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Message-Id: <5a0628cb-84e2-6fab-8fce-a77dc7adceb2@linux.ibm.com>
Date: Thu, 8 Nov 2018 10:43:46 -0500
From: Stefan Berger <stefanb@...ux.ibm.com>
To: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>,
linux-integrity@...r.kernel.org
Cc: linux-security-module@...r.kernel.org,
James Bottomley <James.Bottomley@...senPartnership.com>,
Tomas Winkler <tomas.winkler@...el.com>,
Tadeusz Struk <tadeusz.struk@...el.com>,
Stefan Berger <stefanb@...ux.vnet.ibm.com>,
Nayna Jain <nayna@...ux.ibm.com>,
Peter Huewe <peterhuewe@....de>,
Jason Gunthorpe <jgg@...pe.ca>, Arnd Bergmann <arnd@...db.de>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v5 14/17] tpm: remove TPM_TRANSMIT_UNLOCKED flag
On 11/8/18 9:15 AM, Jarkko Sakkinen wrote:
> Added locking as part of tpm_try_get_ops() and tpm_put_ops() as they are
> anyway used in most of the call sites except in tpmrm_release() where we
> take the locks manually.
>
> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
> ---
> drivers/char/tpm/tpm-chip.c | 2 ++
> drivers/char/tpm/tpm-dev-common.c | 4 +---
> drivers/char/tpm/tpm-interface.c | 8 --------
> drivers/char/tpm/tpm.h | 8 ++------
> drivers/char/tpm/tpm2-cmd.c | 13 ++++---------
> drivers/char/tpm/tpm2-space.c | 15 ++++++---------
> 6 files changed, 15 insertions(+), 35 deletions(-)
>
> diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
> index 32db84683c40..157505b0f755 100644
> --- a/drivers/char/tpm/tpm-chip.c
> +++ b/drivers/char/tpm/tpm-chip.c
> @@ -58,6 +58,7 @@ int tpm_try_get_ops(struct tpm_chip *chip)
> if (!chip->ops)
> goto out_lock;
>
> + mutex_lock(&chip->tpm_mutex);
> return 0;
> out_lock:
> up_read(&chip->ops_sem);
> @@ -75,6 +76,7 @@ EXPORT_SYMBOL_GPL(tpm_try_get_ops);
> */
> void tpm_put_ops(struct tpm_chip *chip)
> {
> + mutex_unlock(&chip->tpm_mutex);
> up_read(&chip->ops_sem);
> put_device(&chip->dev);
> }
> diff --git a/drivers/char/tpm/tpm-dev-common.c b/drivers/char/tpm/tpm-dev-common.c
> index c7dc54930576..582caefcf19b 100644
> --- a/drivers/char/tpm/tpm-dev-common.c
> +++ b/drivers/char/tpm/tpm-dev-common.c
> @@ -33,7 +33,6 @@ static ssize_t tpm_dev_transmit(struct tpm_chip *chip, struct tpm_space *space,
> struct tpm_header *header = (void *)buf;
> ssize_t ret, len;
>
> - mutex_lock(&chip->tpm_mutex);
> 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.
> @@ -48,7 +47,7 @@ static ssize_t tpm_dev_transmit(struct tpm_chip *chip, struct tpm_space *space,
> if (ret)
> goto out_lock;
>
> - len = tpm_transmit(chip, buf, bufsiz, TPM_TRANSMIT_UNLOCKED);
> + len = tpm_transmit(chip, buf, bufsiz, 0);
> if (len < 0)
> ret = len;
>
> @@ -57,7 +56,6 @@ static ssize_t tpm_dev_transmit(struct tpm_chip *chip, struct tpm_space *space,
> else
> ret = tpm2_commit_space(chip, space, buf, &len);
> out_lock:
> - mutex_unlock(&chip->tpm_mutex);
> return ret ? ret : len;
> }
>
> diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
> index 8d75c103f280..5865b9671d20 100644
> --- a/drivers/char/tpm/tpm-interface.c
> +++ b/drivers/char/tpm/tpm-interface.c
> @@ -227,10 +227,6 @@ ssize_t tpm_transmit(struct tpm_chip *chip, u8 *buf, size_t bufsiz,
> memcpy(save, buf, save_size);
>
> for (;;) {
> - if (!(flags & TPM_TRANSMIT_UNLOCKED) &&
> - !(flags & TPM_TRANSMIT_NESTED))
> - mutex_lock(&chip->tpm_mutex);
> -
> if (chip->ops->clk_enable != NULL)
> chip->ops->clk_enable(chip, true);
>
> @@ -257,10 +253,6 @@ ssize_t tpm_transmit(struct tpm_chip *chip, u8 *buf, size_t bufsiz,
> if (chip->ops->clk_enable != NULL)
> chip->ops->clk_enable(chip, false);
>
> - if (!(flags & TPM_TRANSMIT_UNLOCKED) &&
> - !(flags & TPM_TRANSMIT_NESTED))
> - mutex_unlock(&chip->tpm_mutex);
> -
> if (ret < 0)
> break;
> rc = be32_to_cpu(header->return_code);
> diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
> index 10a5bcf806aa..c7c06de651a0 100644
> --- a/drivers/char/tpm/tpm.h
> +++ b/drivers/char/tpm/tpm.h
> @@ -488,14 +488,10 @@ extern struct idr dev_nums_idr;
> /**
> * enum tpm_transmit_flags - flags for tpm_transmit()
> *
> - * @TPM_TRANSMIT_UNLOCKED: do not lock the chip
> - * @TPM_TRANSMIT_NESTED: discard setup steps (power management,
> - * locality) including locking (i.e. implicit
> - * UNLOCKED)
> + * %TPM_TRANSMIT_NESTED: discard setup steps (power management, locality)
> */
> enum tpm_transmit_flags {
> - TPM_TRANSMIT_UNLOCKED = BIT(0),
> - TPM_TRANSMIT_NESTED = BIT(1),
> + TPM_TRANSMIT_NESTED = BIT(0),
> };
>
> ssize_t tpm_transmit(struct tpm_chip *chip, u8 *buf, size_t bufsiz,
> diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
> index f2b0e5c52a57..d6abc964ef66 100644
> --- a/drivers/char/tpm/tpm2-cmd.c
> +++ b/drivers/char/tpm/tpm2-cmd.c
> @@ -652,17 +652,12 @@ int tpm2_unseal_trusted(struct tpm_chip *chip,
> u32 blob_handle;
> int rc;
>
> - mutex_lock(&chip->tpm_mutex);
> - rc = tpm2_load_cmd(chip, payload, options, &blob_handle,
> - TPM_TRANSMIT_UNLOCKED);
> + rc = tpm2_load_cmd(chip, payload, options, &blob_handle, 0);
> if (rc)
> - goto out;
> + return rc;
>
> - rc = tpm2_unseal_cmd(chip, payload, options, blob_handle,
> - TPM_TRANSMIT_UNLOCKED);
> - tpm2_flush_context_cmd(chip, blob_handle, TPM_TRANSMIT_UNLOCKED);
> -out:
> - mutex_unlock(&chip->tpm_mutex);
> + rc = tpm2_unseal_cmd(chip, payload, options, blob_handle, 0);
> + tpm2_flush_context_cmd(chip, blob_handle, 0);
This lock was covering quite a few commands from being interfered by
others. Is this still guaranteed to work after or can different
subsystems like trusted keys and IMA and /dev/tpm0 users interfere with
this previous atomic sequence ?
> return rc;
> }
>
> diff --git a/drivers/char/tpm/tpm2-space.c b/drivers/char/tpm/tpm2-space.c
> index d1c371db1ab7..341d4b90ba2f 100644
> --- a/drivers/char/tpm/tpm2-space.c
> +++ b/drivers/char/tpm/tpm2-space.c
> @@ -38,8 +38,7 @@ static void tpm2_flush_sessions(struct tpm_chip *chip, struct tpm_space *space)
>
> for (i = 0; i < ARRAY_SIZE(space->session_tbl); i++) {
> if (space->session_tbl[i])
> - tpm2_flush_context_cmd(chip, space->session_tbl[i],
> - TPM_TRANSMIT_UNLOCKED);
> + tpm2_flush_context_cmd(chip, space->session_tbl[i], 0);
> }
> }
>
> @@ -83,7 +82,7 @@ static int tpm2_load_context(struct tpm_chip *chip, u8 *buf,
> body_size = sizeof(*ctx) + be16_to_cpu(ctx->blob_size);
> tpm_buf_append(&tbuf, &buf[*offset], body_size);
>
> - rc = tpm_transmit_cmd(chip, &tbuf, 4, TPM_TRANSMIT_UNLOCKED, NULL);
> + rc = tpm_transmit_cmd(chip, &tbuf, 4, 0, NULL);
> if (rc < 0) {
> dev_warn(&chip->dev, "%s: failed with a system error %d\n",
> __func__, rc);
> @@ -131,7 +130,7 @@ static int tpm2_save_context(struct tpm_chip *chip, u32 handle, u8 *buf,
>
> tpm_buf_append_u32(&tbuf, handle);
>
> - rc = tpm_transmit_cmd(chip, &tbuf, 0, TPM_TRANSMIT_UNLOCKED, NULL);
> + rc = tpm_transmit_cmd(chip, &tbuf, 0, 0, NULL);
> if (rc < 0) {
> dev_warn(&chip->dev, "%s: failed with a system error %d\n",
> __func__, rc);
> @@ -167,8 +166,7 @@ void tpm2_flush_space(struct tpm_chip *chip)
>
> for (i = 0; i < ARRAY_SIZE(space->context_tbl); i++)
> if (space->context_tbl[i] && ~space->context_tbl[i])
> - tpm2_flush_context_cmd(chip, space->context_tbl[i],
> - TPM_TRANSMIT_UNLOCKED);
> + tpm2_flush_context_cmd(chip, space->context_tbl[i], 0);
>
> tpm2_flush_sessions(chip, space);
> }
> @@ -417,7 +415,7 @@ static int tpm2_map_response_header(struct tpm_chip *chip, u32 cc, u8 *rsp,
>
> return 0;
> out_no_slots:
> - tpm2_flush_context_cmd(chip, phandle, TPM_TRANSMIT_UNLOCKED);
> + tpm2_flush_context_cmd(chip, phandle, 0);
> dev_warn(&chip->dev, "%s: out of slots for 0x%08X\n", __func__,
> phandle);
> return -ENOMEM;
> @@ -504,8 +502,7 @@ static int tpm2_save_space(struct tpm_chip *chip)
> } else if (rc)
> return rc;
>
> - tpm2_flush_context_cmd(chip, space->context_tbl[i],
> - TPM_TRANSMIT_UNLOCKED);
> + tpm2_flush_context_cmd(chip, space->context_tbl[i], 0);
> space->context_tbl[i] = ~0;
> }
>
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