svn commit: r345438 - in head/sys: conf dev/random dev/tpm sys
Marcin Wojtas
mw at FreeBSD.org
Sat Mar 23 05:13:54 UTC 2019
Author: mw
Date: Sat Mar 23 05:13:51 2019
New Revision: 345438
URL: https://svnweb.freebsd.org/changeset/base/345438
Log:
Allow using TPM as entropy source.
TPM has a built-in RNG, with its own entropy source.
The driver was extended to harvest 16 random bytes from TPM every 10 seconds.
A new build option "TPM_HARVEST" was introduced - for now, however, it
is not enabled by default in the GENERIC config.
Submitted by: Kornel Duleba <mindal at semihalf.com>
Reviewed by: markm, delphij
Approved by: secteam
Obtained from: Semihalf
Sponsored by: Stormshield
Differential Revision: https://reviews.freebsd.org/D19620
Modified:
head/sys/conf/options
head/sys/dev/random/random_harvestq.c
head/sys/dev/tpm/tpm20.c
head/sys/dev/tpm/tpm20.h
head/sys/dev/tpm/tpm_crb.c
head/sys/dev/tpm/tpm_tis.c
head/sys/sys/random.h
Modified: head/sys/conf/options
==============================================================================
--- head/sys/conf/options Sat Mar 23 04:32:10 2019 (r345437)
+++ head/sys/conf/options Sat Mar 23 05:13:51 2019 (r345438)
@@ -983,6 +983,9 @@ RANDOM_LOADABLE opt_global.h
RANDOM_ENABLE_UMA opt_global.h
RANDOM_ENABLE_ETHER opt_global.h
+# This options turns TPM into entropy source.
+TPM_HARVEST opt_tpm.h
+
# BHND(4) driver
BHND_LOGLEVEL opt_global.h
Modified: head/sys/dev/random/random_harvestq.c
==============================================================================
--- head/sys/dev/random/random_harvestq.c Sat Mar 23 04:32:10 2019 (r345437)
+++ head/sys/dev/random/random_harvestq.c Sat Mar 23 05:13:51 2019 (r345438)
@@ -330,6 +330,7 @@ static const char *random_source_descr[ENTROPYSOURCE]
[RANDOM_PURE_BROADCOM] = "PURE_BROADCOM",
[RANDOM_PURE_CCP] = "PURE_CCP",
[RANDOM_PURE_DARN] = "PURE_DARN",
+ [RANDOM_PURE_TPM] = "PURE_TPM",
/* "ENTROPYSOURCE" */
};
Modified: head/sys/dev/tpm/tpm20.c
==============================================================================
--- head/sys/dev/tpm/tpm20.c Sat Mar 23 04:32:10 2019 (r345437)
+++ head/sys/dev/tpm/tpm20.c Sat Mar 23 05:13:51 2019 (r345438)
@@ -28,13 +28,27 @@
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
+#include <sys/random.h>
+
#include "tpm20.h"
+#define TPM_HARVEST_SIZE 16
+/*
+ * Perform a harvest every 10 seconds.
+ * Since discrete TPMs are painfully slow
+ * we don't want to execute this too often
+ * as the chip is likely to be used by others too.
+ */
+#define TPM_HARVEST_INTERVAL 10000000
+
MALLOC_DECLARE(M_TPM20);
MALLOC_DEFINE(M_TPM20, "tpm_buffer", "buffer for tpm 2.0 driver");
static void tpm20_discard_buffer(void *arg);
-static int tpm20_save_state(device_t dev, bool suspend);
+#ifdef TPM_HARVEST
+static void tpm20_harvest(void *arg);
+#endif
+static int tpm20_save_state(device_t dev, bool suspend);
static d_open_t tpm20_open;
static d_close_t tpm20_close;
@@ -175,6 +189,11 @@ tpm20_init(struct tpm_sc *sc)
sx_init(&sc->dev_lock, "TPM driver lock");
cv_init(&sc->buf_cv, "TPM buffer cv");
callout_init(&sc->discard_buffer_callout, 1);
+#ifdef TPM_HARVEST
+ sc->harvest_ticks = TPM_HARVEST_INTERVAL / tick;
+ callout_init(&sc->harvest_callout, 1);
+ callout_reset(&sc->harvest_callout, 0, tpm20_harvest, sc);
+#endif
sc->pending_data_length = 0;
make_dev_args_init(&args);
@@ -195,6 +214,10 @@ void
tpm20_release(struct tpm_sc *sc)
{
+#ifdef TPM_HARVEST
+ callout_drain(&sc->harvest_callout);
+#endif
+
if (sc->buf != NULL)
free(sc->buf, M_TPM20);
@@ -216,6 +239,57 @@ tpm20_shutdown(device_t dev)
{
return (tpm20_save_state(dev, false));
}
+
+#ifdef TPM_HARVEST
+
+/*
+ * Get TPM_HARVEST_SIZE random bytes and add them
+ * into system entropy pool.
+ */
+static void
+tpm20_harvest(void *arg)
+{
+ struct tpm_sc *sc;
+ unsigned char entropy[TPM_HARVEST_SIZE];
+ uint16_t entropy_size;
+ int result;
+ uint8_t cmd[] = {
+ 0x80, 0x01, /* TPM_ST_NO_SESSIONS tag*/
+ 0x00, 0x00, 0x00, 0x0c, /* cmd length */
+ 0x00, 0x00, 0x01, 0x7b, /* cmd TPM_CC_GetRandom */
+ 0x00, TPM_HARVEST_SIZE /* number of bytes requested */
+ };
+
+
+ sc = arg;
+ sx_xlock(&sc->dev_lock);
+
+ memcpy(sc->buf, cmd, sizeof(cmd));
+ result = sc->transmit(sc, sizeof(cmd));
+ if (result != 0) {
+ sx_xunlock(&sc->dev_lock);
+ return;
+ }
+
+ /* Ignore response size */
+ sc->pending_data_length = 0;
+
+ /* The number of random bytes we got is placed right after the header */
+ entropy_size = (uint16_t) sc->buf[TPM_HEADER_SIZE + 1];
+ if (entropy_size > 0) {
+ entropy_size = MIN(entropy_size, TPM_HARVEST_SIZE);
+ memcpy(entropy,
+ sc->buf + TPM_HEADER_SIZE + sizeof(uint16_t),
+ entropy_size);
+ }
+
+ sx_xunlock(&sc->dev_lock);
+ if (entropy_size > 0)
+ random_harvest_queue(entropy, entropy_size, RANDOM_PURE_TPM);
+
+ callout_reset(&sc->harvest_callout, sc->harvest_ticks, tpm20_harvest, sc);
+}
+#endif /* TPM_HARVEST */
static int
tpm20_save_state(device_t dev, bool suspend)
Modified: head/sys/dev/tpm/tpm20.h
==============================================================================
--- head/sys/dev/tpm/tpm20.h Sat Mar 23 04:32:10 2019 (r345437)
+++ head/sys/dev/tpm/tpm20.h Sat Mar 23 05:13:51 2019 (r345438)
@@ -55,6 +55,8 @@ __FBSDID("$FreeBSD$");
#include <dev/acpica/acpivar.h>
#include "opt_acpi.h"
+#include "opt_tpm.h"
+
#define BIT(x) (1 << (x))
/* Timeouts in us */
@@ -120,6 +122,10 @@ struct tpm_sc {
size_t pending_data_length;
struct callout discard_buffer_callout;
+#ifdef TPM_HARVEST
+ struct callout harvest_callout;
+ int harvest_ticks;
+#endif
int (*transmit)(struct tpm_sc *, size_t);
};
Modified: head/sys/dev/tpm/tpm_crb.c
==============================================================================
--- head/sys/dev/tpm/tpm_crb.c Sat Mar 23 04:32:10 2019 (r345437)
+++ head/sys/dev/tpm/tpm_crb.c Sat Mar 23 05:13:51 2019 (r345438)
@@ -165,7 +165,8 @@ tpmcrb_attach(device_t dev)
return (ENXIO);
if(!tpmcrb_request_locality(sc, 0)) {
- tpmcrb_detach(dev);
+ bus_release_resource(dev, SYS_RES_MEMORY,
+ sc->mem_rid, sc->mem_res);
return (ENXIO);
}
@@ -231,12 +232,12 @@ tpmcrb_detach(device_t dev)
struct tpm_sc *sc;
sc = device_get_softc(dev);
+ tpm20_release(sc);
if (sc->mem_res != NULL)
bus_release_resource(dev, SYS_RES_MEMORY,
sc->mem_rid, sc->mem_res);
- tpm20_release(sc);
return (0);
}
Modified: head/sys/dev/tpm/tpm_tis.c
==============================================================================
--- head/sys/dev/tpm/tpm_tis.c Sat Mar 23 04:32:10 2019 (r345437)
+++ head/sys/dev/tpm/tpm_tis.c Sat Mar 23 05:13:51 2019 (r345438)
@@ -162,6 +162,7 @@ tpmtis_detach(device_t dev)
struct tpm_sc *sc;
sc = device_get_softc(dev);
+ tpm20_release(sc);
if (sc->intr_cookie != NULL)
bus_teardown_intr(dev, sc->irq_res, sc->intr_cookie);
@@ -174,7 +175,6 @@ tpmtis_detach(device_t dev)
bus_release_resource(dev, SYS_RES_MEMORY,
sc->mem_rid, sc->mem_res);
- tpm20_release(sc);
return (0);
}
Modified: head/sys/sys/random.h
==============================================================================
--- head/sys/sys/random.h Sat Mar 23 04:32:10 2019 (r345437)
+++ head/sys/sys/random.h Sat Mar 23 05:13:51 2019 (r345438)
@@ -87,6 +87,7 @@ enum random_entropy_source {
RANDOM_PURE_BROADCOM,
RANDOM_PURE_CCP,
RANDOM_PURE_DARN,
+ RANDOM_PURE_TPM,
ENTROPYSOURCE
};
_Static_assert(ENTROPYSOURCE <= 32,
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