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FAILED: patch "[PATCH] tpm_tis: Check return values from get_burstcount." failed to apply to 4.8-stable tree

PATCH [email protected] 1 participant 1 message Jan 4, 2017

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Stable branch TPM device driver
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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 <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

Quoted 1 line

From 26a137e31ffe6fbfdb008554a8d9b3d55bd5c86e Mon Sep 17 00:00:00 2001

From: Josh Zimmerman <[email protected]>
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 [email protected]
Fixes 1107d065fdf1 (tpm_tis: Introduce intermediate layer for TPM access)
Signed-off-by Josh Zimmerman <[email protected]>
Reviewed-by Jarkko Sakkinen <[email protected]>
Signed-off-by Jarkko Sakkinen <[email protected]>
drivers/char/tpm/tpm_tis_core.c +13 -2
index 73f4c4bbc4df..2d1e451fb1b3 100644
@@ -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)