| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <20170524192726.qsxrfjamy2khef37@intel.com>
Date: Wed, 24 May 2017 12:27:26 -0700
From: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
To: Stefan Berger <stefanb@...ux.vnet.ibm.com>
Cc: tpmdd-devel@...ts.sourceforge.net,
linux-security-module@...r.kernel.org,
jgunthorpe@...idianresearch.com, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v5 2/2] tpm: vtpm_proxy: Implement request_locality
function.
On Mon, May 22, 2017 at 10:29:24AM -0400, Stefan Berger wrote:
> On 05/20/2017 08:40 AM, Jarkko Sakkinen wrote:
> > On Mon, May 15, 2017 at 12:51:45PM -0400, Stefan Berger wrote:
> > > Implement the request_locality function. To set the locality on the
> > > backend we define vendor-specific TPM 1.2 and TPM 2 ordinals and send
> > > a command to the backend to set the locality for the next commands.
> > >
> > > To avoid recursing into requesting the locality, we set the
> > > TPM_TRASNMIT_RAW flag when calling tpm_trasnmit_cmd. To avoid recursing
> > > into TPM 2 space related commands, we set the space parameter to NULL.
> > >
> > > Signed-off-by: Stefan Berger <stefanb@...ux.vnet.ibm.com>
> > > ---
> > > drivers/char/tpm/tpm-interface.c | 1 +
> > > drivers/char/tpm/tpm_vtpm_proxy.c | 36 ++++++++++++++++++++++++++++++++++++
> > > include/uapi/linux/vtpm_proxy.h | 4 ++++
> > > 3 files changed, 41 insertions(+)
> > >
> > > diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
> > > index 2eacda2..876d45f 100644
> > > --- a/drivers/char/tpm/tpm-interface.c
> > > +++ b/drivers/char/tpm/tpm-interface.c
> > > @@ -537,6 +537,7 @@ ssize_t tpm_transmit_cmd(struct tpm_chip *chip, struct tpm_space *space,
> > > return 0;
> > > }
> > > +EXPORT_SYMBOL_GPL(tpm_transmit_cmd);
> > > #define TPM_DIGEST_SIZE 20
> > > #define TPM_RET_CODE_IDX 6
> > > diff --git a/drivers/char/tpm/tpm_vtpm_proxy.c b/drivers/char/tpm/tpm_vtpm_proxy.c
> > > index 751059d..66024bf 100644
> > > --- a/drivers/char/tpm/tpm_vtpm_proxy.c
> > > +++ b/drivers/char/tpm/tpm_vtpm_proxy.c
> > > @@ -371,6 +371,41 @@ static bool vtpm_proxy_tpm_req_canceled(struct tpm_chip *chip, u8 status)
> > > return ret;
> > > }
> > > +static int vtpm_proxy_request_locality(struct tpm_chip *chip, int locality)
> > > +{
> > > + struct tpm_buf buf;
> > > + int rc;
> > > + const struct tpm_output_header *header;
> > > +
> > > + if (chip->flags & TPM_CHIP_FLAG_TPM2)
> > > + rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS,
> > > + TPM2_CC_SET_LOCALITY);
> > > + else
> > > + rc = tpm_buf_init(&buf, TPM_TAG_RQU_COMMAND,
> > > + TPM_ORD_SET_LOCALITY);
> > > + if (rc)
> > > + return rc;
> > > + tpm_buf_append_u8(&buf, locality);
> > > +
> > > + rc = tpm_transmit_cmd(chip, NULL, buf.data, tpm_buf_length(&buf), 0,
> > > + TPM_TRANSMIT_UNLOCKED | TPM_TRANSMIT_RAW,
> > > + "attempting to set locality");
> > > + if (rc < 0) {
> > > + locality = rc;
> > > + goto out;
> > > + }
> > > +
> > > + header = (const struct tpm_output_header *)buf.data;
> > > + rc = be32_to_cpu(header->return_code);
> > > + if (rc)
> > > + locality = -1;
> > > +
> > > +out:
> > > + tpm_buf_destroy(&buf);
> > > +
> > > + return locality;
> > > +}
> > > +
> > This looks good.
> >
> > > static const struct tpm_class_ops vtpm_proxy_tpm_ops = {
> > > .flags = TPM_OPS_AUTO_STARTUP,
> > > .recv = vtpm_proxy_tpm_op_recv,
> > > @@ -380,6 +415,7 @@ static const struct tpm_class_ops vtpm_proxy_tpm_ops = {
> > > .req_complete_mask = VTPM_PROXY_REQ_COMPLETE_FLAG,
> > > .req_complete_val = VTPM_PROXY_REQ_COMPLETE_FLAG,
> > > .req_canceled = vtpm_proxy_tpm_req_canceled,
> > > + .request_locality = vtpm_proxy_request_locality,
> > > };
> > > /*
> > > diff --git a/include/uapi/linux/vtpm_proxy.h b/include/uapi/linux/vtpm_proxy.h
> > > index a69e991..58ac73c 100644
> > > --- a/include/uapi/linux/vtpm_proxy.h
> > > +++ b/include/uapi/linux/vtpm_proxy.h
> > > @@ -46,4 +46,8 @@ struct vtpm_proxy_new_dev {
> > > #define VTPM_PROXY_IOC_NEW_DEV _IOWR(0xa1, 0x00, struct vtpm_proxy_new_dev)
> > > +/* vendor specific commands to set locality */
> > > +#define TPM2_CC_SET_LOCALITY 0x20001000
> > > +#define TPM_ORD_SET_LOCALITY 0x20001000
> > > +
> > Maybe we should just have VTPM_CC_SET_LOCALITY? No reason to have TPM
> > version specific constant names. I wonder what would be the best range
> > for these CCs. Maybe 0xF0xxxxxxxx would be better?
>
> I am not sure about that.
>
> >
> > These are not changes that require a new patch set version but we they
> > need to be discussed before merging these changes.
>
> Unfortunately there is one more patch needed. We now need to restrict that
> this particular driver command can only be sent from inside the driver and
> never via any of the TPM devices (/dev/vtpm%d or /dev/tpmrm%d). That patch
> could then either return an error code if tried or return an error message.
> In the case of the TPM 2 spaces commands an error code is returned if a
> command isn't known. We could just do that instead of returning a full TPM
> error message. Here's the patch that would do that.
>
>
> To prevent userspace from sending the TPM driver command to set
> the locality, we need to check every command that is sent from
> user space. To distinguish user space commands from internally
> sent commands we introduce an additional state flag
> STATE_DRIVER_COMMAND that is set while the driver sends this
> command. Similar to the TPM 2 space commands we return an error
> code when this command is detected.
>
> Signed-off-by: Stefan Berger <stefanb@...ux.vnet.ibm.com>
> ---
> drivers/char/tpm/tpm_vtpm_proxy.c | 33 +++++++++++++++++++++++++++++++++
> 1 file changed, 33 insertions(+)
>
> diff --git a/drivers/char/tpm/tpm_vtpm_proxy.c
> b/drivers/char/tpm/tpm_vtpm_proxy.c
> index 66024bf..d25c361 100644
> --- a/drivers/char/tpm/tpm_vtpm_proxy.c
> +++ b/drivers/char/tpm/tpm_vtpm_proxy.c
> @@ -43,6 +43,7 @@ struct proxy_dev {
> #define STATE_OPENED_FLAG BIT(0)
> #define STATE_WAIT_RESPONSE_FLAG BIT(1) /* waiting for emulator response
> */
> #define STATE_REGISTERED_FLAG BIT(2)
> +#define STATE_DRIVER_COMMAND BIT(3) /* sending a driver specific
> command */
>
> size_t req_len; /* length of queued TPM request */
> size_t resp_len; /* length of queued TPM response */
> @@ -299,6 +300,28 @@ static int vtpm_proxy_tpm_op_recv(struct tpm_chip
> *chip, u8 *buf, size_t count)
> return len;
> }
>
> +static int vtpm_proxy_is_driver_command(struct tpm_chip *chip,
> + u8 *buf, size_t count)
> +{
> + struct tpm_input_header *hdr = (struct tpm_input_header*)buf;
> +
> + if (count < sizeof(struct tpm_input_header))
> + return 0;
> +
> + if (chip->flags & TPM_CHIP_FLAG_TPM2) {
> + switch (be32_to_cpu(hdr->ordinal)) {
> + case TPM2_CC_SET_LOCALITY:
> + return 1;
> + }
> + } else {
> + switch (be32_to_cpu(hdr->ordinal)) {
> + case TPM_ORD_SET_LOCALITY:
> + return 1;
> + }
> + }
> + return 0;
> +}
> +
> /*
> * Called when core TPM driver forwards TPM requests to 'server side'.
> *
> @@ -321,6 +344,10 @@ static int vtpm_proxy_tpm_op_send(struct tpm_chip
> *chip, u8 *buf, size_t count)
> return -EIO;
> }
>
> + if (!(proxy_dev->state & STATE_DRIVER_COMMAND) &&
> + vtpm_proxy_is_driver_command(chip, buf, count))
> + return -EFAULT;
> +
> mutex_lock(&proxy_dev->buf_lock);
>
> if (!(proxy_dev->state & STATE_OPENED_FLAG)) {
> @@ -376,6 +403,7 @@ static int vtpm_proxy_request_locality(struct tpm_chip
> *chip, int locality)
> struct tpm_buf buf;
> int rc;
> const struct tpm_output_header *header;
> + struct proxy_dev *proxy_dev = dev_get_drvdata(&chip->dev);
>
> if (chip->flags & TPM_CHIP_FLAG_TPM2)
> rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS,
> @@ -387,9 +415,14 @@ static int vtpm_proxy_request_locality(struct tpm_chip
> *chip, int locality)
> return rc;
> tpm_buf_append_u8(&buf, locality);
>
> + proxy_dev->state |= STATE_DRIVER_COMMAND;
> +
> rc = tpm_transmit_cmd(chip, NULL, buf.data, tpm_buf_length(&buf), 0,
> TPM_TRANSMIT_UNLOCKED | TPM_TRANSMIT_RAW,
> "attempting to set locality");
> +
> + proxy_dev->state &= ~STATE_DRIVER_COMMAND;
> +
> if (rc < 0) {
> locality = rc;
> goto out;
> --
> 2.4.3
>
>
> >
> > > #endif /* _UAPI_LINUX_VTPM_PROXY_H */
> > > --
> > > 2.4.3
> > >
> > /Jarkko
> >
>
Please bump one more patch set version. Thanks.
/Jarkko
Powered by blists - more mailing lists