linux-kernel - Re: [PATCH 1/1] trusted-keys: match tpm_get

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Message-ID: <9eea988ff637af57511107c6c0941bff2aa7c6c5.camel@HansenPartnership.com>
Date:   Thu, 29 Apr 2021 11:50:50 -0700
From:   James Bottomley <James.Bottomley@...senPartnership.com>
To:     Ben Boeckel <me@...boeckel.net>, keyrings@...r.kernel.org
Cc:     Ben Boeckel <mathstuf@...il.com>, linux-integrity@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        linux-security-module@...r.kernel.org,
        Dan Carpenter <dan.carpenter@...cle.com>
Subject: Re: [PATCH 1/1] trusted-keys: match tpm_get_ops on all return paths

On Thu, 2021-04-29 at 14:37 -0400, Ben Boeckel wrote:
> From: Ben Boeckel <mathstuf@...il.com>
> 
> The `tpm_get_ops` call at the beginning of the function is not paired
> with a `tpm_put_ops` on this return path.
> 
> Fixes: f2219745250f ("security: keys: trusted: use ASN.1 TPM2 key
> format for the blobs")
> Reported-by: Dan Carpenter <dan.carpenter@...cle.com>
> Signed-off-by: Ben Boeckel <mathstuf@...il.com>
> ---
>  security/keys/trusted-keys/trusted_tpm2.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/security/keys/trusted-keys/trusted_tpm2.c
> b/security/keys/trusted-keys/trusted_tpm2.c
> index 617fabd4d913..25c2c4d564de 100644
> --- a/security/keys/trusted-keys/trusted_tpm2.c
> +++ b/security/keys/trusted-keys/trusted_tpm2.c
> @@ -335,8 +335,10 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
>  		else
>  			rc = -EPERM;
>  	}
> -	if (blob_len < 0)
> +	if (blob_len < 0) {
> +		tpm_put_ops(chip);
>  		return blob_len;
> +	}
>  
>  	payload->blob_len = blob_len;
>  

Actually, I think this is a better fix to avoid multiple put and
returns.

James

---

diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c
index d225ad140960..cbf2a932577b 100644
--- a/security/keys/trusted-keys/trusted_tpm2.c
+++ b/security/keys/trusted-keys/trusted_tpm2.c
@@ -336,9 +336,9 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
 			rc = -EPERM;
 	}
 	if (blob_len < 0)
-		return blob_len;
-
-	payload->blob_len = blob_len;
+		rc = blob_len;
+	else
+		payload->blob_len = blob_len;
 
 	tpm_put_ops(chip);
 	return rc;