On Tue, Sep 01, 2026 at 02:28:50PM +0800, Jiangshan Yi wrote:
> struct tpm_buf now uses an embedded flexible array for data, which is
> 6 bytes shorter than TPM_BUFSIZE due to the struct header. But
> tpm_transmit_cmd() still passes PAGE_SIZE to tpm_transmit(), and after
> clamping to TPM_BUFSIZE in tpm_try_transmit(), chip->ops->recv() can
> write past the end of data[] by 6 bytes.
>
> Pass buf->capacity to tpm_transmit() instead.
>
> Fixes: 3d9e043dab0a ("tpm-buf: Memory-safe allocations")
> Cc: [email protected]
> Signed-off-by: Jiangshan Yi <[email protected]>
> ---
> drivers/char/tpm/tpm-interface.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/char/tpm/tpm-interface.c
> b/drivers/char/tpm/tpm-interface.c
> index f745a098908b..1ccdbde98b69 100644
> --- a/drivers/char/tpm/tpm-interface.c
> +++ b/drivers/char/tpm/tpm-interface.c
> @@ -268,7 +268,7 @@ ssize_t tpm_transmit_cmd(struct tpm_chip *chip, struct
> tpm_buf *buf,
> int err;
> ssize_t len;
>
> - len = tpm_transmit(chip, buf->data, PAGE_SIZE);
> + len = tpm_transmit(chip, buf->data, buf->capacity);
> if (len < 0)
> return len;
>
> --
> 2.25.1
>
Thank you good catch!
I'll apply this and put to rc2 PR.
BR, Jarkko
