From nobody Fri Nov 29 21:50:09 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 350B81CB318; Sun, 15 Sep 2024 18:05:11 +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=1726423512; cv=none; b=mpB1Opd7O+1JvbLDbjvRHJihni8e6mRqhDbCpphvNyvn/fLGPqrv9i9N0/yWgBJskYTYyMV3agneXbfym8vPVqfHG9lXhoIkBfeHTixj2lcmMD0kdK9ASMC6gB72xyJK/2eUuTNYYtoRqYSx/TuW55MtiMguKAGqTvZswXLAgsw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726423512; c=relaxed/simple; bh=pJB+gvoxB2IwXeXptgWGI8FB54z9gpIY0FmdSPIoBaA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=HpgaURt2JoOB+Nbtd/LtSAJuKE3d5SZP1kxE1aoW3SbvTHEnl3+jjhr2trdEIMqk0/g5C0wCLAcP3qzne0NyYYNOpwMlEKBHJBVTGVwIq03Mwl2chKGuQIp62hqZUGuUjS+AdQV6+if4+S02np3SIzsD9PSPrL3i+ZTow1wZO3g= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=FKX9Uuk1; 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="FKX9Uuk1" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 63E10C4CEC3; Sun, 15 Sep 2024 18:05:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1726423511; bh=pJB+gvoxB2IwXeXptgWGI8FB54z9gpIY0FmdSPIoBaA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FKX9Uuk1spKCi+Hw0guxSwKslWX0t9gJGaHTEwK7+8Ihf/mh+yw2vOme/lnos4xHe h7KlbX+hohx5Cz4HPYVoS09o5fNJ4BagOgaeE1y/HoqGPMl4Uh48bkICkuaqljsS4E k92Y0G1Chlx171QumRuE/TJwftB2Xc6cytenkAndIgW7mfWElsu9XHbkZRyqKX1Q0W JHOYTmM6wgjotukZaAwRyxy/aI7Bx7slJ6ucsErsfwUfTA0vjQIuLLRD0UBGNUzwYj bA1XS8H+OuxVoQmPnsgj2+/rzHbmzrOkilEPvyvSVpGYXG4gFHgUhHgk5Zs2l/aOgv SiTejSKVcTtDQ== 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 , Stefan Berger , Ard Biesheuvel , linux-kernel@vger.kernel.org (open list) Subject: [PATCH 4/4] tpm: flush the session null key only when required Date: Sun, 15 Sep 2024 21:04:46 +0300 Message-ID: <20240915180448.2030115-5-jarkko@kernel.org> X-Mailer: git-send-email 2.46.0 In-Reply-To: <20240915180448.2030115-1-jarkko@kernel.org> References: <20240915180448.2030115-1-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. Signed-off-by: Jarkko Sakkinen --- 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 | 23 +++++++++++++++++++---- include/linux/tpm.h | 2 ++ 6 files changed, 51 insertions(+), 6 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 34ce0d9d4577..8d7b708ce566 100644 --- a/drivers/char/tpm/tpm2-sessions.c +++ b/drivers/char/tpm/tpm2-sessions.c @@ -855,10 +855,21 @@ 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, - null_key); - if (rc !=3D -EINVAL) + &tmp_null_key); + if (rc !=3D -EINVAL) { + if (!rc) { + chip->null_key =3D tmp_null_key; + *null_key =3D tmp_null_key; + } return rc; + } =20 /* an integrity failure may mean the TPM has been reset */ dev_err(&chip->dev, "NULL key integrity failure!\n"); @@ -869,6 +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; } @@ -946,7 +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); @@ -1275,7 +1286,11 @@ 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); + pr_info("%s: rc=3D0x%08x\n", __func__, rc); + 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