drivers/char/random.c

35 #include <linux/random.h>
97 MODULE_PARM_DESC(ratelimit_disable, "Disable random ratelimit suppression");
101  * to supply cryptographically secure random numbers. This applies to: the
124  * cryptographically secure random numbers. This applies to: the /dev/urandom
168 		printk_deferred(KERN_NOTICE "random: %s called from %pS with crng_init=%d\n", \
178  * RNG described at <https://blog.cr.yp.to/20170723-random.html>.
192  * These interfaces will return the requested number of random bytes
195  * functions may be higher performance for one-off random integers,
284  * half of the block containing 32 bytes of random data that may
314  * random data. It also returns up to 32 bytes on its own of random data
367 	 * some random data and a ChaCha state for the caller. All other  in crng_make_state()
408  * This returns random bytes in arbitrary quantities. The quality of the
409  * random bytes is good as /dev/urandom. In order to ensure that the
431 	 * Immediately overwrite the ChaCha key at index 4 with random  in get_random_bytes_user()
471  * Batched entropy returns random integers. The quality of the random
771  * command line option 'random.trust_bootloader'.
777  * add_interrupt_randomness() uses the interrupt timing as random
807 early_param("random.trust_cpu", parse_trust_cpu);
808 early_param("random.trust_bootloader", parse_trust_bootloader);
931  * may produce endless random bits, so this function will sleep for
949  * Handle random seed passed by bootloader, and credit it depending
950  * on the command line option 'random.trust_bootloader'.
1211 	if (!disk || !disk->random)  in add_disk_randomness()
1214 	add_timer_randomness(disk->random, 0x100 + disk_devt(disk));  in add_disk_randomness()
1229 		disk->random = state;  in rand_initialize_disk()
1343  * Reading from /dev/random has the same functionality as calling
1352  * Writing to either /dev/random or /dev/urandom adds entropy to
1355  * Polling on /dev/random indicates when the RNG is initialized, on
1358  * Both /dev/random and /dev/urandom have the same set of ioctls for
1569  * in /proc/sys/kernel/random/ and are as follows:
1573  * - uuid - a random UUID, different each time the file is read.
1582  *   below which write polls to /dev/random will unblock, requesting
1603  * This function is used to return both the bootid UUID, and random
1692 	register_sysctl_init("kernel/random", random_table);  in random_sysctls_init()