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Date: Wed, 27 Apr 2005 17:16:40 -0500 (CDT)
From: Kylene Hall <kjhall@us.ibm.com>
X-X-Sender: kjhall@jo.austin.ibm.com
To: Jeff Garzik <jgarzik@pobox.com>
cc: Greg K-H <greg@kroah.com>, linux-kernel@vger.kernel.org
Subject: [PATCH 5 of 12] Fix TPM driver -- large stack objects
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Message-ID: <Pine.LNX.4.61.0504271445330.3929@jo.austin.ibm.com>
References: <1110415321526@kroah.com> <422FC42B.7@pobox.com>
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On Wed, 9 Mar 2005, Jeff Garzik wrote:
> Greg KH wrote:

<snip>

> > +static ssize_t show_pubek(struct device *dev, char *buf)
> > +{
> > +	u8 data[READ_PUBEK_RESULT_SIZE];
> 
> massive obj on stack

<snip>

> 
> > +static ssize_t show_caps(struct device *dev, char *buf)
> > +{
> > +	u8 data[READ_PUBEK_RESULT_SIZE];
> 
> massive obj on stack

<snip>

The patch below containes fixes for these large stack objects.

Signed-off-by: Kylene Hall <kjhall@us.ibm.com>
---
--- linux-2.6.12-rc2/drivers/char/tpm/tpm.c	2005-04-21 18:11:12.000000000 -0500
+++ linux-2.6.12-rc2-tpmdd/drivers/char/tpm/tpm.c	2005-04-21 18:13:10.000000000 -0500
@@ -253,7 +253,7 @@ static const u8 readpubek[] = {
 
 ssize_t tpm_show_pubek(struct device *dev, char *buf)
 {
-	u8 data[READ_PUBEK_RESULT_SIZE];
+	u8 *data;
 	ssize_t len;
 	int i, rc;
 	char *str = buf;
@@ -263,12 +263,18 @@ ssize_t tpm_show_pubek(struct device *de
 	if (chip == NULL)
 		return -ENODEV;
 
+	data = kmalloc(READ_PUBEK_RESULT_SIZE, GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
 	memcpy(data, readpubek, sizeof(readpubek));
 	memset(data + sizeof(readpubek), 0, 20);	/* zero nonce */
 
-	if ((len = tpm_transmit(chip, data, sizeof(data))) <
-	    READ_PUBEK_RESULT_SIZE)
-		return len;
+	if ((len = tpm_transmit(chip, data, READ_PUBEK_RESULT_SIZE)) <
+	    READ_PUBEK_RESULT_SIZE) {
+		rc = len;
+		goto out;
+	}
 
 	/* 
 	   ignore header 10 bytes
@@ -298,7 +304,10 @@ ssize_t tpm_show_pubek(struct device *de
 		if ((i + 1) % 16 == 0)
 			str += sprintf(str, "\n");
 	}
-	return str - buf;
+	rc = str - buf;
+out:
+	kfree(data);
+	return rc;
 }
 
 EXPORT_SYMBOL_GPL(tpm_show_pubek);
@@ -324,7 +333,7 @@ static const u8 cap_manufacturer[] = {
 
 ssize_t tpm_show_caps(struct device *dev, char *buf)
 {
-	u8 data[READ_PUBEK_RESULT_SIZE];
+	u8 data[sizeof(cap_manufacturer)];
 	ssize_t len;
 	char *str = buf;
 
-
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