@@ -162,4 +162,63 @@ config LRNG_APT_CUTOFF
default 325 if !LRNG_APT_BROKEN
default 32 if LRNG_APT_BROKEN
+menuconfig LRNG_TESTING_MENU
+ bool "LRNG testing interfaces"
+ depends on DEBUG_FS
+ help
+ Enable one or more of the following test interfaces.
+
+ If unsure, say N.
+
+if LRNG_TESTING_MENU
+
+config LRNG_RAW_ENTROPY
+ bool "Enable entropy test interface to LRNG noise source"
+ default y
+ help
+ The test interface allows a privileged process to capture
+ the raw unconditioned noise that is collected by the LRNG
+ for statistical analysis. Extracted noise data is not used
+ to seed the LRNG.
+
+ The raw noise data can be obtained using the lrng_raw
+ debugfs file. Using the option lrng_testing.boot_test=1
+ the raw noise of the first 1000 entropy events since boot
+ can be sampled.
+
+config LRNG_RAW_ARRAY
+ bool "Enable test interface to LRNG raw entropy storage array"
+ help
+ The test interface allows a privileged process to capture
+ the raw noise data that is collected by the LRNG
+ in the per-CPU array for statistical analysis. The purpose
+ of this interface is to verify that the array handling code
+ truly only concatenates data and provides the same entropy
+ rate as the raw unconditioned noise source when assessing
+ the collected data byte-wise.
+
+ The data can be obtained using the lrng_raw_array debugfs
+ file. Using the option lrng_testing.boot_raw_array=1
+ the raw noise of the first 1000 entropy events since boot
+ can be sampled.
+
+config LRNG_IRQ_PERF
+ bool "Enable LRNG interrupt performance monitor"
+ help
+ With this option, the performance monitor of the LRNG
+ interrupt handling code is enabled. The file provides
+ the execution time of the interrupt handler in
+ cycles.
+
+ The interrupt performance data can be obtained using
+ the lrng_irq_perf debugfs file. Using the option
+ lrng_testing.boot_irq_perf=1 the performance data of
+ the first 1000 entropy events since boot can be sampled.
+
+config LRNG_TESTING
+ bool
+ default y if (LRNG_RAW_ENTROPY || LRNG_RAW_ARRAY || LRNG_IRQ_PERF)
+
+endif #LRNG_TESTING_MENU
+
endif # LRNG
@@ -15,3 +15,4 @@ obj-$(CONFIG_LRNG_DRBG) += lrng_drbg.o
obj-$(CONFIG_LRNG_KCAPI) += lrng_kcapi.o
obj-$(CONFIG_LRNG_JENT) += lrng_jent.o
obj-$(CONFIG_LRNG_HEALTH_TESTS) += lrng_health.o
+obj-$(CONFIG_LRNG_TESTING) += lrng_testing.o
new file mode 100644
@@ -0,0 +1,393 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
+/*
+ * Linux Random Number Generator (LRNG) testing interfaces
+ *
+ * Copyright (C) 2019 - 2020, Stephan Mueller <smueller@chronox.de>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/atomic.h>
+#include <linux/bug.h>
+#include <linux/debugfs.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/sched/signal.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/uaccess.h>
+#include <linux/workqueue.h>
+#include <asm/errno.h>
+
+#include "lrng_internal.h"
+
+#define LRNG_TESTING_RINGBUFFER_SIZE 1024
+#define LRNG_TESTING_RINGBUFFER_MASK (LRNG_TESTING_RINGBUFFER_SIZE - 1)
+
+struct lrng_testing {
+ u32 lrng_testing_rb[LRNG_TESTING_RINGBUFFER_SIZE];
+ u32 rb_reader;
+ u32 rb_writer;
+ atomic_t lrng_testing_enabled;
+ spinlock_t lock;
+ wait_queue_head_t read_wait;
+};
+
+/*************************** Generic Data Handling ****************************/
+
+/*
+ * boot variable:
+ * 0 ==> No boot test, gathering of runtime data allowed
+ * 1 ==> Boot test enabled and ready for collecting data, gathering runtime
+ * data is disabled
+ * 2 ==> Boot test completed and disabled, gathering of runtime data is
+ * disabled
+ */
+
+static inline void lrng_testing_reset(struct lrng_testing *data)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&data->lock, flags);
+ data->rb_reader = 0;
+ data->rb_writer = 0;
+ spin_unlock_irqrestore(&data->lock, flags);
+}
+
+static inline void lrng_testing_init(struct lrng_testing *data, u32 boot)
+{
+ /*
+ * The boot time testing implies we have a running test. If the
+ * caller wants to clear it, he has to unset the boot_test flag
+ * at runtime via sysfs to enable regular runtime testing
+ */
+ if (boot)
+ return;
+
+ lrng_testing_reset(data);
+ atomic_set(&data->lrng_testing_enabled, 1);
+ pr_warn("Enabling data collection\n");
+}
+
+static inline void lrng_testing_fini(struct lrng_testing *data)
+{
+ atomic_set(&data->lrng_testing_enabled, 0);
+ lrng_testing_reset(data);
+ pr_warn("Disabling data collection\n");
+}
+
+
+static inline bool lrng_testing_store(struct lrng_testing *data, u32 value,
+ u32 *boot)
+{
+ unsigned long flags;
+
+ if (!atomic_read(&data->lrng_testing_enabled) && (*boot != 1))
+ return false;
+
+ spin_lock_irqsave(&data->lock, flags);
+
+ /*
+ * Disable entropy testing for boot time testing after ring buffer
+ * is filled.
+ */
+ if (*boot) {
+ if (data->rb_writer > LRNG_TESTING_RINGBUFFER_SIZE) {
+ *boot = 2;
+ pr_warn_once("One time data collection test disabled\n");
+ spin_unlock_irqrestore(&data->lock, flags);
+ return false;
+ }
+
+ if (data->rb_writer == 1)
+ pr_warn("One time data collection test enabled\n");
+ }
+
+ data->lrng_testing_rb[data->rb_writer & LRNG_TESTING_RINGBUFFER_MASK] =
+ value;
+ data->rb_writer++;
+
+ spin_unlock_irqrestore(&data->lock, flags);
+
+ if (wq_has_sleeper(&data->read_wait))
+ wake_up_interruptible(&data->read_wait);
+
+ return true;
+}
+
+static inline bool lrng_testing_have_data(struct lrng_testing *data)
+{
+ return ((data->rb_writer & LRNG_TESTING_RINGBUFFER_MASK) !=
+ (data->rb_reader & LRNG_TESTING_RINGBUFFER_MASK));
+}
+
+static inline int lrng_testing_reader(struct lrng_testing *data, u32 *boot,
+ u8 *outbuf, u32 outbuflen)
+{
+ unsigned long flags;
+ int collected_data = 0;
+
+ lrng_testing_init(data, *boot);
+
+ while (outbuflen) {
+ spin_lock_irqsave(&data->lock, flags);
+
+ /* We have no data or reached the writer. */
+ if (!data->rb_writer ||
+ (data->rb_writer == data->rb_reader)) {
+
+ spin_unlock_irqrestore(&data->lock, flags);
+
+ /*
+ * Now we gathered all boot data, enable regular data
+ * collection.
+ */
+ if (*boot) {
+ *boot = 0;
+ goto out;
+ }
+
+ wait_event_interruptible(data->read_wait,
+ lrng_testing_have_data(data));
+ if (signal_pending(current)) {
+ collected_data = -ERESTARTSYS;
+ goto out;
+ }
+
+ continue;
+ }
+
+ /* We copy out word-wise */
+ if (outbuflen < sizeof(u32)) {
+ spin_unlock_irqrestore(&data->lock, flags);
+ goto out;
+ }
+
+ memcpy(outbuf, &data->lrng_testing_rb[data->rb_reader],
+ sizeof(u32));
+ data->rb_reader++;
+
+ spin_unlock_irqrestore(&data->lock, flags);
+
+ outbuf += sizeof(u32);
+ outbuflen -= sizeof(u32);
+ collected_data += sizeof(u32);
+ }
+
+out:
+ if (!lrng_testing_have_data(data))
+ lrng_testing_fini(data);
+ return collected_data;
+}
+
+static int lrng_testing_extract_user(struct file *file, char __user *buf,
+ size_t nbytes, loff_t *ppos,
+ int (*reader)(u8 *outbuf, u32 outbuflen))
+{
+ loff_t pos = *ppos;
+ u8 *tmp, *tmp_aligned;
+ int ret = 0, large_request = (nbytes > 256);
+
+ if (!nbytes)
+ return 0;
+
+ /*
+ * The intention of this interface is for collecting at least
+ * 1000 samples due to the SP800-90B requirements. So, we make no
+ * effort in avoiding allocating more memory that actually needed
+ * by the user. Hence, we allocate sufficient memory to always hold
+ * that amount of data.
+ */
+ tmp = kmalloc(LRNG_TESTING_RINGBUFFER_SIZE + sizeof(u32), GFP_KERNEL);
+ if (!tmp)
+ return -ENOMEM;
+
+ tmp_aligned = PTR_ALIGN(tmp, sizeof(u32));
+
+ while (nbytes) {
+ int i;
+
+ if (large_request && need_resched()) {
+ if (signal_pending(current)) {
+ if (ret == 0)
+ ret = -ERESTARTSYS;
+ break;
+ }
+ schedule();
+ }
+
+ i = min_t(int, nbytes, LRNG_TESTING_RINGBUFFER_SIZE);
+ i = reader(tmp_aligned, i);
+ if (i <= 0) {
+ if (i < 0)
+ ret = i;
+ break;
+ }
+ if (copy_to_user(buf, tmp_aligned, i)) {
+ ret = -EFAULT;
+ break;
+ }
+
+ nbytes -= i;
+ buf += i;
+ ret += i;
+ }
+
+ kzfree(tmp);
+
+ nbytes -= ret;
+ *ppos = pos + nbytes;
+
+ return ret;
+}
+
+/************************* Raw Entropy Data Handling **************************/
+
+#ifdef CONFIG_LRNG_RAW_ENTROPY
+
+static u32 boot_test = 0;
+module_param(boot_test, uint, 0644);
+MODULE_PARM_DESC(boot_test, "Enable gathering boot time entropy of the first entropy events");
+
+static struct lrng_testing lrng_raw = {
+ .rb_reader = 0,
+ .rb_reader = 0,
+ .lock = __SPIN_LOCK_UNLOCKED(lrng_raw.lock),
+ .read_wait = __WAIT_QUEUE_HEAD_INITIALIZER(lrng_raw.read_wait)
+};
+
+bool lrng_raw_entropy_store(u32 value)
+{
+ return lrng_testing_store(&lrng_raw, value, &boot_test);
+}
+
+static int lrng_raw_entropy_reader(u8 *outbuf, u32 outbuflen)
+{
+ return lrng_testing_reader(&lrng_raw, &boot_test, outbuf, outbuflen);
+}
+
+static ssize_t lrng_raw_read(struct file *file, char __user *to,
+ size_t count, loff_t *ppos)
+{
+ return lrng_testing_extract_user(file, to, count, ppos,
+ lrng_raw_entropy_reader);
+}
+
+static const struct file_operations lrng_raw_fops = {
+ .owner = THIS_MODULE,
+ .read = lrng_raw_read,
+};
+
+#endif /* CONFIG_LRNG_RAW_ENTROPY */
+
+/********************** Raw Entropy Array Data Handling ***********************/
+
+#ifdef CONFIG_LRNG_RAW_ARRAY
+
+static u32 boot_raw_array = 0;
+module_param(boot_raw_array, uint, 0644);
+MODULE_PARM_DESC(boot_raw_array, "Enable gathering boot time raw noise array data of the first entropy events");
+
+static struct lrng_testing lrng_raw_array = {
+ .rb_reader = 0,
+ .rb_reader = 0,
+ .lock = __SPIN_LOCK_UNLOCKED(lrng_raw_array.lock),
+ .read_wait = __WAIT_QUEUE_HEAD_INITIALIZER(lrng_raw_array.read_wait)
+};
+
+bool lrng_raw_array_entropy_store(u32 value)
+{
+ return lrng_testing_store(&lrng_raw_array, value, &boot_raw_array);
+}
+
+static int lrng_raw_array_entropy_reader(u8 *outbuf, u32 outbuflen)
+{
+ return lrng_testing_reader(&lrng_raw_array, &boot_raw_array, outbuf,
+ outbuflen);
+}
+
+static ssize_t lrng_raw_array_read(struct file *file, char __user *to,
+ size_t count, loff_t *ppos)
+{
+ return lrng_testing_extract_user(file, to, count, ppos,
+ lrng_raw_array_entropy_reader);
+}
+
+static const struct file_operations lrng_raw_array_fops = {
+ .owner = THIS_MODULE,
+ .read = lrng_raw_array_read,
+};
+
+#endif /* CONFIG_LRNG_RAW_ARRAY */
+
+/******************** Interrupt Performance Data Handling *********************/
+
+#ifdef CONFIG_LRNG_IRQ_PERF
+
+static u32 boot_irq_perf = 0;
+module_param(boot_irq_perf, uint, 0644);
+MODULE_PARM_DESC(boot_irq_perf, "Enable gathering boot time interrupt performance data of the first entropy events");
+
+static struct lrng_testing lrng_irq_perf = {
+ .rb_reader = 0,
+ .rb_reader = 0,
+ .lock = __SPIN_LOCK_UNLOCKED(lrng_irq_perf.lock),
+ .read_wait = __WAIT_QUEUE_HEAD_INITIALIZER(lrng_irq_perf.read_wait)
+};
+
+bool lrng_perf_time(u32 start)
+{
+ return lrng_testing_store(&lrng_irq_perf, random_get_entropy() - start,
+ &boot_irq_perf);
+}
+
+static int lrng_irq_perf_reader(u8 *outbuf, u32 outbuflen)
+{
+ return lrng_testing_reader(&lrng_irq_perf, &boot_irq_perf, outbuf,
+ outbuflen);
+}
+
+static ssize_t lrng_irq_perf_read(struct file *file, char __user *to,
+ size_t count, loff_t *ppos)
+{
+ return lrng_testing_extract_user(file, to, count, ppos,
+ lrng_irq_perf_reader);
+}
+
+static const struct file_operations lrng_irq_perf_fops = {
+ .owner = THIS_MODULE,
+ .read = lrng_irq_perf_read,
+};
+
+#endif /* CONFIG_LRNG_IRQ_PERF */
+
+/**************************************************************************
+ * Debugfs interface
+ **************************************************************************/
+
+static int __init lrng_raw_init(void)
+{
+ struct dentry *lrng_raw_debugfs_root;
+
+
+ lrng_raw_debugfs_root = debugfs_create_dir(KBUILD_MODNAME, NULL);
+
+#ifdef CONFIG_LRNG_RAW_ENTROPY
+ debugfs_create_file_unsafe("lrng_raw", 0400, lrng_raw_debugfs_root,
+ NULL, &lrng_raw_fops);
+#endif
+#ifdef CONFIG_LRNG_RAW_ARRAY
+ debugfs_create_file_unsafe("lrng_raw_array", 0400,
+ lrng_raw_debugfs_root, NULL,
+ &lrng_raw_array_fops);
+#endif
+#ifdef CONFIG_LRNG_IRQ_PERF
+ debugfs_create_file_unsafe("lrng_irq_perf", 0400, lrng_raw_debugfs_root,
+ NULL, &lrng_irq_perf_fops);
+#endif
+
+ return 0;
+}
+
+module_init(lrng_raw_init);