linux-kernel - [PATCH v8 3/5] tpm: Clean up reading of timeout and duration capabilities

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Message-Id: <1466557831-113440-4-git-send-email-eswierk@skyportsystems.com>
Date:	Tue, 21 Jun 2016 18:10:29 -0700
From:	Ed Swierk <eswierk@...portsystems.com>
To:	tpmdd-devel@...ts.sourceforge.net, linux-kernel@...r.kernel.org,
	linux-security-module@...r.kernel.org
Cc:	jarkko.sakkinen@...ux.intel.com, jgunthorpe@...idianresearch.com,
	stefanb@...ibm.com, eswierk@...portsystems.com
Subject: [PATCH v8 3/5] tpm: Clean up reading of timeout and duration capabilities

Call tpm_getcap() from tpm_get_timeouts() to eliminate redundant
code. Return all errors to the caller rather than swallowing them
(e.g. when tpm_transmit_cmd() returns nonzero).

Signed-off-by: Ed Swierk <eswierk@...portsystems.com>
---
 drivers/char/tpm/tpm-interface.c | 74 +++++++++++++++-------------------------
 1 file changed, 27 insertions(+), 47 deletions(-)

diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index cc1e5bc..b65c139 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -461,9 +461,19 @@ ssize_t tpm_getcap(struct device *dev, __be32 subcap_id, cap_t *cap,
 		tpm_cmd.params.getcap_in.subcap_size = cpu_to_be32(4);
 		tpm_cmd.params.getcap_in.subcap = subcap_id;
 	}
+
 	rc = tpm_transmit_cmd(chip, &tpm_cmd, TPM_INTERNAL_RESULT_SIZE, desc);
+
+	if (!rc &&
+	    ((subcap_id == TPM_CAP_PROP_TIS_TIMEOUT &&
+	      be32_to_cpu(tpm_cmd.header.out.length) != TPM_HEADER_SIZE + 20) ||
+	     (subcap_id == TPM_CAP_PROP_TIS_DURATION &&
+	      be32_to_cpu(tpm_cmd.header.out.length) != TPM_HEADER_SIZE + 16)))
+		rc = -EINVAL;
+
 	if (!rc)
 		*cap = tpm_cmd.params.getcap_out.cap;
+
 	return rc;
 }
 
@@ -504,48 +514,30 @@ static int tpm_startup(struct tpm_chip *chip, __be16 startup_type)
 
 int tpm_get_timeouts(struct tpm_chip *chip)
 {
-	struct tpm_cmd_t tpm_cmd;
+	cap_t cap;
 	unsigned long new_timeout[4];
 	unsigned long old_timeout[4];
-	struct duration_t *duration_cap;
 	ssize_t rc;
 
-	tpm_cmd.header.in = tpm_getcap_header;
-	tpm_cmd.params.getcap_in.cap = TPM_CAP_PROP;
-	tpm_cmd.params.getcap_in.subcap_size = cpu_to_be32(4);
-	tpm_cmd.params.getcap_in.subcap = TPM_CAP_PROP_TIS_TIMEOUT;
-	rc = tpm_transmit_cmd(chip, &tpm_cmd, TPM_INTERNAL_RESULT_SIZE, NULL);
-
+	rc = tpm_getcap(chip->pdev, TPM_CAP_PROP_TIS_TIMEOUT, &cap,
+			"attempting to determine the timeouts");
 	if (rc == TPM_ERR_INVALID_POSTINIT) {
 		/* The TPM is not started, we are the first to talk to it.
 		   Execute a startup command. */
-		dev_info(chip->pdev, "Issuing TPM_STARTUP");
+		dev_info(chip->pdev, "Issuing TPM_STARTUP\n");
 		if (tpm_startup(chip, TPM_ST_CLEAR))
 			return rc;
 
-		tpm_cmd.header.in = tpm_getcap_header;
-		tpm_cmd.params.getcap_in.cap = TPM_CAP_PROP;
-		tpm_cmd.params.getcap_in.subcap_size = cpu_to_be32(4);
-		tpm_cmd.params.getcap_in.subcap = TPM_CAP_PROP_TIS_TIMEOUT;
-		rc = tpm_transmit_cmd(chip, &tpm_cmd, TPM_INTERNAL_RESULT_SIZE,
-				  NULL);
-	}
-	if (rc) {
-		dev_err(chip->pdev,
-			"A TPM error (%zd) occurred attempting to determine the timeouts\n",
-			rc);
-		goto duration;
+		rc = tpm_getcap(chip->pdev, TPM_CAP_PROP_TIS_TIMEOUT, &cap,
+				"attempting to determine the timeouts");
 	}
+	if (rc)
+		return rc;
 
-	if (be32_to_cpu(tpm_cmd.header.out.return_code) != 0 ||
-	    be32_to_cpu(tpm_cmd.header.out.length)
-	    != sizeof(tpm_cmd.header.out) + sizeof(u32) + 4 * sizeof(u32))
-		return -EINVAL;
-
-	old_timeout[0] = be32_to_cpu(tpm_cmd.params.getcap_out.cap.timeout.a);
-	old_timeout[1] = be32_to_cpu(tpm_cmd.params.getcap_out.cap.timeout.b);
-	old_timeout[2] = be32_to_cpu(tpm_cmd.params.getcap_out.cap.timeout.c);
-	old_timeout[3] = be32_to_cpu(tpm_cmd.params.getcap_out.cap.timeout.d);
+	old_timeout[0] = be32_to_cpu(cap.timeout.a);
+	old_timeout[1] = be32_to_cpu(cap.timeout.b);
+	old_timeout[2] = be32_to_cpu(cap.timeout.c);
+	old_timeout[3] = be32_to_cpu(cap.timeout.d);
 	memcpy(new_timeout, old_timeout, sizeof(new_timeout));
 
 	/*
@@ -583,29 +575,17 @@ int tpm_get_timeouts(struct tpm_chip *chip)
 	chip->vendor.timeout_c = usecs_to_jiffies(new_timeout[2]);
 	chip->vendor.timeout_d = usecs_to_jiffies(new_timeout[3]);
 
-duration:
-	tpm_cmd.header.in = tpm_getcap_header;
-	tpm_cmd.params.getcap_in.cap = TPM_CAP_PROP;
-	tpm_cmd.params.getcap_in.subcap_size = cpu_to_be32(4);
-	tpm_cmd.params.getcap_in.subcap = TPM_CAP_PROP_TIS_DURATION;
-
-	rc = tpm_transmit_cmd(chip, &tpm_cmd, TPM_INTERNAL_RESULT_SIZE,
-			      "attempting to determine the durations");
+	rc = tpm_getcap(chip->pdev, TPM_CAP_PROP_TIS_DURATION, &cap,
+			"attempting to determine the durations");
 	if (rc)
 		return rc;
 
-	if (be32_to_cpu(tpm_cmd.header.out.return_code) != 0 ||
-	    be32_to_cpu(tpm_cmd.header.out.length)
-	    != sizeof(tpm_cmd.header.out) + sizeof(u32) + 3 * sizeof(u32))
-		return -EINVAL;
-
-	duration_cap = &tpm_cmd.params.getcap_out.cap.duration;
 	chip->vendor.duration[TPM_SHORT] =
-	    usecs_to_jiffies(be32_to_cpu(duration_cap->tpm_short));
+		usecs_to_jiffies(be32_to_cpu(cap.duration.tpm_short));
 	chip->vendor.duration[TPM_MEDIUM] =
-	    usecs_to_jiffies(be32_to_cpu(duration_cap->tpm_medium));
+		usecs_to_jiffies(be32_to_cpu(cap.duration.tpm_medium));
 	chip->vendor.duration[TPM_LONG] =
-	    usecs_to_jiffies(be32_to_cpu(duration_cap->tpm_long));
+		usecs_to_jiffies(be32_to_cpu(cap.duration.tpm_long));
 
 	/* The Broadcom BCM0102 chipset in a Dell Latitude D820 gets the above
 	 * value wrong and apparently reports msecs rather than usecs. So we
-- 
1.9.1