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authorZack Weinberg <zackw@panix.com>2017-06-08 15:39:03 -0400
committerZack Weinberg <zackw@panix.com>2017-06-08 15:39:03 -0400
commit5046dbb4a7eba5eccfd258f92f4735c9ffc8d069 (patch)
tree4470480d904b65cf14ca524f96f79eca818c3eaf /REORG.TODO/stdlib/tst-getrandom.c
parent199fc19d3aaaf57944ef036e15904febe877fc93 (diff)
downloadglibc-zack/build-layout-experiment.tar.gz
glibc-zack/build-layout-experiment.tar.xz
glibc-zack/build-layout-experiment.zip
Prepare for radical source tree reorganization. zack/build-layout-experiment
All top-level files and directories are moved into a temporary storage
directory, REORG.TODO, except for files that will certainly still
exist in their current form at top level when we're done (COPYING,
COPYING.LIB, LICENSES, NEWS, README), all old ChangeLog files (which
are moved to the new directory OldChangeLogs, instead), and the
generated file INSTALL (which is just deleted; in the new order, there
will be no generated files checked into version control).
Diffstat (limited to 'REORG.TODO/stdlib/tst-getrandom.c')
-rw-r--r--REORG.TODO/stdlib/tst-getrandom.c245
1 files changed, 245 insertions, 0 deletions
diff --git a/REORG.TODO/stdlib/tst-getrandom.c b/REORG.TODO/stdlib/tst-getrandom.c
new file mode 100644
index 0000000000..e84a83f248
--- /dev/null
+++ b/REORG.TODO/stdlib/tst-getrandom.c
@@ -0,0 +1,245 @@
+/* Tests for the getentropy, getrandom functions.
+   Copyright (C) 2016-2017 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <errno.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/random.h>
+
+/* Set to true if any errors are encountered.  */
+static bool errors;
+
+/* Test getrandom with a single buffer length.  NB: The passed-in
+   buffer must have room for four extra bytes after the specified
+   length, which are used to test that getrandom leaves those bytes
+   unchanged.  */
+static void
+test_length (char *buffer, size_t length, unsigned int flags)
+{
+  memset (buffer, 0, length);
+  strcpy (buffer + length, "123");
+  ssize_t ret = getrandom (buffer, length, flags);
+  if (ret < 0)
+    {
+      /* EAGAIN is an expected error with GRND_RANDOM and
+         GRND_NONBLOCK.  */
+      if ((flags & GRND_RANDOM)
+          && (flags & GRND_NONBLOCK)
+          && errno == EAGAIN)
+        return;
+      printf ("error: getrandom (%zu, 0x%x): %m\n", length, flags);
+      errors = true;
+      return;
+    }
+ if (ret != length)
+    {
+      if (flags & GRND_RANDOM)
+        {
+          if (ret == 0 || ret > length)
+            {
+              printf ("error: getrandom (%zu, 0x%x) returned %zd\n",
+                      length, flags, ret);
+              errors = true;
+            }
+        }
+      else
+        {
+          printf ("error: getrandom (%zu, 0x%x) returned %zd\n",
+                  length, flags, ret);
+          errors = true;
+        }
+    }
+  if (length >= 7)
+    {
+      /* One spurious test failure in 2**56 is sufficiently
+         unlikely.  */
+      int non_null = 0;
+      for (int i = 0; i < length; ++i)
+        non_null += buffer[i] != 0;
+      if (non_null == 0)
+        {
+          printf ("error: getrandom (%zu, 0x%x) returned all-zero bytes\n",
+                  length, flags);
+          errors = true;
+        }
+    }
+  if (memcmp (buffer + length, "123", 4) != 0)
+    {
+      printf ("error: getrandom (%zu, 0x%x) wrote spurious bytes\n",
+              length, flags);
+      errors = true;
+    }
+}
+
+/* Call getrandom repeatedly to fill the buffer.  */
+static bool
+getrandom_full (char *buffer, size_t length, unsigned int flags)
+{
+  char *end = buffer + length;
+  while (buffer < end)
+    {
+      ssize_t ret = getrandom (buffer, end - buffer, flags);
+      if (ret < 0)
+        {
+          printf ("error: getrandom (%zu, 0x%x): %m\n", length, flags);
+          errors = true;
+          return false;
+        }
+      buffer += ret;
+    }
+
+  return true;
+}
+
+static void
+test_flags (unsigned int flags)
+{
+  /* Test various lengths, but only for !GRND_RANDOM, to conserve
+     entropy.  */
+  {
+    enum { max_length = 300 };
+    char buffer[max_length + 4];
+    if (flags & GRND_RANDOM)
+      test_length (buffer, 0, flags);
+    else
+      {
+        for (int length = 0; length <= 9; ++length)
+          test_length (buffer, length, flags);
+        test_length (buffer, 16, flags);
+        test_length (buffer, max_length, flags);
+      }
+  }
+
+  /* Test that getrandom returns different data.  */
+  if (!(flags & GRND_NONBLOCK))
+    {
+      char buffer1[8];
+      memset (buffer1, 0, sizeof (buffer1));
+
+      char buffer2[8];
+      memset (buffer2, 0, sizeof (buffer2));
+
+      if (getrandom_full (buffer1, sizeof (buffer1), flags)
+          && getrandom_full (buffer2, sizeof (buffer2), flags))
+        {
+          /* The probability that these two 8-byte buffers are equal
+             is very small (assuming that two subsequent calls to
+             getrandom result are independent, uniformly distributed
+             random variables).  */
+          if (memcmp (buffer1, buffer2, sizeof (buffer1)) == 0)
+            {
+              printf ("error: getrandom returns constant value\n");
+              errors = true;
+            }
+        }
+    }
+}
+
+static void
+test_getentropy (void)
+{
+  char buf[16];
+  memset (buf, '@', sizeof (buf));
+  if (getentropy (buf, 0) != 0)
+    {
+      printf ("error: getentropy zero length: %m\n");
+      errors = true;
+      return;
+    }
+  for (size_t i = 0; i < sizeof (buf); ++i)
+    if (buf[i] != '@')
+      {
+        printf ("error: getentropy modified zero-length buffer\n");
+        errors = true;
+        return;
+      }
+
+  if (getentropy (buf, sizeof (buf)) != 0)
+    {
+      printf ("error: getentropy buf: %m\n");
+      errors = true;
+      return;
+    }
+
+  char buf2[256];
+  _Static_assert (sizeof (buf) < sizeof (buf2), "buf and buf2 compatible");
+  memset (buf2, '@', sizeof (buf2));
+  if (getentropy (buf2, sizeof (buf)) != 0)
+    {
+      printf ("error: getentropy buf2: %m\n");
+      errors = true;
+      return;
+    }
+
+  /* The probability that these two buffers are equal is very
+     small. */
+  if (memcmp (buf, buf2, sizeof (buf) == 0))
+    {
+      printf ("error: getentropy appears to return constant bytes\n");
+      errors = true;
+      return;
+    }
+
+  for (size_t i = sizeof (buf); i < sizeof (buf2); ++i)
+    if (buf2[i] != '@')
+      {
+        printf ("error: getentropy wrote beyond the end of the buffer\n");
+        errors = true;
+        return;
+      }
+
+  char buf3[257];
+  if (getentropy (buf3, sizeof (buf3)) == 0)
+    {
+      printf ("error: getentropy successful for 257 byte buffer\n");
+      errors = true;
+      return;
+    }
+  if (errno != EIO)
+    {
+      printf ("error: getentropy wrong error for 257 byte buffer: %m\n");
+      errors = true;
+      return;
+    }
+}
+
+static int
+do_test (void)
+{
+  /* Check if getrandom is not supported by this system.  */
+  if (getrandom (NULL, 0, 0) == -1 && errno == ENOSYS)
+    return 77;
+
+  for (int use_random = 0; use_random < 2; ++use_random)
+    for (int use_nonblock = 0; use_nonblock < 2; ++use_nonblock)
+      {
+        unsigned int flags = 0;
+        if (use_random)
+          flags |= GRND_RANDOM;
+        if (use_nonblock)
+          flags |= GRND_NONBLOCK;
+        test_flags (flags);
+      }
+
+  test_getentropy ();
+
+  return errors;
+}
+
+#include <support/test-driver.c>