The LRNG sysctl interface provides the same controls as the existing /dev/random implementation. These sysctls behave identically and are implemented identically. The goal is to allow a possible merge of the existing /dev/random implementation with this implementation which implies that this patch tries have a very close similarity. Yet, all sysctls are documented at [1]. In addition, it provides the file lrng_type which provides details about the LRNG: - the name of the DRNG that produces the random numbers for /dev/random, /dev/urandom, getrandom(2) - the hash used to produce random numbers from the entropy pool - the number of secondary DRNG instances - indicator whether the LRNG operates SP800-90B compliant - indicator whether a high-resolution timer is identified - only with a high-resolution timer the interrupt noise source will deliver sufficient entropy - indicator whether the LRNG has been minimally seeded (i.e. is the secondary DRNG seeded with at least 128 bits of of entropy) - indicator whether the LRNG has been fully seeded (i.e. is the secondary DRNG seeded with at least 256 bits of entropy) [1] https://www.chronox.de/lrng.html CC: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx> CC: "Alexander E. Patrakov" <patrakov@xxxxxxxxx> CC: "Ahmed S. Darwish" <darwish.07@xxxxxxxxx> CC: "Theodore Y. Ts'o" <tytso@xxxxxxx> CC: Willy Tarreau <w@xxxxxx> CC: Matthew Garrett <mjg59@xxxxxxxxxxxxx> CC: Vito Caputo <vcaputo@xxxxxxxxxxx> CC: Andreas Dilger <adilger.kernel@xxxxxxxxx> CC: Jan Kara <jack@xxxxxxx> CC: Ray Strode <rstrode@xxxxxxxxxx> CC: William Jon McCann <mccann@xxxxxxx> CC: zhangjs <zachary@xxxxxxxxxxxxxxxx> CC: Andy Lutomirski <luto@xxxxxxxxxx> CC: Florian Weimer <fweimer@xxxxxxxxxx> CC: Lennart Poettering <mzxreary@xxxxxxxxxxx> CC: Nicolai Stange <nstange@xxxxxxx> Reviewed-by: Marcelo Henrique Cerri <marcelo.cerri@xxxxxxxxxxxxx> Reviewed-by: Roman Drahtmueller <draht@xxxxxxxxxxxxxx> Tested-by: Roman Drahtmüller <draht@xxxxxxxxxxxxxx> Tested-by: Marcelo Henrique Cerri <marcelo.cerri@xxxxxxxxxxxxx> Tested-by: Neil Horman <nhorman@xxxxxxxxxx> Signed-off-by: Stephan Mueller <smueller@xxxxxxxxxx> --- drivers/char/lrng/Makefile | 1 + drivers/char/lrng/lrng_interfaces.c | 1 - drivers/char/lrng/lrng_internal.h | 4 + drivers/char/lrng/lrng_proc.c | 163 ++++++++++++++++++++++++++++ 4 files changed, 168 insertions(+), 1 deletion(-) create mode 100644 drivers/char/lrng/lrng_proc.c diff --git a/drivers/char/lrng/Makefile b/drivers/char/lrng/Makefile index 0a32f22c2c1a..e69c176f0161 100644 --- a/drivers/char/lrng/Makefile +++ b/drivers/char/lrng/Makefile @@ -9,3 +9,4 @@ obj-y += lrng_pool.o lrng_aux.o \ lrng_interfaces.o \ obj-$(CONFIG_NUMA) += lrng_numa.o +obj-$(CONFIG_SYSCTL) += lrng_proc.o diff --git a/drivers/char/lrng/lrng_interfaces.c b/drivers/char/lrng/lrng_interfaces.c index ff40ed37ddd6..8c4bf53d86ec 100644 --- a/drivers/char/lrng/lrng_interfaces.c +++ b/drivers/char/lrng/lrng_interfaces.c @@ -34,7 +34,6 @@ static DECLARE_WAIT_QUEUE_HEAD(lrng_write_wait); static DECLARE_WAIT_QUEUE_HEAD(lrng_init_wait); static struct fasync_struct *fasync; -struct ctl_table random_table[]; /********************************** Helper ***********************************/ /* Is the DRNG seed level too low? */ diff --git a/drivers/char/lrng/lrng_internal.h b/drivers/char/lrng/lrng_internal.h index c2b0a467548e..349152d3c1b0 100644 --- a/drivers/char/lrng/lrng_internal.h +++ b/drivers/char/lrng/lrng_internal.h @@ -116,7 +116,11 @@ void lrng_cc20_init_state(struct chacha20_state *state); /********************************** /proc *************************************/ +#ifdef CONFIG_SYSCTL +void lrng_pool_inc_numa_node(void); +#else static inline void lrng_pool_inc_numa_node(void) { } +#endif /****************************** LRNG interfaces *******************************/ diff --git a/drivers/char/lrng/lrng_proc.c b/drivers/char/lrng/lrng_proc.c new file mode 100644 index 000000000000..f4ee01f61925 --- /dev/null +++ b/drivers/char/lrng/lrng_proc.c @@ -0,0 +1,163 @@ +// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause +/* + * LRNG proc and sysctl interfaces + * + * Copyright (C) 2016 - 2020, Stephan Mueller <smueller@xxxxxxxxxx> + */ + +#include <linux/lrng.h> +#include <linux/proc_fs.h> +#include <linux/seq_file.h> +#include <linux/sysctl.h> +#include <linux/uuid.h> + +#include "lrng_internal.h" + +/* + * This function is used to return both the bootid UUID, and random + * UUID. The difference is in whether table->data is NULL; if it is, + * then a new UUID is generated and returned to the user. + * + * If the user accesses this via the proc interface, the UUID will be + * returned as an ASCII string in the standard UUID format; if via the + * sysctl system call, as 16 bytes of binary data. + */ +static int lrng_proc_do_uuid(struct ctl_table *table, int write, + void __user *buffer, size_t *lenp, loff_t *ppos) +{ + struct ctl_table fake_table; + unsigned char buf[64], tmp_uuid[16], *uuid; + + uuid = table->data; + if (!uuid) { + uuid = tmp_uuid; + generate_random_uuid(uuid); + } else { + static DEFINE_SPINLOCK(bootid_spinlock); + + spin_lock(&bootid_spinlock); + if (!uuid[8]) + generate_random_uuid(uuid); + spin_unlock(&bootid_spinlock); + } + + sprintf(buf, "%pU", uuid); + + fake_table.data = buf; + fake_table.maxlen = sizeof(buf); + + return proc_dostring(&fake_table, write, buffer, lenp, ppos); +} + +static int lrng_proc_do_entropy(struct ctl_table *table, int write, + void __user *buffer, size_t *lenp, loff_t *ppos) +{ + struct ctl_table fake_table; + int entropy_count; + + entropy_count = lrng_avail_entropy(); + + fake_table.data = &entropy_count; + fake_table.maxlen = sizeof(entropy_count); + + return proc_dointvec(&fake_table, write, buffer, lenp, ppos); +} + +static int lrng_sysctl_poolsize = LRNG_POOL_SIZE_BITS; +static int lrng_min_write_thresh; +static int lrng_max_write_thresh = LRNG_POOL_SIZE_BITS; +static char lrng_sysctl_bootid[16]; +static int lrng_drng_reseed_max_min; + +struct ctl_table random_table[] = { + { + .procname = "poolsize", + .data = &lrng_sysctl_poolsize, + .maxlen = sizeof(int), + .mode = 0444, + .proc_handler = proc_dointvec, + }, + { + .procname = "entropy_avail", + .maxlen = sizeof(int), + .mode = 0444, + .proc_handler = lrng_proc_do_entropy, + }, + { + .procname = "write_wakeup_threshold", + .data = &lrng_write_wakeup_bits, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = &lrng_min_write_thresh, + .extra2 = &lrng_max_write_thresh, + }, + { + .procname = "boot_id", + .data = &lrng_sysctl_bootid, + .maxlen = 16, + .mode = 0444, + .proc_handler = lrng_proc_do_uuid, + }, + { + .procname = "uuid", + .maxlen = 16, + .mode = 0444, + .proc_handler = lrng_proc_do_uuid, + }, + { + .procname = "urandom_min_reseed_secs", + .data = &lrng_drng_reseed_max_time, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec, + .extra1 = &lrng_drng_reseed_max_min, + }, + { } +}; + +/* Number of online DRNGs */ +static u32 numa_drngs = 1; + +void lrng_pool_inc_numa_node(void) +{ + numa_drngs++; +} + +static int lrng_proc_type_show(struct seq_file *m, void *v) +{ + struct lrng_drng *lrng_drng_init = lrng_drng_init_instance(); + unsigned long flags = 0; + unsigned char buf[300]; + + lrng_drng_lock(lrng_drng_init, &flags); + snprintf(buf, sizeof(buf), + "DRNG name: %s\n" + "Hash for reading entropy pool: %s\n" + "DRNG security strength: %d bits\n" + "number of DRNG instances: %u\n" + "SP800-90B compliance: %s\n" + "High-resolution timer: %s\n" + "LRNG minimally seeded: %s\n" + "LRNG fully seeded: %s\n", + lrng_drng_init->crypto_cb->lrng_drng_name(), + lrng_drng_init->crypto_cb->lrng_hash_name(), + LRNG_DRNG_SECURITY_STRENGTH_BITS, numa_drngs, + lrng_sp80090b_compliant() ? "true" : "false", + lrng_pool_highres_timer() ? "true" : "false", + lrng_state_min_seeded() ? "true" : "false", + lrng_state_fully_seeded() ? "true" : "false"); + lrng_drng_unlock(lrng_drng_init, &flags); + + seq_write(m, buf, strlen(buf)); + + return 0; +} + +static int __init lrng_proc_type_init(void) +{ + proc_create_single("lrng_type", 0444, NULL, &lrng_proc_type_show); + return 0; +} + +module_init(lrng_proc_type_init); -- 2.24.1
