diff options
Diffstat (limited to 'crypto/jitterentropy.c')
| -rw-r--r-- | crypto/jitterentropy.c | 154 |
1 files changed, 51 insertions, 103 deletions
diff --git a/crypto/jitterentropy.c b/crypto/jitterentropy.c index 22f48bf4c6f5..c7d7f2caa779 100644 --- a/crypto/jitterentropy.c +++ b/crypto/jitterentropy.c @@ -2,7 +2,7 @@ * Non-physical true random number generator based on timing jitter -- * Jitter RNG standalone code. * - * Copyright Stephan Mueller <smueller@chronox.de>, 2015 - 2020 + * Copyright Stephan Mueller <smueller@chronox.de>, 2015 - 2023 * * Design * ====== @@ -47,7 +47,7 @@ /* * This Jitterentropy RNG is based on the jitterentropy library - * version 2.2.0 provided at https://www.chronox.de/jent.html + * version 3.4.0 provided at https://www.chronox.de/jent.html */ #ifdef __OPTIMIZE__ @@ -57,21 +57,22 @@ typedef unsigned long long __u64; typedef long long __s64; typedef unsigned int __u32; +typedef unsigned char u8; #define NULL ((void *) 0) /* The entropy pool */ struct rand_data { + /* SHA3-256 is used as conditioner */ +#define DATA_SIZE_BITS 256 /* all data values that are vital to maintain the security * of the RNG are marked as SENSITIVE. A user must not * access that information while the RNG executes its loops to * calculate the next random value. */ - __u64 data; /* SENSITIVE Actual random number */ - __u64 old_data; /* SENSITIVE Previous random number */ - __u64 prev_time; /* SENSITIVE Previous time stamp */ -#define DATA_SIZE_BITS ((sizeof(__u64)) * 8) - __u64 last_delta; /* SENSITIVE stuck test */ - __s64 last_delta2; /* SENSITIVE stuck test */ - unsigned int osr; /* Oversample rate */ + void *hash_state; /* SENSITIVE hash state entropy pool */ + __u64 prev_time; /* SENSITIVE Previous time stamp */ + __u64 last_delta; /* SENSITIVE stuck test */ + __s64 last_delta2; /* SENSITIVE stuck test */ + unsigned int osr; /* Oversample rate */ #define JENT_MEMORY_BLOCKS 64 #define JENT_MEMORY_BLOCKSIZE 32 #define JENT_MEMORY_ACCESSLOOPS 128 @@ -117,7 +118,6 @@ struct rand_data { * zero). */ #define JENT_ESTUCK 8 /* Too many stuck results during init. */ #define JENT_EHEALTH 9 /* Health test failed during initialization */ -#define JENT_ERCT 10 /* RCT failed during initialization */ /* * The output n bits can receive more than n bits of min entropy, of course, @@ -302,15 +302,13 @@ static int jent_permanent_health_failure(struct rand_data *ec) * an entropy collection. * * Input: - * @ec entropy collector struct -- may be NULL * @bits is the number of low bits of the timer to consider * @min is the number of bits we shift the timer value to the right at * the end to make sure we have a guaranteed minimum value * * @return Newly calculated loop counter */ -static __u64 jent_loop_shuffle(struct rand_data *ec, - unsigned int bits, unsigned int min) +static __u64 jent_loop_shuffle(unsigned int bits, unsigned int min) { __u64 time = 0; __u64 shuffle = 0; @@ -318,12 +316,7 @@ static __u64 jent_loop_shuffle(struct rand_data *ec, unsigned int mask = (1<<bits) - 1; jent_get_nstime(&time); - /* - * Mix the current state of the random number into the shuffle - * calculation to balance that shuffle a bit more. - */ - if (ec) - time ^= ec->data; + /* * We fold the time value as much as possible to ensure that as many * bits of the time stamp are included as possible. @@ -345,81 +338,32 @@ static __u64 jent_loop_shuffle(struct rand_data *ec, * execution time jitter * * This function injects the individual bits of the time value into the - * entropy pool using an LFSR. + * entropy pool using a hash. * - * The code is deliberately inefficient with respect to the bit shifting - * and shall stay that way. This function is the root cause why the code - * shall be compiled without optimization. This function not only acts as - * folding operation, but this function's execution is used to measure - * the CPU execution time jitter. Any change to the loop in this function - * implies that careful retesting must be done. - * - * @ec [in] entropy collector struct - * @time [in] time stamp to be injected - * @loop_cnt [in] if a value not equal to 0 is set, use the given value as - * number of loops to perform the folding - * @stuck [in] Is the time stamp identified as stuck? + * ec [in] entropy collector + * time [in] time stamp to be injected + * stuck [in] Is the time stamp identified as stuck? * * Output: - * updated ec->data - * - * @return Number of loops the folding operation is performed + * updated hash context in the entropy collector or error code */ -static void jent_lfsr_time(struct rand_data *ec, __u64 time, __u64 loop_cnt, - int stuck) +static int jent_condition_data(struct rand_data *ec, __u64 time, int stuck) { - unsigned int i; - __u64 j = 0; - __u64 new = 0; -#define MAX_FOLD_LOOP_BIT 4 -#define MIN_FOLD_LOOP_BIT 0 - __u64 fold_loop_cnt = - jent_loop_shuffle(ec, MAX_FOLD_LOOP_BIT, MIN_FOLD_LOOP_BIT); - - /* - * testing purposes -- allow test app to set the counter, not - * needed during runtime - */ - if (loop_cnt) - fold_loop_cnt = loop_cnt; - for (j = 0; j < fold_loop_cnt; j++) { - new = ec->data; - for (i = 1; (DATA_SIZE_BITS) >= i; i++) { - __u64 tmp = time << (DATA_SIZE_BITS - i); - - tmp = tmp >> (DATA_SIZE_BITS - 1); - - /* - * Fibonacci LSFR with polynomial of - * x^64 + x^61 + x^56 + x^31 + x^28 + x^23 + 1 which is - * primitive according to - * http://poincare.matf.bg.ac.rs/~ezivkovm/publications/primpol1.pdf - * (the shift values are the polynomial values minus one - * due to counting bits from 0 to 63). As the current - * position is always the LSB, the polynomial only needs - * to shift data in from the left without wrap. - */ - tmp ^= ((new >> 63) & 1); - tmp ^= ((new >> 60) & 1); - tmp ^= ((new >> 55) & 1); - tmp ^= ((new >> 30) & 1); - tmp ^= ((new >> 27) & 1); - tmp ^= ((new >> 22) & 1); - new <<= 1; - new ^= tmp; - } - } - - /* - * If the time stamp is stuck, do not finally insert the value into - * the entropy pool. Although this operation should not do any harm - * even when the time stamp has no entropy, SP800-90B requires that - * any conditioning operation (SP800-90B considers the LFSR to be a - * conditioning operation) to have an identical amount of input - * data according to section 3.1.5. - */ - if (!stuck) - ec->data = new; +#define SHA3_HASH_LOOP (1<<3) + struct { + int rct_count; + unsigned int apt_observations; + unsigned int apt_count; + unsigned int apt_base; + } addtl = { + ec->rct_count, + ec->apt_observations, + ec->apt_count, + ec->apt_base + }; + + return jent_hash_time(ec->hash_state, time, (u8 *)&addtl, sizeof(addtl), + SHA3_HASH_LOOP, stuck); } /* @@ -453,7 +397,7 @@ static void jent_memaccess(struct rand_data *ec, __u64 loop_cnt) #define MAX_ACC_LOOP_BIT 7 #define MIN_ACC_LOOP_BIT 0 __u64 acc_loop_cnt = - jent_loop_shuffle(ec, MAX_ACC_LOOP_BIT, MIN_ACC_LOOP_BIT); + jent_loop_shuffle(MAX_ACC_LOOP_BIT, MIN_ACC_LOOP_BIT); if (NULL == ec || NULL == ec->mem) return; @@ -521,14 +465,15 @@ static int jent_measure_jitter(struct rand_data *ec) stuck = jent_stuck(ec, current_delta); /* Now call the next noise sources which also injects the data */ - jent_lfsr_time(ec, current_delta, 0, stuck); + if (jent_condition_data(ec, current_delta, stuck)) + stuck = 1; return stuck; } /* * Generator of one 64 bit random number - * Function fills rand_data->data + * Function fills rand_data->hash_state * * @ec [in] Reference to entropy collector */ @@ -575,7 +520,7 @@ static void jent_gen_entropy(struct rand_data *ec) * @return 0 when request is fulfilled or an error * * The following error codes can occur: - * -1 entropy_collector is NULL + * -1 entropy_collector is NULL or the generation failed * -2 Intermittent health failure * -3 Permanent health failure */ @@ -605,7 +550,7 @@ int jent_read_entropy(struct rand_data *ec, unsigned char *data, * Perform startup health tests and return permanent * error if it fails. */ - if (jent_entropy_init()) + if (jent_entropy_init(ec->hash_state)) return -3; return -2; @@ -615,7 +560,8 @@ int jent_read_entropy(struct rand_data *ec, unsigned char *data, tocopy = (DATA_SIZE_BITS / 8); else tocopy = len; - jent_memcpy(p, &ec->data, tocopy); + if (jent_read_random_block(ec->hash_state, p, tocopy)) + return -1; len -= tocopy; p += tocopy; @@ -629,7 +575,8 @@ int jent_read_entropy(struct rand_data *ec, unsigned char *data, ***************************************************************************/ struct rand_data *jent_entropy_collector_alloc(unsigned int osr, - unsigned int flags) + unsigned int flags, + void *hash_state) { struct rand_data *entropy_collector; @@ -656,6 +603,8 @@ struct rand_data *jent_entropy_collector_alloc(unsigned int osr, osr = 1; /* minimum sampling rate is 1 */ entropy_collector->osr = osr; + entropy_collector->hash_state = hash_state; + /* fill the data pad with non-zero values */ jent_gen_entropy(entropy_collector); @@ -669,7 +618,7 @@ void jent_entropy_collector_free(struct rand_data *entropy_collector) jent_zfree(entropy_collector); } -int jent_entropy_init(void) +int jent_entropy_init(void *hash_state) { int i; __u64 delta_sum = 0; @@ -682,6 +631,7 @@ int jent_entropy_init(void) /* Required for RCT */ ec.osr = 1; + ec.hash_state = hash_state; /* We could perform statistical tests here, but the problem is * that we only have a few loop counts to do testing. These @@ -719,7 +669,7 @@ int jent_entropy_init(void) /* Invoke core entropy collection logic */ jent_get_nstime(&time); ec.prev_time = time; - jent_lfsr_time(&ec, time, 0, 0); + jent_condition_data(&ec, time, 0); jent_get_nstime(&time2); /* test whether timer works */ @@ -762,14 +712,12 @@ int jent_entropy_init(void) if ((nonstuck % JENT_APT_WINDOW_SIZE) == 0) { jent_apt_reset(&ec, delta & JENT_APT_WORD_MASK); - if (jent_health_failure(&ec)) - return JENT_EHEALTH; } } - /* Validate RCT */ - if (jent_rct_failure(&ec)) - return JENT_ERCT; + /* Validate health test result */ + if (jent_health_failure(&ec)) + return JENT_EHEALTH; /* test whether we have an increasing timer */ if (!(time2 > time)) |