diff options
| author | Josh Zimmerman <joshz@google.com> | 2016-10-27 21:50:09 (GMT) |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-01-12 10:39:38 (GMT) |
| commit | 56d22b9125421217fdea41250cce9dfa0013b483 (patch) | |
| tree | 1c490d972060db0ce3b06535865ce3462120821d | |
| parent | 4ffac6f06dfa77ead74d448d07079e37339e4da0 (diff) | |
| download | linux-56d22b9125421217fdea41250cce9dfa0013b483.tar.xz | |
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.
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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/char/tpm/tpm_tis_core.c | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c index e3bf31b..a1ce060 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) |