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 <stefanb@xxxxxxxxxxxxx>
> > Cc: stable@xxxxxxxxxxxxxxx
> > Fixes: 745b361e989a ("tpm: infrastructure for TPM spaces")
> > Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
> > ---
> > 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
