diff options
Diffstat (limited to 'crypto/ansi_cprng.c')
| -rw-r--r-- | crypto/ansi_cprng.c | 474 |
1 files changed, 0 insertions, 474 deletions
diff --git a/crypto/ansi_cprng.c b/crypto/ansi_cprng.c deleted file mode 100644 index 153523ce6076..000000000000 --- a/crypto/ansi_cprng.c +++ /dev/null @@ -1,474 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0-or-later -/* - * PRNG: Pseudo Random Number Generator - * Based on NIST Recommended PRNG From ANSI X9.31 Appendix A.2.4 using - * AES 128 cipher - * - * (C) Neil Horman <nhorman@tuxdriver.com> - */ - -#include <crypto/internal/cipher.h> -#include <crypto/internal/rng.h> -#include <linux/err.h> -#include <linux/init.h> -#include <linux/module.h> -#include <linux/moduleparam.h> -#include <linux/string.h> - -#define DEFAULT_PRNG_KEY "0123456789abcdef" -#define DEFAULT_PRNG_KSZ 16 -#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 { - 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_cipher *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 succeeded, <0 if something went wrong - */ -static int _get_more_prng_bytes(struct prng_context *ctx, int cont_test) -{ - int i; - unsigned char tmp[DEFAULT_BLK_SZ]; - unsigned char *output = NULL; - - - 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++) { - - switch (i) { - case 0: - /* - * Start by encrypting the counter value - * This gives us an intermediate value I - */ - memcpy(tmp, ctx->DT, DEFAULT_BLK_SZ); - output = ctx->I; - 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); - hexdump("tmp stage 1: ", tmp, DEFAULT_BLK_SZ); - output = ctx->rand_data; - 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)) { - if (cont_test) { - panic("cprng %p Failed repetition check!\n", - ctx); - } - - printk(KERN_ERR - "ctx %p Failed repetition check!\n", - ctx); - - ctx->flags |= PRNG_NEED_RESET; - return -EINVAL; - } - 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); - output = ctx->V; - hexdump("tmp stage 2: ", tmp, DEFAULT_BLK_SZ); - break; - } - - - /* do the encryption */ - crypto_cipher_encrypt_one(ctx->tfm, output, tmp); - - } - - /* - * Now update our DT value - */ - for (i = DEFAULT_BLK_SZ - 1; i >= 0; i--) { - ctx->DT[i] += 1; - if (ctx->DT[i] != 0) - break; - } - - 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 */ -static int get_prng_bytes(char *buf, size_t nbytes, struct prng_context *ctx, - int do_cont_test) -{ - unsigned char *ptr = buf; - unsigned int byte_count = (unsigned int)nbytes; - int err; - - - spin_lock_bh(&ctx->prng_lock); - - err = -EINVAL; - 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; - } - - /* - * Return 0 in case of success as mandated by the kernel - * crypto API interface definition. - */ - err = 0; - - 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, do_cont_test) < 0) { - memset(buf, 0, nbytes); - err = -EINVAL; - goto done; - } - } - - /* - * Copy any data less than an entire block - */ - if (byte_count < DEFAULT_BLK_SZ) { -empty_rbuf: - while (ctx->rand_data_valid < DEFAULT_BLK_SZ) { - *ptr = ctx->rand_data[ctx->rand_data_valid]; - ptr++; - byte_count--; - ctx->rand_data_valid++; - if (byte_count == 0) - goto done; - } - } - - /* - * Now copy whole blocks - */ - for (; byte_count >= DEFAULT_BLK_SZ; byte_count -= DEFAULT_BLK_SZ) { - if (ctx->rand_data_valid == DEFAULT_BLK_SZ) { - if (_get_more_prng_bytes(ctx, do_cont_test) < 0) { - memset(buf, 0, nbytes); - err = -EINVAL; - goto done; - } - } - if (ctx->rand_data_valid > 0) - goto empty_rbuf; - memcpy(ptr, ctx->rand_data, DEFAULT_BLK_SZ); - ctx->rand_data_valid += DEFAULT_BLK_SZ; - ptr += DEFAULT_BLK_SZ; - } - - /* - * Now go back and get any remaining partial block - */ - if (byte_count) - goto remainder; - -done: - spin_unlock_bh(&ctx->prng_lock); - dbgprint(KERN_CRIT "returning %d from get_prng_bytes in context %p\n", - err, ctx); - return err; -} - -static void free_prng_context(struct prng_context *ctx) -{ - crypto_free_cipher(ctx->tfm); -} - -static int reset_prng_context(struct prng_context *ctx, - const unsigned char *key, size_t klen, - const unsigned char *V, const unsigned char *DT) -{ - int ret; - const unsigned char *prng_key; - - spin_lock_bh(&ctx->prng_lock); - ctx->flags |= PRNG_NEED_RESET; - - prng_key = (key != NULL) ? key : (unsigned char *)DEFAULT_PRNG_KEY; - - if (!key) - klen = DEFAULT_PRNG_KSZ; - - 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); - - ctx->rand_data_valid = DEFAULT_BLK_SZ; - - ret = crypto_cipher_setkey(ctx->tfm, prng_key, klen); - if (ret) { - dbgprint(KERN_CRIT "PRNG: setkey() failed flags=%x\n", - crypto_cipher_get_flags(ctx->tfm)); - goto out; - } - - ret = 0; - ctx->flags &= ~PRNG_NEED_RESET; -out: - spin_unlock_bh(&ctx->prng_lock); - return ret; -} - -static int cprng_init(struct crypto_tfm *tfm) -{ - struct prng_context *ctx = crypto_tfm_ctx(tfm); - - spin_lock_init(&ctx->prng_lock); - ctx->tfm = crypto_alloc_cipher("aes", 0, 0); - if (IS_ERR(ctx->tfm)) { - dbgprint(KERN_CRIT "Failed to alloc tfm for context %p\n", - ctx); - return PTR_ERR(ctx->tfm); - } - - if (reset_prng_context(ctx, NULL, DEFAULT_PRNG_KSZ, NULL, NULL) < 0) - return -EINVAL; - - /* - * after allocation, we should always force the user to reset - * so they don't inadvertently use the insecure default values - * without specifying them intentially - */ - ctx->flags |= PRNG_NEED_RESET; - return 0; -} - -static void cprng_exit(struct crypto_tfm *tfm) -{ - free_prng_context(crypto_tfm_ctx(tfm)); -} - -static int cprng_get_random(struct crypto_rng *tfm, - const u8 *src, unsigned int slen, - u8 *rdata, unsigned int dlen) -{ - struct prng_context *prng = crypto_rng_ctx(tfm); - - return get_prng_bytes(rdata, dlen, prng, 0); -} - -/* - * This is the cprng_registered reset method the seed value is - * interpreted as the tuple { V KEY DT} - * V and KEY are required during reset, and DT is optional, detected - * as being present by testing the length of the seed - */ -static int cprng_reset(struct crypto_rng *tfm, - const u8 *seed, unsigned int slen) -{ - struct prng_context *prng = crypto_rng_ctx(tfm); - const u8 *key = seed + DEFAULT_BLK_SZ; - const u8 *dt = NULL; - - if (slen < DEFAULT_PRNG_KSZ + DEFAULT_BLK_SZ) - return -EINVAL; - - if (slen >= (2 * DEFAULT_BLK_SZ + DEFAULT_PRNG_KSZ)) - dt = key + DEFAULT_PRNG_KSZ; - - reset_prng_context(prng, key, DEFAULT_PRNG_KSZ, seed, dt); - - if (prng->flags & PRNG_NEED_RESET) - return -EINVAL; - return 0; -} - -#ifdef CONFIG_CRYPTO_FIPS -static int fips_cprng_get_random(struct crypto_rng *tfm, - const u8 *src, unsigned int slen, - u8 *rdata, unsigned int dlen) -{ - struct prng_context *prng = crypto_rng_ctx(tfm); - - return get_prng_bytes(rdata, dlen, prng, 1); -} - -static int fips_cprng_reset(struct crypto_rng *tfm, - const u8 *seed, unsigned int slen) -{ - u8 rdata[DEFAULT_BLK_SZ]; - const u8 *key = seed + DEFAULT_BLK_SZ; - int rc; - - struct prng_context *prng = crypto_rng_ctx(tfm); - - if (slen < DEFAULT_PRNG_KSZ + DEFAULT_BLK_SZ) - return -EINVAL; - - /* fips strictly requires seed != key */ - if (!memcmp(seed, key, DEFAULT_PRNG_KSZ)) - return -EINVAL; - - rc = cprng_reset(tfm, seed, slen); - - if (!rc) - goto out; - - /* this primes our continuity test */ - rc = get_prng_bytes(rdata, DEFAULT_BLK_SZ, prng, 0); - prng->rand_data_valid = DEFAULT_BLK_SZ; - -out: - return rc; -} -#endif - -static struct rng_alg rng_algs[] = { { - .generate = cprng_get_random, - .seed = cprng_reset, - .seedsize = DEFAULT_PRNG_KSZ + 2 * DEFAULT_BLK_SZ, - .base = { - .cra_name = "stdrng", - .cra_driver_name = "ansi_cprng", - .cra_priority = 100, - .cra_ctxsize = sizeof(struct prng_context), - .cra_module = THIS_MODULE, - .cra_init = cprng_init, - .cra_exit = cprng_exit, - } -#ifdef CONFIG_CRYPTO_FIPS -}, { - .generate = fips_cprng_get_random, - .seed = fips_cprng_reset, - .seedsize = DEFAULT_PRNG_KSZ + 2 * DEFAULT_BLK_SZ, - .base = { - .cra_name = "fips(ansi_cprng)", - .cra_driver_name = "fips_ansi_cprng", - .cra_priority = 300, - .cra_ctxsize = sizeof(struct prng_context), - .cra_module = THIS_MODULE, - .cra_init = cprng_init, - .cra_exit = cprng_exit, - } -#endif -} }; - -/* Module initalization */ -static int __init prng_mod_init(void) -{ - return crypto_register_rngs(rng_algs, ARRAY_SIZE(rng_algs)); -} - -static void __exit prng_mod_fini(void) -{ - crypto_unregister_rngs(rng_algs, ARRAY_SIZE(rng_algs)); -} - -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); -MODULE_ALIAS_CRYPTO("stdrng"); -MODULE_ALIAS_CRYPTO("ansi_cprng"); -MODULE_IMPORT_NS("CRYPTO_INTERNAL"); |