Re: [PATCH V2 3/3] drivers/char/tpm: Add securityfs support for event log

From
Michael Ellerman <hidden>
Date
2012-08-10 07:23:23
Also in
lkml
Reply to
Ashley Lai, 2012-08-09
On Thu, 2012-08-09 at 18:13 -0500, Ashley Lai wrote:
This patch retrieves the event log data from the device tree
during file open. The event log data will then displayed through
securityfs.
Hi Ashley,

Comments inline ..
quoted hunk ↗ jump to hunk
diff --git a/drivers/char/tpm/Makefile b/drivers/char/tpm/Makefile
index 547509d..b53da57 100644
--- a/drivers/char/tpm/Makefile
+++ b/drivers/char/tpm/Makefile
@@ -2,9 +2,15 @@
 # Makefile for the kernel tpm device drivers.
 #
 obj-$(CONFIG_TCG_TPM) += tpm.o
+obj-$(CONFIG_TCG_TPM) += tpm_bios.o
 ifdef CONFIG_ACPI
-	obj-$(CONFIG_TCG_TPM) += tpm_bios.o
 	tpm_bios-objs += tpm_eventlog.o tpm_acpi.o
+else
+ifdef CONFIG_TCG_IBMVTPM
+	tpm_bios-objs += tpm_eventlog.o tpm_of.o
+else
+	tpm_bios-objs += tpm_eventlog.o tpm_noeventlog.o
What does it mean to build tpm_eventlog and tpm_noeventlog ?


quoted hunk ↗ jump to hunk
diff --git a/drivers/char/tpm/tpm_eventlog.h b/drivers/char/tpm/tpm_eventlog.h
index 8e23ccd..21ac6af 100644
--- a/drivers/char/tpm/tpm_eventlog.h
+++ b/drivers/char/tpm/tpm_eventlog.h
@@ -68,4 +68,18 @@ enum tcpa_pc_event_ids {
 };
 
 int read_log(struct tpm_bios_log *log);
+
+extern struct dentry **tpm_bios_log_setup(char *);
+extern void tpm_bios_log_teardown(struct dentry **);
+
+#ifdef CONFIG_PPC64
+#define TPM_NO_EVENT_LOG !of_find_node_by_name(NULL, "ibm,vtpm")
+#else
+#ifdef CONFIG_ACPI
+#define TPM_NO_EVENT_LOG 0
+#else
+#define TPM_NO_EVENT_LOG 1
+#endif
+#endif
This should be a static inline, with the ifdefs inside.

How often is this called? of_find_node_by_name() is not particularly
efficient. It might be better to search once and save a flag indicating
whether you found it.

Also you must call of_node_put() on the result of
of_find_node_by_name(), so at the least you must do:

struct device_node *np;
np = of_find_node_by_name(NULL, "ibm,vtpm");
of_node_put(np);
return (np != NULL);
quoted hunk ↗ jump to hunk
 #endif
diff --git a/drivers/char/tpm/tpm_noeventlog.c b/drivers/char/tpm/tpm_noeventlog.c
new file mode 100644
index 0000000..f30a2bf
--- /dev/null
+++ b/drivers/char/tpm/tpm_noeventlog.c
@@ -0,0 +1,21 @@
+/*
+ * Copyright (C) 2012 IBM Corporation
                ^^
Don't use (C)
quoted hunk ↗ jump to hunk
+ *
+ * Author: Ashley Lai <adlai@us.ibm.com>
+ *
+ * Maintained by: <tpmdd-devel@lists.sourceforge.net>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ */
+
+#include <linux/slab.h>
+#include "tpm_eventlog.h"
+
+int read_log(struct tpm_bios_log *log)
+{
+	return -EINVAL;
+}
Wouldn't it be simpler to put this in a header with the appropriate
ifdefs, and then you'd need less logic in the Makefile?

quoted hunk ↗ jump to hunk
diff --git a/drivers/char/tpm/tpm_of.c b/drivers/char/tpm/tpm_of.c
new file mode 100644
index 0000000..6d44adb
--- /dev/null
+++ b/drivers/char/tpm/tpm_of.c
@@ -0,0 +1,68 @@
+/*
+ * Copyright 2012 IBM Corporation
+ *
+ * Author: Ashley Lai <adlai@us.ibm.com>
+ *
+ * Maintained by: <tpmdd-devel@lists.sourceforge.net>
+ *
+ * Read the event log created by the firmware on PPC64
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ */
+
+#include <linux/slab.h>
+#include <linux/of.h>
+
+#include "tpm.h"
+#include "tpm_eventlog.h"
+
+int read_log(struct tpm_bios_log *log)
+{
+	struct device_node *np;
+	const u32 *sizep;
+	const __be64 *basep;
+
+	if (log->bios_event_log != NULL) {
+		pr_err("%s: ERROR - Eventlog already initialized\n", __func__);
+		return -EFAULT;
+	}
+
+	np = of_find_node_by_name(NULL, "ibm,vtpm");
+	if (!np) {
+		pr_err("%s: ERROR - IBMVTPM not supported\n", __func__);
+		return -ENODEV;
+	}
All your return paths below here must call of_node_put(np).
quoted hunk ↗ jump to hunk
+	sizep = of_get_property(np, "linux,sml-size", NULL);
+	if (sizep == NULL) {
+		pr_err("%s: ERROR - SML size not found\n", __func__);
+		return -EIO;
+	}
+	if (*sizep == 0) {
+		pr_err("%s: ERROR - event log area empty\n", __func__);
+		return -EIO;
+	}
+
+	basep = of_get_property(np, "linux,sml-base", NULL);
+	if (basep == NULL) {
+		pr_err(KERN_ERR "%s: ERROR - SML not found\n", __func__);
+		return -EIO;
+	}
+
+	log->bios_event_log = kmalloc(*sizep, GFP_KERNEL);
+	if (!log->bios_event_log) {
+		pr_err("%s: ERROR - Not enough memory for BIOS measurements\n",
+		       __func__);
+		return -ENOMEM;
+	}
+
+	log->bios_event_log_end = log->bios_event_log + *sizep;
+
+	memcpy(log->bios_event_log, __va(be64_to_cpup(basep)), *sizep);
+
+	return 0;
+}

cheers
Thread (6 messages) 6 messages, 2 authors, last reply 2012-08-13
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