Stefan, are you concerned of not having this in 4.14 and 4.19?
/Jarkko
On Mon, Aug 17, 2020 at 12:14:09PM +0200, gregkh@xxxxxxxxxxxxxxxxxxx wrote:
>
> The patch below does not apply to the 4.14-stable tree.
> If someone wants it applied there, or to any other stable or longterm
> tree, then please email the backport, including the original git commit
> id to <stable@xxxxxxxxxxxxxxx>.
>
> thanks,
>
> greg k-h
>
> ------------------ original commit in Linus's tree ------------------
>
> From 6c4e79d99e6f42b79040f1a33cd4018f5425030b Mon Sep 17 00:00:00 2001
> From: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
> Date: Fri, 3 Jul 2020 01:55:59 +0300
> Subject: [PATCH] tpm: Unify the mismatching TPM space buffer sizes
>
> 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). Parametrize the buffer size while doing this, so that it is easier
> to revisit this later on if required.
>
> Cc: stable@xxxxxxxxxxxxxxx
> Reported-by: Stefan Berger <stefanb@xxxxxxxxxxxxx>
> Fixes: 745b361e989a ("tpm: infrastructure for TPM spaces")
> Reviewed-by: Jerry Snitselaar <jsnitsel@xxxxxxxxxx>
> Tested-by: Stefan Berger <stefanb@xxxxxxxxxxxxx>
> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
>
> diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
> index 8c77e88012e9..ddaeceb7e109 100644
> --- a/drivers/char/tpm/tpm-chip.c
> +++ b/drivers/char/tpm/tpm-chip.c
> @@ -386,13 +386,8 @@ struct tpm_chip *tpm_chip_alloc(struct device *pdev,
> chip->cdev.owner = THIS_MODULE;
> chip->cdevs.owner = THIS_MODULE;
>
> - chip->work_space.context_buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
> - if (!chip->work_space.context_buf) {
> - rc = -ENOMEM;
> - goto out;
> - }
> - chip->work_space.session_buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
> - if (!chip->work_space.session_buf) {
> + rc = tpm2_init_space(&chip->work_space, TPM2_SPACE_BUFFER_SIZE);
> + if (rc) {
> rc = -ENOMEM;
> goto out;
> }
> diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
> index 0fbcede241ea..947d1db0a5cc 100644
> --- a/drivers/char/tpm/tpm.h
> +++ b/drivers/char/tpm/tpm.h
> @@ -59,6 +59,9 @@ enum tpm_addr {
>
> #define TPM_TAG_RQU_COMMAND 193
>
> +/* TPM2 specific constants. */
> +#define TPM2_SPACE_BUFFER_SIZE 16384 /* 16 kB */
> +
> struct stclear_flags_t {
> __be16 tag;
> u8 deactivated;
> @@ -228,7 +231,7 @@ unsigned long tpm2_calc_ordinal_duration(struct tpm_chip *chip, u32 ordinal);
> int tpm2_probe(struct tpm_chip *chip);
> int tpm2_get_cc_attrs_tbl(struct tpm_chip *chip);
> int tpm2_find_cc(struct tpm_chip *chip, u32 cc);
> -int tpm2_init_space(struct tpm_space *space);
> +int tpm2_init_space(struct tpm_space *space, unsigned int buf_size);
> void tpm2_del_space(struct tpm_chip *chip, struct tpm_space *space);
> void tpm2_flush_space(struct tpm_chip *chip);
> int tpm2_prepare_space(struct tpm_chip *chip, struct tpm_space *space, u8 *cmd,
> diff --git a/drivers/char/tpm/tpm2-space.c b/drivers/char/tpm/tpm2-space.c
> index 982d341d8837..784b8b3cb903 100644
> --- a/drivers/char/tpm/tpm2-space.c
> +++ b/drivers/char/tpm/tpm2-space.c
> @@ -38,18 +38,21 @@ static void tpm2_flush_sessions(struct tpm_chip *chip, struct tpm_space *space)
> }
> }
>
> -int tpm2_init_space(struct tpm_space *space)
> +int tpm2_init_space(struct tpm_space *space, unsigned int buf_size)
> {
> - space->context_buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
> + space->context_buf = kzalloc(buf_size, GFP_KERNEL);
> if (!space->context_buf)
> return -ENOMEM;
>
> - space->session_buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
> + space->session_buf = kzalloc(buf_size, GFP_KERNEL);
> if (space->session_buf == NULL) {
> kfree(space->context_buf);
> + /* Prevent caller getting a dangling pointer. */
> + space->context_buf = NULL;
> return -ENOMEM;
> }
>
> + space->buf_size = buf_size;
> return 0;
> }
>
> @@ -311,8 +314,10 @@ 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,
> + space->buf_size);
> + memcpy(chip->work_space.session_buf, space->session_buf,
> + space->buf_size);
>
> rc = tpm2_load_space(chip);
> if (rc) {
> @@ -492,7 +497,7 @@ static int tpm2_save_space(struct tpm_chip *chip)
> continue;
>
> rc = tpm2_save_context(chip, space->context_tbl[i],
> - space->context_buf, PAGE_SIZE,
> + space->context_buf, space->buf_size,
> &offset);
> if (rc == -ENOENT) {
> space->context_tbl[i] = 0;
> @@ -509,9 +514,8 @@ static int tpm2_save_space(struct tpm_chip *chip)
> continue;
>
> rc = tpm2_save_context(chip, space->session_tbl[i],
> - space->session_buf, PAGE_SIZE,
> + space->session_buf, space->buf_size,
> &offset);
> -
> if (rc == -ENOENT) {
> /* handle error saving session, just forget it */
> space->session_tbl[i] = 0;
> @@ -557,8 +561,10 @@ 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,
> + space->buf_size);
> + memcpy(space->session_buf, chip->work_space.session_buf,
> + space->buf_size);
>
> return 0;
> out:
> diff --git a/drivers/char/tpm/tpmrm-dev.c b/drivers/char/tpm/tpmrm-dev.c
> index 7a0a7051a06f..eef0fb06ea83 100644
> --- a/drivers/char/tpm/tpmrm-dev.c
> +++ b/drivers/char/tpm/tpmrm-dev.c
> @@ -21,7 +21,7 @@ static int tpmrm_open(struct inode *inode, struct file *file)
> if (priv == NULL)
> return -ENOMEM;
>
> - rc = tpm2_init_space(&priv->space);
> + rc = tpm2_init_space(&priv->space, TPM2_SPACE_BUFFER_SIZE);
> if (rc) {
> kfree(priv);
> return -ENOMEM;
> diff --git a/include/linux/tpm.h b/include/linux/tpm.h
> index 03e9b184411b..8f4ff39f51e7 100644
> --- a/include/linux/tpm.h
> +++ b/include/linux/tpm.h
> @@ -96,6 +96,7 @@ struct tpm_space {
> u8 *context_buf;
> u32 session_tbl[3];
> u8 *session_buf;
> + u32 buf_size;
> };
>
> struct tpm_bios_log {
>
