| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.9 172/206] tpm_tis: Check return values from get_burstcount. | Date | Tue, 10 Jan 2017 14:37:35 +0100 |
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4.9-stable review patch. If anyone has any objections, please let me know.
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From: Josh Zimmerman <joshz@google.com>
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>
--- drivers/char/tpm/tpm_tis_core.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-)
--- 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 *ch 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_ } 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)
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