From: Ge Yang yangge1116@126.com
Since commit d228814b1913 ("efi/libstub: Add get_event_log() support for CC platforms") reuses TPM2 support code for the CC platforms, when launching a TDX virtual machine with coco measurement enabled, the following error log is generated:
[Firmware Bug]: Failed to parse event in TPM Final Events Log
Call Trace: efi_config_parse_tables() efi_tpm_eventlog_init() tpm2_calc_event_log_size() __calc_tpm2_event_size()
The pcr_idx value in the Intel TDX log header is 1, causing the function __calc_tpm2_event_size() to fail to recognize the log header, ultimately leading to the "Failed to parse event in TPM Final Events Log" error.
According to UEFI Specification 2.10, Section 38.4.1: For TDX, TPM PCR 0 maps to MRTD, so the log header uses TPM PCR 1 instead. To successfully parse the TDX event log header, the check for a pcr_idx value of 0 must be skipped.
According to Table 6 in Section 10.2.1 of the TCG PC Client Specification, the index field does not require the PCR index to be fixed at zero. Therefore, skipping the check for a pcr_idx value of 0 for CC platforms is safe.
Link: https://uefi.org/specs/UEFI/2.10/38_Confidential_Computing.html#intel-trust-... Link: https://trustedcomputinggroup.org/wp-content/uploads/TCG_PCClient_PFP_r1p05_... Fixes: d228814b1913 ("efi/libstub: Add get_event_log() support for CC platforms") Signed-off-by: Ge Yang yangge1116@126.com Cc: stable@vger.kernel.org ---
V4: - remove cc_platform_has(CC_ATTR_GUEST_STATE_ENCRYPT) suggested by Ard
V3: - fix build error
V2: - limit the fix for CC only suggested by Jarkko and Sathyanarayanan
drivers/char/tpm/eventlog/tpm2.c | 6 +++++- drivers/firmware/efi/efi.c | 8 ++++++-- drivers/firmware/efi/libstub/tpm.c | 13 +++++++++---- drivers/firmware/efi/tpm.c | 36 ++++++++++++++++++++---------------- include/linux/efi.h | 4 +++- include/linux/tpm_eventlog.h | 14 +++++++++++--- 6 files changed, 54 insertions(+), 27 deletions(-)
diff --git a/drivers/char/tpm/eventlog/tpm2.c b/drivers/char/tpm/eventlog/tpm2.c index 37a0580..e9484fd 100644 --- a/drivers/char/tpm/eventlog/tpm2.c +++ b/drivers/char/tpm/eventlog/tpm2.c @@ -36,7 +36,11 @@ static size_t calc_tpm2_event_size(struct tcg_pcr_event2_head *event, struct tcg_pcr_event *event_header) { - return __calc_tpm2_event_size(event, event_header, false); + /* + * This function is only used by TPM2 and will not be used by CC. + * Therefore, the argument is_cc_event is set to 0. + */ + return __calc_tpm2_event_size(event, event_header, false, 0); }
static void *tpm2_bios_measurements_start(struct seq_file *m, loff_t *pos) diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index e57bff7..954b8f7 100644 --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -45,6 +45,7 @@ struct efi __read_mostly efi = { .esrt = EFI_INVALID_TABLE_ADDR, .tpm_log = EFI_INVALID_TABLE_ADDR, .tpm_final_log = EFI_INVALID_TABLE_ADDR, + .cc_final_log = EFI_INVALID_TABLE_ADDR, #ifdef CONFIG_LOAD_UEFI_KEYS .mokvar_table = EFI_INVALID_TABLE_ADDR, #endif @@ -613,7 +614,7 @@ static const efi_config_table_type_t common_tables[] __initconst = { {LINUX_EFI_RANDOM_SEED_TABLE_GUID, &efi_rng_seed, "RNG" }, {LINUX_EFI_TPM_EVENT_LOG_GUID, &efi.tpm_log, "TPMEventLog" }, {EFI_TCG2_FINAL_EVENTS_TABLE_GUID, &efi.tpm_final_log, "TPMFinalLog" }, - {EFI_CC_FINAL_EVENTS_TABLE_GUID, &efi.tpm_final_log, "CCFinalLog" }, + {EFI_CC_FINAL_EVENTS_TABLE_GUID, &efi.cc_final_log, "CCFinalLog" }, {LINUX_EFI_MEMRESERVE_TABLE_GUID, &mem_reserve, "MEMRESERVE" }, {LINUX_EFI_INITRD_MEDIA_GUID, &initrd, "INITRD" }, {EFI_RT_PROPERTIES_TABLE_GUID, &rt_prop, "RTPROP" }, @@ -752,7 +753,10 @@ int __init efi_config_parse_tables(const efi_config_table_t *config_tables, if (!IS_ENABLED(CONFIG_X86_32) && efi_enabled(EFI_MEMMAP)) efi_memattr_init();
- efi_tpm_eventlog_init(); + if (efi.tpm_final_log != EFI_INVALID_TABLE_ADDR) + efi_tcg2_eventlog_init(&efi.tpm_log, &efi.tpm_final_log, 0); + else if (efi.cc_final_log != EFI_INVALID_TABLE_ADDR) + efi_tcg2_eventlog_init(&efi.tpm_log, &efi.cc_final_log, 1);
if (mem_reserve != EFI_INVALID_TABLE_ADDR) { unsigned long prsv = mem_reserve; diff --git a/drivers/firmware/efi/libstub/tpm.c b/drivers/firmware/efi/libstub/tpm.c index a5c6c4f..9728060 100644 --- a/drivers/firmware/efi/libstub/tpm.c +++ b/drivers/firmware/efi/libstub/tpm.c @@ -50,7 +50,8 @@ void efi_enable_reset_attack_mitigation(void) static void efi_retrieve_tcg2_eventlog(int version, efi_physical_addr_t log_location, efi_physical_addr_t log_last_entry, efi_bool_t truncated, - struct efi_tcg2_final_events_table *final_events_table) + struct efi_tcg2_final_events_table *final_events_table, + bool is_cc_event) { efi_guid_t linux_eventlog_guid = LINUX_EFI_TPM_EVENT_LOG_GUID; efi_status_t status; @@ -87,7 +88,8 @@ static void efi_retrieve_tcg2_eventlog(int version, efi_physical_addr_t log_loca last_entry_size = __calc_tpm2_event_size((void *)last_entry_addr, (void *)(long)log_location, - false); + false, + is_cc_event); } else { last_entry_size = sizeof(struct tcpa_event) + ((struct tcpa_event *) last_entry_addr)->event_size; @@ -123,7 +125,8 @@ static void efi_retrieve_tcg2_eventlog(int version, efi_physical_addr_t log_loca header = data + offset + final_events_size; event_size = __calc_tpm2_event_size(header, (void *)(long)log_location, - false); + false, + is_cc_event); /* If calc fails this is a malformed log */ if (!event_size) break; @@ -157,6 +160,7 @@ void efi_retrieve_eventlog(void) efi_tcg2_protocol_t *tpm2 = NULL; efi_bool_t truncated; efi_status_t status; + bool is_cc_event = false;
status = efi_bs_call(locate_protocol, &tpm2_guid, NULL, (void **)&tpm2); if (status == EFI_SUCCESS) { @@ -186,11 +190,12 @@ void efi_retrieve_eventlog(void)
final_events_table = get_efi_config_table(EFI_CC_FINAL_EVENTS_TABLE_GUID); + is_cc_event = true; }
if (status != EFI_SUCCESS || !log_location) return;
efi_retrieve_tcg2_eventlog(version, log_location, log_last_entry, - truncated, final_events_table); + truncated, final_events_table, is_cc_event); } diff --git a/drivers/firmware/efi/tpm.c b/drivers/firmware/efi/tpm.c index cdd4310..d79291d 100644 --- a/drivers/firmware/efi/tpm.c +++ b/drivers/firmware/efi/tpm.c @@ -16,14 +16,16 @@ int efi_tpm_final_log_size; EXPORT_SYMBOL(efi_tpm_final_log_size);
-static int __init tpm2_calc_event_log_size(void *data, int count, void *size_info) +static int __init tpm2_calc_event_log_size(void *data, int count, + void *size_info, bool is_cc_event) { struct tcg_pcr_event2_head *header; u32 event_size, size = 0;
while (count > 0) { header = data + size; - event_size = __calc_tpm2_event_size(header, size_info, true); + event_size = __calc_tpm2_event_size(header, size_info, true, + is_cc_event); if (event_size == 0) return -1; size += event_size; @@ -36,7 +38,8 @@ static int __init tpm2_calc_event_log_size(void *data, int count, void *size_inf /* * Reserve the memory associated with the TPM Event Log configuration table. */ -int __init efi_tpm_eventlog_init(void) +int __init efi_tcg2_eventlog_init(unsigned long *log, unsigned long *final_log, + bool is_cc_event) { struct linux_efi_tpm_eventlog *log_tbl; struct efi_tcg2_final_events_table *final_tbl; @@ -44,7 +47,7 @@ int __init efi_tpm_eventlog_init(void) int final_tbl_size; int ret = 0;
- if (efi.tpm_log == EFI_INVALID_TABLE_ADDR) { + if (*log == EFI_INVALID_TABLE_ADDR) { /* * We can't calculate the size of the final events without the * first entry in the TPM log, so bail here. @@ -52,23 +55,23 @@ int __init efi_tpm_eventlog_init(void) return 0; }
- log_tbl = early_memremap(efi.tpm_log, sizeof(*log_tbl)); + log_tbl = early_memremap(*log, sizeof(*log_tbl)); if (!log_tbl) { pr_err("Failed to map TPM Event Log table @ 0x%lx\n", - efi.tpm_log); - efi.tpm_log = EFI_INVALID_TABLE_ADDR; + *log); + *log = EFI_INVALID_TABLE_ADDR; return -ENOMEM; }
tbl_size = sizeof(*log_tbl) + log_tbl->size; - if (memblock_reserve(efi.tpm_log, tbl_size)) { + if (memblock_reserve(*log, tbl_size)) { pr_err("TPM Event Log memblock reserve fails (0x%lx, 0x%x)\n", - efi.tpm_log, tbl_size); + *log, tbl_size); ret = -ENOMEM; goto out; }
- if (efi.tpm_final_log == EFI_INVALID_TABLE_ADDR) { + if (*final_log == EFI_INVALID_TABLE_ADDR) { pr_info("TPM Final Events table not present\n"); goto out; } else if (log_tbl->version != EFI_TCG2_EVENT_LOG_FORMAT_TCG_2) { @@ -76,25 +79,26 @@ int __init efi_tpm_eventlog_init(void) goto out; }
- final_tbl = early_memremap(efi.tpm_final_log, sizeof(*final_tbl)); + final_tbl = early_memremap(*final_log, sizeof(*final_tbl));
if (!final_tbl) { pr_err("Failed to map TPM Final Event Log table @ 0x%lx\n", - efi.tpm_final_log); - efi.tpm_final_log = EFI_INVALID_TABLE_ADDR; + *final_log); + *final_log = EFI_INVALID_TABLE_ADDR; ret = -ENOMEM; goto out; }
final_tbl_size = 0; if (final_tbl->nr_events != 0) { - void *events = (void *)efi.tpm_final_log + void *events = (void *)*final_log + sizeof(final_tbl->version) + sizeof(final_tbl->nr_events);
final_tbl_size = tpm2_calc_event_log_size(events, final_tbl->nr_events, - log_tbl->log); + log_tbl->log, + is_cc_event); }
if (final_tbl_size < 0) { @@ -103,7 +107,7 @@ int __init efi_tpm_eventlog_init(void) goto out_calc; }
- memblock_reserve(efi.tpm_final_log, + memblock_reserve(*final_log, final_tbl_size + sizeof(*final_tbl)); efi_tpm_final_log_size = final_tbl_size;
diff --git a/include/linux/efi.h b/include/linux/efi.h index 7d63d1d..71efec0 100644 --- a/include/linux/efi.h +++ b/include/linux/efi.h @@ -642,6 +642,7 @@ extern struct efi { unsigned long esrt; /* ESRT table */ unsigned long tpm_log; /* TPM2 Event Log table */ unsigned long tpm_final_log; /* TPM2 Final Events Log table */ + unsigned long cc_final_log; /* CC Final Events Log table */ unsigned long mokvar_table; /* MOK variable config table */ unsigned long coco_secret; /* Confidential computing secret table */ unsigned long unaccepted; /* Unaccepted memory table */ @@ -1209,7 +1210,8 @@ struct linux_efi_tpm_eventlog { u8 log[]; };
-extern int efi_tpm_eventlog_init(void); +extern int efi_tcg2_eventlog_init(unsigned long *log, unsigned long *final_log, + bool is_cc_event);
struct efi_tcg2_final_events_table { u64 version; diff --git a/include/linux/tpm_eventlog.h b/include/linux/tpm_eventlog.h index 891368e..b3380c9 100644 --- a/include/linux/tpm_eventlog.h +++ b/include/linux/tpm_eventlog.h @@ -143,6 +143,7 @@ struct tcg_algorithm_info { * @event: Pointer to the event whose size should be calculated * @event_header: Pointer to the initial event containing the digest lengths * @do_mapping: Whether or not the event needs to be mapped + * @is_cc_event: Whether or not the event is from a CC platform * * The TPM2 event log format can contain multiple digests corresponding to * separate PCR banks, and also contains a variable length of the data that @@ -159,7 +160,8 @@ struct tcg_algorithm_info {
static __always_inline u32 __calc_tpm2_event_size(struct tcg_pcr_event2_head *event, struct tcg_pcr_event *event_header, - bool do_mapping) + bool do_mapping, + bool is_cc_event) { struct tcg_efi_specid_event_head *efispecid; struct tcg_event_field *event_field; @@ -201,8 +203,14 @@ static __always_inline u32 __calc_tpm2_event_size(struct tcg_pcr_event2_head *ev count = event->count; event_type = event->event_type;
- /* Verify that it's the log header */ - if (event_header->pcr_idx != 0 || + /* + * Verify that it's the log header. According to the TCG PC Client + * Specification, when identifying a log header, the check for a + * pcr_idx value of 0 is not required. For CC platforms, skipping + * this check during log header is necessary; otherwise, the CC + * platform's log header may fail to be recognized. + */ + if ((!is_cc_event && event_header->pcr_idx != 0) || event_header->event_type != NO_ACTION || memcmp(event_header->digest, zero_digest, sizeof(zero_digest))) { size = 0;