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Add recovery mode protection to new NVRAM locking scheme.

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Also fix the TPM initialization.

Review URL: http://codereview.chromium.org/2344002
This commit is contained in:
Luigi Semenzato
2010-05-28 10:34:31 -07:00
parent 262668fcf3
commit 52a8d2df06
7 changed files with 187 additions and 113 deletions
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35
tests/rollback_index_mock.c
View File

@@ -21,41 +21,32 @@ void SetupTPM(void) {
#endif
}
uint16_t GetStoredVersion(int type) {
void GetStoredVersions(int type, uint16_t* key_version, uint16_t* version) {
switch (type) {
case FIRMWARE_KEY_VERSION:
return g_firmware_key_version;
case FIRMWARE_VERSIONS:
*key_version = g_firmware_key_version;
*version = g_firmware_version;
break;
case FIRMWARE_VERSION:
return g_firmware_version;
break;
case KERNEL_KEY_VERSION:
return g_kernel_key_version;
break;
case KERNEL_VERSION:
return g_kernel_version;
case KERNEL_VERSIONS:
*key_version = g_kernel_key_version;
*version = g_kernel_version;
break;
}
return 0;
}
int WriteStoredVersion(int type, uint16_t version) {
int WriteStoredVersions(int type, uint16_t key_version, uint16_t version) {
switch (type) {
case FIRMWARE_KEY_VERSION:
g_firmware_key_version = version;
break;
case FIRMWARE_VERSION:
case FIRMWARE_VERSIONS:
g_firmware_key_version = key_version;
g_firmware_version = version;
break;
case KERNEL_KEY_VERSION:
g_kernel_key_version = version;
break;
case KERNEL_VERSION:
case KERNEL_VERSIONS:
g_kernel_key_version = key_version;
g_kernel_version = version;
break;
}
#ifndef NDEBUG
debug("Rollback Index Library Mock: Stored Version written.\n");
debug("Rollback Index Library Mock: Stored Versions written.\n");
#endif
return 1;
}

20
vboot_firmware/include/rollback_index.h
View File

@@ -17,20 +17,20 @@ extern uint16_t g_kernel_key_version;
extern uint16_t g_kernel_version;
/* Rollback version types. */
#define FIRMWARE_KEY_VERSION 0
#define FIRMWARE_VERSION 1
#define KERNEL_KEY_VERSION 2
#define KERNEL_VERSION 3
#define FIRMWARE_VERSIONS 0
#define KERNEL_VERSIONS 1
/* TPM NVRAM location indices. */
#define FIRMWARE_KEY_VERSION_NV_INDEX 0x1001
#define FIRMWARE_VERSION_NV_INDEX 0x1002
#define KERNEL_KEY_VERSION_NV_INDEX 0x1003
#define KERNEL_VERSION_NV_INDEX 0x1004
#define FIRMWARE_VERSIONS_NV_INDEX 0x1001
#define KERNEL_VERSIONS_NV_INDEX 0x1002
#define TPM_IS_INITIALIZED_NV_INDEX 0x1003
#define KERNEL_VERSIONS_BACKUP_NV_INDEX 0x1004
#define KERNEL_BACKUP_IS_VALID_NV_INDEX 0x1005
void SetupTPM(void);
uint16_t GetStoredVersion(int type);
int WriteStoredVersion(int type, uint16_t version);
void GetStoredVersions(int type, uint16_t* key_version, uint16_t* version);
int WriteStoredVersions(int type, uint16_t key_version, uint16_t version);
void LockFirmwareVersions();
void LockKernelVersionsByLockingPP();

12
vboot_firmware/lib/firmware_image_fw.c
View File

@@ -252,6 +252,7 @@ int VerifyFirmwareDriver_f(uint8_t* root_key_blob,
uint8_t firmwareA_is_verified = 0; /* Whether firmwareA verify succeeded. */
uint32_t min_lversion; /* Minimum of firmware A and firmware lversion. */
uint32_t stored_lversion; /* Stored logical version in the TPM. */
uint16_t version, key_version; /* Temporary variables */
/* Initialize the TPM since we'll be reading the rollback indices. */
SetupTPM();
@@ -265,8 +266,8 @@ int VerifyFirmwareDriver_f(uint8_t* root_key_blob,
firmwareA_lversion = GetLogicalFirmwareVersion(verification_headerA);
firmwareB_lversion = GetLogicalFirmwareVersion(verification_headerB);
min_lversion = Min(firmwareA_lversion, firmwareB_lversion);
stored_lversion = CombineUint16Pair(GetStoredVersion(FIRMWARE_KEY_VERSION),
GetStoredVersion(FIRMWARE_VERSION));
GetStoredVersions(FIRMWARE_VERSIONS, &key_version, &version);
stored_lversion = CombineUint16Pair(key_version, version);
/* Always try FirmwareA first. */
if (VERIFY_FIRMWARE_SUCCESS == VerifyFirmware(root_key_blob,
verification_headerA,
@@ -280,10 +281,9 @@ int VerifyFirmwareDriver_f(uint8_t* root_key_blob,
if (VERIFY_FIRMWARE_SUCCESS == VerifyFirmware(root_key_blob,
verification_headerB,
firmwareB)) {
WriteStoredVersion(FIRMWARE_KEY_VERSION,
(uint16_t) (min_lversion >> 16));
WriteStoredVersion(FIRMWARE_VERSION,
(uint16_t) (min_lversion & 0x00FFFF));
WriteStoredVersions(FIRMWARE_VERSIONS,
(uint16_t) (min_lversion >> 16),
(uint16_t) (min_lversion & 0xFFFF));
stored_lversion = min_lversion; /* Update stored version as it's used
* later. */
}

2
vboot_firmware/lib/include/tss_constants.h
View File

@@ -24,6 +24,8 @@
#define TPM_LARGE_ENOUGH_COMMAND_SIZE 256 /* saves space in the firmware */
#define TPM_SUCCESS ((uint32_t)0x00000000)
#define TPM_E_BADINDEX ((uint32_t)0x00000002)
#define TPM_NV_INDEX0 ((uint32_t)0x00000000)
#define TPM_NV_INDEX_LOCK ((uint32_t)0xffffffff)
#define TPM_NV_PER_WRITE_STCLEAR (((uint32_t)1)<<14)

12
vboot_firmware/lib/kernel_image_fw.c
View File

@@ -397,6 +397,7 @@ int VerifyKernelDriver_f(uint8_t* firmware_key_blob,
kernel_entry* try_kernel[2]; /* Kernel in try order. */
int try_kernel_which[2]; /* Which corresponding kernel in the try order */
uint32_t try_kernel_lversion[2]; /* Their logical versions. */
uint16_t kernel_version, kernel_key_version; /* Temporary variables */
/* [kernel_to_boot] will eventually contain the boot path to follow
* and is returned to the caller. Initially, we set it to recovery. If
@@ -415,8 +416,8 @@ int VerifyKernelDriver_f(uint8_t* firmware_key_blob,
kernelA_lversion = GetLogicalKernelVersion(kernelA->kernel_blob);
kernelB_lversion = GetLogicalKernelVersion(kernelB->kernel_blob);
min_lversion = Min(kernelA_lversion, kernelB_lversion);
stored_lversion = CombineUint16Pair(GetStoredVersion(KERNEL_KEY_VERSION),
GetStoredVersion(KERNEL_VERSION));
GetStoredVersions(KERNEL_VERSIONS, &kernel_key_version, &kernel_version);
stored_lversion = CombineUint16Pair(kernel_key_version, kernel_version);
/* TODO(gauravsh): The kernel entries kernelA and kernelB come from the
* partition table - verify its signature/checksum before proceeding
@@ -464,10 +465,9 @@ int VerifyKernelDriver_f(uint8_t* firmware_key_blob,
if (VERIFY_KERNEL_SUCCESS == VerifyKernel(firmware_key_blob,
try_kernel[1]->kernel_blob,
dev_mode)) {
WriteStoredVersion(KERNEL_KEY_VERSION,
(uint16_t) (min_lversion >> 16));
WriteStoredVersion(KERNEL_VERSION,
(uint16_t) (min_lversion & 0xFFFF));
WriteStoredVersions(KERNEL_VERSIONS,
(uint16_t) (min_lversion >> 16),
(uint16_t) (min_lversion & 0xFFFF));
stored_lversion = min_lversion; /* Update stored version as it's
* used later. */
}

213
vboot_firmware/lib/rollback_index.c
View File

@@ -19,50 +19,138 @@ uint16_t g_firmware_version = 0;
uint16_t g_kernel_key_version = 0;
uint16_t g_kernel_version = 0;
static void InitializeSpaces(void) {
uint16_t zero = 0;
static int InitializeSpaces(void) {
uint32_t zero = 0;
uint32_t space_holder;
uint32_t firmware_perm = TPM_NV_PER_GLOBALLOCK | TPM_NV_PER_PPWRITE;
uint32_t kernel_perm = TPM_NV_PER_PPWRITE;
debug("Initializing spaces\n");
TlclSetNvLocked(); /* useful only the first time */
TlclDefineSpace(FIRMWARE_KEY_VERSION_NV_INDEX,
firmware_perm, sizeof(uint16_t));
TlclWrite(FIRMWARE_KEY_VERSION_NV_INDEX, (uint8_t*) &zero, sizeof(uint16_t));
if (TlclRead(TPM_IS_INITIALIZED_NV_INDEX,
(uint8_t*) &space_holder, sizeof(space_holder)) == TPM_SUCCESS) {
/* Spaces are already initialized, so this is an error */
return 0;
}
TlclDefineSpace(FIRMWARE_VERSION_NV_INDEX, firmware_perm, sizeof(uint16_t));
TlclWrite(FIRMWARE_VERSION_NV_INDEX, (uint8_t*) &zero, sizeof(uint16_t));
TlclSetNvLocked();
TlclDefineSpace(KERNEL_KEY_VERSION_NV_INDEX, kernel_perm, sizeof(uint16_t));
TlclWrite(KERNEL_KEY_VERSION_NV_INDEX, (uint8_t*) &zero, sizeof(uint16_t));
TlclDefineSpace(FIRMWARE_VERSIONS_NV_INDEX, firmware_perm, sizeof(uint32_t));
TlclWrite(FIRMWARE_VERSIONS_NV_INDEX, (uint8_t*) &zero, sizeof(uint32_t));
TlclDefineSpace(KERNEL_VERSION_NV_INDEX, kernel_perm, sizeof(uint16_t));
TlclWrite(KERNEL_VERSION_NV_INDEX, (uint8_t*) &zero, sizeof(uint16_t));
TlclDefineSpace(KERNEL_VERSIONS_NV_INDEX, kernel_perm, sizeof(uint32_t));
TlclWrite(KERNEL_VERSIONS_NV_INDEX, (uint8_t*) &zero, sizeof(uint32_t));
/* The space KERNEL_VERSIONS_BACKUP_NV_INDEX is used to protect the kernel
* versions when entering recovery mode. The content of space
* KERNEL_BACKUP_IS_VALID determines whether the backup value (1) or the
* regular value (0) should be trusted.
*/
TlclDefineSpace(KERNEL_VERSIONS_BACKUP_NV_INDEX,
firmware_perm, sizeof(uint32_t));
TlclWrite(KERNEL_VERSIONS_BACKUP_NV_INDEX,
(uint8_t*) &zero, sizeof(uint32_t));
TlclDefineSpace(KERNEL_BACKUP_IS_VALID_NV_INDEX,
firmware_perm, sizeof(uint32_t));
TlclWrite(KERNEL_BACKUP_IS_VALID_NV_INDEX,
(uint8_t*) &zero, sizeof(uint32_t));
/* The space TPM_IS_INITIALIZED_NV_INDEX is used to indicate that the TPM
* initialization has completed. Without it we cannot be sure that the last
* space to be created was also initialized (power could have been lost right
* after its creation).
*/
TlclDefineSpace(TPM_IS_INITIALIZED_NV_INDEX, firmware_perm, sizeof(uint32_t));
return 1;
}
static void EnterRecovery(void) {
/* Temporary recovery stub. Currently just initalizes spaces. */
InitializeSpaces();
/* Enters the recovery mode. If |unlocked| is true, there is some problem with
* the TPM, so do not attempt to do any more TPM operations, and particularly
* do not set bGlobalLock.
*/
static void EnterRecovery(int unlocked) {
uint32_t combined_versions;
uint32_t one = 1;
if (!unlocked) {
/* Saves the kernel versions and indicates that we should trust the saved
* ones.
*/
TlclRead(KERNEL_VERSIONS_NV_INDEX, (uint8_t*) &combined_versions,
sizeof(uint32_t));
TlclWrite(KERNEL_VERSIONS_BACKUP_NV_INDEX, (uint8_t*) &combined_versions,
sizeof(uint32_t));
TlclWrite(KERNEL_BACKUP_IS_VALID_NV_INDEX, (uint8_t*) &one,
sizeof(uint32_t));
/* Protects the firmware and backup kernel versions. */
LockFirmwareVersions();
}
debug("entering recovery mode");
/* and then what? */
}
static int GetTPMRollbackIndices(void) {
/* We just perform the reads, making sure they succeed. A failure means that
* the rollback index locations are some how messed up and we must jump to
* recovery */
if (TPM_SUCCESS != TlclRead(FIRMWARE_KEY_VERSION_NV_INDEX,
(uint8_t*) &g_firmware_key_version,
sizeof(g_firmware_key_version)) ||
TPM_SUCCESS != TlclRead(FIRMWARE_KEY_VERSION_NV_INDEX,
(uint8_t*) &g_firmware_key_version,
sizeof(g_firmware_key_version)) ||
TPM_SUCCESS != TlclRead(FIRMWARE_KEY_VERSION_NV_INDEX,
(uint8_t*) &g_firmware_key_version,
sizeof(g_firmware_key_version)) ||
TPM_SUCCESS != TlclRead(FIRMWARE_KEY_VERSION_NV_INDEX,
(uint8_t*) &g_firmware_key_version,
sizeof(g_firmware_key_version)))
uint32_t backup_is_valid;
uint32_t firmware_versions;
uint32_t kernel_versions;
if (TlclRead(KERNEL_BACKUP_IS_VALID_NV_INDEX, (uint8_t*) &backup_is_valid,
sizeof(uint32_t)) != TPM_SUCCESS) {
EnterRecovery(1);
}
if (backup_is_valid) {
/* We reach this path if the previous boot went into recovery mode and we
* made a copy of the kernel versions to protect them.
*/
uint32_t protected_combined_versions;
uint32_t unsafe_combined_versions;
uint32_t result;
uint32_t zero = 0;
if (TlclRead(KERNEL_VERSIONS_BACKUP_NV_INDEX,
(uint8_t*) &protected_combined_versions,
sizeof(uint32_t)) != TPM_SUCCESS) {
EnterRecovery(1);
}
result = TlclRead(KERNEL_VERSIONS_NV_INDEX,
(uint8_t*) &unsafe_combined_versions, sizeof(uint32_t));
if (result == TPM_E_BADINDEX) {
/* Jeez, someone removed the space. This is either hostile or extremely
* incompetent. Foo to them. Politeness and lack of an adequate
* character set prevent me from expressing my true feelings.
*/
TlclDefineSpace(KERNEL_VERSIONS_NV_INDEX, TPM_NV_PER_PPWRITE,
sizeof(uint32_t));
} else if (result != TPM_SUCCESS) {
EnterRecovery(1);
}
if (result == TPM_E_BADINDEX ||
protected_combined_versions != unsafe_combined_versions) {
TlclWrite(KERNEL_VERSIONS_NV_INDEX,
(uint8_t*) &protected_combined_versions, sizeof(uint32_t));
}
/* We recovered and now we can reset the BACKUP_IS_VALID flag.
*/
TlclWrite(KERNEL_BACKUP_IS_VALID_NV_INDEX, (uint8_t*) &zero, 0);
}
/* We perform the reads, making sure they succeed. A failure means that the
* rollback index locations are missing or somehow messed up. We let the
* caller deal with that.
*/
if (TPM_SUCCESS != TlclRead(FIRMWARE_VERSIONS_NV_INDEX,
(uint8_t*) &firmware_versions,
sizeof(firmware_versions)) ||
TPM_SUCCESS != TlclRead(KERNEL_VERSIONS_NV_INDEX,
(uint8_t*) &kernel_versions,
sizeof(kernel_versions)))
return 0;
g_firmware_key_version = firmware_versions >> 16;
g_firmware_version = firmware_versions && 0xffff;
g_kernel_key_version = kernel_versions >> 16;
g_kernel_version = kernel_versions && 0xffff;
return 1;
}
@@ -84,61 +172,52 @@ void SetupTPM(void) {
/* Check that the TPM is enabled and activated. */
if(TlclGetFlags(&disable, &deactivated) != TPM_SUCCESS) {
debug("failed to get TPM flags");
EnterRecovery();
EnterRecovery(1);
}
if (disable || deactivated) {
TlclSetEnable();
if (TlclSetDeactivated(0) != TPM_SUCCESS) {
debug("failed to activate TPM");
EnterRecovery();
EnterRecovery(1);
}
}
/* We expect this to fail the first time we run on a device, indicating that
* the TPM has not been initialized yet. */
if (!GetTPMRollbackIndices()) {
debug("failed to get rollback indices");
EnterRecovery();
if (!InitializeSpaces()) {
/* If InitializeSpaces() fails (possibly because it had been executed
* already), something is wrong. */
EnterRecovery(1);
}
}
}
uint16_t GetStoredVersion(int type) {
void GetStoredVersions(int type, uint16_t* key_version, uint16_t* version) {
switch (type) {
case FIRMWARE_KEY_VERSION:
return g_firmware_key_version;
case FIRMWARE_VERSIONS:
*key_version = g_firmware_key_version;
*version = g_firmware_version;
break;
case FIRMWARE_VERSION:
return g_firmware_version;
break;
case KERNEL_KEY_VERSION:
return g_kernel_key_version;
break;
case KERNEL_VERSION:
return g_kernel_version;
case KERNEL_VERSIONS:
*key_version = g_kernel_key_version;
*version = g_kernel_version;
break;
}
return 0;
}
int WriteStoredVersion(int type, uint16_t version) {
int WriteStoredVersions(int type, uint16_t key_version, uint16_t version) {
uint32_t combined_version = (key_version << 16) & version;
switch (type) {
case FIRMWARE_KEY_VERSION:
return (TPM_SUCCESS == TlclWrite(FIRMWARE_KEY_VERSION_NV_INDEX,
(uint8_t*) &version,
sizeof(uint16_t)));
case FIRMWARE_VERSIONS:
return (TPM_SUCCESS == TlclWrite(FIRMWARE_VERSIONS_NV_INDEX,
(uint8_t*) &combined_version,
sizeof(uint32_t)));
break;
case FIRMWARE_VERSION:
return (TPM_SUCCESS == TlclWrite(FIRMWARE_VERSION_NV_INDEX,
(uint8_t*) &version,
sizeof(uint16_t)));
break;
case KERNEL_KEY_VERSION:
return (TPM_SUCCESS == TlclWrite(KERNEL_KEY_VERSION_NV_INDEX,
(uint8_t*) &version,
sizeof(uint16_t)));
break;
case KERNEL_VERSION:
return (TPM_SUCCESS == TlclWrite(KERNEL_VERSION_NV_INDEX,
(uint8_t*) &version,
sizeof(uint16_t)));
case KERNEL_VERSIONS:
return (TPM_SUCCESS == TlclWrite(KERNEL_VERSIONS_NV_INDEX,
(uint8_t*) &combined_version,
sizeof(uint32_t)));
break;
}
return 0;
@@ -147,13 +226,13 @@ int WriteStoredVersion(int type, uint16_t version) {
void LockFirmwareVersions() {
if (TlclSetGlobalLock() != TPM_SUCCESS) {
debug("failed to set global lock");
EnterRecovery();
EnterRecovery(1);
}
}
void LockKernelVersionsByLockingPP() {
if (TlclLockPhysicalPresence() != TPM_SUCCESS) {
debug("failed to turn off PP");
EnterRecovery();
EnterRecovery(1);
}
}

6
vboot_firmware/linktest/main.c
View File

@@ -9,6 +9,8 @@
int main(void)
{
uint16_t x, y;
// cgptlib.h
GptInit(0);
GptNextKernelEntry(0, 0, 0);
@@ -36,8 +38,8 @@ int main(void)
// rollback_index.h
SetupTPM();
GetStoredVersion(0);
WriteStoredVersion(0, 0);
GetStoredVersions(0, &x, &y);
WriteStoredVersions(0, 0, 0);
LockFirmwareVersions();
LockKernelVersionsByLockingPP();