From nobody Fri Nov 29 20:55:40 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 7134D155333; Mon, 16 Sep 2024 11:07:40 +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=1726484860; cv=none; b=d02A8+hUPxATEZ4bJWycXH4Gszu+p6Eio4+9NcRZGzGv500JMJybWnK1aoBorzuccQ1azc4S+VEybAKiEip3xsl/YLVrr+cwD1ozqxaBG14Xe5/BUNlfssku/0SoG1fyoq10hytY4LEI92Bwv5bqC4vDkAWC1ffwWfDkr4C2fCU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726484860; c=relaxed/simple; bh=LMBOVTLhQra6uPehKBIVfVv9QIeKqZZrvqc1FlP7ctg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=pgGy6h3xlMSfSSfOi/540DuwBcCgSM0gChY1saYoSs2qyD0tKZRHP80VM/KAdoXIylWX4ZcS1s9MClvq5+AKfZjzyoE+FhsFQPZxC9fNBZ7Jjz+80zZ1A5UfX+I1TTK6BHmDWHTCdNVEzSJLDSdzoxb4TtCOQoMZey/iwYDzI7w= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=chJIxOBU; 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="chJIxOBU" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A3208C4CEC4; Mon, 16 Sep 2024 11:07:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1726484860; bh=LMBOVTLhQra6uPehKBIVfVv9QIeKqZZrvqc1FlP7ctg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=chJIxOBUJyJ0GRVx2dPAHMo/r/TFtL7O7XK7dx13FBMhy1pB1vKnB3B73aUY7Ymic /1bcUaPY4/sDEZpXEtYjIoXmHiI8TrTfETpaTU1wJEZPnvJN+GSRFHsxY72PpEGbR8 0/5wKezpu9viUiDZlmSfRnTBBb+jzwaHYcj0Uv8muaGKHQdvfX1J9BBK7FxacC586e 54/nsdwZAImAL+XMKbM4hd5Klygb2qesftiIZdO4wk2TZs2LpNkACDVbTlZK92pC+5 zK02Wcwmg/DN4XMtJwYA+TE9LNrFKBd+xPlhSzTd2pzDNTzSqmsq2UP5Yepcj+9WcC sVy6Yv0H82lSQ== From: Jarkko Sakkinen To: linux-integrity@vger.kernel.org Cc: James.Bottomley@HansenPartnership.com, roberto.sassu@huawei.com, mapengyu@gmail.com, Jarkko Sakkinen , Peter Huewe , Jason Gunthorpe , Mimi Zohar , David Howells , Paul Moore , James Morris , "Serge E. Hallyn" , Stefan Berger , Ard Biesheuvel , linux-kernel@vger.kernel.org (open list), keyrings@vger.kernel.org (open list:KEYS-TRUSTED), linux-security-module@vger.kernel.org (open list:SECURITY SUBSYSTEM) Subject: [PATCH v2 4/6] tpm: flush the null key only when /dev/tpm0 is accessed Date: Mon, 16 Sep 2024 14:07:09 +0300 Message-ID: <20240916110714.1396407-5-jarkko@kernel.org> X-Mailer: git-send-email 2.46.0 In-Reply-To: <20240916110714.1396407-1-jarkko@kernel.org> References: <20240916110714.1396407-1-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 --- 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 9c0356d7ce5e..fc1f3502e6ee 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; } =20 @@ -872,6 +880,7 @@ 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; } @@ -949,7 +958,6 @@ 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); @@ -1281,7 +1289,10 @@ 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 return rc; 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