Functions for initialising and seeding (pseudo-)random number generators, and working with randomness. More...

#include "lib/crypt_ops/crypto_rand.h"
#include "lib/container/smartlist.h"
#include "lib/crypt_ops/compat_openssl.h"
#include "lib/crypt_ops/crypto_util.h"
#include "lib/encoding/binascii.h"
#include "lib/intmath/weakrng.h"
#include "lib/log/log.h"
#include "lib/log/util_bug.h"
#include "lib/malloc/malloc.h"
#include "lib/sandbox/sandbox.h"
#include "lib/string/compat_string.h"
#include "lib/string/util_string.h"
#include "lib/testsupport/testsupport.h"
#include "lib/fs/files.h"
#include "lib/defs/digest_sizes.h"
#include "lib/crypt_ops/crypto_digest.h"
#include "lib/ctime/di_ops.h"
#include <string.h>
#include <errno.h>

Macros
#define	CRYPTO_RAND_PRIVATE

#define	ADD_ENTROPY 32

#define	MAX_DNS_LABEL_SIZE 63

#define	MAX_STRONGEST_RAND_SIZE 256

#define	DLEN DIGEST512_LEN

Functions
void	crypto_seed_weak_rng (tor_weak_rng_t *rng)

static int	crypto_strongest_rand_syscall (uint8_t *out, size_t out_len)

static int	crypto_strongest_rand_fallback (uint8_t *out, size_t out_len)

STATIC int	crypto_strongest_rand_raw (uint8_t *out, size_t out_len)

void	crypto_strongest_rand (uint8_t *out, size_t out_len)

void	crypto_strongest_rand_ (uint8_t *out, size_t out_len)

int	crypto_seed_rng (void)

void	crypto_rand (char *to, size_t n)

void	crypto_rand_unmocked (char *to, size_t n)

uint32_t	crypto_rand_u32 (void)

char *	crypto_random_hostname (int min_rand_len, int max_rand_len, const char prefix, const char suffix)

void *	smartlist_choose (const smartlist_t *sl)

void	smartlist_shuffle (smartlist_t *sl)

int	crypto_force_rand_ssleay (void)

Detailed Description

Functions for initialising and seeding (pseudo-)random number generators, and working with randomness.

Definition in file crypto_rand.c.

Macro Definition Documentation

◆ ADD_ENTROPY

#define ADD_ENTROPY 32

How many bytes of entropy we add at once.

This is how much entropy OpenSSL likes to add right now, so maybe it will work for us too.

Definition at line 94 of file crypto_rand.c.

◆ MAX_DNS_LABEL_SIZE

#define MAX_DNS_LABEL_SIZE 63

Longest recognized DNS query.

Definition at line 99 of file crypto_rand.c.

◆ MAX_STRONGEST_RAND_SIZE

#define MAX_STRONGEST_RAND_SIZE 256

Largest strong entropy request permitted.

Definition at line 104 of file crypto_rand.c.

Function Documentation

◆ crypto_force_rand_ssleay()

int crypto_force_rand_ssleay ( void )

Make sure that openssl is using its default PRNG. Return 1 if we had to adjust it; 0 otherwise.

Definition at line 618 of file crypto_rand.c.

◆ crypto_rand()

void crypto_rand	(	char *	to,
		size_t	n
	)

Write n bytes of strong random data to to. Supports mocking for unit tests.

This function is not allowed to fail; if it would fail to generate strong entropy, it must terminate the process instead.

Definition at line 477 of file crypto_rand.c.

Referenced by connection_or_send_auth_challenge_cell(), crypto_cipher_encrypt_with_iv(), crypto_pk_obsolete_public_hybrid_encrypt(), crypto_rand_double(), crypto_rand_u32(), crypto_rand_uint(), crypto_rand_uint64(), crypto_seed_weak_rng(), curve25519_rand_seckey_bytes(), do_hash_password(), ed25519_secret_key_generate(), fast_server_handshake(), and get_random_virtual_addr().

◆ crypto_rand_u32()

uint32_t crypto_rand_u32 ( void )

Draw an unsigned 32-bit integer uniformly at random.

Definition at line 536 of file crypto_rand.c.

◆ crypto_rand_unmocked()

void crypto_rand_unmocked	(	char *	to,
		size_t	n
	)

Write n bytes of strong random data to to. Most callers will want crypto_rand instead.

This function is not allowed to fail; if it would fail to generate strong entropy, it must terminate the process instead.

Definition at line 490 of file crypto_rand.c.

Referenced by crypto_rand().

◆ crypto_random_hostname()

char* crypto_random_hostname	(	int	min_rand_len,
		int	max_rand_len,
		const char *	prefix,
		const char *	suffix
	)

Generate and return a new random hostname starting with prefix, ending with suffix, and containing no fewer than min_rand_len and no more than max_rand_len random base32 characters. Does not check for failure.

Clip max_rand_len to MAX_DNS_LABEL_SIZE.

Definition at line 552 of file crypto_rand.c.

Referenced by launch_wildcard_check(), and tor_tls_context_init_certificates().

◆ crypto_seed_rng()

int crypto_seed_rng ( void )

Seed the RNG for any and all crypto libraries that we're using with bytes from the operating system. Return 0 on success, -1 on failure.

Definition at line 452 of file crypto_rand.c.

Referenced by add_entropy_callback().

◆ crypto_seed_weak_rng()

void crypto_seed_weak_rng ( tor_weak_rng_t * rng )

Set the seed of the weak RNG to a random value.

Definition at line 110 of file crypto_rand.c.

◆ crypto_strongest_rand()

void crypto_strongest_rand	(	uint8_t *	out,
		size_t	out_len
	)

Try to get out_len bytes of the strongest entropy we can generate, storing it into out.

Definition at line 340 of file crypto_rand.c.

Referenced by curve25519_rand_seckey_bytes(), ed25519_secret_key_generate(), encrypt_descriptor_data(), and sr_generate_our_commit().

◆ crypto_strongest_rand_()

void crypto_strongest_rand_	(	uint8_t *	out,
		size_t	out_len
	)

Try to get out_len bytes of the strongest entropy we can generate, storing it into out. (Mockable version.)

Definition at line 350 of file crypto_rand.c.

Referenced by crypto_strongest_rand().

◆ crypto_strongest_rand_fallback()

static int crypto_strongest_rand_fallback	(	uint8_t *	out,
		size_t	out_len
	)

static

Try to get out_len bytes of the strongest entropy we can generate, via the per-platform fallback mechanism, storing it into out. Return 0 on success, -1 on failure. A maximum request size of 256 bytes is imposed.

Definition at line 239 of file crypto_rand.c.

Referenced by crypto_strongest_rand_raw().

◆ crypto_strongest_rand_raw()

STATIC int crypto_strongest_rand_raw	(	uint8_t *	out,
		size_t	out_len
	)

Try to get out_len bytes of the strongest entropy we can generate, storing it into out. Return 0 on success, -1 on failure. A maximum request size of 256 bytes is imposed.

Definition at line 289 of file crypto_rand.c.

◆ crypto_strongest_rand_syscall()

static int crypto_strongest_rand_syscall	(	uint8_t *	out,
		size_t	out_len
	)

static

Try to get out_len bytes of the strongest entropy we can generate, via system calls, storing it into out. Return 0 on success, -1 on failure. A maximum request size of 256 bytes is imposed.

Definition at line 128 of file crypto_rand.c.

Referenced by crypto_strongest_rand_raw().

◆ smartlist_choose()

void* smartlist_choose ( const smartlist_t * sl )

Return a randomly chosen element of sl; or NULL if sl is empty.

Definition at line 590 of file crypto_rand.c.

Referenced by select_and_add_guard_item_for_sample().

◆ smartlist_shuffle()

void smartlist_shuffle ( smartlist_t * sl )

Scramble the elements of sl into a random order.

Definition at line 602 of file crypto_rand.c.

Macros

Functions