linux-kernel - Re: [PATCH v8 07/12] KEYS: trusted: Remove dead branch from tpm2_unseal

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Message-ID: <57e69d4fd5a40899cd779ee04f29f33009c97431.camel@HansenPartnership.com>
Date: Fri, 19 Dec 2025 15:54:47 -0500
From: James Bottomley <James.Bottomley@...senPartnership.com>
To: Jarkko Sakkinen <jarkko@...nel.org>, linux-integrity@...r.kernel.org
Cc: David Howells <dhowells@...hat.com>, Paul Moore <paul@...l-moore.com>, 
 James Morris <jmorris@...ei.org>, "Serge E. Hallyn" <serge@...lyn.com>,
 Mimi Zohar <zohar@...ux.ibm.com>,  "open list:KEYS/KEYRINGS"
 <keyrings@...r.kernel.org>, "open list:SECURITY SUBSYSTEM"
 <linux-security-module@...r.kernel.org>, open list
 <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v8 07/12] KEYS: trusted: Remove dead branch from
 tpm2_unseal_cmd

On Tue, 2025-12-16 at 11:21 +0200, Jarkko Sakkinen wrote:
> TPM2_Unseal requires TPM2_ST_SESSIONS, and tpm2_unseal_cmd() always
> does set up either password or HMAC session.
> 
> Remove the branch in tpm2_unseal_cmd() conditionally setting
> TPM2_ST_NO_SESSIONS. It is faulty but luckily it is never exercised
> at run-time, and thus does not cause regressions.

Shouldn't that also be

Fixes: b7960b904861 ("tpm2-sessions: Open code tpm_buf_append_hmac_session()")

> Signed-off-by: Jarkko Sakkinen <jarkko@...nel.org>
> ---
>  security/keys/trusted-keys/trusted_tpm2.c | 10 +---------
>  1 file changed, 1 insertion(+), 9 deletions(-)
> 
> diff --git a/security/keys/trusted-keys/trusted_tpm2.c
> b/security/keys/trusted-keys/trusted_tpm2.c
> index d3a5c5f2b926..3666e3e48eab 100644
> --- a/security/keys/trusted-keys/trusted_tpm2.c
> +++ b/security/keys/trusted-keys/trusted_tpm2.c
> @@ -451,10 +451,8 @@ static int tpm2_unseal_cmd(struct tpm_chip
> *chip,
>  			   struct trusted_key_options *options,
>  			   u32 blob_handle)
>  {
> -	struct tpm_header *head;
>  	struct tpm_buf buf;
>  	u16 data_len;
> -	int offset;
>  	u8 *data;
>  	int rc;
>  
> @@ -495,14 +493,8 @@ static int tpm2_unseal_cmd(struct tpm_chip
> *chip,
>  		tpm_buf_append_u16(&buf, options->blobauth_len);
>  		tpm_buf_append(&buf, options->blobauth, options-
> >blobauth_len);
>  
> -		if (tpm2_chip_auth(chip)) {
> +		if (tpm2_chip_auth(chip))

Since the statement above is that the if is always true, why do you
still have it here?

Regards,

James