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authorJulius Werner <jwerner@chromium.org>2015-01-30 18:45:27 -0800
committerAaron Durbin <adurbin@chromium.org>2015-04-20 17:06:28 +0200
commit76e3303290f7f17d5318e87321567188f165cc2a (patch)
tree43efe41ca19f18bb4f96899b91a86da221fb0a70 /src/vendorcode/google
parent5aecacca053c3ce8bdb7b8ce94473703b3240e37 (diff)
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chromeos: vboot2: Add TPM PCR extension support
ChromeOS/vboot devices expect the TPM PCRs 0 and 1 to be extended with digests that attest the chosen boot mode (developer/recovery) and the HWID in a secure way. This patch uses the newly added vboot2 support functions to fetch these digests and store them in the TPM. CQ-DEPEND=CL:244542 BRANCH=veyron BUG=chromium:451609 TEST=Booted Jerry. Confirmed that PCR0 contains the same value as on my vboot1 Blaze and Falco (and PCR1 contains some non-zero hash). Original-Change-Id: I7037b8198c09fccee5440c4c85f0821166784cec Original-Signed-off-by: Julius Werner <jwerner@chromium.org> Original-Reviewed-on: https://chromium-review.googlesource.com/245119 Original-Reviewed-by: Aaron Durbin <adurbin@chromium.org> Original-Reviewed-by: Daisuke Nojiri <dnojiri@chromium.org> (cherry picked from commit 8b44e13098cb7493091f2ce6c4ab423f2cbf0177) Signed-off-by: Aaron Durbin <adurbin@chromium.org> Change-Id: I549de8c07353683633fbf73e4ee62ba0ed72ff89 Reviewed-on: http://review.coreboot.org/9706 Tested-by: build bot (Jenkins) Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org> Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Diffstat (limited to 'src/vendorcode/google')
-rw-r--r--src/vendorcode/google/chromeos/vboot2/antirollback.c17
-rw-r--r--src/vendorcode/google/chromeos/vboot2/verstage.c15
2 files changed, 32 insertions, 0 deletions
diff --git a/src/vendorcode/google/chromeos/vboot2/antirollback.c b/src/vendorcode/google/chromeos/vboot2/antirollback.c
index f420d1611..407b19cec 100644
--- a/src/vendorcode/google/chromeos/vboot2/antirollback.c
+++ b/src/vendorcode/google/chromeos/vboot2/antirollback.c
@@ -35,6 +35,23 @@
} \
} while (0)
+
+uint32_t tpm_extend_pcr(struct vb2_context *ctx, int pcr,
+ enum vb2_pcr_digest which_digest)
+{
+ uint8_t buffer[VB2_PCR_DIGEST_RECOMMENDED_SIZE];
+ uint32_t size = sizeof(buffer);
+ int rv;
+
+ rv = vb2api_get_pcr_digest(ctx, which_digest, buffer, &size);
+ if (rv != VB2_SUCCESS)
+ return rv;
+ if (size < TPM_PCR_DIGEST)
+ return VB2_ERROR_UNKNOWN;
+
+ return tlcl_extend(pcr, buffer, NULL);
+}
+
uint32_t tpm_clear_and_reenable(void)
{
VBDEBUG("TPM: Clear and re-enable\n");
diff --git a/src/vendorcode/google/chromeos/vboot2/verstage.c b/src/vendorcode/google/chromeos/vboot2/verstage.c
index 06d76fe24..0ce4e8924 100644
--- a/src/vendorcode/google/chromeos/vboot2/verstage.c
+++ b/src/vendorcode/google/chromeos/vboot2/verstage.c
@@ -205,6 +205,12 @@ static void save_if_needed(struct vb2_context *ctx)
}
}
+static uint32_t extend_pcrs(struct vb2_context *ctx)
+{
+ return tpm_extend_pcr(ctx, 0, BOOT_MODE_PCR) ||
+ tpm_extend_pcr(ctx, 1, HWID_DIGEST_PCR);
+}
+
/**
* Verify and select the firmware in the RW image
*
@@ -248,6 +254,7 @@ void verstage_main(void)
printk(BIOS_INFO, "Recovery requested (%x)\n", rv);
/* If we need recovery mode, leave firmware selection now */
save_if_needed(&ctx);
+ extend_pcrs(&ctx); /* ignore failures */
timestamp_add_now(TS_END_VBOOT);
return;
}
@@ -284,6 +291,14 @@ void verstage_main(void)
vboot_reboot();
}
+ rv = extend_pcrs(&ctx);
+ if (rv) {
+ printk(BIOS_WARNING, "Failed to extend TPM PCRs (%#x)\n", rv);
+ vb2api_fail(&ctx, VB2_RECOVERY_RO_TPM_U_ERROR, rv);
+ save_if_needed(&ctx);
+ vboot_reboot();
+ }
+
/* Lock TPM */
rv = antirollback_lock_space_firmware();
if (rv) {