From b97aca849edc371e2586ab0a2f12908910cfa500 Mon Sep 17 00:00:00 2001
From: Stephan Mueller <smueller@chronox.de>
Date: Sun, 18 Dec 2022 21:12:42 +0100
Subject: [PATCH 03/25] LRNG - /proc interface

The patch adds 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 entropy)

- indicator whether the LRNG has been fully seeded (i.e. is the
secondary DRNG seeded with at least 256 bits of entropy)

Signed-off-by: Stephan Mueller <smueller@chronox.de>
---
 drivers/char/lrng/Makefile    |  1 +
 drivers/char/lrng/lrng_proc.c | 74 +++++++++++++++++++++++++++++++++++
 drivers/char/lrng/lrng_proc.h |  4 ++
 3 files changed, 79 insertions(+)
 create mode 100644 drivers/char/lrng/lrng_proc.c

--- a/drivers/char/lrng/Makefile
+++ b/drivers/char/lrng/Makefile
@@ -8,6 +8,7 @@ obj-y					+= lrng_es_mgr.o lrng_drng_mgr
 obj-$(CONFIG_LRNG_SHA256)		+= lrng_sha256.o
 obj-$(CONFIG_LRNG_SHA1)			+= lrng_sha1.o
 
+obj-$(CONFIG_SYSCTL)			+= lrng_proc.o
 obj-$(CONFIG_NUMA)			+= lrng_numa.o
 
 obj-$(CONFIG_LRNG_DRNG_CHACHA20)	+= lrng_drng_chacha20.o
--- /dev/null
+++ b/drivers/char/lrng/lrng_proc.c
@@ -0,0 +1,74 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
+/*
+ * LRNG proc interfaces
+ *
+ * Copyright (C) 2022, Stephan Mueller <smueller@chronox.de>
+ */
+
+#include <linux/lrng.h>
+#include <linux/module.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+
+#include "lrng_drng_mgr.h"
+#include "lrng_es_aux.h"
+#include "lrng_es_mgr.h"
+#include "lrng_proc.h"
+
+/* 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 char buf[270];
+	u32 i;
+
+	mutex_lock(&lrng_drng_init->lock);
+	snprintf(buf, sizeof(buf),
+		 "DRNG name: %s\n"
+		 "LRNG security strength in bits: %d\n"
+		 "Number of DRNG instances: %u\n"
+		 "Standards compliance: %sNTG.1 (2011%s)\n"
+		 "LRNG minimally seeded: %s\n"
+		 "LRNG fully seeded: %s\n"
+		 "LRNG entropy level: %u\n",
+		 lrng_drng_init->drng_cb->drng_name(),
+		 lrng_security_strength(),
+		 numa_drngs,
+		 lrng_sp80090c_compliant() ? "SP800-90C, " : "",
+		 lrng_ntg1_2022_compliant() ? " / 2022" : "",
+		 lrng_state_min_seeded() ? "true" : "false",
+		 lrng_state_fully_seeded() ? "true" : "false",
+		 lrng_avail_entropy());
+	seq_write(m, buf, strlen(buf));
+
+	for_each_lrng_es(i) {
+		snprintf(buf, sizeof(buf),
+			 "Entropy Source %u properties:\n"
+			 " Name: %s\n",
+			 i, lrng_es[i]->name);
+		seq_write(m, buf, strlen(buf));
+
+		buf[0] = '\0';
+		lrng_es[i]->state(buf, sizeof(buf));
+		seq_write(m, buf, strlen(buf));
+	}
+
+	mutex_unlock(&lrng_drng_init->lock);
+
+	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);
--- a/drivers/char/lrng/lrng_proc.h
+++ b/drivers/char/lrng/lrng_proc.h
@@ -6,6 +6,10 @@
 #ifndef _LRNG_PROC_H
 #define _LRNG_PROC_H
 
+#ifdef CONFIG_SYSCTL
+void lrng_pool_inc_numa_node(void);
+#else
 static inline void lrng_pool_inc_numa_node(void) { }
+#endif
 
 #endif /* _LRNG_PROC_H */