(ccm_test_process, ev, d)
 int main(int argc, char **argv) {
 #endif /* WITH_CONTIKI */
   long int len;
-  size_t L;			/* max(2,(fls(lm) >> 3) + 1) */
   int n;
 
   rijndael_ctx ctx;
@@ -64,8 +63,7 @@ int main(int argc, char **argv) {
       return -1;
     }
 
-    L = 15 - 13; /* the Nonce in ccm-testdata.c is always 13 Bytes */
-    len = dtls_ccm_encrypt_message(&ctx, data[n].M, L, data[n].nonce, 
+    len = dtls_ccm_encrypt_message(&ctx, data[n].M, data[n].L, data[n].nonce, 
 				   data[n].msg + data[n].la, 
 				   data[n].lm - data[n].la, 
 				   data[n].msg, data[n].la);
@@ -80,7 +78,7 @@ int main(int argc, char **argv) {
     printf("result is (total length = %lu):\n\t", len);
     dump(data[n].msg, len);
 
-    len = dtls_ccm_decrypt_message(&ctx, data[n].M, L, data[n].nonce, 
+    len = dtls_ccm_decrypt_message(&ctx, data[n].M, data[n].L, data[n].nonce, 
 				   data[n].msg + data[n].la, len - data[n].la, 
 				   data[n].msg, data[n].la);