@@ -80,6 +80,8 @@ int tpm_read_log_efi(struct tpm_chip *chip)
goto out;
}
+ efi_tpm_final_log_size -= log_tbl->final_events_early_size;
+
tmp = krealloc(log->bios_event_log,
log_size + efi_tpm_final_log_size,
GFP_KERNEL);
@@ -90,8 +92,15 @@ int tpm_read_log_efi(struct tpm_chip *chip)
}
log->bios_event_log = tmp;
+
+ /*
+ * Copy any of the final events log that didn't also end up in the
+ * main log. Events can be logged in both if events are generated
+ * between GetEventLog() and ExitBootServices().
+ */
memcpy((void *)log->bios_event_log + log_size,
- final_tbl->events, efi_tpm_final_log_size);
+ final_tbl->events + log_tbl->final_events_early_size,
+ efi_tpm_final_log_size);
log->bios_event_log_end = log->bios_event_log +
log_size + efi_tpm_final_log_size;
@@ -926,3 +926,18 @@ efi_status_t efi_exit_boot_services(efi_system_table_t *sys_table_arg,
fail:
return status;
}
+
+void *get_efi_config_table(efi_system_table_t *sys_table, efi_guid_t guid)
+{
+ efi_config_table_t *tables = (efi_config_table_t *)sys_table->tables;
+ int i;
+
+ for (i = 0; i < sys_table->nr_tables; i++) {
+ if (efi_guidcmp(tables[i].guid, guid) != 0)
+ continue;
+
+ return (void *)tables[i].table;
+ }
+
+ return NULL;
+}
@@ -65,6 +65,8 @@ efi_status_t check_platform_features(efi_system_table_t *sys_table_arg);
efi_status_t efi_random_get_seed(efi_system_table_t *sys_table_arg);
+void *get_efi_config_table(efi_system_table_t *sys_table, efi_guid_t guid);
+
/* Helper macros for the usual case of using simple C variables: */
#ifndef fdt_setprop_inplace_var
#define fdt_setprop_inplace_var(fdt, node_offset, name, var) \
@@ -363,26 +363,17 @@ efi_status_t allocate_new_fdt_and_exit_boot(efi_system_table_t *sys_table,
void *get_fdt(efi_system_table_t *sys_table, unsigned long *fdt_size)
{
- efi_guid_t fdt_guid = DEVICE_TREE_GUID;
- efi_config_table_t *tables;
- int i;
+ void *fdt;
- tables = (efi_config_table_t *)sys_table->tables;
+ fdt = get_efi_config_table(sys_table, DEVICE_TREE_GUID);
- for (i = 0; i < sys_table->nr_tables; i++) {
- void *fdt;
+ if (!fdt)
+ return NULL;
- if (efi_guidcmp(tables[i].guid, fdt_guid) != 0)
- continue;
-
- fdt = (void *)tables[i].table;
- if (fdt_check_header(fdt) != 0) {
- pr_efi_err(sys_table, "Invalid header detected on UEFI supplied FDT, ignoring ...\n");
- return NULL;
- }
- *fdt_size = fdt_totalsize(fdt);
- return fdt;
+ if (fdt_check_header(fdt) != 0) {
+ pr_efi_err(sys_table, "Invalid header detected on UEFI supplied FDT, ignoring ...\n");
+ return NULL;
}
-
- return NULL;
+ *fdt_size = fdt_totalsize(fdt);
+ return fdt;
}
@@ -64,11 +64,13 @@ void efi_retrieve_tpm2_eventlog(efi_system_table_t *sys_table_arg)
efi_status_t status;
efi_physical_addr_t log_location = 0, log_last_entry = 0;
struct linux_efi_tpm_eventlog *log_tbl = NULL;
+ struct efi_tcg2_final_events_table *final_events_table;
unsigned long first_entry_addr, last_entry_addr;
size_t log_size, last_entry_size;
efi_bool_t truncated;
int version = EFI_TCG2_EVENT_LOG_FORMAT_TCG_2;
void *tcg2_protocol = NULL;
+ int final_events_size = 0;
status = efi_call_early(locate_protocol, &tcg2_guid, NULL,
&tcg2_protocol);
@@ -134,8 +136,36 @@ void efi_retrieve_tpm2_eventlog(efi_system_table_t *sys_table_arg)
return;
}
+ /*
+ * Figure out whether any events have already been logged to the
+ * final events structure, and if so how much space they take up
+ */
+ final_events_table = get_efi_config_table(sys_table_arg,
+ LINUX_EFI_TPM_FINAL_LOG_GUID);
+ if (final_events_table && final_events_table->nr_events) {
+ struct tcg_pcr_event2_head *header;
+ int offset;
+ void *data;
+ int event_size;
+ int i = final_events_table->nr_events;
+
+ data = (void *)final_events_table;
+ offset = sizeof(final_events_table->version) +
+ sizeof(final_events_table->nr_events);
+
+ while (i) {
+ header = data + offset + final_events_size;
+ event_size = __calc_tpm2_event_size(header,
+ (void *)(long)log_location,
+ false);
+ final_events_size += event_size;
+ i--;
+ }
+ }
+
memset(log_tbl, 0, sizeof(*log_tbl) + log_size);
log_tbl->size = log_size;
+ log_tbl->final_events_early_size = final_events_size;
log_tbl->version = version;
memcpy(log_tbl->log, (void *) first_entry_addr, log_size);
@@ -76,7 +76,7 @@ int __init efi_tpm_eventlog_init(void)
goto out;
}
- tbl_size = tpm2_calc_event_log_size(efi.tpm_final_log
+ tbl_size = tpm2_calc_event_log_size((void *)efi.tpm_final_log
+ sizeof(final_tbl->version)
+ sizeof(final_tbl->nr_events),
final_tbl->nr_events,
@@ -1703,6 +1703,7 @@ struct linux_efi_random_seed {
struct linux_efi_tpm_eventlog {
u32 size;
+ u32 final_events_early_size;
u8 version;
u8 log[];
};
After the first call to GetEventLog() on UEFI systems using the TCG2 crypto agile log format, any further log events (other than those triggered by ExitBootServices()) will be logged in both the main log and also in the Final Events Log. While the kernel only calls GetEventLog() immediately before ExitBootServices(), we can't control whether earlier parts of the boot process have done so. This will result in log entries that exist in both logs, and so the current approach of simply appending the Final Event Log to the main log will result in events being duplicated. We can avoid this problem by looking at the size of the Final Event Log just before we call ExitBootServices() and exporting this to the main kernel. The kernel can then skip over all events that occured before ExitBootServices() and only append events that were not also logged to the main log. Signed-off-by: Matthew Garrett <mjg59@google.com> Reported-by: Joe Richey <joerichey@google.com> Suggested-by: Joe Richey <joerichey@google.com> --- drivers/char/tpm/eventlog/efi.c | 11 ++++++- .../firmware/efi/libstub/efi-stub-helper.c | 15 ++++++++++ drivers/firmware/efi/libstub/efistub.h | 2 ++ drivers/firmware/efi/libstub/fdt.c | 27 ++++++----------- drivers/firmware/efi/libstub/tpm.c | 30 +++++++++++++++++++ drivers/firmware/efi/tpm.c | 2 +- include/linux/efi.h | 1 + 7 files changed, 68 insertions(+), 20 deletions(-)