| From 08711d09c5c90d9c737dfa2c7172783cb6073e66 Mon Sep 17 00:00:00 2001 |
| From: Josh Zimmerman <joshz@google.com> |
| Date: Thu, 27 Oct 2016 14:50:09 -0700 |
| Subject: [PATCH] tpm_tis: Check return values from get_burstcount. |
| |
| commit 26a137e31ffe6fbfdb008554a8d9b3d55bd5c86e upstream. |
| |
| If the TPM we're connecting to uses a static burst count, it will report |
| a burst count of zero throughout the response read. However, get_burstcount |
| assumes that a response of zero indicates that the TPM is not ready to |
| receive more data. In this case, it returns a negative error code, which |
| is passed on to tpm_tis_{write,read}_bytes as a u16, causing |
| them to read/write far too many bytes. |
| |
| This patch checks for negative return codes and bails out from recv_data |
| and tpm_tis_send_data. |
| |
| Cc: stable@vger.kernel.org |
| Fixes: 1107d065fdf1 (tpm_tis: Introduce intermediate layer for TPM access) |
| Signed-off-by: Josh Zimmerman <joshz@google.com> |
| Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> |
| Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> |
| Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> |
| |
| diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c |
| index d66f51b3648e..5e71d6db5455 100644 |
| --- a/drivers/char/tpm/tpm_tis_core.c |
| +++ b/drivers/char/tpm/tpm_tis_core.c |
| @@ -185,7 +185,12 @@ static int recv_data(struct tpm_chip *chip, u8 *buf, size_t count) |
| TPM_STS_DATA_AVAIL | TPM_STS_VALID, |
| chip->timeout_c, |
| &priv->read_queue, true) == 0) { |
| - burstcnt = min_t(int, get_burstcount(chip), count - size); |
| + burstcnt = get_burstcount(chip); |
| + if (burstcnt < 0) { |
| + dev_err(&chip->dev, "Unable to read burstcount\n"); |
| + return burstcnt; |
| + } |
| + burstcnt = min_t(int, burstcnt, count - size); |
| |
| rc = tpm_tis_read_bytes(priv, TPM_DATA_FIFO(priv->locality), |
| burstcnt, buf + size); |
| @@ -271,7 +276,13 @@ static int tpm_tis_send_data(struct tpm_chip *chip, u8 *buf, size_t len) |
| } |
| |
| while (count < len - 1) { |
| - burstcnt = min_t(int, get_burstcount(chip), len - count - 1); |
| + burstcnt = get_burstcount(chip); |
| + if (burstcnt < 0) { |
| + dev_err(&chip->dev, "Unable to read burstcount\n"); |
| + rc = burstcnt; |
| + goto out_err; |
| + } |
| + burstcnt = min_t(int, burstcnt, len - count - 1); |
| rc = tpm_tis_write_bytes(priv, TPM_DATA_FIFO(priv->locality), |
| burstcnt, buf + count); |
| if (rc < 0) |
| -- |
| 2.10.1 |
| |