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bsd/dev/random/randomdev.c xnu-2422.100.13 xnu-201.5
--- xnu/xnu-2422.100.13/bsd/dev/random/randomdev.c
+++ xnu/xnu-201.5/bsd/dev/random/randomdev.c
@@ -1,41 +1,24 @@
 /*
- * Copyright (c) 1999-2009 Apple, Inc. All rights reserved.
+ * Copyright (c) 1999, 2000-2001 Apple Computer, Inc. All rights reserved.
  *
- * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
+ * @APPLE_LICENSE_HEADER_START@
  * 
- * This file contains Original Code and/or Modifications of Original Code
- * as defined in and that are subject to the Apple Public Source License
- * Version 2.0 (the 'License'). You may not use this file except in
- * compliance with the License. The rights granted to you under the License
- * may not be used to create, or enable the creation or redistribution of,
- * unlawful or unlicensed copies of an Apple operating system, or to
- * circumvent, violate, or enable the circumvention or violation of, any
- * terms of an Apple operating system software license agreement.
+ * The contents of this file constitute Original Code as defined in and
+ * are subject to the Apple Public Source License Version 1.1 (the
+ * "License").  You may not use this file except in compliance with the
+ * License.  Please obtain a copy of the License at
+ * http://www.apple.com/publicsource and read it before using this file.
  * 
- * Please obtain a copy of the License at
- * http://www.opensource.apple.com/apsl/ and read it before using this file.
- * 
- * The Original Code and all software distributed under the License are
- * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * This Original Code and all software distributed under the License are
+ * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
- * Please see the License for the specific language governing rights and
- * limitations under the License.
+ * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
+ * License for the specific language governing rights and limitations
+ * under the License.
  * 
- * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
- */
-
-/*
-	WARNING! WARNING! WARNING! WARNING! WARNING! WARNING! WARNING! WARNING! WARNING!
-	
-	THIS FILE IS NEEDED TO PASS FIPS ACCEPTANCE FOR THE RANDOM NUMBER GENERATOR.
-	IF YOU ALTER IT IN ANY WAY, WE WILL NEED TO GO THOUGH FIPS ACCEPTANCE AGAIN,
-	AN OPERATION THAT IS VERY EXPENSIVE AND TIME CONSUMING.  IN OTHER WORDS,
-	DON'T MESS WITH THIS FILE.
-
-	WARNING! WARNING! WARNING! WARNING! WARNING! WARNING! WARNING! WARNING! WARNING!
-*/
+ * @APPLE_LICENSE_HEADER_END@
+ */
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -44,31 +27,17 @@
 #include <sys/ioctl.h>
 #include <sys/conf.h>
 #include <sys/fcntl.h>
-#include <string.h>
 #include <miscfs/devfs/devfs.h>
 #include <kern/lock.h>
-#include <kern/clock.h>
+#include <kern/task.h>
+#include <kern/thread.h>
 #include <sys/time.h>
 #include <sys/malloc.h>
-#include <sys/uio_internal.h>
 
 #include <dev/random/randomdev.h>
 #include <dev/random/YarrowCoreLib/include/yarrow.h>
 
-#include <libkern/OSByteOrder.h>
-#include <libkern/OSAtomic.h>
-
-#include <mach/mach_time.h>
-#include <machine/machine_routines.h>
-
-#include "fips_sha1.h"
-
 #define RANDOM_MAJOR  -1 /* let the kernel pick the device number */
-
-d_ioctl_t       random_ioctl;
-
-/* To generate the seed for the RNG */
-extern uint64_t early_random();
 
 /*
  * A struct describing which functions will get invoked for certain
@@ -80,9 +49,9 @@
 	random_close,		/* close */
 	random_read,		/* read */
 	random_write,		/* write */
-	random_ioctl,		/* ioctl */
-	(stop_fcn_t *)nulldev, /* stop */
-	(reset_fcn_t *)nulldev, /* reset */
+	eno_ioctl,			/* ioctl */
+	nulldev,			/* stop */
+	nulldev,			/* reset */
 	NULL,				/* tty's */
 	eno_select,			/* select */
 	eno_mmap,			/* mmap */
@@ -92,246 +61,22 @@
 	0					/* type */
 };
 
-
-/*
-	WARNING! WARNING! WARNING! WARNING! WARNING! WARNING! WARNING! WARNING! WARNING!
-
-	ANY CODE PROTECTED UNDER "#ifdef __arm__" IS SERIOUSLY SUPPOSED TO BE THERE!
-	IF YOU REMOVE ARM CODE, RANDOM WILL NOT MEAN ANYTHING FOR iPHONES ALL OVER.
-	PLEASE DON'T TOUCH __arm__ CODE IN THIS FILE!
-
-	WARNING! WARNING! WARNING! WARNING! WARNING! WARNING! WARNING! WARNING! WARNING!
-*/
-
-
 /* Used to detect whether we've already been initialized */
-static UInt8 gRandomInstalled = 0;
+static int gRandomInstalled = 0;
 static PrngRef gPrngRef;
 static int gRandomError = 1;
-static lck_grp_t *gYarrowGrp;
-static lck_attr_t *gYarrowAttr;
-static lck_grp_attr_t *gYarrowGrpAttr;
-static lck_mtx_t *gYarrowMutex = 0;
-static UInt8 gYarrowInitializationLock = 0;
+static mutex_t *gYarrowMutex = 0;
 
 #define RESEED_TICKS 50 /* how long a reseed operation can take */
 
-
-typedef u_int8_t BlockWord;
-enum {kBSize = 20};
-typedef BlockWord Block[kBSize];
-enum {kBlockSize = sizeof(Block)};
-
-/* define prototypes to keep the compiler happy... */
-
-void add_blocks(Block a, Block b, BlockWord carry);
-void fips_initialize(void);
-void random_block(Block b, int addOptional);
-u_int32_t CalculateCRC(u_int8_t* buffer, size_t length);
-
-/*
- * Get 120 bits from yarrow
- */
-
-/*
- * add block b to block a
- */
-void
-add_blocks(Block a, Block b, BlockWord carry)
-{
-	int i = kBlockSize - 1;
-	while (i >= 0)
-	{
-		u_int32_t c = (u_int32_t)carry +
-					  (u_int32_t)a[i] +
-					  (u_int32_t)b[i];
-		a[i] = c & 0xff;
-		carry = c >> 8;
-		i -= 1;
-	}
-}
-
-
-
-static char zeros[(512 - kBSize * 8) / 8];
-static Block g_xkey;
-static Block g_random_data;
-static int g_bytes_used;
-static unsigned char g_SelfTestInitialized = 0;
-static u_int32_t gLastBlockChecksum;
-
-static const u_int32_t g_crc_table[] =
-{
-	0x00000000, 0x77073096, 0xEE0E612C, 0x990951BA, 0x076DC419, 0x706AF48F, 0xE963A535, 0x9E6495A3,
-	0x0EDB8832, 0x79DCB8A4, 0xE0D5E91E, 0x97D2D988, 0x09B64C2B, 0x7EB17CBD, 0xE7B82D07, 0x90BF1D91,
-	0x1DB71064, 0x6AB020F2, 0xF3B97148, 0x84BE41DE, 0x1ADAD47D, 0x6DDDE4EB, 0xF4D4B551, 0x83D385C7,
-	0x136C9856, 0x646BA8C0, 0xFD62F97A, 0x8A65C9EC, 0x14015C4F, 0x63066CD9, 0xFA0F3D63, 0x8D080DF5,
-	0x3B6E20C8, 0x4C69105E, 0xD56041E4, 0xA2677172, 0x3C03E4D1, 0x4B04D447, 0xD20D85FD, 0xA50AB56B,
-	0x35B5A8FA, 0x42B2986C, 0xDBBBC9D6, 0xACBCF940, 0x32D86CE3, 0x45DF5C75, 0xDCD60DCF, 0xABD13D59,
-	0x26D930AC, 0x51DE003A, 0xC8D75180, 0xBFD06116, 0x21B4F4B5, 0x56B3C423, 0xCFBA9599, 0xB8BDA50F,
-	0x2802B89E, 0x5F058808, 0xC60CD9B2, 0xB10BE924, 0x2F6F7C87, 0x58684C11, 0xC1611DAB, 0xB6662D3D,
-	0x76DC4190, 0x01DB7106, 0x98D220BC, 0xEFD5102A, 0x71B18589, 0x06B6B51F, 0x9FBFE4A5, 0xE8B8D433,
-	0x7807C9A2, 0x0F00F934, 0x9609A88E, 0xE10E9818, 0x7F6A0DBB, 0x086D3D2D, 0x91646C97, 0xE6635C01,
-	0x6B6B51F4, 0x1C6C6162, 0x856530D8, 0xF262004E, 0x6C0695ED, 0x1B01A57B, 0x8208F4C1, 0xF50FC457,
-	0x65B0D9C6, 0x12B7E950, 0x8BBEB8EA, 0xFCB9887C, 0x62DD1DDF, 0x15DA2D49, 0x8CD37CF3, 0xFBD44C65,
-	0x4DB26158, 0x3AB551CE, 0xA3BC0074, 0xD4BB30E2, 0x4ADFA541, 0x3DD895D7, 0xA4D1C46D, 0xD3D6F4FB,
-	0x4369E96A, 0x346ED9FC, 0xAD678846, 0xDA60B8D0, 0x44042D73, 0x33031DE5, 0xAA0A4C5F, 0xDD0D7CC9,
-	0x5005713C, 0x270241AA, 0xBE0B1010, 0xC90C2086, 0x5768B525, 0x206F85B3, 0xB966D409, 0xCE61E49F,
-	0x5EDEF90E, 0x29D9C998, 0xB0D09822, 0xC7D7A8B4, 0x59B33D17, 0x2EB40D81, 0xB7BD5C3B, 0xC0BA6CAD,
-	0xEDB88320, 0x9ABFB3B6, 0x03B6E20C, 0x74B1D29A, 0xEAD54739, 0x9DD277AF, 0x04DB2615, 0x73DC1683,
-	0xE3630B12, 0x94643B84, 0x0D6D6A3E, 0x7A6A5AA8, 0xE40ECF0B, 0x9309FF9D, 0x0A00AE27, 0x7D079EB1,
-	0xF00F9344, 0x8708A3D2, 0x1E01F268, 0x6906C2FE, 0xF762575D, 0x806567CB, 0x196C3671, 0x6E6B06E7,
-	0xFED41B76, 0x89D32BE0, 0x10DA7A5A, 0x67DD4ACC, 0xF9B9DF6F, 0x8EBEEFF9, 0x17B7BE43, 0x60B08ED5,
-	0xD6D6A3E8, 0xA1D1937E, 0x38D8C2C4, 0x4FDFF252, 0xD1BB67F1, 0xA6BC5767, 0x3FB506DD, 0x48B2364B,
-	0xD80D2BDA, 0xAF0A1B4C, 0x36034AF6, 0x41047A60, 0xDF60EFC3, 0xA867DF55, 0x316E8EEF, 0x4669BE79,
-	0xCB61B38C, 0xBC66831A, 0x256FD2A0, 0x5268E236, 0xCC0C7795, 0xBB0B4703, 0x220216B9, 0x5505262F,
-	0xC5BA3BBE, 0xB2BD0B28, 0x2BB45A92, 0x5CB36A04, 0xC2D7FFA7, 0xB5D0CF31, 0x2CD99E8B, 0x5BDEAE1D,
-	0x9B64C2B0, 0xEC63F226, 0x756AA39C, 0x026D930A, 0x9C0906A9, 0xEB0E363F, 0x72076785, 0x05005713,
-	0x95BF4A82, 0xE2B87A14, 0x7BB12BAE, 0x0CB61B38, 0x92D28E9B, 0xE5D5BE0D, 0x7CDCEFB7, 0x0BDBDF21,
-	0x86D3D2D4, 0xF1D4E242, 0x68DDB3F8, 0x1FDA836E, 0x81BE16CD, 0xF6B9265B, 0x6FB077E1, 0x18B74777,
-	0x88085AE6, 0xFF0F6A70, 0x66063BCA, 0x11010B5C, 0x8F659EFF, 0xF862AE69, 0x616BFFD3, 0x166CCF45,
-	0xA00AE278, 0xD70DD2EE, 0x4E048354, 0x3903B3C2, 0xA7672661, 0xD06016F7, 0x4969474D, 0x3E6E77DB,
-	0xAED16A4A, 0xD9D65ADC, 0x40DF0B66, 0x37D83BF0, 0xA9BCAE53, 0xDEBB9EC5, 0x47B2CF7F, 0x30B5FFE9,
-	0xBDBDF21C, 0xCABAC28A, 0x53B39330, 0x24B4A3A6, 0xBAD03605, 0xCDD70693, 0x54DE5729, 0x23D967BF,
-	0xB3667A2E, 0xC4614AB8, 0x5D681B02, 0x2A6F2B94, 0xB40BBE37, 0xC30C8EA1, 0x5A05DF1B, 0x2D02EF8D,
-};
-
-/*
- * Setup for fips compliance
- */
-
-/*
- * calculate a crc-32 checksum
- */
-u_int32_t CalculateCRC(u_int8_t* buffer, size_t length)
-{
-	u_int32_t crc = 0;
-	
-	size_t i;
-	for (i = 0; i < length; ++i)
-	{
-		u_int32_t temp = (crc ^ ((u_int32_t) buffer[i])) & 0xFF;
-		crc = (crc >> 8) ^ g_crc_table[temp];
-	}
-	
-	return crc;
-}
-
-/*
- * get a random block of data per fips 186-2
- */
-void
-random_block(Block b, int addOptional)
-{
-	SHA1_CTX sha1_ctx;
-	
-	int repeatCount = 0;
-	do
-	{
-		// do one iteration
-		
-		if (addOptional)
-		{
-			// create an xSeed to add.
-			Block xSeed;
-			prngOutput (gPrngRef, (BYTE*) &xSeed, sizeof (xSeed));
-			
-			// add the seed to the previous value of g_xkey
-			add_blocks (g_xkey, xSeed, 0);
-		}
-		
-		// initialize the value of H
-		FIPS_SHA1Init(&sha1_ctx);
-		
-		// to stay compatible with the FIPS specification, we need to flip the bytes in
-		// g_xkey to little endian byte order.  In our case, this makes exactly no difference
-		// (random is random), but we need to do it anyway to keep FIPS happy
-		
-		// compute "G"
-		FIPS_SHA1Update(&sha1_ctx, g_xkey, kBlockSize);
-		
-		// add zeros to fill the internal SHA-1 buffer
-		FIPS_SHA1Update (&sha1_ctx, (const u_int8_t *)zeros, sizeof (zeros));
-		
-		// we have to do a byte order correction here because the sha1 math is being done internally
-		// as u_int32_t, not a stream of bytes.  Since we maintain our data as a byte stream, we need
-		// to convert
-		
-		u_int32_t* finger = (u_int32_t*) b;
-		
-		unsigned j;
-		for (j = 0; j < kBlockSize / sizeof (u_int32_t); ++j)
-		{
-			*finger++ = OSSwapHostToBigInt32(sha1_ctx.h.b32[j]);
-		}		
-		
-		// calculate the CRC-32 of the block
-		u_int32_t new_crc = CalculateCRC(sha1_ctx.h.b8, sizeof (Block));
-		
-		// make sure we don't repeat
-		int cmp = new_crc == gLastBlockChecksum;
-		gLastBlockChecksum = new_crc;
-		if (!g_SelfTestInitialized)
-		{
-			g_SelfTestInitialized = 1;
-			return;
-		}
-		else if (!cmp)
-		{
-			return;
-		}
-		
-		repeatCount += 1;
-		
-		// fix up the next value of g_xkey
-		add_blocks (g_xkey, b, 1);
-	} while (repeatCount < 2);
-	
-	/*
-	 * If we got here, three sucessive checksums of the random number
-	 * generator have been the same.  Since the odds of this happening are
-	 * 1 in 18,446,744,073,709,551,616, (1 in 18 quintillion) one of the following has
-	 * most likely happened:
-	 *
-	 * 1: There is a significant bug in this code.
-	 * 2: There has been a massive system failure.
-	 * 3: The universe has ceased to exist.
-	 *
-	 * There is no good way to recover from any of these cases. We
-	 * therefore panic.
-	 */
-	 
-	 panic("FIPS random self-test failed.");
-}
-
 /*
  *Initialize ONLY the Yarrow generator.
  */
-void
-PreliminarySetup(void)
+void PreliminarySetup ()
 {
     prng_error_status perr;
-
-	/* Multiple threads can enter this as a result of an earlier
-	 * check of gYarrowMutex.  We make sure that only one of them
-	 * can enter at a time.  If one of them enters and discovers
-	 * that gYarrowMutex is no longer NULL, we know that another
-	 * thread has initialized the Yarrow state and we can exit.
-	 */
-	
-	/* The first thread that enters this function will find
-	 * gYarrowInitializationLock set to 0.  It will atomically
-	 * set the value to 1 and, seeing that it was zero, drop
-	 * out of the loop.  Other threads will see that the value is
-	 * 1 and continue to loop until we are initialized.
-     */
-
-	while (OSTestAndSet(0, &gYarrowInitializationLock)); /* serialize access to this function */
-	
-	if (gYarrowMutex) {
-		/*  we've already been initialized, clear and get out */
-		goto function_exit;
-	}
+    struct timeval tt;
+    char buffer [16];
 
     /* create a Yarrow object */
     perr = prngInitialize(&gPrngRef);
@@ -343,19 +88,21 @@
 	/* clear the error flag, reads and write should then work */
     gRandomError = 0;
 
-    uint64_t tt;
-    char buffer [16];
-
     /* get a little non-deterministic data as an initial seed. */
-	/* On OSX, securityd will add much more entropy as soon as it */
-	/* comes up.  On iOS, entropy is added with each system interrupt. */
-    tt = early_random();
-
+    microtime(&tt);
+
+    /*
+	 * So how much of the system clock is entropic?
+	 * It's hard to say, but assume that at least the
+	 * least significant byte of a 64 bit structure
+	 * is entropic.  It's probably more, how can you figure
+	 * the exact time the user turned the computer on, for example.
+    */
     perr = prngInput(gPrngRef, (BYTE*) &tt, sizeof (tt), SYSTEM_SOURCE, 8);
     if (perr != 0) {
         /* an error, complain */
         printf ("Couldn't seed Yarrow.\n");
-        goto function_exit;
+        return;
     }
     
     /* turn the data around */
@@ -365,39 +112,7 @@
     perr = prngForceReseed(gPrngRef, RESEED_TICKS);
     
     /* make a mutex to control access */
-    gYarrowGrpAttr = lck_grp_attr_alloc_init();
-    gYarrowGrp     = lck_grp_alloc_init("random", gYarrowGrpAttr);
-    gYarrowAttr    = lck_attr_alloc_init();
-    gYarrowMutex   = lck_mtx_alloc_init(gYarrowGrp, gYarrowAttr);
-	
-	fips_initialize ();
-
-function_exit:
-	/* allow other threads to figure out whether or not we have been initialized. */
-	gYarrowInitializationLock = 0;
-}
-
-const Block kKnownAnswer = {0x92, 0xb4, 0x04, 0xe5, 0x56, 0x58, 0x8c, 0xed, 0x6c, 0x1a, 0xcd, 0x4e, 0xbf, 0x05, 0x3f, 0x68, 0x09, 0xf7, 0x3a, 0x93};
-
-void
-fips_initialize(void)
-{
-	/* So that we can do the self test, set the seed to zero */
-	memset(&g_xkey, 0, sizeof(g_xkey));
-	
-	/* other initializations */
-	memset (zeros, 0, sizeof (zeros));
-	g_bytes_used = 0;
-	random_block(g_random_data, FALSE);
-	
-	// check here to see if we got the initial data we were expecting
-	if (memcmp(kKnownAnswer, g_random_data, kBlockSize) != 0)
-	{
-		panic("FIPS random self test failed");
-	}
-	
-	// now do the random block again to make sure that userland doesn't get predicatable data
-	random_block(g_random_data, TRUE);
+    gYarrowMutex = mutex_alloc(0);
 }
 
 /*
@@ -405,15 +120,18 @@
  * and to register ourselves with devfs
  */
 void
-random_init(void)
+random_init()
 {
 	int ret;
 
-	if (OSTestAndSet(0, &gRandomInstalled)) {
-		/* do this atomically so that it works correctly with
-		 multiple threads */
+	if (gRandomInstalled)
 		return;
-	}
+
+	/* install us in the file system */
+	gRandomInstalled = 1;
+
+	/* setup yarrow and the mutex */
+	PreliminarySetup();
 
 	ret = cdevsw_add(RANDOM_MAJOR, &random_cdevsw);
 	if (ret < 0) {
@@ -423,32 +141,14 @@
 	}
 
 	devfs_make_node(makedev (ret, 0), DEVFS_CHAR,
-		UID_ROOT, GID_WHEEL, 0666, "random", 0);
+		UID_ROOT, GID_WHEEL, 0644, "random", 0);
 
 	/*
 	 * also make urandom 
 	 * (which is exactly the same thing in our context)
 	 */
 	devfs_make_node(makedev (ret, 1), DEVFS_CHAR,
-		UID_ROOT, GID_WHEEL, 0666, "urandom", 0);
-
-	/* setup yarrow and the mutex if needed*/
-	PreliminarySetup();
-}
-
-int
-random_ioctl(	__unused dev_t dev, u_long cmd, __unused caddr_t data, 
-				__unused int flag, __unused struct proc *p  )
-{
-	switch (cmd) {
-	case FIONBIO:
-	case FIOASYNC:
-		break;
-	default:
-		return ENODEV;
-	}
-
-	return (0);
+		UID_ROOT, GID_WHEEL, 0644, "urandom", 0);
 }
 
 /*
@@ -457,7 +157,7 @@
  */
  
 int
-random_open(__unused dev_t dev, int flags, __unused int devtype, __unused struct proc *p)
+random_open(dev_t dev, int flags, int devtype, struct proc *p)
 {
 	if (gRandomError != 0) {
 		/* forget it, yarrow didn't come up */
@@ -471,10 +171,8 @@
 	if (flags & FWRITE) {
 		if (securelevel >= 2)
 			return (EPERM);
-#ifndef __APPLE__
-		if ((securelevel >= 1) && proc_suser(p))
+		if ((securelevel >= 1) && suser(p->p_ucred, &p->p_acflag))
 			return (EPERM);
-#endif	/* !__APPLE__ */
 	}
 
 	return (0);
@@ -486,7 +184,7 @@
  */
  
 int
-random_close(__unused dev_t dev, __unused int flags, __unused int mode, __unused struct proc *p)
+random_close(dev_t dev, int flags, int mode, struct proc *p)
 {
 	return (0);
 }
@@ -497,7 +195,7 @@
  * prng.
  */
 int
-random_write (__unused dev_t dev, struct uio *uio, __unused int ioflag)
+random_write (dev_t dev, struct uio *uio, int ioflag)
 {
     int retCode = 0;
     char rdBuffer[256];
@@ -507,21 +205,21 @@
     }
     
     /* get control of the Yarrow instance, Yarrow is NOT thread safe */
-    lck_mtx_lock(gYarrowMutex);
+    mutex_lock(gYarrowMutex);
     
     /* Security server is sending us entropy */
 
-    while (uio_resid(uio) > 0 && retCode == 0) {
+    while (uio->uio_resid > 0 && retCode == 0) {
         /* get the user's data */
-        int bytesToInput = min(uio_resid(uio), sizeof (rdBuffer));
+        int bytesToInput = min(uio->uio_resid, sizeof (rdBuffer));
         retCode = uiomove(rdBuffer, bytesToInput, uio);
         if (retCode != 0)
             goto /*ugh*/ error_exit;
         
         /* put it in Yarrow */
         if (prngInput(gPrngRef, (BYTE*) rdBuffer,
-			bytesToInput, SYSTEM_SOURCE,
-        	bytesToInput * 8) != 0) {
+			sizeof (rdBuffer), SYSTEM_SOURCE,
+        	sizeof (rdBuffer) * 8) != 0) {
             retCode = EIO;
             goto error_exit;
         }
@@ -536,10 +234,50 @@
     /* retCode should be 0 at this point */
     
 error_exit: /* do this to make sure the mutex unlocks. */
-    lck_mtx_unlock(gYarrowMutex);
+    mutex_unlock(gYarrowMutex);
     return (retCode);
 }
 
+/*
+ * return data to the caller.  Results unpredictable.
+ */ 
+int
+random_read(dev_t dev, struct uio *uio, int ioflag)
+{
+    int retCode = 0;
+    char wrBuffer[512];
+
+    if (gRandomError != 0)
+        return (ENOTSUP);
+
+   /* lock down the mutex */
+    mutex_lock(gYarrowMutex);
+
+    while (uio->uio_resid > 0 && retCode == 0) {
+        /* get the user's data */
+        int bytesToRead = min(uio->uio_resid, sizeof (wrBuffer));
+        
+        /* get the data from Yarrow */
+        if (prngOutput(gPrngRef, (BYTE *) wrBuffer, sizeof (wrBuffer)) != 0) {
+            printf ("Couldn't read data from Yarrow.\n");
+            
+            /* something's really weird */
+            retCode = EIO;
+            goto error_exit;
+        }
+        
+        retCode = uiomove(wrBuffer, bytesToRead, uio);
+        
+        if (retCode != 0)
+            goto error_exit;
+    }
+    
+    retCode = 0;
+    
+error_exit:
+    mutex_unlock(gYarrowMutex);
+    return retCode;
+}
 
 /* export good random numbers to the rest of the kernel */
 void
@@ -549,67 +287,18 @@
         PreliminarySetup ();
     }
     
-    lck_mtx_lock(gYarrowMutex);
-
-
-	int bytes_read = 0;
-
-	int bytes_remaining = numbytes;
-    while (bytes_remaining > 0) {
-        int bytes_to_read = min(bytes_remaining, kBlockSize - g_bytes_used);
-        if (bytes_to_read == 0)
-		{
-			random_block(g_random_data, TRUE);
-			g_bytes_used = 0;
-			bytes_to_read = min(bytes_remaining, kBlockSize);
-		}
-		
-		memmove ((u_int8_t*) buffer + bytes_read, ((u_int8_t*)g_random_data)+ g_bytes_used, bytes_to_read);
-		g_bytes_used += bytes_to_read;
-		bytes_read += bytes_to_read;
-		bytes_remaining -= bytes_to_read;
-    }
-
-    lck_mtx_unlock(gYarrowMutex);
-}
-
-/*
- * return data to the caller.  Results unpredictable.
- */ 
-int
-random_read(__unused dev_t dev, struct uio *uio, __unused int ioflag)
-{
-    int retCode = 0;
-	
-    if (gRandomError != 0)
-        return (ENOTSUP);
-
-    char buffer[64];
-
-	user_ssize_t bytes_remaining = uio_resid(uio);
-    while (bytes_remaining > 0 && retCode == 0) {
-		user_ssize_t bytesToRead = min(sizeof(buffer), bytes_remaining);
-        read_random(buffer, bytesToRead);
-        retCode = uiomove(buffer, bytesToRead, uio);
-
-        if (retCode != 0)
-            goto error_exit;
-		
-		bytes_remaining = uio_resid(uio);
-    }
-    
-    retCode = 0;
-    
-error_exit:
-    return retCode;
-}
-/*
- * Return an u_int32_t pseudo-random number.
- */
-u_int32_t
-RandomULong(void)
-{
-	u_int32_t buf;
+    mutex_lock(gYarrowMutex);
+    prngOutput(gPrngRef, (BYTE *) buffer, numbytes);
+    mutex_unlock(gYarrowMutex);
+}
+
+/*
+ * Return an unsigned long pseudo-random number.
+ */
+u_long
+RandomULong()
+{
+	u_long buf;
 	read_random(&buf, sizeof (buf));
 	return (buf);
 }