2020-06-26 16:17:09

by Jarkko Sakkinen

Subject: [PATCH] tpm: Define TPM2_SPACE_BUFFER_SIZE to replace the use of PAGE_SIZE

The size of the buffers for storing context's and sessions can vary from
arch to arch as PAGE_SIZE can be anything between 4 kB and 256 kB (the
maximum for PPC64). Define a fixed buffer size set to 16 kB. This should
be enough for most use with three handles (that is how many we allow at
the moment).

Reported-by: Stefan Berger <[email protected]>
Cc: [email protected]
Fixes: 745b361e989a ("tpm: infrastructure for TPM spaces")
Signed-off-by: Jarkko Sakkinen <[email protected]>
---
drivers/char/tpm/tpm2-space.c | 27 ++++++++++++++++-----------
1 file changed, 16 insertions(+), 11 deletions(-)

diff --git a/drivers/char/tpm/tpm2-space.c b/drivers/char/tpm/tpm2-space.c
index 982d341d8837..9bef646093d1 100644
--- a/drivers/char/tpm/tpm2-space.c
+++ b/drivers/char/tpm/tpm2-space.c
@@ -15,6 +15,8 @@
#include <asm/unaligned.h>
#include "tpm.h"

+#define TPM2_SPACE_BUFFER_SIZE 16384 /* 16 kB */
+
enum tpm2_handle_types {
TPM2_HT_HMAC_SESSION = 0x02000000,
TPM2_HT_POLICY_SESSION = 0x03000000,
@@ -40,11 +42,11 @@ static void tpm2_flush_sessions(struct tpm_chip *chip, struct tpm_space *space)

int tpm2_init_space(struct tpm_space *space)
{
- space->context_buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
+ space->context_buf = kzalloc(TPM2_SPACE_BUFFER_SIZE, GFP_KERNEL);
if (!space->context_buf)
return -ENOMEM;

- space->session_buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
+ space->session_buf = kzalloc(TPM2_SPACE_BUFFER_SIZE, GFP_KERNEL);
if (space->session_buf == NULL) {
kfree(space->context_buf);
return -ENOMEM;
@@ -311,8 +313,10 @@ int tpm2_prepare_space(struct tpm_chip *chip, struct tpm_space *space, u8 *cmd,
sizeof(space->context_tbl));
memcpy(&chip->work_space.session_tbl, &space->session_tbl,
sizeof(space->session_tbl));
- memcpy(chip->work_space.context_buf, space->context_buf, PAGE_SIZE);
- memcpy(chip->work_space.session_buf, space->session_buf, PAGE_SIZE);
+ memcpy(chip->work_space.context_buf, space->context_buf,
+ TPM2_SPACE_BUFFER_SIZE);
+ memcpy(chip->work_space.session_buf, space->session_buf,
+ TPM2_SPACE_BUFFER_SIZE);

rc = tpm2_load_space(chip);
if (rc) {
@@ -492,8 +496,8 @@ static int tpm2_save_space(struct tpm_chip *chip)
continue;

rc = tpm2_save_context(chip, space->context_tbl[i],
- space->context_buf, PAGE_SIZE,
- &offset);
+ space->context_buf,
+ TPM2_SPACE_BUFFER_SIZE, &offset);
if (rc == -ENOENT) {
space->context_tbl[i] = 0;
continue;
@@ -509,9 +513,8 @@ static int tpm2_save_space(struct tpm_chip *chip)
continue;

rc = tpm2_save_context(chip, space->session_tbl[i],
- space->session_buf, PAGE_SIZE,
- &offset);
-
+ space->session_buf,
+ TPM2_SPACE_BUFFER_SIZE, &offset);
if (rc == -ENOENT) {
/* handle error saving session, just forget it */
space->session_tbl[i] = 0;
@@ -557,8 +560,10 @@ int tpm2_commit_space(struct tpm_chip *chip, struct tpm_space *space,
sizeof(space->context_tbl));
memcpy(&space->session_tbl, &chip->work_space.session_tbl,
sizeof(space->session_tbl));
- memcpy(space->context_buf, chip->work_space.context_buf, PAGE_SIZE);
- memcpy(space->session_buf, chip->work_space.session_buf, PAGE_SIZE);
+ memcpy(space->context_buf, chip->work_space.context_buf,
+ TPM2_SPACE_BUFFER_SIZE);
+ memcpy(space->session_buf, chip->work_space.session_buf,
+ TPM2_SPACE_BUFFER_SIZE);

return 0;
out:
--
2.25.1

2020-06-26 17:21:55

by Stefan Berger

Subject: Re: [PATCH] tpm: Define TPM2_SPACE_BUFFER_SIZE to replace the use of PAGE_SIZE

On 6/26/20 10:34 AM, Jarkko Sakkinen wrote:
> The size of the buffers for storing context's and sessions can vary from
> arch to arch as PAGE_SIZE can be anything between 4 kB and 256 kB (the
> maximum for PPC64). Define a fixed buffer size set to 16 kB. This should
> be enough for most use with three handles (that is how many we allow at
> the moment).
>
> Reported-by: Stefan Berger <[email protected]>
> Cc: [email protected]
> Fixes: 745b361e989a ("tpm: infrastructure for TPM spaces")
> Signed-off-by: Jarkko Sakkinen <[email protected]>
> ---
> drivers/char/tpm/tpm2-space.c | 27 ++++++++++++++++-----------
> 1 file changed, 16 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/char/tpm/tpm2-space.c b/drivers/char/tpm/tpm2-space.c
> index 982d341d8837..9bef646093d1 100644
> --- a/drivers/char/tpm/tpm2-space.c
> +++ b/drivers/char/tpm/tpm2-space.c
> @@ -15,6 +15,8 @@
> #include <asm/unaligned.h>
> #include "tpm.h"
>
> +#define TPM2_SPACE_BUFFER_SIZE 16384 /* 16 kB */
> +
> enum tpm2_handle_types {
> TPM2_HT_HMAC_SESSION = 0x02000000,
> TPM2_HT_POLICY_SESSION = 0x03000000,
> @@ -40,11 +42,11 @@ static void tpm2_flush_sessions(struct tpm_chip *chip, struct tpm_space *space)
>
> int tpm2_init_space(struct tpm_space *space)
> {
> - space->context_buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
> + space->context_buf = kzalloc(TPM2_SPACE_BUFFER_SIZE, GFP_KERNEL);
> if (!space->context_buf)
> return -ENOMEM;
>
> - space->session_buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
> + space->session_buf = kzalloc(TPM2_SPACE_BUFFER_SIZE, GFP_KERNEL);
> if (space->session_buf == NULL) {
> kfree(space->context_buf);
> return -ENOMEM;
> @@ -311,8 +313,10 @@ int tpm2_prepare_space(struct tpm_chip *chip, struct tpm_space *space, u8 *cmd,
> sizeof(space->context_tbl));
> memcpy(&chip->work_space.session_tbl, &space->session_tbl,
> sizeof(space->session_tbl));
> - memcpy(chip->work_space.context_buf, space->context_buf, PAGE_SIZE);
> - memcpy(chip->work_space.session_buf, space->session_buf, PAGE_SIZE);
> + memcpy(chip->work_space.context_buf, space->context_buf,
> + TPM2_SPACE_BUFFER_SIZE);
> + memcpy(chip->work_space.session_buf, space->session_buf,
> + TPM2_SPACE_BUFFER_SIZE);
>
> rc = tpm2_load_space(chip);
> if (rc) {
> @@ -492,8 +496,8 @@ static int tpm2_save_space(struct tpm_chip *chip)
> continue;
>
> rc = tpm2_save_context(chip, space->context_tbl[i],
> - space->context_buf, PAGE_SIZE,
> - &offset);
> + space->context_buf,
> + TPM2_SPACE_BUFFER_SIZE, &offset);
> if (rc == -ENOENT) {
> space->context_tbl[i] = 0;
> continue;
> @@ -509,9 +513,8 @@ static int tpm2_save_space(struct tpm_chip *chip)
> continue;
>
> rc = tpm2_save_context(chip, space->session_tbl[i],
> - space->session_buf, PAGE_SIZE,
> - &offset);
> -
> + space->session_buf,
> + TPM2_SPACE_BUFFER_SIZE, &offset);
> if (rc == -ENOENT) {
> /* handle error saving session, just forget it */
> space->session_tbl[i] = 0;
> @@ -557,8 +560,10 @@ int tpm2_commit_space(struct tpm_chip *chip, struct tpm_space *space,
> sizeof(space->context_tbl));
> memcpy(&space->session_tbl, &chip->work_space.session_tbl,
> sizeof(space->session_tbl));
> - memcpy(space->context_buf, chip->work_space.context_buf, PAGE_SIZE);
> - memcpy(space->session_buf, chip->work_space.session_buf, PAGE_SIZE);
> + memcpy(space->context_buf, chip->work_space.context_buf,
> + TPM2_SPACE_BUFFER_SIZE);
> + memcpy(space->session_buf, chip->work_space.session_buf,
> + TPM2_SPACE_BUFFER_SIZE);


work_space.session_buf and context_buf also need allocation changes,
otherwise we read from a smaller buffer here. See comment to other patch
about tpm-chip.c .


>
> return 0;
> out:

2020-07-02 20:49:22

by Jarkko Sakkinen

Subject: Re: [PATCH] tpm: Define TPM2_SPACE_BUFFER_SIZE to replace the use of PAGE_SIZE

On Fri, Jun 26, 2020 at 12:47:02PM -0400, Stefan Berger wrote:
> On 6/26/20 10:34 AM, Jarkko Sakkinen wrote:
> > The size of the buffers for storing context's and sessions can vary from
> > arch to arch as PAGE_SIZE can be anything between 4 kB and 256 kB (the
> > maximum for PPC64). Define a fixed buffer size set to 16 kB. This should
> > be enough for most use with three handles (that is how many we allow at
> > the moment).
> >
> > Reported-by: Stefan Berger <[email protected]>
> > Cc: [email protected]
> > Fixes: 745b361e989a ("tpm: infrastructure for TPM spaces")
> > Signed-off-by: Jarkko Sakkinen <[email protected]>
> > ---
> > drivers/char/tpm/tpm2-space.c | 27 ++++++++++++++++-----------
> > 1 file changed, 16 insertions(+), 11 deletions(-)
> >
> > diff --git a/drivers/char/tpm/tpm2-space.c b/drivers/char/tpm/tpm2-space.c
> > index 982d341d8837..9bef646093d1 100644
> > --- a/drivers/char/tpm/tpm2-space.c
> > +++ b/drivers/char/tpm/tpm2-space.c
> > @@ -15,6 +15,8 @@
> > #include <asm/unaligned.h>
> > #include "tpm.h"
> > +#define TPM2_SPACE_BUFFER_SIZE 16384 /* 16 kB */
> > +
> > enum tpm2_handle_types {
> > TPM2_HT_HMAC_SESSION = 0x02000000,
> > TPM2_HT_POLICY_SESSION = 0x03000000,
> > @@ -40,11 +42,11 @@ static void tpm2_flush_sessions(struct tpm_chip *chip, struct tpm_space *space)
> > int tpm2_init_space(struct tpm_space *space)
> > {
> > - space->context_buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
> > + space->context_buf = kzalloc(TPM2_SPACE_BUFFER_SIZE, GFP_KERNEL);
> > if (!space->context_buf)
> > return -ENOMEM;
> > - space->session_buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
> > + space->session_buf = kzalloc(TPM2_SPACE_BUFFER_SIZE, GFP_KERNEL);
> > if (space->session_buf == NULL) {
> > kfree(space->context_buf);
> > return -ENOMEM;
> > @@ -311,8 +313,10 @@ int tpm2_prepare_space(struct tpm_chip *chip, struct tpm_space *space, u8 *cmd,
> > sizeof(space->context_tbl));
> > memcpy(&chip->work_space.session_tbl, &space->session_tbl,
> > sizeof(space->session_tbl));
> > - memcpy(chip->work_space.context_buf, space->context_buf, PAGE_SIZE);
> > - memcpy(chip->work_space.session_buf, space->session_buf, PAGE_SIZE);
> > + memcpy(chip->work_space.context_buf, space->context_buf,
> > + TPM2_SPACE_BUFFER_SIZE);
> > + memcpy(chip->work_space.session_buf, space->session_buf,
> > + TPM2_SPACE_BUFFER_SIZE);
> > rc = tpm2_load_space(chip);
> > if (rc) {
> > @@ -492,8 +496,8 @@ static int tpm2_save_space(struct tpm_chip *chip)
> > continue;
> > rc = tpm2_save_context(chip, space->context_tbl[i],
> > - space->context_buf, PAGE_SIZE,
> > - &offset);
> > + space->context_buf,
> > + TPM2_SPACE_BUFFER_SIZE, &offset);
> > if (rc == -ENOENT) {
> > space->context_tbl[i] = 0;
> > continue;
> > @@ -509,9 +513,8 @@ static int tpm2_save_space(struct tpm_chip *chip)
> > continue;
> > rc = tpm2_save_context(chip, space->session_tbl[i],
> > - space->session_buf, PAGE_SIZE,
> > - &offset);
> > -
> > + space->session_buf,
> > + TPM2_SPACE_BUFFER_SIZE, &offset);
> > if (rc == -ENOENT) {
> > /* handle error saving session, just forget it */
> > space->session_tbl[i] = 0;
> > @@ -557,8 +560,10 @@ int tpm2_commit_space(struct tpm_chip *chip, struct tpm_space *space,
> > sizeof(space->context_tbl));
> > memcpy(&space->session_tbl, &chip->work_space.session_tbl,
> > sizeof(space->session_tbl));
> > - memcpy(space->context_buf, chip->work_space.context_buf, PAGE_SIZE);
> > - memcpy(space->session_buf, chip->work_space.session_buf, PAGE_SIZE);
> > + memcpy(space->context_buf, chip->work_space.context_buf,
> > + TPM2_SPACE_BUFFER_SIZE);
> > + memcpy(space->session_buf, chip->work_space.session_buf,
> > + TPM2_SPACE_BUFFER_SIZE);
>
>
> work_space.session_buf and context_buf also need allocation changes,
> otherwise we read from a smaller buffer here. See comment to other patch
> about tpm-chip.c .

Thank you, a good catch. I'll send an update.

/Jarkko