[PATCH] tpmdd: remove global event log
Kylene Jo Hall [Sun, 8 Jan 2006 09:03:48 +0000 (01:03 -0800)]
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

index 5e1f4df..aedf7a8 100644 (file)
 #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 = {