From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A52F51B983F; Wed, 8 Apr 2026 08:27:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775636821; cv=none; b=JYRX1MrhoXnfEsZSuvYrBXcYlpAar4nG6vi36jyF31xHns6ZDT1eoxRaH6dNwQVX54iqZReTgUM9Z0yEd53CBkeCdYRnw5l+plM3UGPcGQEMrK+0LQqh+5X5ohqkioerMkBUgDWggk6sY5k9SIJkC0JDnjcNmfLAXJBMBRbeVGg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775636821; c=relaxed/simple; bh=CnPXUWZUmD4m56Ii+lL8em+qHWgknOpC8DreUJCxk0s=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=J0jdvHYtdTONeHeL3J1v4zVhDraVaV0PzaXwfzQ+5Lk2fo1fGCrZ5tlAvpaUi96wrguQpnHWZ4h8SjOBKIH0M/sXKQOTgjl9A99pRhefs2Aqy7hfBVv8hYlmUp/bxAUQ/M1PFvTL934z64HTH/26nWlC3DRVdqr3jsddEVqX61I= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=OPVZIet2; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="OPVZIet2" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EEBC5C19424; Wed, 8 Apr 2026 08:27:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1775636821; bh=CnPXUWZUmD4m56Ii+lL8em+qHWgknOpC8DreUJCxk0s=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=OPVZIet2qpTcTLo6zAIEy/F+zxBMM6MOd4A9aO9Iy82qbG9aOH5xjv5DWRNGfsyyy 6Py29N9Z5tnvaFUPXEWFWtLM7ctTiWIuuw1Hd2M6IaK7uTDm7K36RuT2mRiHw1dOOo WZetN1YEhFSIAIYGJkiXXsO5f8MzqJDcvASrBviUOT/lkxJ+fyz1FBXrIIMMIq6id/ KZD0WKmjo1FvsSQe0fe3vtWCIyaeEkTghwRlgULuBxxE74V1JSwQWfF5/rMIGa+YlE TGNB0nVUef1lhvw0LCq3JhZa2z3jtc6Z3+b6n4Gjd70fGrkT5hIP4mPOUPfwfSGPTF zee9+Up4HUd3w== Date: Wed, 8 Apr 2026 11:26:57 +0300 From: Jarkko Sakkinen To: Nayna Jain Cc: linux-integrity@vger.kernel.org, keyrings@vger.kernel.org, Srish Srinivasan , James Bottomley , Mimi Zohar , David Howells , Paul Moore , James Morris , "Serge E. Hallyn" , Ahmad Fatoum , Pengutronix Kernel Team , open list , "open list:SECURITY SUBSYSTEM" Subject: Re: [PATCH v2] KEYS: trusted: Debugging as a feature Message-ID: References: <20260324110043.67248-1-jarkko@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Mon, Apr 06, 2026 at 10:42:00PM -0400, Nayna Jain wrote: > > On 3/24/26 7:00 AM, Jarkko Sakkinen wrote: > > TPM_DEBUG, and other similar flags, are a non-standard way to specify a > > feature in Linux kernel. Introduce CONFIG_TRUSTED_KEYS_DEBUG for > > trusted keys, and use it to replace these ad-hoc feature flags. > > > > Given that trusted keys debug dumps can contain sensitive data, harden > > the feature as follows: > > > > 1. In the Kconfig description postulate that pr_debug() statements must be > > used. > > 2. Use pr_debug() statements in TPM 1.x driver to print the protocol dump. > > > > Traces, when actually needed, can be easily enabled by providing > > trusted.dyndbg='+p' in the kernel command-line. > > > > Cc: Srish Srinivasan > > Reported-by: Nayna Jain > > Closes: https://lore.kernel.org/all/7f8b8478-5cd8-4d97-bfd0-341fd5cf10f9@linux.ibm.com/ > > Signed-off-by: Jarkko Sakkinen > > --- > > v2: > > - Implement for all trusted keys backends. > > - Add HAVE_TRUSTED_KEYS_DEBUG as it is a good practice despite full > > coverage. > > --- > > include/keys/trusted-type.h | 18 +++++------- > > security/keys/trusted-keys/Kconfig | 19 ++++++++++++ > > security/keys/trusted-keys/trusted_caam.c | 4 +-- > > security/keys/trusted-keys/trusted_tpm1.c | 36 +++++++++++------------ > > 4 files changed, 46 insertions(+), 31 deletions(-) > > > > diff --git a/include/keys/trusted-type.h b/include/keys/trusted-type.h > > index 03527162613f..620a1f890b6b 100644 > > --- a/include/keys/trusted-type.h > > +++ b/include/keys/trusted-type.h > > @@ -83,18 +83,16 @@ struct trusted_key_source { > > extern struct key_type key_type_trusted; > > -#define TRUSTED_DEBUG 0 > > - > > -#if TRUSTED_DEBUG > > +#ifdef CONFIG_TRUSTED_KEYS_DEBUG > > static inline void dump_payload(struct trusted_key_payload *p) > > { > > - pr_info("key_len %d\n", p->key_len); > > - print_hex_dump(KERN_INFO, "key ", DUMP_PREFIX_NONE, > > - 16, 1, p->key, p->key_len, 0); > > - pr_info("bloblen %d\n", p->blob_len); > > - print_hex_dump(KERN_INFO, "blob ", DUMP_PREFIX_NONE, > > - 16, 1, p->blob, p->blob_len, 0); > > - pr_info("migratable %d\n", p->migratable); > > + pr_debug("key_len %d\n", p->key_len); > > + print_hex_dump_debug("key ", DUMP_PREFIX_NONE, > > + 16, 1, p->key, p->key_len, 0); > > + pr_debug("bloblen %d\n", p->blob_len); > > + print_hex_dump_debug("blob ", DUMP_PREFIX_NONE, > > + 16, 1, p->blob, p->blob_len, 0); > > + pr_debug("migratable %d\n", p->migratable); > > } > > #else > > static inline void dump_payload(struct trusted_key_payload *p) > > diff --git a/security/keys/trusted-keys/Kconfig b/security/keys/trusted-keys/Kconfig > > index 9e00482d886a..2ad9ba0e03f1 100644 > > --- a/security/keys/trusted-keys/Kconfig > > +++ b/security/keys/trusted-keys/Kconfig > > @@ -1,10 +1,25 @@ > > config HAVE_TRUSTED_KEYS > > bool > > +config HAVE_TRUSTED_KEYS_DEBUG > > + bool > > + > > +config TRUSTED_KEYS_DEBUG > > + bool "Debug trusted keys" > > + depends on HAVE_TRUSTED_KEYS_DEBUG > > + default n > > + help > > + Trusted keys backends and core code that support debug dumps > > + can opt-in that feature here. Dumps must only use DEBUG > > + level output, as sensitive data may pass by. In the > > + kernel-command line traces can be enabled via > > + trusted.dyndbg='+p'. > > Would it be good idea to add an explicit note/warning: > > > NOTE: This option is intended for debugging purposes only. Do not enable on > production systems as debug output may expose sensitive cryptographic > material. > If you are unsure, say N. > > Apart from this, looks good to me. > > Reviewed-by: Nayna Jain Thank, I'll add your tag but would you mind quickly screening v3 again where I add "trusted.debug=0|1". And yes, your suggestion about extra warning makes sense. Let's make this safe as possible. Mistakes do happen... and then those measures pay off :-) BR, Jarkko