1 files changed, 250 insertions, 0 deletions
diff --git a/entropy.c b/entropy.c
new file mode 100644
index 0000000..c178c00
--- /dev/null
+++ b/entropy.c
@@ -0,0 +1,250 @@
+/*
+ * Copyright (c) 2001 Damien Miller.  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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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 "includes.h"
+
+#ifdef WITH_OPENSSL
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#ifdef HAVE_SYS_UN_H
+# include <sys/un.h>
+#endif
+
+#include <netinet/in.h>
+#include <arpa/inet.h>
+
+#include <errno.h>
+#include <signal.h>
+#include <string.h>
+#include <unistd.h>
+#include <stddef.h> /* for offsetof */
+
+#include <openssl/rand.h>
+#include <openssl/crypto.h>
+#include <openssl/err.h>
+
+#include "openbsd-compat/openssl-compat.h"
+
+#include "ssh.h"
+#include "misc.h"
+#include "xmalloc.h"
+#include "atomicio.h"
+#include "pathnames.h"
+#include "log.h"
+#include "sshbuf.h"
+#include "ssherr.h"
+
+/*
+ * Portable OpenSSH PRNG seeding:
+ * If OpenSSL has not "internally seeded" itself (e.g. pulled data from
+ * /dev/random), then collect RANDOM_SEED_SIZE bytes of randomness from
+ * PRNGd.
+ */
+#ifndef OPENSSL_PRNG_ONLY
+
+#define RANDOM_SEED_SIZE 48
+
+/*
+ * Collect 'len' bytes of entropy into 'buf' from PRNGD/EGD daemon
+ * listening either on 'tcp_port', or via Unix domain socket at *
+ * 'socket_path'.
+ * Either a non-zero tcp_port or a non-null socket_path must be
+ * supplied.
+ * Returns 0 on success, -1 on error
+ */
+int
+get_random_bytes_prngd(unsigned char *buf, int len,
+    unsigned short tcp_port, char *socket_path)
+{
+	int fd, addr_len, rval, errors;
+	u_char msg[2];
+	struct sockaddr_storage addr;
+	struct sockaddr_in *addr_in = (struct sockaddr_in *)&addr;
+	struct sockaddr_un *addr_un = (struct sockaddr_un *)&addr;
+	mysig_t old_sigpipe;
+
+	/* Sanity checks */
+	if (socket_path == NULL && tcp_port == 0)
+		fatal("You must specify a port or a socket");
+	if (socket_path != NULL &&
+	    strlen(socket_path) >= sizeof(addr_un->sun_path))
+		fatal("Random pool path is too long");
+	if (len <= 0 || len > 255)
+		fatal("Too many bytes (%d) to read from PRNGD", len);
+
+	memset(&addr, '\0', sizeof(addr));
+
+	if (tcp_port != 0) {
+		addr_in->sin_family = AF_INET;
+		addr_in->sin_addr.s_addr = htonl(INADDR_LOOPBACK);
+		addr_in->sin_port = htons(tcp_port);
+		addr_len = sizeof(*addr_in);
+	} else {
+		addr_un->sun_family = AF_UNIX;
+		strlcpy(addr_un->sun_path, socket_path,
+		    sizeof(addr_un->sun_path));
+		addr_len = offsetof(struct sockaddr_un, sun_path) +
+		    strlen(socket_path) + 1;
+	}
+
+	old_sigpipe = signal(SIGPIPE, SIG_IGN);
+
+	errors = 0;
+	rval = -1;
+reopen:
+	fd = socket(addr.ss_family, SOCK_STREAM, 0);
+	if (fd == -1) {
+		error("Couldn't create socket: %s", strerror(errno));
+		goto done;
+	}
+
+	if (connect(fd, (struct sockaddr*)&addr, addr_len) == -1) {
+		if (tcp_port != 0) {
+			error("Couldn't connect to PRNGD port %d: %s",
+			    tcp_port, strerror(errno));
+		} else {
+			error("Couldn't connect to PRNGD socket \"%s\": %s",
+			    addr_un->sun_path, strerror(errno));
+		}
+		goto done;
+	}
+
+	/* Send blocking read request to PRNGD */
+	msg[0] = 0x02;
+	msg[1] = len;
+
+	if (atomicio(vwrite, fd, msg, sizeof(msg)) != sizeof(msg)) {
+		if (errno == EPIPE && errors < 10) {
+			close(fd);
+			errors++;
+			goto reopen;
+		}
+		error("Couldn't write to PRNGD socket: %s",
+		    strerror(errno));
+		goto done;
+	}
+
+	if (atomicio(read, fd, buf, len) != (size_t)len) {
+		if (errno == EPIPE && errors < 10) {
+			close(fd);
+			errors++;
+			goto reopen;
+		}
+		error("Couldn't read from PRNGD socket: %s",
+		    strerror(errno));
+		goto done;
+	}
+
+	rval = 0;
+done:
+	signal(SIGPIPE, old_sigpipe);
+	if (fd != -1)
+		close(fd);
+	return rval;
+}
+
+static int
+seed_from_prngd(unsigned char *buf, size_t bytes)
+{
+#ifdef PRNGD_PORT
+	debug("trying egd/prngd port %d", PRNGD_PORT);
+	if (get_random_bytes_prngd(buf, bytes, PRNGD_PORT, NULL) == 0)
+		return 0;
+#endif
+#ifdef PRNGD_SOCKET
+	debug("trying egd/prngd socket %s", PRNGD_SOCKET);
+	if (get_random_bytes_prngd(buf, bytes, 0, PRNGD_SOCKET) == 0)
+		return 0;
+#endif
+	return -1;
+}
+
+void
+rexec_send_rng_seed(struct sshbuf *m)
+{
+	u_char buf[RANDOM_SEED_SIZE];
+	size_t len = sizeof(buf);
+	int r;
+
+	if (RAND_bytes(buf, sizeof(buf)) <= 0) {
+		error("Couldn't obtain random bytes (error %ld)",
+		    ERR_get_error());
+		len = 0;
+	}
+	if ((r = sshbuf_put_string(m, buf, len)) != 0)
+		fatal("%s: buffer error: %s", __func__, ssh_err(r));
+	explicit_bzero(buf, sizeof(buf));
+}
+
+void
+rexec_recv_rng_seed(struct sshbuf *m)
+{
+	u_char *buf = NULL;
+	size_t len = 0;
+	int r;
+
+	if ((r = sshbuf_get_string_direct(m, &buf, &len)) != 0
+		fatal("%s: buffer error: %s", __func__, ssh_err(r));
+
+	debug3("rexec_recv_rng_seed: seeding rng with %u bytes", len);
+	RAND_add(buf, len, len);
+}
+#endif /* OPENSSL_PRNG_ONLY */
+
+void
+seed_rng(void)
+{
+#ifndef OPENSSL_PRNG_ONLY
+	unsigned char buf[RANDOM_SEED_SIZE];
+#endif
+	if (!ssh_compatible_openssl(OPENSSL_VERSION_NUMBER, SSLeay()))
+		fatal("OpenSSL version mismatch. Built against %lx, you "
+		    "have %lx", (u_long)OPENSSL_VERSION_NUMBER, SSLeay());
+
+#ifndef OPENSSL_PRNG_ONLY
+	if (RAND_status() == 1) {
+		debug3("RNG is ready, skipping seeding");
+		return;
+	}
+
+	if (seed_from_prngd(buf, sizeof(buf)) == -1)
+		fatal("Could not obtain seed from PRNGd");
+	RAND_add(buf, sizeof(buf), sizeof(buf));
+	memset(buf, '\0', sizeof(buf));
+
+#endif /* OPENSSL_PRNG_ONLY */
+	if (RAND_status() != 1)
+		fatal("PRNG is not seeded");
+}
+
+#else /* WITH_OPENSSL */
+
+/* Handled in arc4random() */
+void
+seed_rng(void)
+{
+}
+
+#endif /* WITH_OPENSSL */