The patch below does not apply to the 4.16-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@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From e2fb992d82c626c43ed0566e07c410e56a087af3 Mon Sep 17 00:00:00 2001
From: James Bottomley James.Bottomley@HansenPartnership.com Date: Wed, 21 Mar 2018 11:43:48 -0700 Subject: [PATCH] tpm: add retry logic MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit
TPM2 can return TPM2_RC_RETRY to any command and when it does we get unexpected failures inside the kernel that surprise users (this is mostly observed in the trusted key handling code). The UEFI 2.6 spec has advice on how to handle this:
The firmware SHALL not return TPM2_RC_RETRY prior to the completion of the call to ExitBootServices().
Implementer’s Note: the implementation of this function should check the return value in the TPM response and, if it is TPM2_RC_RETRY, resend the command. The implementation may abort if a sufficient number of retries has been done.
So we follow that advice in our tpm_transmit() code using TPM2_DURATION_SHORT as the initial wait duration and TPM2_DURATION_LONG as the maximum wait time. This should fix all the in-kernel use cases and also means that user space TSS implementations don't have to have their own retry handling.
Signed-off-by: James Bottomley James.Bottomley@HansenPartnership.com Cc: stable@vger.kernel.org Reviewed-by: Jarkko Sakkinen jarkko.sakkinen@linux.intel.com Tested-by: Jarkko Sakkinen jarkko.sakkinen@linux.intel.com Signed-off-by: Jarkko Sakkinen jarkko.sakkinen@linux.intel.com
diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c index 22288ff70a0b..d5379a79274c 100644 --- a/drivers/char/tpm/tpm-interface.c +++ b/drivers/char/tpm/tpm-interface.c @@ -399,21 +399,10 @@ static void tpm_relinquish_locality(struct tpm_chip *chip) chip->locality = -1; }
-/** - * tpm_transmit - Internal kernel interface to transmit TPM commands. - * - * @chip: TPM chip to use - * @space: tpm space - * @buf: TPM command buffer - * @bufsiz: length of the TPM command buffer - * @flags: tpm transmit flags - bitmap - * - * Return: - * 0 when the operation is successful. - * A negative number for system errors (errno). - */ -ssize_t tpm_transmit(struct tpm_chip *chip, struct tpm_space *space, - u8 *buf, size_t bufsiz, unsigned int flags) +static ssize_t tpm_try_transmit(struct tpm_chip *chip, + struct tpm_space *space, + u8 *buf, size_t bufsiz, + unsigned int flags) { struct tpm_output_header *header = (void *)buf; int rc; @@ -544,6 +533,62 @@ ssize_t tpm_transmit(struct tpm_chip *chip, struct tpm_space *space, return rc ? rc : len; }
+/** + * tpm_transmit - Internal kernel interface to transmit TPM commands. + * + * @chip: TPM chip to use + * @space: tpm space + * @buf: TPM command buffer + * @bufsiz: length of the TPM command buffer + * @flags: tpm transmit flags - bitmap + * + * A wrapper around tpm_try_transmit that handles TPM2_RC_RETRY + * returns from the TPM and retransmits the command after a delay up + * to a maximum wait of TPM2_DURATION_LONG. + * + * Note: TPM1 never returns TPM2_RC_RETRY so the retry logic is TPM2 + * only + * + * Return: + * the length of the return when the operation is successful. + * A negative number for system errors (errno). + */ +ssize_t tpm_transmit(struct tpm_chip *chip, struct tpm_space *space, + u8 *buf, size_t bufsiz, unsigned int flags) +{ + struct tpm_output_header *header = (struct tpm_output_header *)buf; + /* space for header and handles */ + u8 save[TPM_HEADER_SIZE + 3*sizeof(u32)]; + unsigned int delay_msec = TPM2_DURATION_SHORT; + u32 rc = 0; + ssize_t ret; + const size_t save_size = min(space ? sizeof(save) : TPM_HEADER_SIZE, + bufsiz); + + /* + * Subtlety here: if we have a space, the handles will be + * transformed, so when we restore the header we also have to + * restore the handles. + */ + memcpy(save, buf, save_size); + + for (;;) { + ret = tpm_try_transmit(chip, space, buf, bufsiz, flags); + if (ret < 0) + break; + rc = be32_to_cpu(header->return_code); + if (rc != TPM2_RC_RETRY) + break; + delay_msec *= 2; + if (delay_msec > TPM2_DURATION_LONG) { + dev_err(&chip->dev, "TPM is in retry loop\n"); + break; + } + tpm_msleep(delay_msec); + memcpy(buf, save, save_size); + } + return ret; +} /** * tpm_transmit_cmd - send a tpm command to the device * The function extracts tpm out header return code diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h index ab3bcdd4d328..67656a97793a 100644 --- a/drivers/char/tpm/tpm.h +++ b/drivers/char/tpm/tpm.h @@ -115,6 +115,7 @@ enum tpm2_return_codes { TPM2_RC_COMMAND_CODE = 0x0143, TPM2_RC_TESTING = 0x090A, /* RC_WARN */ TPM2_RC_REFERENCE_H0 = 0x0910, + TPM2_RC_RETRY = 0x0922, };
enum tpm2_algorithms {