osfmk/prng/random.h

   1 /*
   2  * Copyright (c) 2019 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28
  29 #ifndef _PRNG_RANDOM_H_
  30 #define _PRNG_RANDOM_H_
  31
  32 __BEGIN_DECLS
  33
  34 #include <corecrypto/cckprng.h>
  35
  36 #ifdef XNU_KERNEL_PRIVATE
  37
  38 #define ENTROPY_BUFFER_BYTE_SIZE 32
  39
  40 #define ENTROPY_BUFFER_SIZE (ENTROPY_BUFFER_BYTE_SIZE / sizeof(uint32_t))
  41
  42 // This mask can be applied to EntropyData.sample_count to get an
  43 // index suitable for storing the next sample in
  44 // EntropyData.buffer. Note that ENTROPY_BUFFER_SIZE must be a power
  45 // of two for the following mask calculation to be valid.
  46 #define ENTROPY_BUFFER_INDEX_MASK (ENTROPY_BUFFER_SIZE - 1)
  47
  48 typedef struct entropy_data {
  49         /*
  50          * TODO: Should sample_count be volatile?  Are we exposed to any races that
  51          * we care about if it is not?
  52          */
  53
  54         // At 32 bits, this counter can overflow. Since we're primarily
  55         // interested in the delta from one read to the next, we don't
  56         // worry about this too much.
  57         uint32_t sample_count;
  58         uint32_t buffer[ENTROPY_BUFFER_SIZE];
  59 } entropy_data_t;
  60
  61 extern entropy_data_t EntropyData;
  62
  63 /* Trace codes for DBG_SEC_KERNEL: */
  64 #define ENTROPY_READ(n) SECURITYDBG_CODE(DBG_SEC_KERNEL, n) /* n: 0 .. 3 */
  65
  66 void random_cpu_init(int cpu);
  67
  68
  69 #endif /* XNU_KERNEL_PRIVATE */
  70
  71 void register_and_init_prng(struct cckprng_ctx *ctx, const struct cckprng_funcs *funcs);
  72
  73 #include <kern/simple_lock.h>
  74 /* Definitions for boolean PRNG */
  75 #define RANDOM_BOOL_GEN_SEED_COUNT 4
  76 struct bool_gen {
  77         unsigned int seed[RANDOM_BOOL_GEN_SEED_COUNT];
  78         unsigned int state;
  79         decl_simple_lock_data(, lock);
  80 };
  81
  82 extern void random_bool_init(struct bool_gen * bg);
  83
  84 extern void random_bool_gen_entropy(struct bool_gen * bg, unsigned int * buffer, int count);
  85
  86 extern unsigned int random_bool_gen_bits(struct bool_gen * bg, unsigned int * buffer, unsigned int count, unsigned int numbits);
  87
  88 __END_DECLS
  89
  90 #endif /* _PRNG_RANDOM_H_ */