1 files changed, 109 insertions, 0 deletions
diff --git a/source4/heimdal/lib/krb5/crypto-rand.c b/source4/heimdal/lib/krb5/crypto-rand.c
new file mode 100644
index 0000000000..49bd679362
--- /dev/null
+++ b/source4/heimdal/lib/krb5/crypto-rand.c
@@ -0,0 +1,109 @@
+/*
+ * Copyright (c) 1997 - 2008 Kungliga Tekniska Högskolan
+ * (Royal Institute of Technology, Stockholm, Sweden).
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * 3. Neither the name of the Institute nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include "krb5_locl.h"
+
+#define ENTROPY_NEEDED 128
+
+static HEIMDAL_MUTEX crypto_mutex = HEIMDAL_MUTEX_INITIALIZER;
+
+static int
+seed_something(void)
+{
+    char buf[1024], seedfile[256];
+
+    /* If there is a seed file, load it. But such a file cannot be trusted,
+       so use 0 for the entropy estimate */
+    if (RAND_file_name(seedfile, sizeof(seedfile))) {
+	int fd;
+	fd = open(seedfile, O_RDONLY | O_BINARY | O_CLOEXEC);
+	if (fd >= 0) {
+	    ssize_t ret;
+	    rk_cloexec(fd);
+	    ret = read(fd, buf, sizeof(buf));
+	    if (ret > 0)
+		RAND_add(buf, ret, 0.0);
+	    close(fd);
+	} else
+	    seedfile[0] = '\0';
+    } else
+	seedfile[0] = '\0';
+
+    /* Calling RAND_status() will try to use /dev/urandom if it exists so
+       we do not have to deal with it. */
+    if (RAND_status() != 1) {
+#ifndef _WIN32
+	krb5_context context;
+	const char *p;
+
+	/* Try using egd */
+	if (!krb5_init_context(&context)) {
+	    p = krb5_config_get_string(context, NULL, "libdefaults",
+				       "egd_socket", NULL);
+	    if (p != NULL)
+		RAND_egd_bytes(p, ENTROPY_NEEDED);
+	    krb5_free_context(context);
+	}
+#else
+	/* TODO: Once a Windows CryptoAPI RAND method is defined, we
+	   can use that and failover to another method. */
+#endif
+    }
+
+    if (RAND_status() == 1)	{
+	/* Update the seed file */
+	if (seedfile[0])
+	    RAND_write_file(seedfile);
+
+	return 0;
+    } else
+	return -1;
+}
+
+KRB5_LIB_FUNCTION void KRB5_LIB_CALL
+krb5_generate_random_block(void *buf, size_t len)
+{
+    static int rng_initialized = 0;
+
+    HEIMDAL_MUTEX_lock(&crypto_mutex);
+    if (!rng_initialized) {
+	if (seed_something())
+	    krb5_abortx(NULL, "Fatal: could not seed the "
+			"random number generator");
+
+	rng_initialized = 1;
+    }
+    HEIMDAL_MUTEX_unlock(&crypto_mutex);
+    if (RAND_bytes(buf, len) <= 0)
+	krb5_abortx(NULL, "Failed to generate random block");
+}