[S] Change in coreboot[master]: vboot: Allow for comparison of hash without zero-padding

[Julius Werner (Code Review)]

Julius Werner has submitted this change. ( https://review.coreboot.org/c/coreboot/+/69762 )

Change subject: vboot: Allow for comparison of hash without zero-padding
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vboot: Allow for comparison of hash without zero-padding

Adjust asserts to allow to store and compare (at S3 resume) hashes
without padding to maximum hash length / slot size.

Signed-off-by: Jakub Czapiga 
Change-Id: If6d46e0b58dbca86af56221b7ff2606ab2d1799a
Reviewed-on: https://review.coreboot.org/c/coreboot/+/69762
Tested-by: build bot (Jenkins) 
Reviewed-by: Julius Werner 
Reviewed-by: Yu-Ping Wu 
Reviewed-by: Eric Lai 
---
M src/ec/google/chromeec/vboot_storage.c
M src/security/vboot/vboot_logic.c
2 files changed, 21 insertions(+), 3 deletions(-)

Approvals:
  build bot (Jenkins): Verified
  Julius Werner: Looks good to me, approved
  Yu-Ping Wu: Looks good to me, approved
  Eric Lai: Looks good to me, approved

diff --git a/src/ec/google/chromeec/vboot_storage.c b/src/ec/google/chromeec/vboot_storage.c
index f708b3e..63e1314 100644
--- a/src/ec/google/chromeec/vboot_storage.c
+++ b/src/ec/google/chromeec/vboot_storage.c
@@ -14,8 +14,8 @@
    uint32_t lock_status;
    int num_slots;

-	/* Ensure the digests being saved match the EC's slot size. */
-	assert(digest_size == EC_VSTORE_SLOT_SIZE);
+	/* Ensure the digests being saved does not exceed the EC's slot size. */
+	assert(digest_size > 0 && digest_size <= EC_VSTORE_SLOT_SIZE);

if (google_chromeec_vstore_write(slot, digest, digest_size))
    	return -1;
diff --git a/src/security/vboot/vboot_logic.c b/src/security/vboot/vboot_logic.c
index 98a044c..f7b4801 100644
--- a/src/security/vboot/vboot_logic.c
+++ b/src/security/vboot/vboot_logic.c
@@ -86,7 +86,7 @@
    	uint8_t saved_hash[VBOOT_MAX_HASH_SIZE];
    	const size_t saved_hash_sz = sizeof(saved_hash);

-		assert(slot_hash_sz == saved_hash_sz);
+		assert(slot_hash_sz <= saved_hash_sz);

printk(BIOS_DEBUG, "Platform is resuming.\n");