Add a data-independent variant of memcmp and a d-i memeq function.

The tor_memcmp code is by Robert Ransom, and the tor_memeq code is
by me.  Both incorporate some ideas from DJB's stuff.

1 files changed, 55 insertions, 0 deletions

diff --git a/src/or/test.c b/src/or/test.c
index b08f202c20..dc71db4e1d 100644
--- a/src/or/test.c
+++ b/src/or/test.c
@@ -43,6 +43,7 @@ const char tor_svn_revision[] = "";
 #include "torgzip.h"
 #include "mempool.h"
 #include "memarea.h"
+#include "di_ops.h"
 
 #ifdef USE_DMALLOC
 #include <dmalloc.h>
@@ -1331,6 +1332,59 @@ test_util(void)
   ;
 }
 
+static void
+test_util_di_ops(void)
+{
+#define LT -1
+#define GT 1
+#define EQ 0
+  const struct {
+    const char *a; int want_sign; const char *b;
+  } examples[] = {
+    { "Foo", EQ, "Foo" },
+    { "foo", GT, "bar", },
+    { "foobar", EQ ,"foobar" },
+    { "foobar", LT, "foobaw" },
+    { "foobar", GT, "f00bar" },
+    { "foobar", GT, "boobar" },
+    { "", EQ, "" },
+    { NULL, 0, NULL },
+  };
+
+  int i;
+
+  for (i = 0; examples[i].a; ++i) {
+    size_t len = strlen(examples[i].a);
+    int eq1, eq2, neq1, neq2, cmp1, cmp2;
+    test_eq(len, strlen(examples[i].b));
+    /* We do all of the operations, with operands in both orders. */
+    eq1 = tor_memeq(examples[i].a, examples[i].b, len);
+    eq2 = tor_memeq(examples[i].b, examples[i].a, len);
+    neq1 = tor_memneq(examples[i].a, examples[i].b, len);
+    neq2 = tor_memneq(examples[i].b, examples[i].a, len);
+    cmp1 = tor_memcmp(examples[i].a, examples[i].b, len);
+    cmp2 = tor_memcmp(examples[i].b, examples[i].a, len);
+
+    /* Check for correctness of cmp1 */
+    if (cmp1 < 0 && examples[i].want_sign != LT)
+      test_fail();
+    else if (cmp1 > 0 && examples[i].want_sign != GT)
+      test_fail();
+    else if (cmp1 == 0 && examples[i].want_sign != EQ)
+      test_fail();
+
+    /* Check for consistency of everything else with cmp1 */
+    test_eq(eq1, eq2);
+    test_eq(neq1, neq2);
+    test_eq(cmp1, -cmp2);
+    test_eq(eq1, cmp1 == 0);
+    test_eq(neq1, !eq1);
+  }
+
+ done:
+  ;
+}
+
 /** Helper: assert that IPv6 addresses <b>a</b> and <b>b</b> are the same.  On
  * failure, reports an error, describing the addresses as <b>e1</b> and
  * <b>e2</b>, and reporting the line number as <b>line</b>. */
@@ -4753,6 +4807,7 @@ static struct {
   SUBENT(crypto, aes_iv),
   SUBENT(crypto, base32_decode),
   ENT(util),
+  SUBENT(util, di_ops),
   SUBENT(util, ip6_helpers),
   SUBENT(util, gzip),
   SUBENT(util, datadir),