--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/nss/lib/freebl/drbg.c	Mon Jul 28 10:47:06 2014 +0200
@@ -0,0 +1,914 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifdef FREEBL_NO_DEPEND
+#include "stubs.h"
+#endif
+
+#include "prerror.h"
+#include "secerr.h"
+
+#include "prtypes.h"
+#include "prinit.h"
+#include "blapi.h"
+#include "blapii.h"
+#include "nssilock.h"
+#include "secitem.h"
+#include "sha_fast.h"
+#include "sha256.h"
+#include "secrng.h"	/* for RNG_SystemRNG() */
+#include "secmpi.h"
+
+/* PRNG_SEEDLEN defined in NIST SP 800-90 section 10.1 
+ * for SHA-1, SHA-224, and SHA-256 it's 440 bits.
+ * for SHA-384 and SHA-512 it's 888 bits */
+#define PRNG_SEEDLEN      (440/PR_BITS_PER_BYTE)
+static const PRInt64 PRNG_MAX_ADDITIONAL_BYTES = LL_INIT(0x1, 0x0);
+						/* 2^35 bits or 2^32 bytes */
+#define PRNG_MAX_REQUEST_SIZE 0x10000		/* 2^19 bits or 2^16 bytes */
+#define PRNG_ADDITONAL_DATA_CACHE_SIZE (8*1024) /* must be less than
+						 *  PRNG_MAX_ADDITIONAL_BYTES
+						 */
+
+/* RESEED_COUNT is how many calls to the prng before we need to reseed 
+ * under normal NIST rules, you must return an error. In the NSS case, we
+ * self-reseed with RNG_SystemRNG(). Count can be a large number. For code
+ * simplicity, we specify count with 2 components: RESEED_BYTE (which is 
+ * the same as LOG256(RESEED_COUNT)) and RESEED_VALUE (which is the same as
+ * RESEED_COUNT / (256 ^ RESEED_BYTE)). Another way to look at this is
+ * RESEED_COUNT = RESEED_VALUE * (256 ^ RESEED_BYTE). For Hash based DRBG
+ * we use the maximum count value, 2^48, or RESEED_BYTE=6 and RESEED_VALUE=1
+ */
+#define RESEED_BYTE 6
+#define RESEED_VALUE 1
+
+#define PRNG_RESET_RESEED_COUNT(rng) \
+	PORT_Memset((rng)->reseed_counter, 0, sizeof (rng)->reseed_counter); \
+	(rng)->reseed_counter[RESEED_BYTE] = 1;
+
+
+/*
+ * The actual values of this enum are specified in SP 800-90, 10.1.1.*
+ * The spec does not name the types, it only uses bare values 
+ */
+typedef enum {
+   prngCGenerateType = 0,   	/* used when creating a new 'C' */
+   prngReseedType = 1,	    	/* used in reseeding */
+   prngAdditionalDataType = 2,  /* used in mixing additional data */
+   prngGenerateByteType = 3	/* used when mixing internal state while
+				 * generating bytes */
+} prngVTypes;
+
+/*
+ * Global RNG context
+ */ 
+struct RNGContextStr {
+    PZLock   *lock;        /* Lock to serialize access to global rng */
+    /*
+     * NOTE, a number of steps in the drbg algorithm need to hash 
+     * V_type || V. The code, therefore, depends on the V array following 
+     * immediately after V_type to avoid extra copies. To accomplish this
+     * in a way that compiliers can't perturb, we declare V_type and V
+     * as a V_Data array and reference them by macros */
+    PRUint8  V_Data[PRNG_SEEDLEN+1]; /* internal state variables */
+#define  V_type  V_Data[0]
+#define  V(rng)       (((rng)->V_Data)+1)
+#define  VSize(rng)   ((sizeof (rng)->V_Data) -1)
+    PRUint8  C[PRNG_SEEDLEN];        /* internal state variables */
+    PRUint8  oldV[PRNG_SEEDLEN];     /* for continuous rng checking */
+    /* If we get calls for the PRNG to return less than the length of our
+     * hash, we extend the request for a full hash (since we'll be doing
+     * the full hash anyway). Future requests for random numbers are fulfilled
+     * from the remainder of the bytes we generated. Requests for bytes longer
+     * than the hash size are fulfilled directly from the HashGen function
+     * of the random number generator. */
+    PRUint8  reseed_counter[RESEED_BYTE+1]; /* number of requests since the 
+					     * last reseed. Need only be
+					     * big enough to hold the whole
+					     * reseed count */
+    PRUint8  data[SHA256_LENGTH];	/* when we request less than a block
+					 * save the rest of the rng output for 
+					 * another partial block */
+    PRUint8  dataAvail;            /* # bytes of output available in our cache,
+	                            * [0...SHA256_LENGTH] */
+    /* store additional data that has been shovelled off to us by
+     * RNG_RandomUpdate. */
+    PRUint8  additionalDataCache[PRNG_ADDITONAL_DATA_CACHE_SIZE];
+    PRUint32 additionalAvail;
+    PRBool   isValid;          /* false if RNG reaches an invalid state */
+};
+
+typedef struct RNGContextStr RNGContext;
+static RNGContext *globalrng = NULL;
+static RNGContext theGlobalRng;
+
+
+/*
+ * The next several functions are derived from the NIST SP 800-90
+ * spec. In these functions, an attempt was made to use names consistent
+ * with the names in the spec, even if they differ from normal NSS usage.
+ */
+
+/*
+ * Hash Derive function defined in NISP SP 800-90 Section 10.4.1.
+ * This function is used in the Instantiate and Reseed functions.
+ * 
+ * NOTE: requested_bytes cannot overlap with input_string_1 or input_string_2.
+ * input_string_1 and input_string_2 are logically concatentated. 
+ * input_string_1 must be supplied.
+ * if input_string_2 is not supplied, NULL should be passed for this parameter.
+ */
+static SECStatus
+prng_Hash_df(PRUint8 *requested_bytes, unsigned int no_of_bytes_to_return, 
+	const PRUint8 *input_string_1, unsigned int input_string_1_len, 
+	const PRUint8 *input_string_2, unsigned int input_string_2_len)
+{
+    SHA256Context ctx;
+    PRUint32 tmp;
+    PRUint8 counter;
+
+    tmp=SHA_HTONL(no_of_bytes_to_return*8);
+
+    for (counter = 1 ; no_of_bytes_to_return > 0; counter++) {
+	unsigned int hash_return_len;
+ 	SHA256_Begin(&ctx);
+ 	SHA256_Update(&ctx, &counter, 1);
+ 	SHA256_Update(&ctx, (unsigned char *)&tmp, sizeof tmp);
+ 	SHA256_Update(&ctx, input_string_1, input_string_1_len);
+	if (input_string_2) {
+ 	    SHA256_Update(&ctx, input_string_2, input_string_2_len);
+	}
+	SHA256_End(&ctx, requested_bytes, &hash_return_len,
+		no_of_bytes_to_return);
+	requested_bytes += hash_return_len;
+	no_of_bytes_to_return -= hash_return_len;
+    }
+    return SECSuccess;
+}
+
+
+/*
+ * Hash_DRBG Instantiate NIST SP 800-80 10.1.1.2
+ *
+ * NOTE: bytes & len are entropy || nonce || personalization_string. In
+ * normal operation, NSS calculates them all together in a single call.
+ */
+static SECStatus
+prng_instantiate(RNGContext *rng, const PRUint8 *bytes, unsigned int len)
+{
+    if (len < PRNG_SEEDLEN) {
+	/* if the seedlen is to small, it's probably because we failed to get
+	 * enough random data */
+	PORT_SetError(SEC_ERROR_NEED_RANDOM);
+	return SECFailure;
+    }
+    prng_Hash_df(V(rng), VSize(rng), bytes, len, NULL, 0);
+    rng->V_type = prngCGenerateType;
+    prng_Hash_df(rng->C,sizeof rng->C,rng->V_Data,sizeof rng->V_Data,NULL,0);
+    PRNG_RESET_RESEED_COUNT(rng)
+    return SECSuccess;
+}
+    
+
+/*
+ * Update the global random number generator with more seeding
+ * material. Use the Hash_DRBG reseed algorithm from NIST SP-800-90
+ * section 10.1.1.3
+ *
+ * If entropy is NULL, it is fetched from the noise generator.
+ */
+static SECStatus
+prng_reseed(RNGContext *rng, const PRUint8 *entropy, unsigned int entropy_len,
+	const PRUint8 *additional_input, unsigned int additional_input_len)
+{
+    PRUint8 noiseData[(sizeof rng->V_Data)+PRNG_SEEDLEN];
+    PRUint8 *noise = &noiseData[0];
+
+    /* if entropy wasn't supplied, fetch it. (normal operation case) */
+    if (entropy == NULL) {
+    	entropy_len = (unsigned int) RNG_SystemRNG(
+			&noiseData[sizeof rng->V_Data], PRNG_SEEDLEN);
+    } else {
+	/* NOTE: this code is only available for testing, not to applications */
+	/* if entropy was too big for the stack variable, get it from malloc */
+	if (entropy_len > PRNG_SEEDLEN) {
+	    noise = PORT_Alloc(entropy_len + (sizeof rng->V_Data));
+	    if (noise == NULL) {
+		return SECFailure;
+	    }
+	}
+	PORT_Memcpy(&noise[sizeof rng->V_Data],entropy, entropy_len);
+    }
+
+    if (entropy_len < 256/PR_BITS_PER_BYTE) {
+	/* noise == &noiseData[0] at this point, so nothing to free */
+	PORT_SetError(SEC_ERROR_NEED_RANDOM);
+	return SECFailure;
+    }
+
+    rng->V_type = prngReseedType;
+    PORT_Memcpy(noise, rng->V_Data, sizeof rng->V_Data);
+    prng_Hash_df(V(rng), VSize(rng), noise, (sizeof rng->V_Data) + entropy_len,
+		additional_input, additional_input_len);
+    /* clear potential CSP */
+    PORT_Memset(noise, 0, (sizeof rng->V_Data) + entropy_len); 
+    rng->V_type = prngCGenerateType;
+    prng_Hash_df(rng->C,sizeof rng->C,rng->V_Data,sizeof rng->V_Data,NULL,0);
+    PRNG_RESET_RESEED_COUNT(rng)
+
+    if (noise != &noiseData[0]) {
+	PORT_Free(noise);
+    }
+    return SECSuccess;
+}
+
+/*
+ * SP 800-90 requires we rerun our health tests on reseed
+ */
+static SECStatus
+prng_reseed_test(RNGContext *rng, const PRUint8 *entropy, 
+	unsigned int entropy_len, const PRUint8 *additional_input, 
+	unsigned int additional_input_len)
+{
+    SECStatus rv;
+
+    /* do health checks in FIPS mode */
+    rv = PRNGTEST_RunHealthTests();
+    if (rv != SECSuccess) {
+	/* error set by PRNGTEST_RunHealTests() */
+	rng->isValid = PR_FALSE;
+	return SECFailure;
+    }
+    return prng_reseed(rng, entropy, entropy_len, 
+				additional_input, additional_input_len);
+}
+
+/*
+ * build some fast inline functions for adding.
+ */
+#define PRNG_ADD_CARRY_ONLY(dest, start, cy) \
+   carry = cy; \
+   for (k1=start; carry && k1 >=0 ; k1--) { \
+	carry = !(++dest[k1]); \
+   } 
+
+/*
+ * NOTE: dest must be an array for the following to work.
+ */
+#define PRNG_ADD_BITS(dest, dest_len, add, len) \
+    carry = 0; \
+    for (k1=dest_len -1, k2=len-1; k2 >= 0; --k1, --k2) { \
+	carry += dest[k1]+ add[k2]; \
+	dest[k1] = (PRUint8) carry; \
+	carry >>= 8; \
+    }
+
+#define PRNG_ADD_BITS_AND_CARRY(dest, dest_len, add, len) \
+    PRNG_ADD_BITS(dest, dest_len, add, len) \
+    PRNG_ADD_CARRY_ONLY(dest, k1, carry)
+
+/*
+ * This function expands the internal state of the prng to fulfill any number
+ * of bytes we need for this request. We only use this call if we need more
+ * than can be supplied by a single call to SHA256_HashBuf. 
+ *
+ * This function is specified in NIST SP 800-90 section 10.1.1.4, Hashgen
+ */
+static void
+prng_Hashgen(RNGContext *rng, PRUint8 *returned_bytes, 
+	     unsigned int no_of_returned_bytes)
+{
+    PRUint8 data[VSize(rng)];
+
+    PORT_Memcpy(data, V(rng), VSize(rng));
+    while (no_of_returned_bytes) {
+	SHA256Context ctx;
+	unsigned int len;
+	unsigned int carry;
+	int k1;
+
+ 	SHA256_Begin(&ctx);
+ 	SHA256_Update(&ctx, data, sizeof data);
+	SHA256_End(&ctx, returned_bytes, &len, no_of_returned_bytes);
+	returned_bytes += len;
+	no_of_returned_bytes -= len;
+	/* The carry parameter is a bool (increment or not). 
+	 * This increments data if no_of_returned_bytes is not zero */
+	PRNG_ADD_CARRY_ONLY(data, (sizeof data)- 1, no_of_returned_bytes);
+    }
+    PORT_Memset(data, 0, sizeof data); 
+}
+
+/* 
+ * Generates new random bytes and advances the internal prng state.	
+ * additional bytes are only used in algorithm testing.
+ * 
+ * This function is specified in NIST SP 800-90 section 10.1.1.4
+ */
+static SECStatus
+prng_generateNewBytes(RNGContext *rng, 
+		PRUint8 *returned_bytes, unsigned int no_of_returned_bytes,
+		const PRUint8 *additional_input,
+		unsigned int additional_input_len)
+{
+    PRUint8 H[SHA256_LENGTH]; /* both H and w since they 
+			       * aren't used concurrently */
+    unsigned int carry;
+    int k1, k2;
+
+    if (!rng->isValid) {
+	PORT_SetError(SEC_ERROR_LIBRARY_FAILURE);
+	return SECFailure;
+    }
+    /* This code only triggers during tests, normal
+     * prng operation does not use additional_input */
+    if (additional_input){
+	SHA256Context ctx;
+	/* NIST SP 800-90 defines two temporaries in their calculations,
+	 * w and H. These temporaries are the same lengths, and used
+	 * at different times, so we use the following macro to collapse
+	 * them to the same variable, but keeping their unique names for
+	 * easy comparison to the spec */
+#define w H
+	rng->V_type = prngAdditionalDataType;
+ 	SHA256_Begin(&ctx);
+ 	SHA256_Update(&ctx, rng->V_Data, sizeof rng->V_Data);
+ 	SHA256_Update(&ctx, additional_input, additional_input_len);
+	SHA256_End(&ctx, w, NULL, sizeof w);
+	PRNG_ADD_BITS_AND_CARRY(V(rng), VSize(rng), w, sizeof w)
+	PORT_Memset(w, 0, sizeof w);
+#undef w 
+    }
+
+    if (no_of_returned_bytes == SHA256_LENGTH) {
+	/* short_cut to hashbuf and save a copy and a clear */
+	SHA256_HashBuf(returned_bytes, V(rng), VSize(rng) );
+    } else {
+    	prng_Hashgen(rng, returned_bytes, no_of_returned_bytes);
+    }
+    /* advance our internal state... */
+    rng->V_type = prngGenerateByteType;
+    SHA256_HashBuf(H, rng->V_Data, sizeof rng->V_Data);
+    PRNG_ADD_BITS_AND_CARRY(V(rng), VSize(rng), H, sizeof H)
+    PRNG_ADD_BITS(V(rng), VSize(rng), rng->C, sizeof rng->C);
+    PRNG_ADD_BITS_AND_CARRY(V(rng), VSize(rng), rng->reseed_counter, 
+					sizeof rng->reseed_counter)
+    PRNG_ADD_CARRY_ONLY(rng->reseed_counter,(sizeof rng->reseed_counter)-1, 1);
+
+    /* continuous rng check */
+    if (memcmp(V(rng), rng->oldV, sizeof rng->oldV) == 0) {
+	rng->isValid = PR_FALSE;
+	PORT_SetError(SEC_ERROR_LIBRARY_FAILURE);
+	return SECFailure;
+    }
+    PORT_Memcpy(rng->oldV, V(rng), sizeof rng->oldV);
+    return SECSuccess;
+}
+
+/* Use NSPR to prevent RNG_RNGInit from being called from separate
+ * threads, creating a race condition.
+ */
+static const PRCallOnceType pristineCallOnce;
+static PRCallOnceType coRNGInit;
+static PRStatus rng_init(void)
+{
+    PRUint8 bytes[PRNG_SEEDLEN*2]; /* entropy + nonce */
+    unsigned int numBytes;
+    SECStatus rv = SECSuccess;
+
+    if (globalrng == NULL) {
+	/* bytes needs to have enough space to hold
+	 * a SHA256 hash value. Blow up at compile time if this isn't true */
+	PR_STATIC_ASSERT(sizeof(bytes) >= SHA256_LENGTH);
+	/* create a new global RNG context */
+	globalrng = &theGlobalRng;
+        PORT_Assert(NULL == globalrng->lock);
+	/* create a lock for it */
+	globalrng->lock = PZ_NewLock(nssILockOther);
+	if (globalrng->lock == NULL) {
+	    globalrng = NULL;
+	    PORT_SetError(PR_OUT_OF_MEMORY_ERROR);
+	    return PR_FAILURE;
+	}
+
+	/* Try to get some seed data for the RNG */
+	numBytes = (unsigned int) RNG_SystemRNG(bytes, sizeof bytes);
+	PORT_Assert(numBytes == 0 || numBytes == sizeof bytes);
+	if (numBytes != 0) {
+	    /* if this is our first call,  instantiate, otherwise reseed 
+	     * prng_instantiate gets a new clean state, we want to mix
+	     * any previous entropy we may have collected */
+	    if (V(globalrng)[0] == 0) {
+		rv = prng_instantiate(globalrng, bytes, numBytes);
+	    } else {
+		rv = prng_reseed_test(globalrng, bytes, numBytes, NULL, 0);
+	    }
+	    memset(bytes, 0, numBytes);
+	} else {
+	    PZ_DestroyLock(globalrng->lock);
+	    globalrng->lock = NULL;
+	    globalrng = NULL;
+	    return PR_FAILURE;
+	}
+ 
+	if (rv != SECSuccess) {
+	    return PR_FAILURE;
+	}
+	/* the RNG is in a valid state */
+	globalrng->isValid = PR_TRUE;
+
+	/* fetch one random value so that we can populate rng->oldV for our
+	 * continous random number test. */
+	prng_generateNewBytes(globalrng, bytes, SHA256_LENGTH, NULL, 0);
+
+	/* Fetch more entropy into the PRNG */
+	RNG_SystemInfoForRNG();
+    }
+    return PR_SUCCESS;
+}
+
+/*
+ * Clean up the global RNG context
+ */
+static void
+prng_freeRNGContext(RNGContext *rng)
+{
+    PRUint8 inputhash[VSize(rng) + (sizeof rng->C)];
+
+    /* destroy context lock */
+    SKIP_AFTER_FORK(PZ_DestroyLock(globalrng->lock));
+
+    /* zero global RNG context except for C & V to preserve entropy */
+    prng_Hash_df(inputhash, sizeof rng->C, rng->C, sizeof rng->C, NULL, 0); 
+    prng_Hash_df(&inputhash[sizeof rng->C], VSize(rng), V(rng), VSize(rng), 
+								  NULL, 0); 
+    memset(rng, 0, sizeof *rng);
+    memcpy(rng->C, inputhash, sizeof rng->C); 
+    memcpy(V(rng), &inputhash[sizeof rng->C], VSize(rng)); 
+
+    memset(inputhash, 0, sizeof inputhash);
+}
+
+/*
+ * Public functions
+ */
+
+/*
+ * Initialize the global RNG context and give it some seed input taken
+ * from the system.  This function is thread-safe and will only allow
+ * the global context to be initialized once.  The seed input is likely
+ * small, so it is imperative that RNG_RandomUpdate() be called with
+ * additional seed data before the generator is used.  A good way to
+ * provide the generator with additional entropy is to call
+ * RNG_SystemInfoForRNG().  Note that C_Initialize() does exactly that.
+ */
+SECStatus 
+RNG_RNGInit(void)
+{
+    /* Allow only one call to initialize the context */
+    PR_CallOnce(&coRNGInit, rng_init);
+    /* Make sure there is a context */
+    return (globalrng != NULL) ? SECSuccess : SECFailure;
+}
+
+/*
+** Update the global random number generator with more seeding
+** material.
+*/
+SECStatus 
+RNG_RandomUpdate(const void *data, size_t bytes)
+{
+    SECStatus rv;
+
+    /* Make sure our assumption that size_t is unsigned is true */
+    PR_STATIC_ASSERT(((size_t)-1) > (size_t)1);
+
+#if defined(NS_PTR_GT_32) || (defined(NSS_USE_64) && !defined(NS_PTR_LE_32))
+    /*
+     * NIST 800-90 requires us to verify our inputs. This value can
+     * come from the application, so we need to make sure it's within the
+     * spec. The spec says it must be less than 2^32 bytes (2^35 bits).
+     * This can only happen if size_t is greater than 32 bits (i.e. on
+     * most 64 bit platforms). The 90% case (perhaps 100% case), size_t
+     * is less than or equal to 32 bits if the platform is not 64 bits, and
+     * greater than 32 bits if it is a 64 bit platform. The corner
+     * cases are handled with explicit defines NS_PTR_GT_32 and NS_PTR_LE_32.
+     *
+     * In general, neither NS_PTR_GT_32 nor NS_PTR_LE_32 will need to be 
+     * defined. If you trip over the next two size ASSERTS at compile time,
+     * you will need to define them for your platform.
+     *
+     * if 'sizeof(size_t) > 4' is triggered it means that we were expecting
+     *   sizeof(size_t) to be greater than 4, but it wasn't. Setting 
+     *   NS_PTR_LE_32 will correct that mistake.
+     *
+     * if 'sizeof(size_t) <= 4' is triggered, it means that we were expecting
+     *   sizeof(size_t) to be less than or equal to 4, but it wasn't. Setting 
+     *   NS_PTR_GT_32 will correct that mistake.
+     */
+
+    PR_STATIC_ASSERT(sizeof(size_t) > 4);
+
+    if (bytes > PRNG_MAX_ADDITIONAL_BYTES) {
+	bytes = PRNG_MAX_ADDITIONAL_BYTES;
+    }
+#else
+    PR_STATIC_ASSERT(sizeof(size_t) <= 4);
+#endif
+
+    PZ_Lock(globalrng->lock);
+    /* if we're passed more than our additionalDataCache, simply
+     * call reseed with that data */
+    if (bytes > sizeof (globalrng->additionalDataCache)) {
+	rv = prng_reseed_test(globalrng, NULL, 0, data, (unsigned int) bytes);
+    /* if we aren't going to fill or overflow the buffer, just cache it */
+    } else if (bytes < ((sizeof globalrng->additionalDataCache)
+				- globalrng->additionalAvail)) {
+	PORT_Memcpy(globalrng->additionalDataCache+globalrng->additionalAvail,
+		    data, bytes);
+	globalrng->additionalAvail += (PRUint32) bytes;
+	rv = SECSuccess;
+    } else {
+	/* we are going to fill or overflow the buffer. In this case we will
+	 * fill the entropy buffer, reseed with it, start a new buffer with the
+	 * remainder. We know the remainder will fit in the buffer because
+	 * we already handled the case where bytes > the size of the buffer.
+	 */
+	size_t bufRemain = (sizeof globalrng->additionalDataCache) 
+					- globalrng->additionalAvail;
+	/* fill the rest of the buffer */
+	if (bufRemain) {
+	    PORT_Memcpy(globalrng->additionalDataCache
+			+globalrng->additionalAvail, 
+			data, bufRemain);
+	    data = ((unsigned char *)data) + bufRemain;
+	    bytes -= bufRemain;
+	}
+	/* reseed from buffer */
+	rv = prng_reseed_test(globalrng, NULL, 0, 
+				        globalrng->additionalDataCache, 
+					sizeof globalrng->additionalDataCache);
+
+	/* copy the rest into the cache */
+	PORT_Memcpy(globalrng->additionalDataCache, data, bytes);
+	globalrng->additionalAvail = (PRUint32) bytes;
+    }
+		
+    PZ_Unlock(globalrng->lock);
+    return rv;
+}
+
+/*
+** Generate some random bytes, using the global random number generator
+** object.
+*/
+static SECStatus 
+prng_GenerateGlobalRandomBytes(RNGContext *rng,
+                               void *dest, size_t len)
+{
+    SECStatus rv = SECSuccess;
+    PRUint8 *output = dest;
+    /* check for a valid global RNG context */
+    PORT_Assert(rng != NULL);
+    if (rng == NULL) {
+	PORT_SetError(SEC_ERROR_INVALID_ARGS);
+	return SECFailure;
+    }
+    /* FIPS limits the amount of entropy available in a single request */
+    if (len > PRNG_MAX_REQUEST_SIZE) {
+	PORT_SetError(SEC_ERROR_INVALID_ARGS);
+	return SECFailure;
+    }
+    /* --- LOCKED --- */
+    PZ_Lock(rng->lock);
+    /* Check the amount of seed data in the generator.  If not enough,
+     * don't produce any data.
+     */
+    if (rng->reseed_counter[0] >= RESEED_VALUE) {
+	rv = prng_reseed_test(rng, NULL, 0, NULL, 0);
+	PZ_Unlock(rng->lock);
+	if (rv != SECSuccess) {
+	    return rv;
+	}
+	RNG_SystemInfoForRNG();
+	PZ_Lock(rng->lock);
+    }
+    /*
+     * see if we have enough bytes to fulfill the request.
+     */
+    if (len <= rng->dataAvail) {
+	memcpy(output, rng->data + ((sizeof rng->data) - rng->dataAvail), len);
+	memset(rng->data + ((sizeof rng->data) - rng->dataAvail), 0, len);
+	rng->dataAvail -= len;
+	rv = SECSuccess;
+    /* if we are asking for a small number of bytes, cache the rest of 
+     * the bytes */
+    } else if (len < sizeof rng->data) {
+	rv = prng_generateNewBytes(rng, rng->data, sizeof rng->data, 
+			rng->additionalAvail ? rng->additionalDataCache : NULL,
+			rng->additionalAvail);
+	rng->additionalAvail = 0;
+	if (rv == SECSuccess) {
+	    memcpy(output, rng->data, len);
+	    memset(rng->data, 0, len); 
+	    rng->dataAvail = (sizeof rng->data) - len;
+	}
+    /* we are asking for lots of bytes, just ask the generator to pass them */
+    } else {
+	rv = prng_generateNewBytes(rng, output, len,
+			rng->additionalAvail ? rng->additionalDataCache : NULL,
+			rng->additionalAvail);
+	rng->additionalAvail = 0;
+    }
+    PZ_Unlock(rng->lock);
+    /* --- UNLOCKED --- */
+    return rv;
+}
+
+/*
+** Generate some random bytes, using the global random number generator
+** object.
+*/
+SECStatus 
+RNG_GenerateGlobalRandomBytes(void *dest, size_t len)
+{
+    return prng_GenerateGlobalRandomBytes(globalrng, dest, len);
+}
+
+void
+RNG_RNGShutdown(void)
+{
+    /* check for a valid global RNG context */
+    PORT_Assert(globalrng != NULL);
+    if (globalrng == NULL) {
+	/* Should set a "not initialized" error code. */
+	PORT_SetError(SEC_ERROR_NO_MEMORY);
+	return;
+    }
+    /* clear */
+    prng_freeRNGContext(globalrng);
+    globalrng = NULL;
+    /* reset the callonce struct to allow a new call to RNG_RNGInit() */
+    coRNGInit = pristineCallOnce;
+}
+
+/*
+ * Test case interface. used by fips testing and power on self test
+ */
+ /* make sure the test context is separate from the global context, This
+  * allows us to test the internal random number generator without losing
+  * entropy we may have previously collected. */
+RNGContext testContext;
+
+/*
+ * Test vector API. Use NIST SP 800-90 general interface so one of the
+ * other NIST SP 800-90 algorithms may be used in the future.
+ */
+SECStatus
+PRNGTEST_Instantiate(const PRUint8 *entropy, unsigned int entropy_len, 
+		const PRUint8 *nonce, unsigned int nonce_len,
+		const PRUint8 *personal_string, unsigned int ps_len)
+{
+   int bytes_len = entropy_len + nonce_len + ps_len;
+   PRUint8 *bytes = NULL;
+   SECStatus rv;
+
+   if (entropy_len < 256/PR_BITS_PER_BYTE) {
+	PORT_SetError(SEC_ERROR_NEED_RANDOM);
+	return SECFailure;
+   }
+
+   bytes = PORT_Alloc(bytes_len);
+   if (bytes == NULL) {
+	PORT_SetError(SEC_ERROR_NO_MEMORY);
+	return SECFailure;
+   }
+   /* concatenate the various inputs, internally NSS only instantiates with
+    * a single long string */
+   PORT_Memcpy(bytes, entropy, entropy_len);
+   if (nonce) {
+	PORT_Memcpy(&bytes[entropy_len], nonce, nonce_len);
+   } else {
+	PORT_Assert(nonce_len == 0);
+   }
+   if (personal_string) {
+       PORT_Memcpy(&bytes[entropy_len+nonce_len], personal_string, ps_len);
+   } else {
+	PORT_Assert(ps_len == 0);
+   }
+   rv = prng_instantiate(&testContext, bytes, bytes_len);
+   PORT_ZFree(bytes, bytes_len);
+   if (rv == SECFailure) {
+	return SECFailure;
+   }
+   testContext.isValid = PR_TRUE;
+   return SECSuccess;
+}
+
+SECStatus
+PRNGTEST_Reseed(const PRUint8 *entropy, unsigned int entropy_len, 
+		  const PRUint8 *additional, unsigned int additional_len)
+{
+    if (!testContext.isValid) {
+	PORT_SetError(SEC_ERROR_LIBRARY_FAILURE);
+	return SECFailure;
+    }
+   /* This magic input tells us to set the reseed count to it's max count, 
+    * so we can simulate PRNGTEST_Generate reaching max reseed count */
+    if ((entropy == NULL) && (entropy_len == 0) && 
+		(additional == NULL) && (additional_len == 0)) {
+	testContext.reseed_counter[0] = RESEED_VALUE;
+	return SECSuccess;
+    }
+    return prng_reseed(&testContext, entropy, entropy_len, additional,
+			additional_len);
+
+}
+
+SECStatus
+PRNGTEST_Generate(PRUint8 *bytes, unsigned int bytes_len, 
+		  const PRUint8 *additional, unsigned int additional_len)
+{
+    SECStatus rv;
+    if (!testContext.isValid) {
+	PORT_SetError(SEC_ERROR_LIBRARY_FAILURE);
+	return SECFailure;
+    }
+    /* replicate reseed test from prng_GenerateGlobalRandomBytes */
+    if (testContext.reseed_counter[0] >= RESEED_VALUE) {
+	rv = prng_reseed(&testContext, NULL, 0, NULL, 0);
+	if (rv != SECSuccess) {
+	    return rv;
+	}
+    }
+    return prng_generateNewBytes(&testContext, bytes, bytes_len,
+			additional, additional_len);
+
+}
+
+SECStatus
+PRNGTEST_Uninstantiate()
+{
+    if (!testContext.isValid) {
+	PORT_SetError(SEC_ERROR_LIBRARY_FAILURE);
+	return SECFailure;
+    }
+   PORT_Memset(&testContext, 0, sizeof testContext);
+   return SECSuccess;
+}
+
+SECStatus
+PRNGTEST_RunHealthTests()
+{
+   static const PRUint8 entropy[] = {
+			0x8e,0x9c,0x0d,0x25,0x75,0x22,0x04,0xf9,
+			0xc5,0x79,0x10,0x8b,0x23,0x79,0x37,0x14,
+			0x9f,0x2c,0xc7,0x0b,0x39,0xf8,0xee,0xef,
+			0x95,0x0c,0x97,0x59,0xfc,0x0a,0x85,0x41,
+			0x76,0x9d,0x6d,0x67,0x00,0x4e,0x19,0x12,
+			0x02,0x16,0x53,0xea,0xf2,0x73,0xd7,0xd6,
+			0x7f,0x7e,0xc8,0xae,0x9c,0x09,0x99,0x7d,
+			0xbb,0x9e,0x48,0x7f,0xbb,0x96,0x46,0xb3,
+			0x03,0x75,0xf8,0xc8,0x69,0x45,0x3f,0x97,
+			0x5e,0x2e,0x48,0xe1,0x5d,0x58,0x97,0x4c };
+   static const PRUint8 rng_known_result[] = {
+			0x16,0xe1,0x8c,0x57,0x21,0xd8,0xf1,0x7e,
+			0x5a,0xa0,0x16,0x0b,0x7e,0xa6,0x25,0xb4,
+			0x24,0x19,0xdb,0x54,0xfa,0x35,0x13,0x66,
+			0xbb,0xaa,0x2a,0x1b,0x22,0x33,0x2e,0x4a,
+			0x14,0x07,0x9d,0x52,0xfc,0x73,0x61,0x48,
+			0xac,0xc1,0x22,0xfc,0xa4,0xfc,0xac,0xa4,
+			0xdb,0xda,0x5b,0x27,0x33,0xc4,0xb3 };
+   static const PRUint8 reseed_entropy[] = {
+			0xc6,0x0b,0x0a,0x30,0x67,0x07,0xf4,0xe2,
+			0x24,0xa7,0x51,0x6f,0x5f,0x85,0x3e,0x5d,
+			0x67,0x97,0xb8,0x3b,0x30,0x9c,0x7a,0xb1,
+			0x52,0xc6,0x1b,0xc9,0x46,0xa8,0x62,0x79 };
+   static const PRUint8 additional_input[] = {
+			0x86,0x82,0x28,0x98,0xe7,0xcb,0x01,0x14,
+			0xae,0x87,0x4b,0x1d,0x99,0x1b,0xc7,0x41,
+			0x33,0xff,0x33,0x66,0x40,0x95,0x54,0xc6,
+			0x67,0x4d,0x40,0x2a,0x1f,0xf9,0xeb,0x65 };
+   static const PRUint8 rng_reseed_result[] = {
+			0x02,0x0c,0xc6,0x17,0x86,0x49,0xba,0xc4,
+			0x7b,0x71,0x35,0x05,0xf0,0xdb,0x4a,0xc2,
+			0x2c,0x38,0xc1,0xa4,0x42,0xe5,0x46,0x4a,
+			0x7d,0xf0,0xbe,0x47,0x88,0xb8,0x0e,0xc6,
+			0x25,0x2b,0x1d,0x13,0xef,0xa6,0x87,0x96,
+			0xa3,0x7d,0x5b,0x80,0xc2,0x38,0x76,0x61,
+			0xc7,0x80,0x5d,0x0f,0x05,0x76,0x85 };
+   static const PRUint8 rng_no_reseed_result[] = {
+			0xc4,0x40,0x41,0x8c,0xbf,0x2f,0x70,0x23,
+			0x88,0xf2,0x7b,0x30,0xc3,0xca,0x1e,0xf3,
+			0xef,0x53,0x81,0x5d,0x30,0xed,0x4c,0xf1,
+			0xff,0x89,0xa5,0xee,0x92,0xf8,0xc0,0x0f,
+			0x88,0x53,0xdf,0xb6,0x76,0xf0,0xaa,0xd3,
+			0x2e,0x1d,0x64,0x37,0x3e,0xe8,0x4a,0x02,
+			0xff,0x0a,0x7f,0xe5,0xe9,0x2b,0x6d };
+
+   SECStatus rng_status = SECSuccess;
+   PR_STATIC_ASSERT(sizeof(rng_known_result) >= sizeof(rng_reseed_result));
+   PRUint8 result[sizeof(rng_known_result)];
+
+   /********************************************/
+   /*   First test instantiate error path.     */
+   /*   In this case we supply enough entropy, */
+   /*   but not enough seed. This will trigger */
+   /*   the code that checks for a entropy     */
+   /*   source failure.                        */
+   /********************************************/
+   rng_status = PRNGTEST_Instantiate(entropy, 256/PR_BITS_PER_BYTE, 
+				     NULL, 0, NULL, 0);
+   if (rng_status == SECSuccess) {
+	PORT_SetError(SEC_ERROR_LIBRARY_FAILURE);
+	return SECFailure;
+   }
+   if (PORT_GetError() != SEC_ERROR_NEED_RANDOM) {
+	PORT_SetError(SEC_ERROR_LIBRARY_FAILURE);
+	return SECFailure;
+   }
+   /* we failed with the proper error code, we can continue */
+
+   /********************************************/
+   /* Generate random bytes with a known seed. */
+   /********************************************/
+   rng_status = PRNGTEST_Instantiate(entropy, sizeof entropy, 
+				     NULL, 0, NULL, 0);
+   if (rng_status != SECSuccess) {
+	/* Error set by PRNGTEST_Instantiate */
+	return SECFailure;
+   }
+   rng_status = PRNGTEST_Generate(result, sizeof rng_known_result, NULL, 0);
+   if ( ( rng_status != SECSuccess)  ||
+        ( PORT_Memcmp( result, rng_known_result,
+                       sizeof rng_known_result ) != 0 ) ) {
+	PRNGTEST_Uninstantiate();
+	PORT_SetError(SEC_ERROR_LIBRARY_FAILURE);
+	return SECFailure;
+   }
+   rng_status = PRNGTEST_Reseed(reseed_entropy, sizeof reseed_entropy,
+				additional_input, sizeof additional_input);
+   if (rng_status != SECSuccess) {
+	/* Error set by PRNG_Reseed */
+	PRNGTEST_Uninstantiate();
+	return SECFailure;
+   }
+   rng_status = PRNGTEST_Generate(result, sizeof rng_reseed_result, NULL, 0);
+   if ( ( rng_status != SECSuccess)  ||
+        ( PORT_Memcmp( result, rng_reseed_result,
+                       sizeof rng_reseed_result ) != 0 ) ) {
+	PRNGTEST_Uninstantiate();
+	PORT_SetError(SEC_ERROR_LIBRARY_FAILURE);
+	return SECFailure;
+   }
+   /* This magic forces the reseed count to it's max count, so we can see if
+    * PRNGTEST_Generate will actually when it reaches it's count */
+   rng_status = PRNGTEST_Reseed(NULL, 0, NULL, 0);
+   if (rng_status != SECSuccess) {
+	PRNGTEST_Uninstantiate();
+	/* Error set by PRNG_Reseed */
+	return SECFailure;
+   }
+   /* This generate should now reseed */
+   rng_status = PRNGTEST_Generate(result, sizeof rng_reseed_result, NULL, 0);
+   if ( ( rng_status != SECSuccess)  ||
+	/* NOTE we fail if the result is equal to the no_reseed_result. 
+         * no_reseed_result is the value we would have gotten if we didn't
+	 * do an automatic reseed in PRNGTEST_Generate */
+        ( PORT_Memcmp( result, rng_no_reseed_result,
+                       sizeof rng_no_reseed_result ) == 0 ) ) {
+	PRNGTEST_Uninstantiate();
+	PORT_SetError(SEC_ERROR_LIBRARY_FAILURE);
+	return SECFailure;
+   }
+   /* make sure reseed fails when we don't supply enough entropy */
+   rng_status = PRNGTEST_Reseed(reseed_entropy, 4, NULL, 0);
+   if (rng_status == SECSuccess) {
+	PRNGTEST_Uninstantiate();
+	PORT_SetError(SEC_ERROR_LIBRARY_FAILURE);
+	return SECFailure;
+   }
+   if (PORT_GetError() != SEC_ERROR_NEED_RANDOM) {
+	PRNGTEST_Uninstantiate();
+	PORT_SetError(SEC_ERROR_LIBRARY_FAILURE);
+	return SECFailure;
+   }
+   rng_status = PRNGTEST_Uninstantiate();
+   if (rng_status != SECSuccess) {
+	/* Error set by PRNG_Uninstantiate */
+	return rng_status;
+   }
+   /* make sure uninstantiate fails if the contest is not initiated (also tests
+    * if the context was cleared in the previous Uninstantiate) */
+   rng_status = PRNGTEST_Uninstantiate();
+   if (rng_status == SECSuccess) {
+	PORT_SetError(SEC_ERROR_LIBRARY_FAILURE);
+	return SECFailure;
+   }
+   if (PORT_GetError() != SEC_ERROR_LIBRARY_FAILURE) {
+	return rng_status;
+   }
+  
+   return SECSuccess;
+}