svn commit: r324394 - in head/sys: dev/random sys
Conrad Meyer
cem at FreeBSD.org
Sat Oct 7 19:02:05 UTC 2017
Author: cem
Date: Sat Oct 7 19:02:03 2017
New Revision: 324394
URL: https://svnweb.freebsd.org/changeset/base/324394
Log:
random(4): Gather entropy from Pure sources
At initialization, hc_source_mask only includes non-Pure sources.
The patch changes source registration to enable the registered source in the
hc_source_mask bitmask. This mask governs which sources are harvested.
This patch also disallows userspace from disabling such sources.
PR: 222807
Submitted by: W. Dean Freeman <badfilemagic AT gmail.com>
Reviewed by: jmg (earlier version), delphij
Approved by: secteam (delphij)
Obtained from: HBSD 0054e3e170e083811acc9f3b637f8be8a86c03e7
Security: yes
Differential Revision: https://reviews.freebsd.org/D12611
Modified:
head/sys/dev/random/random_harvestq.c
head/sys/dev/random/randomdev.c
head/sys/sys/random.h
Modified: head/sys/dev/random/random_harvestq.c
==============================================================================
--- head/sys/dev/random/random_harvestq.c Sat Oct 7 18:59:29 2017 (r324393)
+++ head/sys/dev/random/random_harvestq.c Sat Oct 7 19:02:03 2017 (r324394)
@@ -1,4 +1,6 @@
/*-
+ * Copyright (c) 2017 Oliver Pinter
+ * Copyright (c) 2017 W. Dean Freeman
* Copyright (c) 2000-2015 Mark R V Murray
* Copyright (c) 2013 Arthur Mesh
* Copyright (c) 2004 Robert N. M. Watson
@@ -240,8 +242,28 @@ read_rate_increment(u_int chunk)
}
/* ARGSUSED */
-RANDOM_CHECK_UINT(harvestmask, 0, RANDOM_HARVEST_EVERYTHING_MASK);
+static int
+random_check_uint_harvestmask(SYSCTL_HANDLER_ARGS)
+{
+ int error;
+ u_int value, orig_value;
+ orig_value = value = harvest_context.hc_source_mask;
+ error = sysctl_handle_int(oidp, &value, 0, req);
+ if (error != 0 || req->newptr == NULL)
+ return (error);
+
+ if (flsl(value) > ENTROPYSOURCE)
+ return (EINVAL);
+
+ /*
+ * Disallow userspace modification of pure entropy sources.
+ */
+ harvest_context.hc_source_mask = (value & ~RANDOM_HARVEST_PURE_MASK) |
+ (orig_value & RANDOM_HARVEST_PURE_MASK);
+ return (0);
+}
+
/* ARGSUSED */
static int
random_print_harvestmask(SYSCTL_HANDLER_ARGS)
@@ -252,7 +274,7 @@ random_print_harvestmask(SYSCTL_HANDLER_ARGS)
error = sysctl_wire_old_buffer(req, 0);
if (error == 0) {
sbuf_new_for_sysctl(&sbuf, NULL, 128, req);
- for (i = RANDOM_ENVIRONMENTAL_END; i >= 0; i--)
+ for (i = ENTROPYSOURCE - 1; i >= 0; i--)
sbuf_cat(&sbuf, (harvest_context.hc_source_mask & (1 << i)) ? "1" : "0");
error = sbuf_finish(&sbuf);
sbuf_delete(&sbuf);
@@ -272,7 +294,7 @@ static const char *random_source_descr[ENTROPYSOURCE]
[RANDOM_SWI] = "SWI",
[RANDOM_FS_ATIME] = "FS_ATIME",
[RANDOM_UMA] = "UMA", /* ENVIRONMENTAL_END */
- [RANDOM_PURE_OCTEON] = "PURE_OCTEON",
+ [RANDOM_PURE_OCTEON] = "PURE_OCTEON", /* PURE_START */
[RANDOM_PURE_SAFE] = "PURE_SAFE",
[RANDOM_PURE_GLXSB] = "PURE_GLXSB",
[RANDOM_PURE_UBSEC] = "PURE_UBSEC",
@@ -291,15 +313,22 @@ random_print_harvestmask_symbolic(SYSCTL_HANDLER_ARGS)
{
struct sbuf sbuf;
int error, i;
+ bool first;
+ first = true;
error = sysctl_wire_old_buffer(req, 0);
if (error == 0) {
sbuf_new_for_sysctl(&sbuf, NULL, 128, req);
- for (i = RANDOM_ENVIRONMENTAL_END; i >= 0; i--) {
- sbuf_cat(&sbuf, (i == RANDOM_ENVIRONMENTAL_END) ? "" : ",");
+ for (i = ENTROPYSOURCE - 1; i >= 0; i--) {
+ if (i >= RANDOM_PURE_START &&
+ (harvest_context.hc_source_mask & (1 << i)) == 0)
+ continue;
+ if (!first)
+ sbuf_cat(&sbuf, ",");
sbuf_cat(&sbuf, !(harvest_context.hc_source_mask & (1 << i)) ? "[" : "");
sbuf_cat(&sbuf, random_source_descr[i]);
sbuf_cat(&sbuf, !(harvest_context.hc_source_mask & (1 << i)) ? "]" : "");
+ first = false;
}
error = sbuf_finish(&sbuf);
sbuf_delete(&sbuf);
@@ -321,8 +350,7 @@ random_harvestq_init(void *unused __unused)
SYSCTL_ADD_PROC(&random_clist,
SYSCTL_CHILDREN(random_sys_o),
OID_AUTO, "mask", CTLTYPE_UINT | CTLFLAG_RW,
- &harvest_context.hc_source_mask, 0,
- random_check_uint_harvestmask, "IU",
+ NULL, 0, random_check_uint_harvestmask, "IU",
"Entropy harvesting mask");
SYSCTL_ADD_PROC(&random_clist,
SYSCTL_CHILDREN(random_sys_o),
@@ -493,6 +521,20 @@ random_harvest_direct(const void *entropy, u_int size,
memcpy(event.he_entropy, entropy, size);
random_harvestq_fast_process_event(&event);
explicit_bzero(&event, sizeof(event));
+}
+
+void
+random_harvest_register_source(enum random_entropy_source source)
+{
+
+ harvest_context.hc_source_mask |= (1 << source);
+}
+
+void
+random_harvest_deregister_source(enum random_entropy_source source)
+{
+
+ harvest_context.hc_source_mask &= ~(1 << source);
}
MODULE_VERSION(random_harvestq, 1);
Modified: head/sys/dev/random/randomdev.c
==============================================================================
--- head/sys/dev/random/randomdev.c Sat Oct 7 18:59:29 2017 (r324393)
+++ head/sys/dev/random/randomdev.c Sat Oct 7 19:02:03 2017 (r324394)
@@ -1,4 +1,5 @@
/*-
+ * Copyright (c) 2017 Oliver Pinter
* Copyright (c) 2000-2015 Mark R V Murray
* All rights reserved.
*
@@ -321,6 +322,8 @@ random_source_register(struct random_source *rsource)
rrs = malloc(sizeof(*rrs), M_ENTROPY, M_WAITOK);
rrs->rrs_source = rsource;
+ random_harvest_register_source(rsource->rs_source);
+
printf("random: registering fast source %s\n", rsource->rs_ident);
LIST_INSERT_HEAD(&source_list, rrs, rrs_entries);
}
@@ -331,6 +334,9 @@ random_source_deregister(struct random_source *rsource
struct random_sources *rrs = NULL;
KASSERT(rsource != NULL, ("invalid input to %s", __func__));
+
+ random_harvest_deregister_source(rsource->rs_source);
+
LIST_FOREACH(rrs, &source_list, rrs_entries)
if (rrs->rrs_source == rsource) {
LIST_REMOVE(rrs, rrs_entries);
Modified: head/sys/sys/random.h
==============================================================================
--- head/sys/sys/random.h Sat Oct 7 18:59:29 2017 (r324393)
+++ head/sys/sys/random.h Sat Oct 7 19:02:03 2017 (r324394)
@@ -81,7 +81,8 @@ enum random_entropy_source {
RANDOM_UMA, /* Special!! UMA/SLAB Allocator */
RANDOM_ENVIRONMENTAL_END = RANDOM_UMA,
/* Fast hardware random-number sources from here on. */
- RANDOM_PURE_OCTEON,
+ RANDOM_PURE_START,
+ RANDOM_PURE_OCTEON = RANDOM_PURE_START,
RANDOM_PURE_SAFE,
RANDOM_PURE_GLXSB,
RANDOM_PURE_UBSEC,
@@ -95,6 +96,7 @@ enum random_entropy_source {
};
#define RANDOM_HARVEST_EVERYTHING_MASK ((1 << (RANDOM_ENVIRONMENTAL_END + 1)) - 1)
+#define RANDOM_HARVEST_PURE_MASK (((1 << ENTROPYSOURCE) - 1) & (-1UL << RANDOM_PURE_START))
#define RANDOM_LEGACY_BOOT_ENTROPY_MODULE "/boot/entropy"
#define RANDOM_CACHED_BOOT_ENTROPY_MODULE "boot_entropy_cache"
@@ -104,10 +106,14 @@ enum random_entropy_source {
void random_harvest_queue(const void *, u_int, u_int, enum random_entropy_source);
void random_harvest_fast(const void *, u_int, u_int, enum random_entropy_source);
void random_harvest_direct(const void *, u_int, u_int, enum random_entropy_source);
+void random_harvest_register_source(enum random_entropy_source);
+void random_harvest_deregister_source(enum random_entropy_source);
#else
#define random_harvest_queue(a, b, c, d) do {} while (0)
#define random_harvest_fast(a, b, c, d) do {} while (0)
#define random_harvest_direct(a, b, c, d) do {} while (0)
+#define random_harvest_register_source(a) do {} while (0)
+#define random_harvest_deregister_source(a) do {} while (0)
#endif
#if defined(RANDOM_ENABLE_UMA)
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