security/tpm: Include mrc.bin in CRTM if present

mrc.bin, on platforms where it is present, is code executed on CPU, so
it should be considered a part of CRTM.

cbfs_locate_file_in_region() is hooked to measurement here too, since
mrc.bin is loaded with it, and CBFS_TYPE_MRC (the type of mrc.bin) is
measured to TPM_CRTM_PCR rather than TPM_RUNTIME_DATA_PCR.

TODO: I have heard that SMM is too resource-limited to link with vboot
library, so currently tspi_measure_cbfs_hook() is masked in SMM.
Please correct me if I am wrong.

Change-Id: Ib4c3cf47b919864056baf725001ca8a4aaafa110
Signed-off-by: Bill XIE <persmule@hardenedlinux.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/38858
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>

src/lib/cbfs.c

@@ -56,7 +56,10 @@ int cbfs_boot_locate(struct cbfsf *fh, const char *name, uint32_t *type)
 		 * Files can be added to the RO_REGION_ONLY config option to use this feature.
 		 */
 		printk(BIOS_DEBUG, "Fall back to RO region for %s\n", name);
-		ret = cbfs_locate_file_in_region(fh, "COREBOOT", name, type);
+		if (fmap_locate_area_as_rdev("COREBOOT", &rdev))
+			ERROR("RO region not found\n");
+		else
+			ret = cbfs_locate(fh, &rdev, name, type);
 	}
 
 	if (!ret)
@@ -86,14 +89,18 @@ int cbfs_locate_file_in_region(struct cbfsf *fh, const char *region_name,
 			       const char *name, uint32_t *type)
 {
 	struct region_device rdev;
-
+	int ret = 0;
 	if (fmap_locate_area_as_rdev(region_name, &rdev)) {
 		LOG("%s region not found while looking for %s\n",
 		    region_name, name);
 		return -1;
 	}
 
-	return cbfs_locate(fh, &rdev, name, type);
+	ret = cbfs_locate(fh, &rdev, name, type);
+	if (!ret)
+		if (tspi_measure_cbfs_hook(fh, name))
+			return -1;
+	return ret;
 }
 
 size_t cbfs_load_and_decompress(const struct region_device *rdev, size_t offset,

src/security/tpm/tspi/crtm.c

@@ -133,10 +133,14 @@ uint32_t tspi_measure_cbfs_hook(struct cbfsf *fh, const char *name)
 	cbfs_file_data(&rdev, fh);
 
 	switch (cbfs_type) {
-	case CBFS_TYPE_MRC:
 	case CBFS_TYPE_MRC_CACHE:
 		pcr_index = TPM_RUNTIME_DATA_PCR;
 		break;
+	/*
+	 * mrc.bin is code executed on CPU, so it
+	 * should not be considered runtime data
+	 */
+	case CBFS_TYPE_MRC:
 	case CBFS_TYPE_STAGE:
 	case CBFS_TYPE_SELF:
 	case CBFS_TYPE_FIT:

src/security/tpm/tspi/crtm.h

@@ -50,7 +50,7 @@ uint32_t tspi_init_crtm(void);
  */
 int tspi_measure_cache_to_pcr(void);
 
-#if CONFIG(TPM_MEASURED_BOOT)
+#if !ENV_SMM && CONFIG(TPM_MEASURED_BOOT)
 /*
  * Measures cbfs data via hook (cbfs)
  * fh is the cbfs file handle to measure