[Qemu-devel] [PATCH V1 7/8] Add a menu for TPM control

[Stefan Berger]

This patch provides an addtional menu entry that enables the user to control
certain aspects of the TPM.

If a working TPM has been detected, the top level BIOS menu
will look like this:

Press F12 for boot menu.
Press F11 to TPM menu.

Upon pressing F11 the TPM menu will be shown:

1. Enable TPM
2. Disable TPM
3. Activate TPM
4. Deactivate TPM
5. Clear ownership
6. Allow installation of owner
7. Prevent installation of owner
Escape for previous menu.
TPM is enabled, active, does not have an owner but one can be installed.

The code for the above 7 menu items is part of this patch.

Signed-off-by: Stefan Berger <address@hidden>


---
 src/boot.c    |   10 -
 src/tcgbios.c |  576 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 584 insertions(+), 2 deletions(-)

Index: seabios/src/tcgbios.c
===================================================================
--- seabios.orig/src/tcgbios.c
+++ seabios/src/tcgbios.c
@@ -1,4 +1,4 @@
-/*
+;/*
  *  Implementation of the TCG BIOS extension according to the specification
  *  described in
  *  
https://www.trustedcomputinggroup.org/specs/PCClient/TCG_PCClientImplementationforBIOS_1-20_1-00.pdf
@@ -95,6 +95,11 @@ static tcpa_state_t tcpa_state = {
 
 extern struct tpm_driver tpm_drivers[];
 
+typedef struct {
+    u16 revision;
+    u8  op;
+} tpm_bios_cfg_t;
+
 
 /********************************************************
   Extensions for TCG-enabled BIOS
@@ -1633,4 +1638,573 @@ tcpa_measure_post(void *from, void *to)
 }
 
 
+
+static u32
+assert_physical_presence(void)
+{
+    u32 rc = 0;
+    u32 returnCode;
+
+    rc = build_and_send_cmd(TPM_ORD_PhysicalPresence,
+                            PhysicalPresence_CMD_ENABLE,
+                            sizeof(PhysicalPresence_CMD_ENABLE),
+                            NULL, 10, &returnCode);
+
+#ifdef DEBUG_TCGBIOS
+    printf("Return code from TSC_PhysicalPresence(CMD_ENABLE) = 0x%08x\n",
+           returnCode);
+#endif
+    if (rc || returnCode)
+        goto err_exit;
+
+    rc = build_and_send_cmd(TPM_ORD_PhysicalPresence,
+                            PhysicalPresence_PRESENT,
+                            sizeof(PhysicalPresence_PRESENT),
+                            NULL, 10, &returnCode);
+
+#ifdef DEBUG_TCGBIOS
+    printf("Return code from TSC_PhysicalPresence(PRESENT) = 0x%08x\n",
+           returnCode);
+#endif
+    if (rc || returnCode)
+        goto err_exit;
+
+    return 0;
+
+err_exit:
+#ifdef DEBUG_TCGBIOS
+    dprintf(1,"TCGBIOS: TPM malfunctioning (line %d).\n", __LINE__);
+#endif
+    tcpa_state.tpm_working = 0;
+    if (rc)
+        return rc;
+    return TCG_TCG_COMMAND_ERROR;
+}
+
+
+static u32
+read_permanent_flags(char *buf, int buf_len)
+{
+    u32 rc;
+    u32 returnCode;
+    struct tpm_res_getcap_perm_flags pf;
+
+    memset(buf, 0x0, buf_len);
+
+    rc = build_and_send_cmd(TPM_ORD_GetCapability,
+                            GetCapability_Permanent_Flags,
+                            sizeof(GetCapability_Permanent_Flags),
+                            (u8 *)&pf,
+                            sizeof(struct tpm_res_getcap_perm_flags),
+                            &returnCode);
+
+#ifdef DEBUG_TCGBIOS
+    dprintf(1, "TCGBIOS: Return code from TPM_GetCapability() = 0x%08x\n",
+        returnCode);
+#endif
+
+    if (rc || returnCode)
+        goto err_exit;
+
+    memcpy(buf, &pf.perm_flags, buf_len);
+
+    return 0;
+
+err_exit:
+#ifdef DEBUG_TCGBIOS
+    dprintf(1,"TCGBIOS: TPM malfunctioning (line %d).\n", __LINE__);
+#endif
+    tcpa_state.tpm_working = 0;
+    if (rc)
+        return rc;
+    return TCG_TCG_COMMAND_ERROR;
+}
+
+
+static u32
+read_has_owner(u8 *has_owner)
+{
+    u32 rc;
+    u32 returnCode;
+    struct tpm_res_getcap_ownerauth oauth;
+
+    rc = build_and_send_cmd(TPM_ORD_GetCapability,
+                            GetCapability_OwnerAuth,
+                            sizeof(GetCapability_OwnerAuth),
+                            (u8 *)&oauth,
+                            sizeof(struct tpm_res_getcap_ownerauth),
+                            &returnCode);
+
+#ifdef DEBUG_TCGBIOS
+    dprintf(1, "TCGBIOS: Return code from TPM_GetCapability() = 0x%08x\n",
+        returnCode);
+#endif
+
+    if (rc || returnCode)
+        goto err_exit;
+
+    *has_owner = oauth.flag;
+
+    return 0;
+
+err_exit:
+#ifdef DEBUG_TCGBIOS
+    dprintf(1,"TCGBIOS: TPM malfunctioning (line %d).\n", __LINE__);
+#endif
+    tcpa_state.tpm_working = 0;
+    if (rc)
+        return rc;
+    return TCG_TCG_COMMAND_ERROR;
+}
+
+
+static u32
+disable_tpm(int disable, int verbose)
+{
+    u32 rc;
+    u32 returnCode;
+    struct tpm_permanent_flags pf;
+
+    rc = read_permanent_flags((char *)&pf, sizeof(pf));
+    if (rc)
+        return rc;
+
+    if (!!pf.flags[PERM_FLAG_IDX_DISABLE] == !!disable) {
+        if (verbose)
+            printf("TPM is already %s.\n,",
+                   disable ? "disabled" : "enabled");
+        return 0;
+    }
+
+    rc = assert_physical_presence();
+    if (rc) {
+#ifdef DEBUG_TCGBIOS
+        dprintf(1, "TCGBIOS: Asserting physical presence "
+                   "failed.\n");
+#endif
+        return rc;
+    }
+
+    rc = build_and_send_cmd(disable ? TPM_ORD_PhysicalDisable
+                                    : TPM_ORD_PhysicalEnable,
+                            NULL, 0, NULL, 10, &returnCode);
+#ifdef DEBUG_TCGBIOS
+    printf("Return code from TPM_Physical%sable = 0x%08x\n",
+           disable ? "Dis" : "En", returnCode);
+#endif
+    if (rc || returnCode)
+            goto err_exit;
+
+
+    return 0;
+
+err_exit:
+#ifdef DEBUG_TCGBIOS
+    dprintf(1, "TCGBIOS: %sabling the TPM failed.\n",
+            disable ? "Dis" : "En");
+    dprintf(1,"TCGBIOS: TPM malfunctioning (line %d).\n", __LINE__);
+#endif
+    tcpa_state.tpm_working = 0;
+    if (rc)
+        return rc;
+    return TCG_TCG_COMMAND_ERROR;
+}
+
+
+static u32
+deactivate_tpm(int deactivate, int allow_reset, int verbose)
+{
+    u32 rc;
+    u32 returnCode;
+    struct tpm_permanent_flags pf;
+
+    rc = read_permanent_flags((char *)&pf, sizeof(pf));
+    if (rc)
+        return rc;
+
+    if (!!pf.flags[PERM_FLAG_IDX_DEACTIVATED] == !!deactivate) {
+        if (verbose)
+            printf("TPM is already %s.\n",
+                   deactivate ? "deactivated" : "activated");
+        return 0;
+    }
+
+    if (pf.flags[PERM_FLAG_IDX_DISABLE]) {
+        if (verbose)
+            printf("TPM must first be enabled.\n");
+        return 0;
+    }
+
+    rc = assert_physical_presence();
+    if (rc) {
+#ifdef DEBUG_TCGBIOS
+        dprintf(1, "TCGBIOS: Asserting physical presence "
+                   "failed.\n");
+#endif
+        return rc;
+    }
+
+    rc = build_and_send_cmd(TPM_ORD_PhysicalSetDeactivated,
+                            deactivate ? CommandFlag_TRUE
+                                       : CommandFlag_FALSE,
+                            deactivate ? sizeof(CommandFlag_TRUE)
+                                       : sizeof(CommandFlag_FALSE),
+                            NULL, 10, &returnCode);
+#ifdef DEBUG_TCGBIOS
+    printf("Return code from PhysicalSetDeactivated(%d) = 0x%08x\n",
+           deactivate ? 1 : 0, returnCode);
+#endif
+    if (rc || returnCode)
+        goto err_exit;
+
+    if (!deactivate && allow_reset) {
+        if (verbose) {
+            printf("Requiring a reboot to activate the TPM.\n");
+
+            msleep(2000);
+        }
+        reset_vector();
+    }
+
+    return 0;
+
+err_exit:
+#ifdef DEBUG_TCGBIOS
+    dprintf(1,"TCGBIOS: TPM malfunctioning (line %d).\n", __LINE__);
+#endif
+    tcpa_state.tpm_working = 0;
+    if (rc)
+        return rc;
+    return TCG_TCG_COMMAND_ERROR;
+}
+
+
+static u32
+enable_activate(int allow_reset, int verbose)
+{
+    u32 rc;
+
+    rc = disable_tpm(0, verbose);
+    if (rc)
+        return rc;
+
+    rc = deactivate_tpm(0, allow_reset, verbose);
+
+    return rc;
+}
+
+
+static u32
+force_clear(int enable_activate_before, int enable_activate_after, int verbose)
+{
+    u32 rc;
+    u32 returnCode;
+    u8 has_owner;
+
+    rc = read_has_owner(&has_owner);
+    if (rc)
+        return rc;
+    if (!has_owner) {
+        if (verbose)
+            printf("TPM does not have an owner.\n");
+        return 0;
+    }
+
+    if (enable_activate_before) {
+        rc = enable_activate(0, verbose);
+        if (rc) {
+#ifdef DEBUG_TCGBIOS
+            dprintf(1, "TCGBIOS: Enabling/activating the TPM "
+                       "failed.\n");
+#endif
+            return rc;
+        }
+    }
+
+    rc = assert_physical_presence();
+    if (rc) {
+#ifdef DEBUG_TCGBIOS
+        dprintf(1, "TCGBIOS: Asserting physical presence "
+                   "failed.\n");
+#endif
+        return rc;
+    }
+
+    rc = build_and_send_cmd(TPM_ORD_ForceClear,
+                            NULL, 0, NULL, 10, &returnCode);
+#ifdef DEBUG_TCGBIOS
+    printf("Return code from TPM_ForceClear() = 0x%08x\n", returnCode);
+#endif
+    if (rc || returnCode)
+        goto err_exit;
+
+    if (!enable_activate_after) {
+        if (verbose)
+            printf("Owner successfully cleared.\n"
+                   "You will need to enable/activate the TPM again.\n\n");
+        return 0;
+    }
+
+    enable_activate(1, verbose);
+
+    return 0;
+
+err_exit:
+#ifdef DEBUG_TCGBIOS
+    dprintf(1,"TCGBIOS: TPM malfunctioning (line %d).\n", __LINE__);
+#endif
+    tcpa_state.tpm_working = 0;
+    if (rc)
+        return rc;
+    return TCG_TCG_COMMAND_ERROR;
+}
+
+
+static u32
+set_owner_install(int allow, int verbose)
+{
+    u32 rc, returnCode;
+    u8 has_owner;
+    struct tpm_permanent_flags pf;
+
+    rc = read_has_owner(&has_owner);
+    if (rc)
+        return rc;
+    if (has_owner) {
+        if (verbose)
+            printf("Must first remove owner.\n");
+        return 0;
+    }
+
+    rc = read_permanent_flags((char *)&pf, sizeof(pf));
+    if (rc)
+        return rc;
+
+    if (pf.flags[PERM_FLAG_IDX_DISABLE]) {
+        if (verbose)
+            printf("TPM must first be enable.\n");
+        return 0;
+    }
+
+    rc = assert_physical_presence();
+    if (rc) {
+#ifdef DEBUG_TCGBIOS
+        dprintf(1, "TCGBIOS: Asserting physical presence failed.\n");
+#endif
+        return rc;
+    }
+
+    rc = build_and_send_cmd(TPM_ORD_SetOwnerInstall,
+                            (allow) ? CommandFlag_TRUE :
+                                      CommandFlag_FALSE,
+                            sizeof(CommandFlag_TRUE),
+                            NULL, 10, &returnCode);
+#ifdef DEBUG_TCGBIOS
+    printf("Return code from TPM_SetOwnerInstall() = 0x%08x\n",
+           returnCode);
+#endif
+    if (rc || returnCode)
+        goto err_exit;
+
+    if (verbose)
+        printf("Installation of owner %s.\n", allow ? "enabled" : "disabled");
+
+    return 0;
+
+err_exit:
+#ifdef DEBUG_TCGBIOS
+    dprintf(1,"TCGBIOS: TPM malfunctioning (line %d).\n", __LINE__);
+#endif
+    tcpa_state.tpm_working = 0;
+    if (rc)
+        return rc;
+    return TCG_TCG_COMMAND_ERROR;
+}
+
+
+static void
+show_tpm_state(void)
+{
+    struct tpm_permanent_flags pf;
+    u8 has_owner;
+
+    if (read_permanent_flags((char *)&pf, sizeof(pf)) ||
+        read_has_owner(&has_owner))
+        return;
+
+    printf("TPM is ");
+
+    if (pf.flags[PERM_FLAG_IDX_DISABLE])
+        printf("disabled");
+    else
+        printf("enabled");
+
+    if (pf.flags[PERM_FLAG_IDX_DEACTIVATED])
+        printf(", deactivated");
+    else
+        printf(", active");
+
+    if (has_owner)
+        printf(" and has an owner.\n");
+    else {
+        printf(", does not have an owner ");
+        if (pf.flags[PERM_FLAG_IDX_OWNERSHIP])
+            printf("but one can be installed.\n");
+        else
+            printf("and an owner cannot be installed.\n");
+    }
+
+}
+
+
+static u32
+tcpa_process_cfg(const tpm_bios_cfg_t *cfg, int verbose)
+{
+    u32 rc = 0;
+
+#ifdef DEBUG_TCGBIOS
+    printf("TCGBIOS: cfg rev = %d, op = %d\n", cfg->revision, cfg->op);
+#endif
+    if (cfg->revision < 1)
+        return 0;
+
+    switch (cfg->op) {
+        case 0: /* no-op */
+            break;
+
+        case 1:
+            rc = disable_tpm(0, verbose);
+            break;
+
+        case 2:
+            rc = disable_tpm(1, verbose);
+            break;
+
+        case 3:
+            rc = deactivate_tpm(0, 1, verbose);
+            break;
+
+        case 4:
+            rc = deactivate_tpm(1, 1, verbose);
+            break;
+
+        case 5:
+            rc = force_clear(0, 0, verbose);
+            break;
+
+        case 6:
+            rc = enable_activate(1, verbose);
+            break;
+
+        case 7:
+            rc = deactivate_tpm(1, 1, verbose);
+            if (!rc)
+                rc = disable_tpm(1, verbose);
+            break;
+
+        case 8:
+            rc = set_owner_install(1, verbose);
+            break;
+
+        case 9:
+            rc = set_owner_install(0, verbose);
+            break;
+
+        case 10:
+            rc = enable_activate(1, verbose);
+            if (!rc)
+                rc = set_owner_install(1, verbose);
+            break;
+
+        case 11:
+            rc = set_owner_install(0, verbose);
+            if (!rc) {
+                rc = deactivate_tpm(1, 1, verbose);
+                if (!rc)
+                    rc = disable_tpm(1, verbose);
+            }
+            break;
+
+        case 14:
+            rc = force_clear(0, 1, verbose);
+            break;
+
+        case 21:
+            rc = force_clear(1, 0, verbose);
+            break;
+
+        case 22:
+            rc = force_clear(1, 1, verbose);
+            break;
+
+        default:
+            break;
+    }
+
+    if (rc)
+        printf("Op %d: An error occurred: 0x%x\n", cfg->op, rc);
+
+    return rc;
+}
+
+
+void
+tcpa_menu(void)
+{
+    int show_menu = 1;
+    int scan_code;
+    u32 rc;
+    tpm_bios_cfg_t cfg = {
+        .revision = 1,
+        .op  = 0,
+    };
+
+    while (get_keystroke(0) >= 0)
+        ;
+    wait_threads();
+
+    for (;;) {
+        if (show_menu) {
+            printf("1. Enable TPM\n"
+                   "2. Disable TPM\n"
+                   "3. Activate TPM\n"
+                   "4. Deactivate TPM\n"
+                   "5. Clear ownership\n"
+                   "6. Allow installation of owner\n"
+                   "7. Prevent installation of owner\n"
+                   "Escape for previous menu.\n");
+            show_menu = 0;
+            show_tpm_state();
+        }
+
+        cfg.op = 0;
+
+        scan_code = get_keystroke(1000);
+
+        switch (scan_code) {
+        case 1:
+            // ESC
+            return;
+        case 2 ... 5:
+            cfg.op = scan_code - 1;
+            break;
+        case 6: /* force clear */
+            cfg.op = 21;
+            break;
+        case 7 ... 8:
+            cfg.op = scan_code + 1;
+            break;
+        default:
+            continue;
+        }
+
+        rc = tcpa_process_cfg(&cfg, 1);
+
+        if (rc)
+            printf("An error occurred: 0x%x\n", rc);
+
+        show_menu = 1;
+    }
+}
+
 #endif /* CONFIG_TCGBIOS */
Index: seabios/src/boot.c
===================================================================
--- seabios.orig/src/boot.c
+++ seabios/src/boot.c
@@ -364,11 +364,19 @@ interactive_bootmenu(void)
     while (get_keystroke(0) >= 0)
         ;
 
-    printf("Press F12 for boot menu.\n\n");
+again:
+    printf("Press F12 for boot menu.\n");
+    if (has_working_tpm())
+        printf("Press F11 to TPM menu.\n");
+    printf("\n");
 
     enable_bootsplash();
     int scan_code = get_keystroke(CONFIG_BOOTMENU_WAIT);
     disable_bootsplash();
+    if (has_working_tpm() && scan_code == 0x85) {
+         tcpa_menu();
+         goto again;
+    }
     if (scan_code != 0x86)
         /* not F12 */
         return;