The patch below does not apply to the 4.8-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@xxxxxxxxxxxxxxx>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 26a137e31ffe6fbfdb008554a8d9b3d55bd5c86e Mon Sep 17 00:00:00 2001
From: Josh Zimmerman <joshz@xxxxxxxxxx>
Date: Thu, 27 Oct 2016 14:50:09 -0700
Subject: [PATCH] tpm_tis: Check return values from get_burstcount.
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@xxxxxxxxxxxxxxx
Fixes: 1107d065fdf1 (tpm_tis: Introduce intermediate layer for TPM access)
Signed-off-by: Josh Zimmerman <joshz@xxxxxxxxxx>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
index 73f4c4bbc4df..2d1e451fb1b3 100644
--- a/drivers/char/tpm/tpm_tis_core.c
+++ b/drivers/char/tpm/tpm_tis_core.c
@@ -187,7 +187,12 @@ static int recv_data(struct tpm_chip *chip, u8 *buf, size_t count)
&priv->read_queue, true);
if (rc < 0)
return rc;
- 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);
@@ -276,7 +281,13 @@ 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)
--
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