Re: [PATCH v14 4/5] security: keys: trusted: use ASN.1 TPM2 key format for the blobs

[James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>]

On Mon, 2020-11-30 at 10:10 +0800, kernel test robot wrote:
[...]
>  > 331		if (payload->blob_len < 0)
>    332			return payload->blob_len;

OK, I can rework this to use the signed version of blob len as below.

James

---

diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c
index e50563f58900..0d4c6f138b94 100644
--- a/security/keys/trusted-keys/trusted_tpm2.c
+++ b/security/keys/trusted-keys/trusted_tpm2.c
@@ -242,7 +242,7 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
 		      struct trusted_key_payload *payload,
 		      struct trusted_key_options *options)
 {
-	unsigned int blob_len;
+	int blob_len = 0;
 	struct tpm_buf buf;
 	u32 hash;
 	u32 flags;
@@ -400,10 +400,9 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
 		goto out;
 	}
 
-	payload->blob_len =
-		tpm2_key_encode(payload, options,
-				&buf.data[TPM_HEADER_SIZE + 4],
-				blob_len);
+	blob_len = tpm2_key_encode(payload, options,
+				   &buf.data[TPM_HEADER_SIZE + 4],
+				   blob_len);
 
 out:
 	tpm_buf_destroy(&buf);
@@ -414,8 +413,10 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
 		else
 			rc = -EPERM;
 	}
-	if (payload->blob_len < 0)
-		return payload->blob_len;
+	if (blob_len < 0)
+		return blob_len;
+
+	payload->blob_len = blob_len;
 
 	return rc;
 }