x86 FSP: add TPM-NV anti-rollback with a persistent version floor and boot audit counters

Author: dgarske

.github/workflows/test-build-kontron-vx3060-s2.yml

@@ -46,10 +46,6 @@ jobs:
           export DEBIAN_FRONTEND=noninteractive
           sudo apt-get update -o Acquire::Retries=3
           sudo apt-get install --no-install-recommends -y -q -o Acquire::Retries=3 nasm gcc-multilib
-      - name: setup git
-        run: |
-          git config --global user.email "you@example.com"
-          git config --global user.name "Your Name"
       - name: run test
         run: |
           cp config/examples/kontron_vx3060_s2.config .config

.github/workflows/test-x86-fsp-qemu.yml

@@ -46,10 +46,6 @@ jobs:
           export DEBIAN_FRONTEND=noninteractive
           sudo apt-get update -o Acquire::Retries=3
           sudo apt-get install --no-install-recommends -y -q -o Acquire::Retries=3 nasm gcc-multilib qemu-system-x86 swtpm uuid-dev
-      - name: setup git
-        run: |
-          git config --global user.email "you@example.com"
-          git config --global user.name "Your Name"
       - name: run test
         run: |
           ./tools/scripts/x86_fsp/qemu/test_qemu.sh
@@ -70,10 +66,25 @@ jobs:
           export DEBIAN_FRONTEND=noninteractive
           sudo apt-get update -o Acquire::Retries=3
           sudo apt-get install --no-install-recommends -y -q -o Acquire::Retries=3 nasm gcc-multilib qemu-system-x86 uuid-dev dosfstools mtools e2fsprogs
-      - name: setup git
-        run: |
-          git config --global user.email "you@example.com"
-          git config --global user.name "Your Name"
       - name: run test
         run: |
           ./tools/scripts/x86_fsp/qemu/test_qemu.sh -f
+
+  # TPM-NV anti-rollback: the floor anchors on a fresh swtpm, survives a TPM
+  # restart, and a validly signed downgrade boots and is counted.
+  fsp_qemu_antirollback_test:
+    runs-on: ubuntu-latest
+    timeout-minutes: 15
+
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          submodules: true
+      - name: install req
+        run: |
+          export DEBIAN_FRONTEND=noninteractive
+          sudo apt-get update -o Acquire::Retries=3
+          sudo apt-get install --no-install-recommends -y -q -o Acquire::Retries=3 nasm gcc-multilib qemu-system-x86 swtpm uuid-dev
+      - name: run test
+        run: |
+          ./tools/scripts/x86_fsp/qemu/test_qemu.sh -r

.gitignore

@@ -181,6 +181,8 @@ tools/unit-tests/unit-update-flash-enc
 tools/unit-tests/unit-update-flash-db
 tools/unit-tests/unit-update-flash-enc-full
 tools/unit-tests/unit-update-ram
+tools/unit-tests/unit-boot-state
+tools/unit-tests/unit-boot-state-halt
 tools/unit-tests/unit-boot-x86-fsp
 tools/unit-tests/unit-image-rsa
 tools/unit-tests/unit-multiboot

arch.mk

@@ -2312,6 +2312,10 @@ ifeq ("${FSP}", "1")
     OBJS += src/x86/fsp_s.o
     UPDATE_OBJS := src/update_disk.o
     CFLAGS+=-DWOLFBOOT_UPDATE_DISK
+    ifeq ($(ANTI_ROLLBACK),1)
+      OBJS += src/boot_state.o
+      OBJS += src/boot_state_tpm.o
+    endif
     ifeq ($(64BIT),1)
       LDFLAGS += -m elf_x86_64 --oformat elf64-x86-64
       CFLAGS += -m64

config/examples/x86_fsp_qemu_antirollback.config

@@ -0,0 +1,45 @@
+ARCH=x86_64
+TARGET=x86_fsp_qemu
+WOLFBOOT_SMALL_STACK=1
+SIGN=ECC256
+HASH=SHA256
+DEBUG=1
+SPMATH=1
+FORCE_32BIT=1
+ENCRYPTION=0
+WOLFBOOT_NO_PARTITIONS=1
+
+# TPM Keystore options
+#WOLFBOOT_TPM_KEYSTORE?=1
+#WOLFBOOT_TPM_KEYSTORE_NV_BASE?=0x01800200
+#WOLFBOOT_TPM_POLICY_NV_INDEX?=0x01800201
+
+# 4gb - 8mb
+WOLFBOOT_LOAD_BASE=0x2000000
+WOLFBOOT_LOAD_ADDRESS=0x1000000
+
+# required for keytools
+WOLFBOOT_SECTOR_SIZE?=0x1000
+WOLFBOOT_DATA_ADDRESS=0x1000000
+
+FSP_M_BASE=0xffe30000
+FSP_S_BASE=0xffed6000
+FSP_T_BASE=0xfffe0000
+FSP_S_LOAD_BASE=0x0FED5F00
+WOLFBOOT_ORIGIN=0xfff80000
+
+BOOTLOADER_PARTITION_SIZE=0xe0000
+BIOS_REGION_SIZE=0x800000
+MACHINE_OBJ=src/x86/qemu_fsp.o
+FSP_T_BIN=./src/x86/fsp_t.bin
+FSP_M_BIN=./src/x86/fsp_m.bin
+FSP_S_BIN=./src/x86/fsp_s.bin
+STAGE1_AUTH=1
+64BIT=1
+ELF=1
+MULTIBOOT2=1
+
+# TPM-NV anti-rollback (version floor and audit counters), tested by
+# tools/scripts/x86_fsp/qemu/test_qemu.sh -r
+ANTI_ROLLBACK=1
+ANTI_ROLLBACK_HALT_ON_FAILURE=1

include/boot_state.h

@@ -0,0 +1,85 @@
+/* boot_state.h
+ *
+ * Persistent anti-rollback reference and boot audit counters.
+ *
+ * Copyright (C) 2026 wolfSSL Inc.
+ *
+ * This file is part of wolfBoot.
+ *
+ * wolfBoot is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * wolfBoot is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335, USA
+ */
+
+/* Anti-rollback state: anchor = highest version ever booted (trust on first
+ * use), record = last booted. See the Anti-rollback section of Targets.md. */
+
+#ifndef BOOT_STATE_H
+#define BOOT_STATE_H
+
+#include <stdint.h>
+
+#define BOOT_STATE_MAGIC   0x42535431UL /* "BST1" */
+#define BOOT_STATE_VERSION 1
+
+/* Result of loading the persisted state. */
+#define BOOT_STATE_OK            0  /* loaded and trustworthy */
+#define BOOT_STATE_UNPROVISIONED 1  /* nothing stored yet; not an error */
+#define BOOT_STATE_CORRUPT     (-1) /* stored but unusable -- fatal */
+#define BOOT_STATE_UNAVAILABLE (-2) /* backend could not be reached */
+
+/* Failure codes recorded in last_fail_code. */
+#define BOOT_FAIL_NONE            0
+#define BOOT_FAIL_NO_IMAGE        1
+#define BOOT_FAIL_VERIFY_PRIMARY  2
+#define BOOT_FAIL_VERIFY_BOTH     3
+#define BOOT_FAIL_ROLLBACK        4
+
+/* On-storage layout. Packed and explicitly sized so the representation does
+ * not shift between the bootloader and any provisioning tool. */
+struct boot_state {
+    uint32_t magic;
+    uint32_t anchor;
+    uint32_t record;
+    uint32_t rollback_count;
+    uint32_t last_rollback_from;
+    uint32_t last_rollback_to;
+    uint32_t boot_fail_count;
+    uint32_t last_fail_code;
+    uint16_t struct_version;
+    uint16_t reserved;
+    uint32_t crc;
+} __attribute__((packed));
+
+/* Backend, implemented per platform. v1 uses TPM NV (src/boot_state_tpm.c). */
+int boot_state_backend_read(uint8_t *buf, uint32_t len);
+int boot_state_backend_write(const uint8_t *buf, uint32_t len);
+/* Write-locks the record until the next TPM reset, so the booted OS cannot
+ * rewrite it. */
+int boot_state_backend_lock(void);
+
+/* Load the persisted state. Returns one of the BOOT_STATE_* codes above. */
+int boot_state_load(struct boot_state *st);
+
+/* Called once an image has verified, immediately before handing off.
+ * Applies the rollback check, updates anchor and record, and persists. */
+void boot_state_on_boot(uint32_t booted_version);
+/* Lock the stored state against the OS without recording a boot (golden
+ * slot). Halts on failure with ANTI_ROLLBACK_HALT_ON_FAILURE. */
+void boot_state_lock(void);
+
+/* Called when the boot policy has decided no image may be booted. Records the
+ * failure so the evidence survives the power cycle. */
+void boot_state_on_failure(uint32_t fail_code);
+
+#endif /* BOOT_STATE_H */

include/tpm.h

@@ -40,6 +40,9 @@ extern WOLFTPM2_KEY     wolftpm_srk;
 #ifndef WOLFBOOT_TPM_SEAL_NV_BASE
     #define WOLFBOOT_TPM_SEAL_NV_BASE     0x01400300
 #endif
+#ifndef WOLFBOOT_TPM_BOOT_STATE_NV_BASE
+    #define WOLFBOOT_TPM_BOOT_STATE_NV_BASE 0x01400400
+#endif
 /* The PCR bank algorithm and its digest size must always agree. They used to
  * be defined together under a single #ifndef on the algorithm, which meant
  * overriding only WOLFBOOT_TPM_PCR_ALG left WOLFBOOT_TPM_PCR_DIG_SZ undefined

options.mk

@@ -57,6 +57,20 @@ ifeq ($(ACPI),1)
   CFLAGS+=-D"WOLFBOOT_ACPI"
 endif
 
+# TPM NV version floor and boot audit counters (see docs/Targets.md).
+# HALT_ON_FAILURE also halts when the TPM state cannot be read or locked.
+ifeq ($(ANTI_ROLLBACK),1)
+  ifeq ($(filter $(TARGET),x86_fsp_qemu kontron_vx3060_s2 nai_68int6),)
+    $(error ANTI_ROLLBACK=1 is only wired into the x86 FSP disk boot)
+  endif
+  CFLAGS+=-D"WOLFBOOT_ANTI_ROLLBACK"
+  # The backend is TPM NV (src/boot_state_tpm.c), so wolfTPM is required.
+  WOLFTPM:=1
+  ifeq ($(ANTI_ROLLBACK_HALT_ON_FAILURE),1)
+    CFLAGS+=-D"WOLFBOOT_ANTI_ROLLBACK_HALT_ON_FAILURE"
+  endif
+endif
+
 ifeq ($(USE_CLANG),1)
   ifeq ($(USE_GCC),1)
     $(error USE_CLANG=1 is incompatible with USE_GCC=1; set USE_GCC=0)