Revert crypto: prng - Deterministic CPRNG

This patch is clearly not ready yet for prime time.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto/Kconfig

@@ -666,15 +666,6 @@ config CRYPTO_LZO
 	help
 	  This is the LZO algorithm.
 
-comment "Random Number Generation"
-
-config CRYPTO_PRNG
-	tristate "Pseudo Random Number Generation for Cryptographic modules"
-	help
-	  This option enables the generic pseudo random number generator
-	  for cryptographic modules.  Uses the Algorithm specified in
-	  ANSI X9.31 A.2.4
-
 source "drivers/crypto/Kconfig"
 
 endif	# if CRYPTO

crypto/Makefile

@@ -69,7 +69,7 @@ obj-$(CONFIG_CRYPTO_MICHAEL_MIC) += michael_mic.o
 obj-$(CONFIG_CRYPTO_CRC32C) += crc32c.o
 obj-$(CONFIG_CRYPTO_AUTHENC) += authenc.o
 obj-$(CONFIG_CRYPTO_LZO) += lzo.o
-obj-$(CONFIG_CRYPTO_PRNG) += prng.o
+
 obj-$(CONFIG_CRYPTO_TEST) += tcrypt.o
 
 #

crypto/prng.c

-/*
- * PRNG: Pseudo Random Number Generator
- *       Based on NIST Recommended PRNG From ANSI X9.31 Appendix A.2.4 using
- *       AES 128 cipher in RFC3686 ctr mode
- *
- *  (C) Neil Horman <nhorman@tuxdriver.com>
- *
- *  This program is free software; you can redistribute it and/or modify it
- *  under the terms of the GNU General Public License as published by the
- *  Free Software Foundation; either version 2 of the License, or (at your
- *  any later version.
- *
- *
- */
-
-#include <linux/err.h>
-#include <linux/init.h>
-#include <linux/module.h>
-#include <linux/mm.h>
-#include <linux/slab.h>
-#include <linux/fs.h>
-#include <linux/scatterlist.h>
-#include <linux/string.h>
-#include <linux/crypto.h>
-#include <linux/highmem.h>
-#include <linux/moduleparam.h>
-#include <linux/jiffies.h>
-#include <linux/timex.h>
-#include <linux/interrupt.h>
-#include <linux/miscdevice.h>
-#include "prng.h"
-
-#define TEST_PRNG_ON_START 0
-
-#define DEFAULT_PRNG_KEY "0123456789abcdef1011"
-#define DEFAULT_PRNG_KSZ 20
-#define DEFAULT_PRNG_IV "defaultv"
-#define DEFAULT_PRNG_IVSZ 8
-#define DEFAULT_BLK_SZ 16
-#define DEFAULT_V_SEED "zaybxcwdveuftgsh"
-
-/*
- * Flags for the prng_context flags field
- */
-
-#define PRNG_FIXED_SIZE 0x1
-#define PRNG_NEED_RESET 0x2
-
-/*
- * Note: DT is our counter value
- * 	 I is our intermediate value
- *	 V is our seed vector
- * See http://csrc.nist.gov/groups/STM/cavp/documents/rng/931rngext.pdf
- * for implementation details
- */
-
-
-struct prng_context {
-	char *prng_key;
-	char *prng_iv;
-	spinlock_t prng_lock;
-	unsigned char rand_data[DEFAULT_BLK_SZ];
-	unsigned char last_rand_data[DEFAULT_BLK_SZ];
-	unsigned char DT[DEFAULT_BLK_SZ];
-	unsigned char I[DEFAULT_BLK_SZ];
-	unsigned char V[DEFAULT_BLK_SZ];
-	u32 rand_data_valid;
-	struct crypto_blkcipher *tfm;
-	u32 flags;
-};
-
-static int dbg;
-
-static void hexdump(char *note, unsigned char *buf, unsigned int len)
-{
-	if (dbg) {
-		printk(KERN_CRIT "%s", note);
-		print_hex_dump(KERN_CONT, "", DUMP_PREFIX_OFFSET,
-				16, 1,
-				buf, len, false);
-	}
-}
-
-#define dbgprint(format, args...) do {if(dbg) printk(format, ##args);} while(0)
-
-static void xor_vectors(unsigned char *in1, unsigned char *in2,
-		        unsigned char *out, unsigned int size)
-{
-	int i;
-
-	for (i=0;i<size;i++)
-		out[i] = in1[i] ^ in2[i];
-
-}
-/*
- * Returns DEFAULT_BLK_SZ bytes of random data per call
- * returns 0 if generation succeded, <0 if something went wrong
- */
-static int _get_more_prng_bytes(struct prng_context *ctx)
-{
-	int i;
-	struct blkcipher_desc desc;
-	struct scatterlist sg_in, sg_out;
-	int ret;
-	unsigned char tmp[DEFAULT_BLK_SZ];
-
-	desc.tfm = ctx->tfm;
-	desc.flags = 0;
-
-
-	dbgprint(KERN_CRIT "Calling _get_more_prng_bytes for context %p\n",ctx);
-
-	hexdump("Input DT: ", ctx->DT, DEFAULT_BLK_SZ);
-	hexdump("Input I: ", ctx->I, DEFAULT_BLK_SZ);
-	hexdump("Input V: ", ctx->V, DEFAULT_BLK_SZ);
-
-	/*
-	 * This algorithm is a 3 stage state machine
-	 */
-	for (i=0;i<3;i++) {
-
-		desc.tfm = ctx->tfm;
-		desc.flags = 0;
-		switch (i) {
-			case 0:
-				/*
-				 * Start by encrypting the counter value
-				 * This gives us an intermediate value I
-				 */
-				memcpy(tmp, ctx->DT, DEFAULT_BLK_SZ);
-				sg_init_one(&sg_out, &ctx->I[0], DEFAULT_BLK_SZ);
-				hexdump("tmp stage 0: ", tmp, DEFAULT_BLK_SZ);
-				break;
-			case 1:
-
-				/*
-				 * Next xor I with our secret vector V
-				 * encrypt that result to obtain our
-				 * pseudo random data which we output
-				 */
-				xor_vectors(ctx->I, ctx->V, tmp, DEFAULT_BLK_SZ);
-				sg_init_one(&sg_out, &ctx->rand_data[0], DEFAULT_BLK_SZ);
-				hexdump("tmp stage 1: ", tmp, DEFAULT_BLK_SZ);
-				break;
-			case 2:
-				/*
-				 * First check that we didn't produce the same random data
-				 * that we did last time around through this
-				 */
-				if (!memcmp(ctx->rand_data, ctx->last_rand_data, DEFAULT_BLK_SZ)) {
-					printk(KERN_ERR "ctx %p Failed repetition check!\n",
-						ctx);
-					ctx->flags |= PRNG_NEED_RESET;
-					return -1;
-				}
-				memcpy(ctx->last_rand_data, ctx->rand_data, DEFAULT_BLK_SZ);
-
-				/*
-				 * Lastly xor the random data with I
-				 * and encrypt that to obtain a new secret vector V
-				 */
-				xor_vectors(ctx->rand_data, ctx->I, tmp, DEFAULT_BLK_SZ);
-				sg_init_one(&sg_out, &ctx->V[0], DEFAULT_BLK_SZ);
-				hexdump("tmp stage 2: ", tmp, DEFAULT_BLK_SZ);
-				break;
-		}
-
-		/* Initialize our input buffer */
-		sg_init_one(&sg_in, &tmp[0], DEFAULT_BLK_SZ);
-
-		/* do the encryption */
-		ret = crypto_blkcipher_encrypt(&desc, &sg_out, &sg_in, DEFAULT_BLK_SZ);
-
-		/* And check the result */
-		if (ret) {
-			dbgprint(KERN_CRIT "Encryption of new block failed for context %p\n",ctx);
-			ctx->rand_data_valid = DEFAULT_BLK_SZ;
-			return -1;
-		}
-
-	}
-
-	/*
-	 * Now update our DT value
-	 */
-	for (i=DEFAULT_BLK_SZ-1;i>0;i--) {
-		ctx->DT[i] = ctx->DT[i-1];
-	}
-	ctx->DT[0] += 1;
-
-	dbgprint("Returning new block for context %p\n",ctx);
-	ctx->rand_data_valid = 0;
-
-	hexdump("Output DT: ", ctx->DT, DEFAULT_BLK_SZ);
-	hexdump("Output I: ", ctx->I, DEFAULT_BLK_SZ);
-	hexdump("Output V: ", ctx->V, DEFAULT_BLK_SZ);
-	hexdump("New Random Data: ", ctx->rand_data, DEFAULT_BLK_SZ);
-
-	return 0;
-}
-
-/* Our exported functions */
-int get_prng_bytes(char *buf, int nbytes, struct prng_context *ctx)
-{
-	unsigned long flags;
-	unsigned char *ptr = buf;
-	unsigned int byte_count = (unsigned int)nbytes;
-	int err;
-
-
-	if (nbytes < 0)
-		return -EINVAL;
-
-	spin_lock_irqsave(&ctx->prng_lock, flags);
-
-	err = -EFAULT;
-	if (ctx->flags & PRNG_NEED_RESET)
-		goto done;
-
-	/*
-	 * If the FIXED_SIZE flag is on, only return whole blocks of
-	 * pseudo random data
-	 */
-	err = -EINVAL;
-	if (ctx->flags & PRNG_FIXED_SIZE) {
-		if (nbytes < DEFAULT_BLK_SZ)
-			goto done;
-		byte_count = DEFAULT_BLK_SZ;
-	}
-
-	err = byte_count;
-
-	dbgprint(KERN_CRIT "getting %d random bytes for context %p\n",byte_count, ctx);
-
-
-remainder:
-	if (ctx->rand_data_valid == DEFAULT_BLK_SZ) {
-		if (_get_more_prng_bytes(ctx) < 0) {
-			memset(buf, 0, nbytes);
-			err = -EFAULT;
-			goto done;
-		}
-	}
-
-	/*
-	 * Copy up to the next whole block size
-	 */
-	if (byte_count < DEFAULT_BLK_SZ) {
-		for (;ctx->rand_data_valid < DEFAULT_BLK_SZ; ctx->rand_data_valid++) {
-			*ptr = ctx->rand_data[ctx->rand_data_valid];
-			ptr++;
-			byte_count--;
-			if (byte_count == 0)
-				goto done;
-		}
-	}
-
-	/*
-	 * Now copy whole blocks
-	 */
-	for(;byte_count >= DEFAULT_BLK_SZ; byte_count -= DEFAULT_BLK_SZ) {
-		if (_get_more_prng_bytes(ctx) < 0) {
-			memset(buf, 0, nbytes);
-			err = -1;
-			goto done;
-		}
-		memcpy(ptr, ctx->rand_data, DEFAULT_BLK_SZ);
-		ctx->rand_data_valid += DEFAULT_BLK_SZ;
-		ptr += DEFAULT_BLK_SZ;
-	}
-
-	/*
-	 * Now copy any extra partial data
-	 */
-	if (byte_count)
-		goto remainder;
-
-done:
-	spin_unlock_irqrestore(&ctx->prng_lock, flags);
-	dbgprint(KERN_CRIT "returning %d from get_prng_bytes in context %p\n",err, ctx);
-	return err;
-}
-EXPORT_SYMBOL_GPL(get_prng_bytes);
-
-struct prng_context *alloc_prng_context(void)
-{
-	struct prng_context *ctx=kzalloc(sizeof(struct prng_context), GFP_KERNEL);
-
-	spin_lock_init(&ctx->prng_lock);
-
-	if (reset_prng_context(ctx, NULL, NULL, NULL, NULL)) {
-		kfree(ctx);
-		ctx = NULL;
-	}
-
-	dbgprint(KERN_CRIT "returning context %p\n",ctx);
-	return ctx;
-}
-
-EXPORT_SYMBOL_GPL(alloc_prng_context);
-
-void free_prng_context(struct prng_context *ctx)
-{
-	crypto_free_blkcipher(ctx->tfm);
-	kfree(ctx);
-}
-EXPORT_SYMBOL_GPL(free_prng_context);
-
-int reset_prng_context(struct prng_context *ctx,
-		       unsigned char *key, unsigned char *iv,
-		       unsigned char *V, unsigned char *DT)
-{
-	int ret;
-	int iv_len;
-	int rc = -EFAULT;
-
-	spin_lock(&ctx->prng_lock);
-	ctx->flags |= PRNG_NEED_RESET;
-
-	if (key)
-		memcpy(ctx->prng_key,key,strlen(ctx->prng_key));
-	else
-		ctx->prng_key = DEFAULT_PRNG_KEY;
-
-	if (iv)
-		memcpy(ctx->prng_iv,iv, strlen(ctx->prng_iv));
-	else
-		ctx->prng_iv = DEFAULT_PRNG_IV;
-
-	if (V)
-		memcpy(ctx->V,V,DEFAULT_BLK_SZ);
-	else
-		memcpy(ctx->V,DEFAULT_V_SEED,DEFAULT_BLK_SZ);
-
-	if (DT)
-		memcpy(ctx->DT, DT, DEFAULT_BLK_SZ);
-	else
-		memset(ctx->DT, 0, DEFAULT_BLK_SZ);
-
-	memset(ctx->rand_data,0,DEFAULT_BLK_SZ);
-	memset(ctx->last_rand_data,0,DEFAULT_BLK_SZ);
-
-	if (ctx->tfm)
-		crypto_free_blkcipher(ctx->tfm);
-
-	ctx->tfm = crypto_alloc_blkcipher("rfc3686(ctr(aes))",0,0);
-	if (!ctx->tfm) {
-		dbgprint(KERN_CRIT "Failed to alloc crypto tfm for context %p\n",ctx->tfm);
-		goto out;
-	}
-
-	ctx->rand_data_valid = DEFAULT_BLK_SZ;
-
-	ret = crypto_blkcipher_setkey(ctx->tfm, ctx->prng_key, strlen(ctx->prng_key));
-	if (ret) {
-		dbgprint(KERN_CRIT "PRNG: setkey() failed flags=%x\n",
-			crypto_blkcipher_get_flags(ctx->tfm));
-		crypto_free_blkcipher(ctx->tfm);
-		goto out;
-	}
-
-	iv_len = crypto_blkcipher_ivsize(ctx->tfm);
-	if (iv_len) {
-		crypto_blkcipher_set_iv(ctx->tfm, ctx->prng_iv, iv_len);
-	}
-	rc = 0;
-	ctx->flags &= ~PRNG_NEED_RESET;
-out:
-	spin_unlock(&ctx->prng_lock);
-
-	return rc;
-
-}
-EXPORT_SYMBOL_GPL(reset_prng_context);
-
-/* Module initalization */
-static int __init prng_mod_init(void)
-{
-
-#ifdef TEST_PRNG_ON_START
-	int i;
-	unsigned char tmpbuf[DEFAULT_BLK_SZ];
-
-	struct prng_context *ctx = alloc_prng_context();
-	if (ctx == NULL)
-		return -EFAULT;
-	for (i=0;i<16;i++) {
-		if (get_prng_bytes(tmpbuf, DEFAULT_BLK_SZ, ctx) < 0) {
-			free_prng_context(ctx);
-			return -EFAULT;
-		}
-	}
-	free_prng_context(ctx);
-#endif
-
-	return 0;
-}
-
-static void __exit prng_mod_fini(void)
-{
-	return;
-}
-
-MODULE_LICENSE("GPL");
-MODULE_DESCRIPTION("Software Pseudo Random Number Generator");
-MODULE_AUTHOR("Neil Horman <nhorman@tuxdriver.com>");
-module_param(dbg, int, 0);
-MODULE_PARM_DESC(dbg, "Boolean to enable debugging (0/1 == off/on)");
-module_init(prng_mod_init);
-module_exit(prng_mod_fini);

crypto/prng.h

-/*
- * PRNG: Pseudo Random Number Generator
- *
- *  (C) Neil Horman <nhorman@tuxdriver.com>
- *
- *  This program is free software; you can redistribute it and/or modify it
- *  under the terms of the GNU General Public License as published by the
- *  Free Software Foundation; either version 2 of the License, or (at your
- *  any later version.
- *
- *
- */
-
-#ifndef _PRNG_H_
-#define _PRNG_H_
-struct prng_context;
-
-int get_prng_bytes(char *buf, int nbytes, struct prng_context *ctx);
-struct prng_context *alloc_prng_context(void);
-int reset_prng_context(struct prng_context *ctx,
-			unsigned char *key, unsigned char *iv,
-			unsigned char *V,
-			unsigned char *DT);
-void free_prng_context(struct prng_context *ctx);
-
-#endif
-