Secdev driver

MAINTAINERS

@@ -512,6 +512,11 @@ M:	Wei Liu <[email protected]>
 S:	Supported
 T:	git https://xenbits.xenproject.org/git-http/seabios.git
 
+SECURITY HARDWARE DRIVERS
+M:	Daniel P. Smith <[email protected]>
+S:	Maintained
+F:	xen/drivers/security/
+
 STUB DOMAINS
 M:	Samuel Thibault <[email protected]>
 S:	Supported

xen/arch/x86/setup.c

@@ -23,6 +23,7 @@
 #include <xen/dmi.h>
 #include <xen/pfn.h>
 #include <xen/nodemask.h>
+#include <xen/secdev.h>
 #include <xen/virtual_region.h>
 #include <xen/watchdog.h>
 #include <public/version.h>
@@ -951,6 +952,35 @@ static struct domain *__init create_dom0(const module_t *image,
         write_cr4(read_cr4() & ~X86_CR4_SMAP);
     }
 
+    /* Dom0 can now be measure as the comand line has been finalized. */
+    if ( secdev_available(SECDEV_TPM) )
+    {
+        void *image_base = bootstrap_map(image);
+        secdev_opt_t opts = { 0 };
+
+        opts.tpm.domain.locality = SECDEV_TPM_DEFAULT_LOCALITY;
+        opts.tpm.domain.pcr = SECDEV_TPM_DEFAULT_PCR;
+
+        opts.tpm.domain.kern = image_base + headroom;
+        opts.tpm.domain.kern_size = image->mod_end - headroom;
+
+        opts.tpm.domain.cmdline = cmdline;
+
+        printk(XENLOG_INFO "%pd: measuring kernel%s\n", d,
+            initrd ? " and ramdisk" : "");
+
+        if ( initrd )
+        {
+            opts.tpm.domain.initrd = bootstrap_map(initrd);
+            opts.tpm.domain.initrd_size = initrd->mod_end;
+        }
+
+        if ( secdev_measure_domain(SECDEV_TPM, &opts) < 0 )
+            printk(XENLOG_ERR " Domain measurement failed\n");
+
+        bootstrap_map(NULL);
+    }
+
     if ( construct_dom0(d, image, headroom, initrd, cmdline) != 0 )
         panic("Could not construct domain 0\n");
 
@@ -1770,6 +1800,9 @@ void __init noreturn __start_xen(unsigned long mbi_p)
 
     tboot_probe();
 
+    if ( secdev_init() == 0 )
+        printk("Security Devices initialized\n");
+
     open_softirq(NEW_TLBFLUSH_CLOCK_PERIOD_SOFTIRQ, new_tlbflush_clock_period);
 
     if ( opt_watchdog ) 

xen/drivers/Kconfig

@@ -10,6 +10,8 @@ source "drivers/passthrough/Kconfig"
 
 source "drivers/pci/Kconfig"
 
+source "drivers/security/Kconfig"
+
 source "drivers/video/Kconfig"
 
 config HAS_VPCI

xen/drivers/Makefile

@@ -5,3 +5,4 @@ obj-$(CONFIG_HAS_VPCI) += vpci/
 obj-$(CONFIG_HAS_PASSTHROUGH) += passthrough/
 obj-$(CONFIG_ACPI) += acpi/
 obj-$(CONFIG_VIDEO) += video/
+obj-$(CONFIG_SECURITY_DEVICES) += security/

xen/drivers/security/Kconfig

@@ -0,0 +1,19 @@
+
+config SECURITY_DEVICES
+	bool "Security Devices (UNSUPPORTED)" if UNSUPPORTED
+	default n
+	---help---
+	  Enable Xen to manage and use platform security hardware.
+
+	  Say Y here if your platform has security hardware.
+
+config TPM_HARDWARE
+	bool "TPM Support"
+	default y
+	depends on SECURITY_DEVICES
+	select CRYPTO
+	---help---
+	  Xen will take control of a TPM, if present, and make it available
+	  for the hypervisor and domains.
+
+	  Say Y here if it is desired for Xen to use the TPM.

xen/drivers/security/Makefile

@@ -0,0 +1,2 @@
+obj-$(CONFIG_SECURITY_DEVICES) += secdev.o
+obj-$(CONFIG_TPM_HARDWARE) += tpm/

xen/drivers/security/secdev.c

@@ -0,0 +1,106 @@
+/* SPDX-License-Identifier: BSD-3-Clause */
+
+/*
+ * Copyright (c) 2023, Apertus Solutions, LLC
+ * All rights reserved.
+ */
+
+#include <xen/err.h>
+#include <xen/lib.h>
+
+#include "secdev.h"
+#include "tpm/tpm_drv.h"
+
+static struct {
+    struct secdev_handle *tpm;
+} dev_handles;
+
+static struct secdev_handle *get_dev_handle(secdev_id_t id)
+{
+    switch ( id )
+    {
+    case SECDEV_TPM:
+        if ( dev_handles.tpm != NULL )
+            return dev_handles.tpm;
+
+        printk(XENLOG_ERR "Requested TPM but no TPM was registered\n");
+        break;
+    default:
+        printk(XENLOG_ERR "Unknown device id (%d)\n", id);
+    }
+
+    return NULL;
+}
+
+ssize_t secdev_getrandom(enum secdev_id dev_id, secdev_opt_t *opts)
+{
+    struct secdev_handle *h = get_dev_handle(dev_id);
+    secdev_result_t res;
+    int ret = 0;
+
+    if ( h == NULL )
+        return -EINVAL;
+
+    if ( h->getrandom == NULL )
+    {
+        printk(XENLOG_ERR "getrandom() unsupported by security device (%d) \n",
+               dev_id);
+        return -EINVAL;
+    }
+
+    ret = h->getrandom(opts, &res);
+    if ( ret < 0 )
+        return ret;
+
+    return res.tpm.random.len;
+}
+
+int secdev_measure_buffer(enum secdev_id dev_id, secdev_opt_t *opts)
+{
+    struct secdev_handle *h = get_dev_handle(dev_id);
+    secdev_result_t res;
+
+    if ( h == NULL )
+        return -EINVAL;
+
+    if ( h->measure_buffer == NULL )
+    {
+        printk(XENLOG_ERR "measure_domain() unsupported by security device (%d) \n",
+               dev_id);
+        return -EINVAL;
+    }
+
+    return h->measure_buffer(opts, &res);
+}
+
+int secdev_measure_domain(enum secdev_id dev_id, secdev_opt_t *opts)
+{
+    struct secdev_handle *h = get_dev_handle(dev_id);
+    secdev_result_t res;
+
+    if ( h == NULL )
+        return -EINVAL;
+
+    if ( h->measure_domain == NULL )
+    {
+        printk(XENLOG_ERR "measure_domain() unsupported by security device (%d) \n",
+               dev_id);
+        return -EINVAL;
+    }
+
+    return h->measure_domain(opts, &res);
+}
+
+bool secdev_available(enum secdev_id dev_id)
+{
+    return (get_dev_handle(dev_id) != NULL);
+}
+
+int secdev_init(void)
+{
+#ifdef CONFIG_TPM_HARDWARE
+    dev_handles.tpm = tpm_driver_init();
+#endif
+
+    return 0;
+}

xen/drivers/security/secdev.h

@@ -0,0 +1,38 @@
+/* SPDX-License-Identifier: BSD-3-Clause */
+
+/*
+ * Copyright (c) 2023, Apertus Solutions, LLC
+ * All rights reserved.
+ */
+
+#ifndef __SECDEV_H__
+#define __SECDEV_H__
+
+#include <xen/lib/hash.h>
+#include <xen/secdev.h>
+
+struct tpm_dev_result {
+    union {
+        struct {
+            ssize_t len;
+        } random;
+        struct {
+            hash_t digest;
+        } measure;
+    };
+};
+
+typedef union secdev_result {
+    struct tpm_dev_result tpm;
+} secdev_result_t;
+
+struct secdev_handle {
+    int (*getrandom)(secdev_opt_t *opts, secdev_result_t *res);
+    int (*measure_buffer)(secdev_opt_t *opts, secdev_result_t *res);
+    int (*register_domain)(secdev_opt_t *opts, secdev_result_t *res);
+    int (*measure_domain)(secdev_opt_t *opts, secdev_result_t *res);
+    int (*launch_domain)(secdev_opt_t *opts, secdev_result_t *res);
+    int (*direct_op)(secdev_opt_t *opts, secdev_result_t *res);
+};
+
+#endif

xen/drivers/security/tpm/Makefile

@@ -0,0 +1,5 @@
+obj-y += tpm.o
+obj-y += tpm_mmio.o
+obj-y += tpm_12.o
+obj-y += tpm_20.o
+obj-y += tpm_drv.o