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 6784D15382E; Mon, 7 Apr 2025 12:32:40 +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=1744029160; cv=none; b=KWAxGg0/+SCMfZ7GazLxmEKZ0LJlW8ewtfscGSTTz23OlnqwgORboDYEBYQFPU9UuyJ2jjo0SeZFHptlhiNsCYz+sr8TRz9M2xyEUqXbWSgLSZrn99rSc5+fC7VOwK0EXODvtnTDJP9tHbTWCgpusdCqDxs4hSnrorQdDN2BBRg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744029160; c=relaxed/simple; bh=C2hUbIPOqtG04WpoGSHIQr7eWr+HJM7/fdl8jvapedc=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=hAwHJt7DuMxCIyon5asSR7fueBeJowd4tBmk3V45yHUogkwPPEYr1LsuGtJz8qkdXqkRW8aQRa42B7UewWuDEE8FIVaKLN5S9ZVDBrrtXLKW4Rd0qnSUCpjbj3g+uFKgtsOnOtUJ2dIQHwQd+UHHDvtEe3gFrc9mUS3NsM7Dikw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Z1D0ZHtp; 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="Z1D0ZHtp" Received: by smtp.kernel.org (Postfix) with ESMTPSA id ADA7AC4CEDD; Mon, 7 Apr 2025 12:32:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1744029160; bh=C2hUbIPOqtG04WpoGSHIQr7eWr+HJM7/fdl8jvapedc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Z1D0ZHtpGqv8mh9PT3FG56iuyZCJrHW+vIA1JLwYTMxNIl/9ukZGy7iUTaa7C8XZi r1lxOy7yq2FhMlgElHelPdp5xLQ0oQNiHQBmlXOYj03YicfmI7SQA0zdzR+vmDuswF bzwl6Fs+jmQbpagDmdYBaUPU74Yzd6sc7l4eXYeCSKjvyCLGDfMXa5a3z0xofLWkVw W7+QC3ZIgXkInE6tvLjVD9jjEjNp9mTOZuEc6GGXqUOzdPzBQvOWluntdwHqKbDPdC iPtVgXPDg7BB9t7Hnf/wUR3MNAMVvXRCcOu+si2mU+7qeEHhjTJmAFFT+6a6l/aqnK c5vmdKD19Jcgw== Date: Mon, 7 Apr 2025 15:32:35 +0300 From: Jarkko Sakkinen To: keyrings@vger.kernel.org Cc: stable@vger.kernel.org, Herbert Xu , David Howells , Lukas Wunner , Ignat Korchagin , "David S. Miller" , Peter Huewe , Jason Gunthorpe , James Bottomley , Ard Biesheuvel , linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org, linux-integrity@vger.kernel.org Subject: Re: [PATCH v4] tpm: Mask TPM RC in tpm2_start_auth_session() Message-ID: References: <20250407072057.81062-1-jarkko@kernel.org> <20250407122806.15400-1-jarkko@kernel.org> Precedence: bulk X-Mailing-List: linux-integrity@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: <20250407122806.15400-1-jarkko@kernel.org> On Mon, Apr 07, 2025 at 03:28:05PM +0300, Jarkko Sakkinen wrote: > tpm2_start_auth_session() does not mask TPM RC correctly from the callers: > > [ 28.766528] tpm tpm0: A TPM error (2307) occurred start auth session > > Process TPM RCs inside tpm2_start_auth_session(), and map them to POSIX > error codes. > > Cc: stable@vger.kernel.org # v6.10+ > Fixes: 699e3efd6c64 ("tpm: Add HMAC session start and end functions") > Reported-by: Herbert Xu > Closes: https://lore.kernel.org/linux-integrity/Z_NgdRHuTKP6JK--@gondor.apana.org.au/ > Signed-off-by: Jarkko Sakkinen > --- > v4: > - tpm_to_ret() > v3: > - rc > 0 > v2: > - Investigate TPM rc only after destroying tpm_buf. > --- > drivers/char/tpm/tpm2-sessions.c | 20 ++++++-------------- > include/linux/tpm.h | 21 +++++++++++++++++++++ > 2 files changed, 27 insertions(+), 14 deletions(-) > > diff --git a/drivers/char/tpm/tpm2-sessions.c b/drivers/char/tpm/tpm2-sessions.c > index 3f89635ba5e8..102e099f22c1 100644 > --- a/drivers/char/tpm/tpm2-sessions.c > +++ b/drivers/char/tpm/tpm2-sessions.c > @@ -40,11 +40,6 @@ > * > * These are the usage functions: > * > - * tpm2_start_auth_session() which allocates the opaque auth structure > - * and gets a session from the TPM. This must be called before > - * any of the following functions. The session is protected by a > - * session_key which is derived from a random salt value > - * encrypted to the NULL seed. > * tpm2_end_auth_session() kills the session and frees the resources. > * Under normal operation this function is done by > * tpm_buf_check_hmac_response(), so this is only to be used on > @@ -963,16 +958,13 @@ static int tpm2_load_null(struct tpm_chip *chip, u32 *null_key) > } > > /** > - * tpm2_start_auth_session() - create a HMAC authentication session with the TPM > - * @chip: the TPM chip structure to create the session with > + * tpm2_start_auth_session() - Create an a HMAC authentication session > + * @chip: A TPM chip > * > - * This function loads the NULL seed from its saved context and starts > - * an authentication session on the null seed, fills in the > - * @chip->auth structure to contain all the session details necessary > - * for performing the HMAC, encrypt and decrypt operations and > - * returns. The NULL seed is flushed before this function returns. > + * Loads the ephemeral key (null seed), and starts an HMAC authenticated > + * session. The null seed is flushed before the return. > * > - * Return: zero on success or actual error encountered. > + * Returns zero on success, or a POSIX error code. > */ > int tpm2_start_auth_session(struct tpm_chip *chip) > { > @@ -1024,7 +1016,7 @@ int tpm2_start_auth_session(struct tpm_chip *chip) > /* hash algorithm for session */ > tpm_buf_append_u16(&buf, TPM_ALG_SHA256); > > - rc = tpm_transmit_cmd(chip, &buf, 0, "start auth session"); > + rc = tpm_to_ret(tpm_transmit_cmd(chip, &buf, 0, "StartAuthSession")); The cool thing here is that e.g., in the case of tpm2_start_auth_session, there is two implementation options: 1. tpm_to_ret(tpm2_start_auth_session) 2. tpm_to_ret(tpm_transmit_cmd) Just want to expose this choice.. > tpm2_flush_context(chip, null_key); > > if (rc == TPM2_RC_SUCCESS) > diff --git a/include/linux/tpm.h b/include/linux/tpm.h > index 6c3125300c00..c826d5a9d894 100644 > --- a/include/linux/tpm.h > +++ b/include/linux/tpm.h > @@ -257,8 +257,29 @@ enum tpm2_return_codes { > TPM2_RC_TESTING = 0x090A, /* RC_WARN */ > TPM2_RC_REFERENCE_H0 = 0x0910, > TPM2_RC_RETRY = 0x0922, > + TPM2_RC_SESSION_MEMORY = 0x0903, > }; > > +/* > + * Convert a return value from tpm_transmit_cmd() to a POSIX return value. The > + * fallback return value is -EFAULT. > + */ > +static inline ssize_t tpm_to_ret(ssize_t ret) > +{ > + /* Already a POSIX error: */ > + if (ret < 0) > + return ret; > + > + switch (ret) { > + case TPM2_RC_SUCCESS: > + return 0; > + case TPM2_RC_SESSION_MEMORY: > + return -ENOMEM; > + default: > + return -EFAULT; > + } > +} > + > enum tpm2_command_codes { > TPM2_CC_FIRST = 0x011F, > TPM2_CC_HIERARCHY_CONTROL = 0x0121, > -- > 2.39.5 > BR, Jarkko