[PATCH] tpmdd: remove global event log

Remove global event log in the tpm bios event measurement log code that
would have caused problems when the code was run concurrently.  A log is
now allocated and attached to the seq file upon open and destroyed
appropriately.
Signed-off-by: Kylene Jo Hall <kjhall@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

drivers/char/tpm/tpm_bios.c

@@ -29,6 +29,11 @@
 #define MAX_TEXT_EVENT		1000	/* Max event string length */
 #define ACPI_TCPA_SIG		"TCPA"	/* 0x41504354 /'TCPA' */
 
+struct tpm_bios_log {
+	void *bios_event_log;
+	void *bios_event_log_end;
+};
+
 struct acpi_tcpa {
 	struct acpi_table_header hdr;
 	u16 reserved;
@@ -117,39 +122,34 @@ static const char* tcpa_pc_event_id_strings[] = {
 	"S-CRTM POST Contents",
 };
 
-/* (Binary) bios measurement buffer */
-static void *tcg_eventlog;
-static void *tcg_eventlog_addr_limit;	/* MAX */
-
 /* returns pointer to start of pos. entry of tcg log */
 static void *tpm_bios_measurements_start(struct seq_file *m, loff_t *pos)
 {
 	loff_t i;
-	void *addr = tcg_eventlog;
+	struct tpm_bios_log *log = m->private;
+	void *addr = log->bios_event_log;
+	void *limit = log->bios_event_log_end;
 	struct tcpa_event *event;
 
 	/* read over *pos measurements */
 	for (i = 0; i < *pos; i++) {
 		event = addr;
 
-		if ((addr + sizeof(struct tcpa_event)) <
-		    tcg_eventlog_addr_limit) {
+		if ((addr + sizeof(struct tcpa_event)) < limit) {
 			if (event->event_type == 0 && event->event_size == 0)
 				return NULL;
-			addr +=
-			    sizeof(struct tcpa_event) + event->event_size;
+			addr += sizeof(struct tcpa_event) + event->event_size;
 		}
 	}
 
 	/* now check if current entry is valid */
-	if ((addr + sizeof(struct tcpa_event)) >= tcg_eventlog_addr_limit)
+	if ((addr + sizeof(struct tcpa_event)) >= limit)
 		return NULL;
 
 	event = addr;
 
 	if ((event->event_type == 0 && event->event_size == 0) ||
-	    ((addr + sizeof(struct tcpa_event) + event->event_size) >=
-	     tcg_eventlog_addr_limit))
+	    ((addr + sizeof(struct tcpa_event) + event->event_size) >= limit))
 		return NULL;
 
 	return addr;
@@ -159,11 +159,13 @@ static void *tpm_bios_measurements_next(struct seq_file *m, void *v,
 					loff_t *pos)
 {
 	struct tcpa_event *event = v;
+	struct tpm_bios_log *log = m->private;
+	void *limit = log->bios_event_log_end;
 
 	v += sizeof(struct tcpa_event) + event->event_size;
 
 	/* now check if current entry is valid */
-	if ((v + sizeof(struct tcpa_event)) >= tcg_eventlog_addr_limit)
+	if ((v + sizeof(struct tcpa_event)) >= limit)
 		return NULL;
 
 	event = v;
@@ -172,8 +174,7 @@ static void *tpm_bios_measurements_next(struct seq_file *m, void *v,
 		return NULL;
 
 	if ((event->event_type == 0 && event->event_size == 0) ||
-	    ((v + sizeof(struct tcpa_event) + event->event_size) >=
-	     tcg_eventlog_addr_limit))
+	    ((v + sizeof(struct tcpa_event) + event->event_size) >= limit))
 		return NULL;
 
 	(*pos)++;
@@ -312,10 +313,14 @@ static int tpm_binary_bios_measurements_show(struct seq_file *m, void *v)
 static int tpm_bios_measurements_release(struct inode *inode,
 					 struct file *file)
 {
-	if (tcg_eventlog) {
-		kfree(tcg_eventlog);
-		tcg_eventlog = NULL;
+	struct seq_file *seq = file->private_data;
+	struct tpm_bios_log *log = seq->private;
+
+	if (log) {
+		kfree(log->bios_event_log);
+		kfree(log);
 	}
+
 	return seq_release(inode, file);
 }
 
@@ -367,13 +372,13 @@ static struct seq_operations tpm_binary_b_measurments_seqops = {
 };
 
 /* read binary bios log */
-static int read_log(void)
+static int read_log(struct tpm_bios_log *log)
 {
 	struct acpi_tcpa *buff;
 	acpi_status status;
 	void *virt;
 
-	if (tcg_eventlog != NULL) {
+	if (log->bios_event_log != NULL) {
 		printk(KERN_ERR
 		       "%s: ERROR - Eventlog already initialized\n",
 		       __func__);
@@ -393,25 +398,24 @@ static int read_log(void)
 	}
 
 	if (buff->log_max_len == 0) {
-		printk(KERN_ERR "%s: ERROR - TCPA log area empty\n",
-		       __func__);
+		printk(KERN_ERR "%s: ERROR - TCPA log area empty\n", __func__);
 		return -EIO;
 	}
 
 	/* malloc EventLog space */
-	tcg_eventlog = kmalloc(buff->log_max_len, GFP_KERNEL);
-	if (!tcg_eventlog) {
+	log->bios_event_log = kmalloc(buff->log_max_len, GFP_KERNEL);
+	if (!log->bios_event_log) {
 		printk
 		    ("%s: ERROR - Not enough  Memory for BIOS measurements\n",
 		     __func__);
 		return -ENOMEM;
 	}
 
-	tcg_eventlog_addr_limit = tcg_eventlog + buff->log_max_len;
+	log->bios_event_log_end = log->bios_event_log + buff->log_max_len;
 
 	acpi_os_map_memory(buff->log_start_addr, buff->log_max_len, &virt);
 
-	memcpy(tcg_eventlog, virt, buff->log_max_len);
+	memcpy(log->bios_event_log, virt, buff->log_max_len);
 
 	acpi_os_unmap_memory(virt, buff->log_max_len);
 	return 0;
@@ -421,12 +425,26 @@ static int tpm_ascii_bios_measurements_open(struct inode *inode,
 					    struct file *file)
 {
 	int err;
+	struct tpm_bios_log *log;
+	struct seq_file *seq;
 
-	if ((err = read_log()))
+	log = kzalloc(sizeof(struct tpm_bios_log), GFP_KERNEL);
+	if (!log)
+		return -ENOMEM;
+
+	if ((err = read_log(log)))
 		return err;
 
 	/* now register seq file */
-	return seq_open(file, &tpm_ascii_b_measurments_seqops);
+	err = seq_open(file, &tpm_ascii_b_measurments_seqops);
+	if (!err) {
+		seq = file->private_data;
+		seq->private = log;
+	} else {
+		kfree(log->bios_event_log);
+		kfree(log);
+	}
+	return err;
 }
 
 struct file_operations tpm_ascii_bios_measurements_ops = {
@@ -440,12 +458,26 @@ static int tpm_binary_bios_measurements_open(struct inode *inode,
 					     struct file *file)
 {
 	int err;
+	struct tpm_bios_log *log;
+	struct seq_file *seq;
 
-	if ((err = read_log()))
+	log = kzalloc(sizeof(struct tpm_bios_log), GFP_KERNEL);
+	if (!log)
+		return -ENOMEM;
+
+	if ((err = read_log(log)))
 		return err;
 
 	/* now register seq file */
-	return seq_open(file, &tpm_binary_b_measurments_seqops);
+	err = seq_open(file, &tpm_binary_b_measurments_seqops);
+	if (!err) {
+		seq = file->private_data;
+		seq->private = log;
+	} else {
+		kfree(log->bios_event_log);
+		kfree(log);
+	}
+	return err;
 }
 
 struct file_operations tpm_binary_bios_measurements_ops = {