Support for BIOS interrupt handler

This patch implements the TCG BIOS interrupt handler 1ah. It is for
example used by trusted grub.

This patch adds an implementation of SHA1 (following NIST specs., IETF RFC 3147
and Wikipedia) for speeding up measurements of code. Trusted Grub for example
makes use of this interface and measures (calculates SHA1) of the Linux kernel
and initrd. Those files can be rather large and hunting their bytes through
the TIS interface as part of the int handler commands invoked by trusted grub
does take quite some time due to the many vmexits the interface is creating
(one per byte).

There is also a threshold for the size of data to hash (100k) below which
the TPM is used and above the internal faster SHA1 algorithm is used.

This patch for example enables trusted grub to interact with the TPM
and take additional measurements.

Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

1 files changed, 558 insertions, 13 deletions

diff --git a/src/tcgbios.c b/src/tcgbios.c
index 73ff1f37..c837ab64 100644
--- a/src/tcgbios.c
+++ b/src/tcgbios.c
@@ -22,6 +22,7 @@
 #include "output.h" // dprintf
 #include "std/acpi.h"  // RSDP_SIGNATURE, rsdt_descriptor
 #include "bregs.h" // struct bregs
+#include "sha1.h" // sha1
 
 
 static const u8 Startup_ST_CLEAR[2] = { 0x00, TPM_ST_CLEAR };
@@ -286,7 +287,7 @@ transmit(u8 locty, const struct iovec iovec[],
  * If a buffer is provided, the response will be copied into it.
  */
 static u32
-build_and_send_cmd_od(u32 ordinal, const u8 *append, u32 append_size,
+build_and_send_cmd_od(u8 locty, u32 ordinal, const u8 *append, u32 append_size,
                       u8 *resbuffer, u32 return_size, u32 *returnCode,
                       const u8 *otherdata, u32 otherdata_size,
                       enum tpmDurationType to_t)
@@ -298,7 +299,6 @@ build_and_send_cmd_od(u32 ordinal, const u8 *append, u32 append_size,
     u8 obuffer[MAX_RESPONSE_SIZE];
     struct tpm_req_header *trqh = (struct tpm_req_header *)ibuffer;
     struct tpm_rsp_header *trsh = (struct tpm_rsp_header *)obuffer;
-    u8 locty = 0;
     struct iovec iovec[3];
     u32 obuffer_len = sizeof(obuffer);
     u32 idx = 1;
@@ -325,7 +325,8 @@ build_and_send_cmd_od(u32 ordinal, const u8 *append, u32 append_size,
     memset(obuffer, 0x0, sizeof(obuffer));
 
     trqh->tag     = cpu_to_be16(0xc1);
-    trqh->totlen  = cpu_to_be32(TPM_REQ_HEADER_SIZE + append_size + otherdata_size);
+    trqh->totlen  = cpu_to_be32(TPM_REQ_HEADER_SIZE + append_size +
+                                otherdata_size);
     trqh->ordinal = cpu_to_be32(ordinal);
 
     if (append_size)
@@ -346,11 +347,11 @@ build_and_send_cmd_od(u32 ordinal, const u8 *append, u32 append_size,
 
 
 static u32
-build_and_send_cmd(u32 ordinal, const u8 *append, u32 append_size,
+build_and_send_cmd(u8 locty, u32 ordinal, const u8 *append, u32 append_size,
                    u8 *resbuffer, u32 return_size, u32 *returnCode,
                    enum tpmDurationType to_t)
 {
-    return build_and_send_cmd_od(ordinal, append, append_size,
+    return build_and_send_cmd_od(locty, ordinal, append, append_size,
                                  resbuffer, return_size, returnCode,
                                  NULL, 0, to_t);
 }
@@ -366,7 +367,7 @@ determine_timeouts(void)
     struct tpm_driver *td = &tpm_drivers[tpm_state.tpm_driver_to_use];
     u32 i;
 
-    rc = build_and_send_cmd(TPM_ORD_GetCapability,
+    rc = build_and_send_cmd(0, TPM_ORD_GetCapability,
                             GetCapability_Timeouts,
                             sizeof(GetCapability_Timeouts),
                             (u8 *)&timeouts,
@@ -379,7 +380,7 @@ determine_timeouts(void)
     if (rc || returnCode)
         goto err_exit;
 
-    rc = build_and_send_cmd(TPM_ORD_GetCapability,
+    rc = build_and_send_cmd(0, TPM_ORD_GetCapability,
                             GetCapability_Durations,
                             sizeof(GetCapability_Durations),
                             (u8 *)&durations,
@@ -434,7 +435,7 @@ tpm_startup(void)
         return TCG_GENERAL_ERROR;
 
     dprintf(DEBUG_tcg, "TCGBIOS: Starting with TPM_Startup(ST_CLEAR)\n");
-    rc = build_and_send_cmd(TPM_ORD_Startup,
+    rc = build_and_send_cmd(0, TPM_ORD_Startup,
                             Startup_ST_CLEAR, sizeof(Startup_ST_CLEAR),
                             NULL, 10, &returnCode, TPM_DURATION_TYPE_SHORT);
 
@@ -452,7 +453,7 @@ tpm_startup(void)
     if (rc || returnCode)
         goto err_exit;
 
-    rc = build_and_send_cmd(TPM_ORD_SelfTestFull, NULL, 0,
+    rc = build_and_send_cmd(0, TPM_ORD_SelfTestFull, NULL, 0,
                             NULL, 10, &returnCode, TPM_DURATION_TYPE_LONG);
 
     dprintf(DEBUG_tcg, "Return code from TPM_SelfTestFull = 0x%08x\n",
@@ -461,7 +462,7 @@ tpm_startup(void)
     if (rc || returnCode)
         goto err_exit;
 
-    rc = build_and_send_cmd(TSC_ORD_ResetEstablishmentBit, NULL, 0,
+    rc = build_and_send_cmd(3, TSC_ORD_ResetEstablishmentBit, NULL, 0,
                             NULL, 10, &returnCode, TPM_DURATION_TYPE_SHORT);
 
     dprintf(DEBUG_tcg, "Return code from TSC_ResetEstablishmentBit = 0x%08x\n",
@@ -510,14 +511,14 @@ tpm_leave_bios(void)
     if (!has_working_tpm())
         return TCG_GENERAL_ERROR;
 
-    rc = build_and_send_cmd(TPM_ORD_PhysicalPresence,
+    rc = build_and_send_cmd(0, TPM_ORD_PhysicalPresence,
                             PhysicalPresence_CMD_ENABLE,
                             sizeof(PhysicalPresence_CMD_ENABLE),
                             NULL, 10, &returnCode, TPM_DURATION_TYPE_SHORT);
     if (rc || returnCode)
         goto err_exit;
 
-    rc = build_and_send_cmd(TPM_ORD_PhysicalPresence,
+    rc = build_and_send_cmd(0, TPM_ORD_PhysicalPresence,
                             PhysicalPresence_NOT_PRESENT_LOCK,
                             sizeof(PhysicalPresence_NOT_PRESENT_LOCK),
                             NULL, 10, &returnCode, TPM_DURATION_TYPE_SHORT);
@@ -535,6 +536,550 @@ err_exit:
     return TCG_TCG_COMMAND_ERROR;
 }
 
+static int
+is_valid_pcpes(struct pcpes *pcpes)
+{
+    return (pcpes->eventtype != 0);
+}
+
+
+static u8 *
+get_lasa_last_ptr(u16 *entry_count, u8 **log_area_start_address_next)
+{
+    struct pcpes *pcpes;
+    u32 log_area_minimum_length = 0;
+    u8 *log_area_start_address_base =
+        get_lasa_base_ptr(&log_area_minimum_length);
+    u8 *log_area_start_address_last = NULL;
+    u8 *end = log_area_start_address_base + log_area_minimum_length;
+    u32 size;
+
+    if (entry_count)
+        *entry_count = 0;
+
+    if (!log_area_start_address_base)
+        return NULL;
+
+    while (log_area_start_address_base < end) {
+        pcpes = (struct pcpes *)log_area_start_address_base;
+        if (!is_valid_pcpes(pcpes))
+            break;
+        if (entry_count)
+            (*entry_count)++;
+        size = pcpes->eventdatasize + offsetof(struct pcpes, event);
+        log_area_start_address_last = log_area_start_address_base;
+        log_area_start_address_base += size;
+    }
+
+    if (log_area_start_address_next)
+        *log_area_start_address_next = log_area_start_address_base;
+
+    return log_area_start_address_last;
+}
+
+
+static u32
+tpm_sha1_calc(const u8 *data, u32 length, u8 *hash)
+{
+    u32 rc;
+    u32 returnCode;
+    struct tpm_res_sha1start start;
+    struct tpm_res_sha1complete complete;
+    u32 blocks = length / 64;
+    u32 rest = length & 0x3f;
+    u32 numbytes, numbytes_no;
+    u32 offset = 0;
+
+    rc = build_and_send_cmd(0, TPM_ORD_SHA1Start,
+                            NULL, 0,
+                            (u8 *)&start,
+                            sizeof(struct tpm_res_sha1start),
+                            &returnCode, TPM_DURATION_TYPE_SHORT);
+
+    if (rc || returnCode)
+        goto err_exit;
+
+    while (blocks > 0) {
+
+        numbytes = be32_to_cpu(start.max_num_bytes);
+        if (numbytes > blocks * 64)
+             numbytes = blocks * 64;
+
+        numbytes_no = cpu_to_be32(numbytes);
+
+        rc = build_and_send_cmd_od(0, TPM_ORD_SHA1Update,
+                                   (u8 *)&numbytes_no, sizeof(numbytes_no),
+                                   NULL, 0, &returnCode,
+                                   &data[offset], numbytes,
+                                   TPM_DURATION_TYPE_SHORT);
+
+        if (rc || returnCode)
+            goto err_exit;
+
+        offset += numbytes;
+        blocks -= (numbytes / 64);
+    }
+
+    numbytes_no = cpu_to_be32(rest);
+
+    rc = build_and_send_cmd_od(0, TPM_ORD_SHA1Complete,
+                              (u8 *)&numbytes_no, sizeof(numbytes_no),
+                              (u8 *)&complete,
+                              sizeof(struct tpm_res_sha1complete),
+                              &returnCode,
+                              &data[offset], rest, TPM_DURATION_TYPE_SHORT);
+
+    if (rc || returnCode)
+        goto err_exit;
+
+    memcpy(hash, complete.hash, sizeof(complete.hash));
+
+    return 0;
+
+err_exit:
+    dprintf(DEBUG_tcg, "TCGBIOS: TPM SHA1 malfunctioning.\n");
+
+    tpm_state.tpm_working = 0;
+    if (rc)
+        return rc;
+    return TCG_TCG_COMMAND_ERROR;
+}
+
+
+static u32
+sha1_calc(const u8 *data, u32 length, u8 *hash)
+{
+    if (length < tpm_drivers[tpm_state.tpm_driver_to_use].sha1threshold)
+        return tpm_sha1_calc(data, length, hash);
+
+    return sha1(data, length, hash);
+}
+
+
+/*
+ * Extend the ACPI log with the given entry by copying the
+ * entry data into the log.
+ * Input
+ *  Pointer to the structure to be copied into the log
+ *
+ * Output:
+ *  lower 16 bits of return code contain entry number
+ *  if entry number is '0', then upper 16 bits contain error code.
+ */
+static u32
+tpm_extend_acpi_log(void *entry_ptr, u16 *entry_count)
+{
+    u32 log_area_minimum_length, size;
+    u8 *log_area_start_address_base =
+        get_lasa_base_ptr(&log_area_minimum_length);
+    u8 *log_area_start_address_next = NULL;
+    struct pcpes *pcpes = (struct pcpes *)entry_ptr;
+
+    get_lasa_last_ptr(entry_count, &log_area_start_address_next);
+
+    dprintf(DEBUG_tcg, "TCGBIOS: LASA_BASE = %p, LASA_NEXT = %p\n",
+            log_area_start_address_base, log_area_start_address_next);
+
+    if (log_area_start_address_next == NULL || log_area_minimum_length == 0)
+        return TCG_PC_LOGOVERFLOW;
+
+    size = pcpes->eventdatasize + offsetof(struct pcpes, event);
+
+    if ((log_area_start_address_next + size - log_area_start_address_base) >
+        log_area_minimum_length) {
+        dprintf(DEBUG_tcg, "TCGBIOS: LOG OVERFLOW: size = %d\n", size);
+        return TCG_PC_LOGOVERFLOW;
+    }
+
+    memcpy(log_area_start_address_next, entry_ptr, size);
+
+    (*entry_count)++;
+
+    return 0;
+}
+
+
+static u32
+is_preboot_if_shutdown(void)
+{
+    return tpm_state.if_shutdown;
+}
+
+
+static u32
+shutdown_preboot_interface(void)
+{
+    u32 rc = 0;
+
+    if (!is_preboot_if_shutdown()) {
+        tpm_state.if_shutdown = 1;
+    } else {
+        rc = TCG_INTERFACE_SHUTDOWN;
+    }
+
+    return rc;
+}
+
+
+static void
+tpm_shutdown(void)
+{
+    reset_acpi_log();
+    shutdown_preboot_interface();
+}
+
+
+static u32
+pass_through_to_tpm(struct pttti *pttti, struct pttto *pttto)
+{
+    u32 rc = 0;
+    u32 resbuflen = 0;
+    struct tpm_req_header *trh;
+    u8 locty = 0;
+    struct iovec iovec[2];
+    const u32 *tmp;
+
+    if (is_preboot_if_shutdown()) {
+        rc = TCG_INTERFACE_SHUTDOWN;
+        goto err_exit;
+    }
+
+    trh = (struct tpm_req_header *)pttti->tpmopin;
+
+    if (pttti->ipblength < sizeof(struct pttti) + TPM_REQ_HEADER_SIZE ||
+        pttti->opblength < sizeof(struct pttto) ||
+        be32_to_cpu(trh->totlen)  + sizeof(struct pttti) > pttti->ipblength ) {
+        rc = TCG_INVALID_INPUT_PARA;
+        goto err_exit;
+    }
+
+    resbuflen = pttti->opblength - offsetof(struct pttto, tpmopout);
+
+    iovec[0].data   = pttti->tpmopin;
+    tmp = (const u32 *)&((u8 *)iovec[0].data)[2];
+    iovec[0].length = cpu_to_be32(*tmp);
+
+    iovec[1].data   = NULL;
+    iovec[1].length = 0;
+
+    rc = transmit(locty, iovec, pttto->tpmopout, &resbuflen,
+                  TPM_DURATION_TYPE_LONG /* worst case */);
+    if (rc)
+        goto err_exit;
+
+    pttto->opblength = offsetof(struct pttto, tpmopout) + resbuflen;
+    pttto->reserved  = 0;
+
+err_exit:
+    if (rc != 0) {
+        pttto->opblength = 4;
+        pttto->reserved = 0;
+    }
+
+    return rc;
+}
+
+
+static u32
+tpm_extend(u8 *hash, u32 pcrindex)
+{
+    u32 rc;
+    struct pttto_extend pttto;
+    struct pttti_extend pttti = {
+        .pttti = {
+            .ipblength = sizeof(struct pttti_extend),
+            .opblength = sizeof(struct pttto_extend),
+        },
+        .req = {
+            .tag      = cpu_to_be16(0xc1),
+            .totlen   = cpu_to_be32(sizeof(pttti.req)),
+            .ordinal  = cpu_to_be32(TPM_ORD_Extend),
+            .pcrindex = cpu_to_be32(pcrindex),
+        },
+    };
+
+    memcpy(pttti.req.digest, hash, sizeof(pttti.req.digest));
+
+    rc = pass_through_to_tpm(&pttti.pttti, &pttto.pttto);
+
+    if (rc == 0) {
+        if (pttto.pttto.opblength < TPM_RSP_HEADER_SIZE ||
+            pttto.pttto.opblength !=
+                sizeof(struct pttto) + be32_to_cpu(pttto.rsp.totlen) ||
+            be16_to_cpu(pttto.rsp.tag) != 0xc4) {
+            rc = TCG_FATAL_COM_ERROR;
+        }
+    }
+
+    if (rc)
+        tpm_shutdown();
+
+    return rc;
+}
+
+
+static u32
+hash_all(const struct hai *hai, u8 *hash)
+{
+    if (is_preboot_if_shutdown() != 0)
+        return TCG_INTERFACE_SHUTDOWN;
+
+    if (hai->ipblength != sizeof(struct hai) ||
+        hai->hashdataptr == 0 ||
+        hai->hashdatalen == 0 ||
+        hai->algorithmid != TPM_ALG_SHA)
+        return TCG_INVALID_INPUT_PARA;
+
+    return sha1_calc((const u8 *)hai->hashdataptr, hai->hashdatalen, hash);
+}
+
+
+static u32
+hash_log_event(const struct hlei *hlei, struct hleo *hleo)
+{
+    u32 rc = 0;
+    u16 size;
+    struct pcpes *pcpes;
+    u16 entry_count;
+
+    if (is_preboot_if_shutdown() != 0) {
+        rc = TCG_INTERFACE_SHUTDOWN;
+        goto err_exit;
+    }
+
+    size = hlei->ipblength;
+    if (size != sizeof(*hlei)) {
+        rc = TCG_INVALID_INPUT_PARA;
+        goto err_exit;
+    }
+
+    pcpes = (struct pcpes *)hlei->logdataptr;
+
+    if (pcpes->pcrindex >= 24 ||
+        pcpes->pcrindex  != hlei->pcrindex ||
+        pcpes->eventtype != hlei->logeventtype) {
+        rc = TCG_INVALID_INPUT_PARA;
+        goto err_exit;
+    }
+
+    if ((hlei->hashdataptr != 0) && (hlei->hashdatalen != 0)) {
+        rc = sha1_calc((const u8 *)hlei->hashdataptr,
+                       hlei->hashdatalen, pcpes->digest);
+        if (rc)
+            return rc;
+    }
+
+    rc = tpm_extend_acpi_log((void *)hlei->logdataptr, &entry_count);
+    if (rc)
+        goto err_exit;
+
+    /* updating the log was fine */
+    hleo->opblength = sizeof(struct hleo);
+    hleo->reserved  = 0;
+    hleo->eventnumber = entry_count;
+
+err_exit:
+    if (rc != 0) {
+        hleo->opblength = 2;
+        hleo->reserved = 0;
+    }
+
+    return rc;
+}
+
+
+static u32
+hash_log_extend_event(const struct hleei_short *hleei_s, struct hleeo *hleeo)
+{
+    u32 rc = 0;
+    struct hleo hleo;
+    struct hleei_long *hleei_l = (struct hleei_long *)hleei_s;
+    const void *logdataptr;
+    u32 logdatalen;
+    struct pcpes *pcpes;
+
+    /* short or long version? */
+    switch (hleei_s->ipblength) {
+    case sizeof(struct hleei_short):
+        /* short */
+        logdataptr = hleei_s->logdataptr;
+        logdatalen = hleei_s->logdatalen;
+    break;
+
+    case sizeof(struct hleei_long):
+        /* long */
+        logdataptr = hleei_l->logdataptr;
+        logdatalen = hleei_l->logdatalen;
+    break;
+
+    default:
+        /* bad input block */
+        rc = TCG_INVALID_INPUT_PARA;
+        goto err_exit;
+    }
+
+    pcpes = (struct pcpes *)logdataptr;
+
+    struct hlei hlei = {
+        .ipblength   = sizeof(hlei),
+        .hashdataptr = hleei_s->hashdataptr,
+        .hashdatalen = hleei_s->hashdatalen,
+        .pcrindex    = hleei_s->pcrindex,
+        .logeventtype= pcpes->eventtype,
+        .logdataptr  = logdataptr,
+        .logdatalen  = logdatalen,
+    };
+
+    rc = hash_log_event(&hlei, &hleo);
+    if (rc)
+        goto err_exit;
+
+    hleeo->opblength = sizeof(struct hleeo);
+    hleeo->reserved  = 0;
+    hleeo->eventnumber = hleo.eventnumber;
+
+    rc = tpm_extend(pcpes->digest, hleei_s->pcrindex);
+
+err_exit:
+    if (rc != 0) {
+        hleeo->opblength = 4;
+        hleeo->reserved  = 0;
+    }
+
+    return rc;
+
+}
+
+
+static u32
+tss(struct ti *ti, struct to *to)
+{
+    u32 rc = 0;
+
+    if (is_preboot_if_shutdown() == 0) {
+        rc = TCG_PC_UNSUPPORTED;
+    } else {
+        rc = TCG_INTERFACE_SHUTDOWN;
+    }
+
+    to->opblength = sizeof(struct to);
+    to->reserved  = 0;
+
+    return rc;
+}
+
+
+static u32
+compact_hash_log_extend_event(u8 *buffer,
+                              u32 info,
+                              u32 length,
+                              u32 pcrindex,
+                              u32 *edx_ptr)
+{
+    u32 rc = 0;
+    struct hleeo hleeo;
+    struct pcpes pcpes = {
+        .pcrindex      = pcrindex,
+        .eventtype     = EV_COMPACT_HASH,
+        .eventdatasize = sizeof(info),
+        .event         = info,
+    };
+    struct hleei_short hleei = {
+        .ipblength   = sizeof(hleei),
+        .hashdataptr = buffer,
+        .hashdatalen = length,
+        .pcrindex    = pcrindex,
+        .logdataptr  = &pcpes,
+        .logdatalen  = sizeof(pcpes),
+    };
+
+    rc = hash_log_extend_event(&hleei, &hleeo);
+    if (rc == 0)
+        *edx_ptr = hleeo.eventnumber;
+
+    return rc;
+}
+
+
+void VISIBLE32FLAT
+tpm_interrupt_handler32(struct bregs *regs)
+{
+    if (!CONFIG_TCGBIOS)
+        return;
+
+    set_cf(regs, 0);
+
+    if (!has_working_tpm()) {
+        regs->eax = TCG_GENERAL_ERROR;
+        return;
+    }
+
+    switch ((enum irq_ids)regs->al) {
+    case TCG_StatusCheck:
+        if (is_tpm_present() == 0) {
+            /* no TPM available */
+            regs->eax = TCG_PC_TPM_NOT_PRESENT;
+        } else {
+            regs->eax = 0;
+            regs->ebx = TCG_MAGIC;
+            regs->ch = TCG_VERSION_MAJOR;
+            regs->cl = TCG_VERSION_MINOR;
+            regs->edx = 0x0;
+            regs->esi = (u32)get_lasa_base_ptr(NULL);
+            regs->edi =
+                  (u32)get_lasa_last_ptr(NULL, NULL);
+        }
+        break;
+
+    case TCG_HashLogExtendEvent:
+        regs->eax =
+            hash_log_extend_event(
+                  (struct hleei_short *)input_buf32(regs),
+                  (struct hleeo *)output_buf32(regs));
+        break;
+
+    case TCG_PassThroughToTPM:
+        regs->eax =
+            pass_through_to_tpm((struct pttti *)input_buf32(regs),
+                                (struct pttto *)output_buf32(regs));
+        break;
+
+    case TCG_ShutdownPreBootInterface:
+        regs->eax = shutdown_preboot_interface();
+        break;
+
+    case TCG_HashLogEvent:
+        regs->eax = hash_log_event((struct hlei*)input_buf32(regs),
+                                   (struct hleo*)output_buf32(regs));
+        break;
+
+    case TCG_HashAll:
+        regs->eax =
+            hash_all((struct hai*)input_buf32(regs),
+                     (u8 *)output_buf32(regs));
+        break;
+
+    case TCG_TSS:
+        regs->eax = tss((struct ti*)input_buf32(regs),
+                    (struct to*)output_buf32(regs));
+        break;
+
+    case TCG_CompactHashLogExtendEvent:
+        regs->eax =
+          compact_hash_log_extend_event((u8 *)input_buf32(regs),
+                                        regs->esi,
+                                        regs->ecx,
+                                        regs->edx,
+                                        &regs->edx);
+        break;
+
+    default:
+        set_cf(regs, 1);
+    }
+
+    return;
+}
+
 
 u32
 tpm_s3_resume(void)
@@ -550,7 +1095,7 @@ tpm_s3_resume(void)
 
     dprintf(DEBUG_tcg, "TCGBIOS: Resuming with TPM_Startup(ST_STATE)\n");
 
-    rc = build_and_send_cmd(TPM_ORD_Startup,
+    rc = build_and_send_cmd(0, TPM_ORD_Startup,
                             Startup_ST_STATE, sizeof(Startup_ST_STATE),
                             NULL, 10, &returnCode, TPM_DURATION_TYPE_SHORT);