From patchwork Wed Sep 18 20:35:47 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jarkko Sakkinen X-Patchwork-Id: 13807146 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 B89E81CB53B; Wed, 18 Sep 2024 20:36:24 +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=1726691784; cv=none; b=u9qCxi9mdvB2uspkIoop/O6uEuKsPZynjbGeIPcD6lR6OCHhl9pybLAtkzA3pt6Tr4LepesWe3k0UNL3kYiQsMKNSapNeCrsHSd2YApSSu8OjaWdpwAe+PeWcvN9tmIDuHsA4W8p+u4OLQrsBY53n/LP5Pb8dPutrgWvhbLUPH4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726691784; c=relaxed/simple; bh=kbo0Z0RhoCm2kz1JvajJujVV7vc6cCJXd+V6ZXLaxNQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=pGUlqb4E3X6YK74FA7RjKe9N1cN3Q5aVP+3jTERv55mTuY9L2E5zIzwHXMIcdKfCdqZFa7fL7DQvT3FBsHtek5IJvdB+DzVbUtpcmHc2Rb8PVQOmZRKgvo5YfnKMIguNk4f4Fh6FX18E0YyrnN/lrvePweGRINMsm/clHjkgRQw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=KQjphzQz; 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="KQjphzQz" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C8CB6C4CEC2; Wed, 18 Sep 2024 20:36:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1726691784; bh=kbo0Z0RhoCm2kz1JvajJujVV7vc6cCJXd+V6ZXLaxNQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KQjphzQzeQzXPggjPjBamdrZnOPySVFuzTmP10LeZ9m17oQgKwbnsa7GQElmuu8gX pEcqwGsBoT0Ch0rsj+JiRvCfSh1/W14PnNZEi71jjJm6BQfUjpal165hCqOj4ldpnB /da5sCjABT6uR/BChrqEcJ0x0tVvvH4jLP3ZAwl4MRfV8xZ7S8ZOY5glW1Q1JPqPmn 65ELZaBIhw14S/NsRTtBg265pmP40sha26BvstXFdwiO2pIt5aw4xiL5+OfNk2OWqO lrNenMzVkzrVBXcLyzEEfbLEG0iujzJGWEMqEBpIAIpgRtFHpscEXnNOc/hPByzoq6 4skR5AkAA4S9w== From: Jarkko Sakkinen To: linux-integrity@vger.kernel.org Cc: James.Bottomley@HansenPartnership.com, roberto.sassu@huawei.com, mapengyu@gmail.com, Jarkko Sakkinen , stable@vger.kernel.org, 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 v4 3/5] tpm: flush the null key only when /dev/tpm0 is accessed Date: Wed, 18 Sep 2024 23:35:47 +0300 Message-ID: <20240918203559.192605-4-jarkko@kernel.org> X-Mailer: git-send-email 2.46.0 In-Reply-To: <20240918203559.192605-1-jarkko@kernel.org> References: <20240918203559.192605-1-jarkko@kernel.org> Precedence: bulk X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 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. Cc: stable@vger.kernel.org # v6.10+ Fixes: d2add27cf2b8 ("tpm: Add NULL primary creation") Tested-by: Pengyu Ma Signed-off-by: Jarkko Sakkinen --- v4: - Changed to bug fix as not having the patch there is a major hit to bootup times. 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 = tpm_try_get_ops(chip); + if (!rc) { + if (chip->flags & TPM_CHIP_FLAG_TPM2) { + tpm2_flush_context(chip, chip->null_key); + chip->null_key = 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-common.c index 30b4c288c1bb..4eaa8e05c291 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, struct tpm_space *space, struct tpm_header *header = (void *)buf; ssize_t ret, len; +#ifdef CONFIG_TCG_TPM2_HMAC + if (chip->flags & TPM_CHIP_FLAG_TPM2) { + tpm2_flush_context(chip, chip->null_key); + chip->null_key = 0; + } +#endif + ret = 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-interface.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) rc = 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 = 0; +#endif tpm2_shutdown(chip, TPM2_SU_STATE); - else + } else { rc = tpm1_pm_suspend(chip, tpm_suspend_pcr); + } 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 handle) struct tpm_buf buf; int rc; + if (!handle) + return; + rc = 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-sessions.c index a62f64e21511..42eb910e9acc 100644 --- a/drivers/char/tpm/tpm2-sessions.c +++ b/drivers/char/tpm/tpm2-sessions.c @@ -920,11 +920,19 @@ static int tpm2_load_null(struct tpm_chip *chip, u32 *null_key) u32 tmp_null_key; int rc; + /* fast path */ + if (chip->null_key) { + *null_key = chip->null_key; + return 0; + } + rc = tpm2_load_context(chip, chip->null_key_context, &offset, &tmp_null_key); if (rc != -EINVAL) { - if (!rc) + if (!rc) { + chip->null_key = tmp_null_key; *null_key = tmp_null_key; + } return rc; } dev_info(&chip->dev, "the null key has been reset\n"); @@ -935,6 +943,7 @@ static int tpm2_load_null(struct tpm_chip *chip, u32 *null_key) /* Return the null key if the name has not been changed: */ if (memcmp(name, chip->null_key_name, sizeof(name)) == 0) { + chip->null_key = tmp_null_key; *null_key = tmp_null_key; return 0; } @@ -1005,7 +1014,6 @@ int tpm2_start_auth_session(struct tpm_chip *chip) tpm_buf_append_u16(&buf, TPM_ALG_SHA256); rc = tpm_transmit_cmd(chip, &buf, 0, "start auth session"); - tpm2_flush_context(chip, null_key); if (rc == TPM2_RC_SUCCESS) rc = tpm2_parse_start_auth_session(auth, &buf); @@ -1337,7 +1345,10 @@ static int tpm2_create_null_primary(struct tpm_chip *chip) rc = 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 = null_key; } 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 */ + /* loaded null key */ + u32 null_key; /* saved context for NULL seed */ u8 null_key_context[TPM2_MAX_CONTEXT_SIZE]; /* name of NULL seed */