On Thu, May 04, 2023 at 02:50:21PM +0000, Ross Philipson wrote:
From: "Daniel P. Smith" <dpsmith@xxxxxxxxxxxxxxxxxxxx>
The Secure Launch platform module is a late init module. During the
init call, the TPM event log is read and measurements taken in the
early boot stub code are located. These measurements are extended
into the TPM PCRs using the mainline TPM kernel driver.
The platform module also registers the securityfs nodes to allow
access to TXT register fields on Intel along with the fetching of
and writing events to the late launch TPM log.
Signed-off-by: Daniel P. Smith <dpsmith@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: garnetgrimm <grimmg@xxxxxxxxxxxx>
Signed-off-by: Ross Philipson <ross.philipson@xxxxxxxxxx>
Hi Ross,
a few more items from my side.
...
diff --git a/arch/x86/kernel/slmodule.c b/arch/x86/kernel/slmodule.c
...
+/*
+ * Securityfs exposure
+ */
+struct memfile {
+ char *name;
+ void *addr;
+ size_t size;
+};
+
+static struct memfile sl_evtlog = {"eventlog", 0, 0};
I don't think the 0 fields are necessary above, memset will zero
any fields not explicitly set. But if you want to go that way, then
I think the first one should be NULL, as the addr field is a pointer.
+static void *txt_heap;
+static struct txt_heap_event_log_pointer2_1_element __iomem *evtlog20;
+static DEFINE_MUTEX(sl_evt_log_mutex);
+static ssize_t sl_evtlog_read(struct file *file, char __user *buf,
+ size_t count, loff_t *pos)
+{
+ ssize_t size;
+
+ if (!sl_evtlog.addr)
+ return 0;
+
+ mutex_lock(&sl_evt_log_mutex);
+ size = simple_read_from_buffer(buf, count, pos, sl_evtlog.addr,
+ sl_evtlog.size);
+ mutex_unlock(&sl_evt_log_mutex);
+
+ return size;
+}
+
+static ssize_t sl_evtlog_write(struct file *file, const char __user *buf,
+ size_t datalen, loff_t *ppos)
nit: the line above doesn't align to the '(' on the line before that.
+{
+ ssize_t result;
+ char *data;
+
+ if (!sl_evtlog.addr)
+ return 0;
+
+ /* No partial writes. */
+ result = -EINVAL;
+ if (*ppos != 0)
+ goto out;
+
+ data = memdup_user(buf, datalen);
+ if (IS_ERR(data)) {
+ result = PTR_ERR(data);
+ goto out;
+ }
+
+ mutex_lock(&sl_evt_log_mutex);
+ if (evtlog20)
+ result = tpm20_log_event(evtlog20, sl_evtlog.addr,
+ sl_evtlog.size, datalen, data);
Sparse says that the type of the first argument of tmp20_log_event is:
struct txt_heap_event_log_pointer2_1_element *
However, the type of evtlog20 is:
struct txt_heap_event_log_pointer2_1_element __iomem *
+ else
+ result = tpm12_log_event(sl_evtlog.addr, sl_evtlog.size,
+ datalen, data);
+ mutex_unlock(&sl_evt_log_mutex);
+
+ kfree(data);
+out:
+ return result;
+}
...
+static long slaunch_expose_securityfs(void)
+{
+ long ret = 0;
+ int i;
+
+ slaunch_dir = securityfs_create_dir("slaunch", NULL);
+ if (IS_ERR(slaunch_dir))
+ return PTR_ERR(slaunch_dir);
+
+ if (slaunch_get_flags() & SL_FLAG_ARCH_TXT) {
+ txt_dir = securityfs_create_dir("txt", slaunch_dir);
+ if (IS_ERR(txt_dir)) {
+ ret = PTR_ERR(txt_dir);
+ goto remove_slaunch;
+ }
+
+ for (i = 0; i < ARRAY_SIZE(sl_txt_files); i++) {
+ txt_entries[i] = securityfs_create_file(
+ sl_txt_files[i].name, 0440,
+ txt_dir, NULL,
+ sl_txt_files[i].fops);
+ if (IS_ERR(txt_entries[i])) {
+ ret = PTR_ERR(txt_entries[i]);
+ goto remove_files;
+ }
+ }
+
nit: no blank line here.
+ }
+
+ if (sl_evtlog.addr > 0) {
addr is a pointer. So perhaps:
if (sl_evtlog.addr) {
+ event_file = securityfs_create_file(
+ sl_evtlog.name, 0440,
+ slaunch_dir, NULL,
+ &sl_evtlog_ops);
+ if (IS_ERR(event_file)) {
+ ret = PTR_ERR(event_file);
+ goto remove_files;
+ }
+ }
+
+ return 0;
+
+remove_files:
+ if (slaunch_get_flags() & SL_FLAG_ARCH_TXT) {
+ while (--i >= 0)
+ securityfs_remove(txt_entries[i]);
+ securityfs_remove(txt_dir);
+ }
+remove_slaunch:
+ securityfs_remove(slaunch_dir);
+
+ return ret;
+}
...
+static void slaunch_intel_evtlog(void __iomem *txt)
+{
+ struct slr_entry_log_info *log_info;
+ struct txt_os_mle_data *params;
+ struct slr_table *slrt;
+ void *os_sinit_data;
+ u64 base, size;
+
+ memcpy_fromio(&base, txt + TXT_CR_HEAP_BASE, sizeof(base));
+ memcpy_fromio(&size, txt + TXT_CR_HEAP_SIZE, sizeof(size));
+
+ /* now map TXT heap */
+ txt_heap = memremap(base, size, MEMREMAP_WB);
+ if (!txt_heap)
+ slaunch_txt_reset(txt,
+ "Error failed to memremap TXT heap\n",
+ SL_ERROR_HEAP_MAP);
nit: These lines are not aligned to the opening '('
+
+ params = (struct txt_os_mle_data *)txt_os_mle_data_start(txt_heap);
+
+ /* Get the SLRT and remap it */
+ slrt = memremap(params->slrt, sizeof(*slrt), MEMREMAP_WB);
+ if (!slrt)
+ slaunch_txt_reset(txt,
+ "Error failed to memremap SLR Table\n",
+ SL_ERROR_SLRT_MAP);
+ size = slrt->size;
+ memunmap(slrt);
+
+ slrt = memremap(params->slrt, size, MEMREMAP_WB);
+ if (!slrt)
+ slaunch_txt_reset(txt,
+ "Error failed to memremap SLR Table\n",
+ SL_ERROR_SLRT_MAP);
+
+ log_info = (struct slr_entry_log_info *)
+ slr_next_entry_by_tag(slrt, NULL, SLR_ENTRY_LOG_INFO);
+ if (!log_info)
+ slaunch_txt_reset(txt,
+ "Error failed to memremap SLR Table\n",
+ SL_ERROR_SLRT_MISSING_ENTRY);
+
+ sl_evtlog.size = log_info->size;
+ sl_evtlog.addr = memremap(log_info->addr, log_info->size,
+ MEMREMAP_WB);
+ if (!sl_evtlog.addr)
+ slaunch_txt_reset(txt,
+ "Error failed to memremap TPM event log\n",
+ SL_ERROR_EVENTLOG_MAP);
+
+ memunmap(slrt);
+
+ /* Determine if this is TPM 1.2 or 2.0 event log */
+ if (memcmp(sl_evtlog.addr + sizeof(struct tcg_pcr_event),
+ TCG_SPECID_SIG, sizeof(TCG_SPECID_SIG)))
+ return; /* looks like it is not 2.0 */
+
+ /* For TPM 2.0 logs, the extended heap element must be located */
+ os_sinit_data = txt_os_sinit_data_start(txt_heap);
+
The return type of tmp20_find_lot2_1_element() is:
struct txt_heap_event_log_pointer2_1_element *
However, the type of evtlog20 is:
struct txt_heap_event_log_pointer2_1_element __iomem *
+ evtlog20 = tpm20_find_log2_1_element(os_sinit_data);
+
+ /*
+ * If this fails, things are in really bad shape. Any attempt to write
+ * events to the log will fail.
+ */
+ if (!evtlog20)
+ slaunch_txt_reset(txt,
+ "Error failed to find TPM20 event log element\n",
+ SL_ERROR_TPM_INVALID_LOG20);
+}
+
+static void slaunch_tpm20_extend_event(struct tpm_chip *tpm, void __iomem *txt,
+ struct tcg_pcr_event2_head *event)
+{
+ u16 *alg_id_field = (u16 *)((u8 *)event +
+ sizeof(struct tcg_pcr_event2_head));
+ struct tpm_digest *digests;
+ u8 *dptr;
+ int ret;
+ u32 i, j;
+
+ digests = kcalloc(tpm->nr_allocated_banks, sizeof(*digests),
+ GFP_KERNEL);
+ if (!digests)
+ slaunch_txt_reset(txt,
+ "Failed to allocate array of digests\n",
+ SL_ERROR_GENERIC);
+
+ for (i = 0; i < tpm->nr_allocated_banks; i++)
+ digests[i].alg_id = tpm->allocated_banks[i].alg_id;
+
+
nit: one blank line is enough.
+ /* Early SL code ensured there was a max count of 2 digests */
+ for (i = 0; i < event->count; i++) {
+ dptr = (u8 *)alg_id_field + sizeof(u16);
+
+ for (j = 0; j < tpm->nr_allocated_banks; j++) {
+ if (digests[j].alg_id != *alg_id_field)
+ continue;
+
+ switch (digests[j].alg_id) {
+ case TPM_ALG_SHA256:
+ memcpy(&digests[j].digest[0], dptr,
+ SHA256_DIGEST_SIZE);
+ alg_id_field = (u16 *)((u8 *)alg_id_field +
+ SHA256_DIGEST_SIZE + sizeof(u16));
+ break;
+ case TPM_ALG_SHA1:
+ memcpy(&digests[j].digest[0], dptr,
+ SHA1_DIGEST_SIZE);
+ alg_id_field = (u16 *)((u8 *)alg_id_field +
+ SHA1_DIGEST_SIZE + sizeof(u16));
+ default:
+ break;
+ }
+ }
+ }
+
+ ret = tpm_pcr_extend(tpm, event->pcr_idx, digests);
+ if (ret) {
+ pr_err("Error extending TPM20 PCR, result: %d\n", ret);
+ slaunch_txt_reset(txt,
+ "Failed to extend TPM20 PCR\n",
+ SL_ERROR_TPM_EXTEND);
+ }
+
+ kfree(digests);
+}
+
+static void slaunch_tpm20_extend(struct tpm_chip *tpm, void __iomem *txt)
+{
+ struct tcg_pcr_event *event_header;
+ struct tcg_pcr_event2_head *event;
+ int start = 0, end = 0, size;
+
+ event_header = (struct tcg_pcr_event *)(sl_evtlog.addr +
+ evtlog20->first_record_offset);
Sparse says that evtlog20 shouldn't be dereferenced because it
has a __iomem attribute.
+
+ /* Skip first TPM 1.2 event to get to first TPM 2.0 event */
+ event = (struct tcg_pcr_event2_head *)((u8 *)event_header +
+ sizeof(struct tcg_pcr_event) +
+ event_header->event_size);
+
+ while ((void *)event < sl_evtlog.addr + evtlog20->next_record_offset) {
Ditto.
+ size = __calc_tpm2_event_size(event, event_header, false);
+ if (!size)
+ slaunch_txt_reset(txt,
+ "TPM20 invalid event in event log\n",
+ SL_ERROR_TPM_INVALID_EVENT);
+
+ /*
+ * Marker events indicate where the Secure Launch early stub
+ * started and ended adding post launch events.
+ */
+ if (event->event_type == TXT_EVTYPE_SLAUNCH_END) {
+ end = 1;
+ break;
+ } else if (event->event_type == TXT_EVTYPE_SLAUNCH_START) {
+ start = 1;
+ goto next;
+ }
+
+ if (start)
+ slaunch_tpm20_extend_event(tpm, txt, event);
+
+next:
+ event = (struct tcg_pcr_event2_head *)((u8 *)event + size);
+ }
+
+ if (!start || !end)
+ slaunch_txt_reset(txt,
+ "Missing start or end events for extending TPM20 PCRs\n",
+ SL_ERROR_TPM_EXTEND);
+}
...
+static void slaunch_pcr_extend(void __iomem *txt)
+{
+ struct tpm_chip *tpm;
+
+ tpm = tpm_default_chip();
+ if (!tpm)
+ slaunch_txt_reset(txt,
+ "Could not get default TPM chip\n",
+ SL_ERROR_TPM_INIT);
+ if (evtlog20)
+ slaunch_tpm20_extend(tpm, txt);
+ else
+ slaunch_tpm12_extend(tpm, txt);
+}
+
+static int __init slaunch_module_init(void)
+{
+ void __iomem *txt;
+
+ /* Check to see if Secure Launch happened */
+ if ((slaunch_get_flags() & (SL_FLAG_ACTIVE|SL_FLAG_ARCH_TXT)) !=
+ (SL_FLAG_ACTIVE|SL_FLAG_ARCH_TXT))
nit: spaces around '|'
Likewise elsewhere in this patch.
+ return 0;
+
+ txt = ioremap(TXT_PRIV_CONFIG_REGS_BASE, TXT_NR_CONFIG_PAGES *
+ PAGE_SIZE);
+ if (!txt)
+ panic("Error ioremap of TXT priv registers\n");
+
+ /* Only Intel TXT is supported at this point */
+ slaunch_intel_evtlog(txt);
+
+ slaunch_pcr_extend(txt);
+
+ iounmap(txt);
+
+ return slaunch_expose_securityfs();
+}
...
