From 599c03530ae1b63df396d35b9227d239d451e8fd Mon Sep 17 00:00:00 2001
From: =?utf8?q?Lutz=20J=C3=A4nicke?= <jaenicke@openssl.org>
Date: Tue, 9 Jan 2001 16:44:59 +0000
Subject: [PATCH] Add automatic query of EGD sockets to RAND_poll(). The EGD
 sockets are only queried when the /dev/[u]random devices did not return
 enough entropy. Only the amount of entropy missing to reach the required
 minimum is queried, as EGD may be drained. Queried locations are:
 /etc/entropy, /var/run/egd-pool

---
 CHANGES                 |  6 +++++
 crypto/rand/rand.h      |  1 +
 crypto/rand/rand_egd.c  | 50 ++++++++++++++++++++++++++++++++---------
 crypto/rand/rand_unix.c | 28 +++++++++++++++++++++--
 e_os.h                  |  6 +++++
 5 files changed, 79 insertions(+), 12 deletions(-)

diff --git a/CHANGES b/CHANGES
index b0a1f58c55..75fdcc509b 100644
--- a/CHANGES
+++ b/CHANGES
@@ -10,6 +10,12 @@
      (and "OBJ_cleanup" in crypto/objects/obj_dat.c as an example).
      [Geoff Thorpe]
 
+  *) Add automatic query of EGD sockets in RAND_poll() for the unix variant.
+     If an EGD or PRNGD is running and enough entropy is returned, automatic
+     seeding like with /dev/[u]random will be performed.
+     Positions tried are: /etc/entropy, /var/run/egd-pool.
+     [Lutz Jaenicke]
+
   *) Change the Unix RAND_poll() variant to be able to poll several
      random devices and only read data for a small fragment of time
      to avoid hangs.  Also separate out the Unix variant to it's own
diff --git a/crypto/rand/rand.h b/crypto/rand/rand.h
index eb9c8c034d..1331db99db 100644
--- a/crypto/rand/rand.h
+++ b/crypto/rand/rand.h
@@ -91,6 +91,7 @@ int  RAND_load_file(const char *file,long max_bytes);
 int  RAND_write_file(const char *file);
 const char *RAND_file_name(char *file,int num);
 int RAND_status(void);
+int RAND_query_egd_bytes(const char *path, unsigned char *buf, int bytes);
 int RAND_egd(const char *path);
 int RAND_egd_bytes(const char *path,int bytes);
 void ERR_load_RAND_strings(void);
diff --git a/crypto/rand/rand_egd.c b/crypto/rand/rand_egd.c
index 02a0d86fa3..28fb1f2c60 100644
--- a/crypto/rand/rand_egd.c
+++ b/crypto/rand/rand_egd.c
@@ -60,6 +60,10 @@
  */
 
 #if defined(WIN32) || defined(VMS) || defined(__VMS)
+int RAND_query_egd_bytes(const char *path, unsigned char *buf, int bytes)
+	{
+	return(-1);
+	}
 int RAND_egd(const char *path)
 	{
 	return(-1);
@@ -81,13 +85,13 @@ int RAND_egd_bytes(const char *path,int bytes)
 #  define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
 #endif
 
-int RAND_egd(const char *path)
+int RAND_query_egd_bytes(const char *path, unsigned char *buf, int bytes)
 	{
-	int ret = -1;
+	int ret = 0;
 	struct sockaddr_un addr;
 	int len, num;
 	int fd = -1;
-	unsigned char buf[256];
+	unsigned char egdbuf[2];
 
 	memset(&addr, 0, sizeof(addr));
 	addr.sun_family = AF_UNIX;
@@ -98,18 +102,44 @@ int RAND_egd(const char *path)
 	fd = socket(AF_UNIX, SOCK_STREAM, 0);
 	if (fd == -1) return (-1);
 	if (connect(fd, (struct sockaddr *)&addr, len) == -1) goto err;
-	buf[0] = 1;
-	buf[1] = 255;
-	write(fd, buf, 2);
-	if (read(fd, buf, 1) != 1) goto err;
-	if (buf[0] == 0) goto err;
-	num = read(fd, buf, 255);
+
+	while(bytes > 0)
+	    {
+	    egdbuf[0] = 1;
+	    egdbuf[1] = bytes < 255 ? bytes : 255;
+	    write(fd, egdbuf, 2);
+	    if (read(fd, egdbuf, 1) != 1)
+		{
+		ret=-1;
+		goto err;
+		}
+	    if(egdbuf[0] == 0)
+		goto err;
+	    num = read(fd, buf + ret, egdbuf[0]);
+	    if (num < 1)
+		{
+		ret=-1;
+		goto err;
+		}
+	    ret += num;
+	    bytes-=num;
+	    }
+ err:
+	if (fd != -1) close(fd);
+	return(ret);
+	}
+
+int RAND_egd(const char *path)
+	{
+	int num, ret;
+	unsigned char buf[256];
+
+	num = RAND_query_egd_bytes(path, buf, 255);
 	if (num < 1) goto err;
 	RAND_seed(buf, num);
 	if (RAND_status() == 1)
 		ret = num;
  err:
-	if (fd != -1) close(fd);
 	return(ret);
 	}
 
diff --git a/crypto/rand/rand_unix.c b/crypto/rand/rand_unix.c
index 658d35f81c..b68e2bab91 100644
--- a/crypto/rand/rand_unix.c
+++ b/crypto/rand/rand_unix.c
@@ -125,13 +125,19 @@ int RAND_poll(void)
 {
 	unsigned long l;
 	pid_t curr_pid = getpid();
-#ifdef DEVRANDOM
+#if defined(DEVRANDOM) || defined(DEVRANDOM_EGD)
 	unsigned char tmpbuf[ENTROPY_NEEDED];
 	int n = 0;
+#endif
+#ifdef DEVRANDOM
 	static const char *randomfiles[] = { DEVRANDOM, NULL };
 	const char **randomfile = NULL;
 	int fd;
 #endif
+#ifdef DEVRANDOM_EGD
+	static const char *egdsockets[] = { DEVRANDOM_EGD, NULL };
+	const char **egdsocket = NULL;
+#endif
 
 #ifdef DEVRANDOM
 	/* Use a random entropy pool device. Linux, FreeBSD and OpenBSD
@@ -185,6 +191,24 @@ int RAND_poll(void)
 			close(fd);
 			}
 		}
+#endif
+
+#ifdef DEVRANDOM_EGD
+	/* Use an EGD socket to read entropy from an EGD or PRNGD entropy
+	 * collecting daemon. */
+
+	for (egdsocket = egdsockets; *egdsocket && n < ENTROPY_NEEDED; egdsocket++)
+		{
+		int r;
+
+		r = RAND_query_egd_bytes(*egdsocket, (unsigned char *)tmpbuf+n,
+					 ENTROPY_NEEDED-n);
+		if (r > 0)
+			n += r;
+		}
+#endif
+
+#if defined(DEVRANDOM) || defined(DEVRANDOM_EGD)
 	if (n > 0)
 		{
 		RAND_add(tmpbuf,sizeof tmpbuf,n);
@@ -201,7 +225,7 @@ int RAND_poll(void)
 	l=time(NULL);
 	RAND_add(&l,sizeof(l),0);
 
-#ifdef DEVRANDOM
+#if defined(DEVRANDOM) || defined(DEVRANDOM_EGD)
 	return 1;
 #endif
 	return 0;
diff --git a/e_os.h b/e_os.h
index d658191987..e23e254454 100644
--- a/e_os.h
+++ b/e_os.h
@@ -81,6 +81,12 @@ extern "C" {
  * My default, we will try to read at least one of these files */
 #define DEVRANDOM "/dev/urandom","/dev/random","/dev/srandom"
 #endif
+#ifndef DEVRANDOM_EGD
+/* set this to a comma-seperated list of 'egd' sockets to try out. These
+ * sockets will be tried in the order listed in case accessing the device files
+ * listed in DEVRANDOM did not return enough entropy. */
+#define DEVRANDOM_EGD "/etc/entropy","/var/run/egd-pool"
+#endif
 
 #if defined(__MWERKS__) && defined(macintosh)
 # if macintosh==1
-- 
2.25.1