From nobody Fri Nov 29 19:30:55 2024 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 4B73B194AE6; Tue, 17 Sep 2024 15:45:08 +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=1726587909; cv=none; b=A3FCdklooJYBAvVbJ55OyjFuMmrLJDAhruJ8k0ti6KqCsG40oUZHnMxWFUjXg31Q1PXkDNcfMR7T1vGV26kaKfFniOhu6l8duqUhnXj4h21t7pt8q/2DuYyYjQLR3cCtlMHNhduFB7V54pnVTKvuHEhg+nDE21Fi8wJwt/pG3/Q= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726587909; c=relaxed/simple; bh=C3Mpaxh2OV6YvryYeWN6bkOf7x9QWfSOd3mncoa4OuE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=mjqliJ3i44g+OVX/suibt/LWuPQEluMb3hwgAeLVzNIkfzn02fpnpWeb1j2J9cRnYut4asovnznjirB5BHoAPI/gKEGpF13U2JHLi9hw260uTwEcVLvoRro0u4FO3SK2xwZMzgcgZ34qONVEhBx4AXCqPtW1DoOfbT3J0IAaEqY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=lqK7quu1; 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="lqK7quu1" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 76696C4CEC5; Tue, 17 Sep 2024 15:45:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1726587908; bh=C3Mpaxh2OV6YvryYeWN6bkOf7x9QWfSOd3mncoa4OuE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=lqK7quu1NRBUgl9TMeGqUFdTSBklwF5p+aTLQXsLLk96BOpABcIe4nOmkKmDZ7piZ w8KIZo+Dz9Y/ZvkX5JenFxV/99NvTcYENtlbg0TP+z0rfkuYeMCdRYACfGGGnnTnTb CHI0sGLM7u/V6w+ZDm87iHtLki/uECxDhTXQFJkGHEz87xac4wknH15FXAdu1PQDed 49PduawY+2jfvLw49IaUs/slyet8l8DXgP7TQ2n4CXzST3fcQXHkET1H1x0udkbr5Y hhZnjrwRwRGRszwrzxONs7RgYui3IAPy54ueA0f5YnyDbBhoRimAph/l4JWr0L4IjO MfwgYnXQGgQTA== From: Jarkko Sakkinen To: linux-integrity@vger.kernel.org Cc: James.Bottomley@HansenPartnership.com, roberto.sassu@huawei.com, mapengyu@gmail.com, Jarkko Sakkinen , Mimi Zohar , David Howells , Paul Moore , James Morris , "Serge E. Hallyn" , keyrings@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v3 4/7] tpm: flush the null key only when /dev/tpm0 is accessed Date: Tue, 17 Sep 2024 18:44:33 +0300 Message-ID: <20240917154444.702370-5-jarkko@kernel.org> X-Mailer: git-send-email 2.46.0 In-Reply-To: <20240917154444.702370-1-jarkko@kernel.org> References: <20240917154444.702370-1-jarkko@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Instead of flushing and reloading the null key for every single auth session, flush it only when: 1. User space needs to access /dev/tpm{rm}0. 2. When going to sleep. 3. When unregistering the chip. This removes the need to load and swap the null key between TPM and regular memory per transaction, when the user space is not using the chip. Tested-by: Pengyu Ma Signed-off-by: Jarkko Sakkinen --- v3: - Unchanged. v2: - Refined the commit message. - Added tested-by from Pengyu Ma . - Removed spurious pr_info() statement. --- drivers/char/tpm/tpm-chip.c | 13 +++++++++++++ drivers/char/tpm/tpm-dev-common.c | 7 +++++++ drivers/char/tpm/tpm-interface.c | 9 +++++++-- drivers/char/tpm/tpm2-cmd.c | 3 +++ drivers/char/tpm/tpm2-sessions.c | 17 ++++++++++++++--- include/linux/tpm.h | 2 ++ 6 files changed, 46 insertions(+), 5 deletions(-) diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c index 854546000c92..0ea00e32f575 100644 --- a/drivers/char/tpm/tpm-chip.c +++ b/drivers/char/tpm/tpm-chip.c @@ -674,6 +674,19 @@ EXPORT_SYMBOL_GPL(tpm_chip_register); */ void tpm_chip_unregister(struct tpm_chip *chip) { +#ifdef CONFIG_TCG_TPM2_HMAC + int rc; + + rc =3D tpm_try_get_ops(chip); + if (!rc) { + if (chip->flags & TPM_CHIP_FLAG_TPM2) { + tpm2_flush_context(chip, chip->null_key); + chip->null_key =3D 0; + } + tpm_put_ops(chip); + } +#endif + tpm_del_legacy_sysfs(chip); if (tpm_is_hwrng_enabled(chip)) hwrng_unregister(&chip->hwrng); diff --git a/drivers/char/tpm/tpm-dev-common.c b/drivers/char/tpm/tpm-dev-c= ommon.c index c3fbbf4d3db7..4bc07963e260 100644 --- a/drivers/char/tpm/tpm-dev-common.c +++ b/drivers/char/tpm/tpm-dev-common.c @@ -27,6 +27,13 @@ static ssize_t tpm_dev_transmit(struct tpm_chip *chip, s= truct tpm_space *space, struct tpm_header *header =3D (void *)buf; ssize_t ret, len; =20 +#ifdef CONFIG_TCG_TPM2_HMAC + if (chip->flags & TPM_CHIP_FLAG_TPM2) { + tpm2_flush_context(chip, chip->null_key); + chip->null_key =3D 0; + } +#endif + ret =3D tpm2_prepare_space(chip, space, buf, bufsiz); /* If the command is not implemented by the TPM, synthesize a * response with a TPM2_RC_COMMAND_CODE return for user-space. diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interf= ace.c index 5da134f12c9a..bfa47d48b0f2 100644 --- a/drivers/char/tpm/tpm-interface.c +++ b/drivers/char/tpm/tpm-interface.c @@ -379,10 +379,15 @@ int tpm_pm_suspend(struct device *dev) =20 rc =3D tpm_try_get_ops(chip); if (!rc) { - if (chip->flags & TPM_CHIP_FLAG_TPM2) + if (chip->flags & TPM_CHIP_FLAG_TPM2) { +#ifdef CONFIG_TCG_TPM2_HMAC + tpm2_flush_context(chip, chip->null_key); + chip->null_key =3D 0; +#endif tpm2_shutdown(chip, TPM2_SU_STATE); - else + } else { rc =3D tpm1_pm_suspend(chip, tpm_suspend_pcr); + } =20 tpm_put_ops(chip); } diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c index 1e856259219e..aba024cbe7c5 100644 --- a/drivers/char/tpm/tpm2-cmd.c +++ b/drivers/char/tpm/tpm2-cmd.c @@ -364,6 +364,9 @@ void tpm2_flush_context(struct tpm_chip *chip, u32 hand= le) struct tpm_buf buf; int rc; =20 + if (!handle) + return; + rc =3D tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_FLUSH_CONTEXT); if (rc) { dev_warn(&chip->dev, "0x%08x was not flushed, out of memory\n", diff --git a/drivers/char/tpm/tpm2-sessions.c b/drivers/char/tpm/tpm2-sessi= ons.c index 03c56f0eda49..5227bf6097a0 100644 --- a/drivers/char/tpm/tpm2-sessions.c +++ b/drivers/char/tpm/tpm2-sessions.c @@ -855,11 +855,19 @@ static int tpm2_load_null(struct tpm_chip *chip, u32 = *null_key) u32 tmp_null_key; int rc; =20 + /* fast path */ + if (chip->null_key) { + *null_key =3D chip->null_key; + return 0; + } + rc =3D tpm2_load_context(chip, chip->null_key_context, &offset, &tmp_null_key); if (rc !=3D -EINVAL) { - if (!rc) + if (!rc) { + chip->null_key =3D tmp_null_key; *null_key =3D tmp_null_key; + } return rc; } dev_info(&chip->dev, "the null key has been reset\n"); @@ -870,6 +878,7 @@ static int tpm2_load_null(struct tpm_chip *chip, u32 *n= ull_key) =20 /* Return the null key if the name has not been changed: */ if (memcmp(name, chip->null_key_name, sizeof(name)) =3D=3D 0) { + chip->null_key =3D tmp_null_key; *null_key =3D tmp_null_key; return 0; } @@ -940,7 +949,6 @@ int tpm2_start_auth_session(struct tpm_chip *chip) tpm_buf_append_u16(&buf, TPM_ALG_SHA256); =20 rc =3D tpm_transmit_cmd(chip, &buf, 0, "start auth session"); - tpm2_flush_context(chip, null_key); =20 if (rc =3D=3D TPM2_RC_SUCCESS) rc =3D tpm2_parse_start_auth_session(auth, &buf); @@ -1272,7 +1280,10 @@ static int tpm2_create_null_primary(struct tpm_chip = *chip) =20 rc =3D tpm2_save_context(chip, null_key, chip->null_key_context, sizeof(chip->null_key_context), &offset); - tpm2_flush_context(chip, null_key); + if (rc) + tpm2_flush_context(chip, null_key); + else + chip->null_key =3D null_key; } =20 if (rc < 0) diff --git a/include/linux/tpm.h b/include/linux/tpm.h index e93ee8d936a9..4eb39db80e05 100644 --- a/include/linux/tpm.h +++ b/include/linux/tpm.h @@ -205,6 +205,8 @@ struct tpm_chip { #ifdef CONFIG_TCG_TPM2_HMAC /* details for communication security via sessions */ =20 + /* loaded null key */ + u32 null_key; /* saved context for NULL seed */ u8 null_key_context[TPM2_MAX_CONTEXT_SIZE]; /* name of NULL seed */ --=20 2.46.0