[coreboot-gerrit] Change in coreboot[master]: security/tpm: Include mrc.bin in CRTM if present

[Philipp Deppenwiese (Code Review)]

Philipp Deppenwiese has submitted this change. ( https://review.coreboot.org/c/coreboot/+/38858 )

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

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 
Reviewed-on: https://review.coreboot.org/c/coreboot/+/38858
Tested-by: build bot (Jenkins) 
Reviewed-by: Julius Werner 
---
M src/lib/cbfs.c
M src/security/tpm/tspi/crtm.c
M src/security/tpm/tspi/crtm.h
3 files changed, 16 insertions(+), 5 deletions(-)

Approvals:
  build bot (Jenkins): Verified
  Julius Werner: Looks good to me, approved

diff --git a/src/lib/cbfs.c b/src/lib/cbfs.c
index 4392ab7..ccd7e6a 100644
--- a/src/lib/cbfs.c
+++ b/src/lib/cbfs.c
@@ -56,7 +56,10 @@
    	 * 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 @@
    		       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,
diff --git a/src/security/tpm/tspi/crtm.c b/src/security/tpm/tspi/crtm.c
index dc7d7d2..304cea3 100644
--- a/src/security/tpm/tspi/crtm.c
+++ b/src/security/tpm/tspi/crtm.c
@@ -133,10 +133,14 @@
    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:
diff --git a/src/security/tpm/tspi/crtm.h b/src/security/tpm/tspi/crtm.h
index dfd91e1..eb62495 100644
--- a/src/security/tpm/tspi/crtm.h
+++ b/src/security/tpm/tspi/crtm.h
@@ -50,7 +50,7 @@
  */
 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