ACPI: hotkey.c fixes, fix for potential crash of hotkey.c

While going through the code, I found out some memory leaks and potential
crashes in drivers/acpi/hotkey.c Please find the patch to fix them.

This patch does the following,

1. Fixes memory leaks in error paths of hotkey_write_config

2. Fixes freeing unallocated pointers in the error paths of hotkey_write_config

3. Uses a loop instead of linear searching for parsing the userspace
   input in get_params

4. Uses array of char * instead of passing 4 pointer parameters
   explicitly into the init_{poll_}hotkey_* static functions

Signed-off-by: Andrew Morton <akpm@osdl.org>
Acked-by: Luming Yu <luming.yu@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 119 insertions, 162 deletions

diff --git a/drivers/acpi/hotkey.c b/drivers/acpi/hotkey.c
index 32c9d88fd196..1ba2db671865 100644
--- a/drivers/acpi/hotkey.c
+++ b/drivers/acpi/hotkey.c
@@ -91,6 +91,14 @@ enum {
         HK_EVENT_ENTERRING_S5,
 };
 
+enum conf_entry_enum {
+        bus_handle = 0,
+        bus_method = 1,
+        action_handle = 2,
+        method = 3,
+        LAST_CONF_ENTRY
+};
+
 /*  procdir we use */
 static struct proc_dir_entry *hotkey_proc_dir;
 static struct proc_dir_entry *hotkey_config;
@@ -244,19 +252,15 @@ static int hotkey_info_open_fs(struct inode *inode, struct file *file)
 
 static char *format_result(union acpi_object *object)
 {
-        char *buf = NULL;
-
-        buf = (char *)kmalloc(RESULT_STR_LEN, GFP_KERNEL);
-        if (buf)
-                memset(buf, 0, RESULT_STR_LEN);
-        else
-                goto do_fail;
+        char *buf;
 
+        buf = kzalloc(RESULT_STR_LEN, GFP_KERNEL);
+        if (!buf)
+                return NULL;
         /* Now, just support integer type */
         if (object->type == ACPI_TYPE_INTEGER)
                 sprintf(buf, "%d\n", (u32) object->integer.value);
-      do_fail:
-        return (buf);
+        return buf;
 }
 
 static int hotkey_polling_seq_show(struct seq_file *seq, void *offset)
@@ -486,98 +490,102 @@ static void free_hotkey_device(union acpi_hotkey *key)
 
 static void free_hotkey_buffer(union acpi_hotkey *key)
 {
+        /* key would never be null, action method could be */
         kfree(key->event_hotkey.action_method);
 }
 
 static void free_poll_hotkey_buffer(union acpi_hotkey *key)
 {
+        /* key would never be null, others could be*/
         kfree(key->poll_hotkey.action_method);
         kfree(key->poll_hotkey.poll_method);
         kfree(key->poll_hotkey.poll_result);
 }
 static int
-init_hotkey_device(union acpi_hotkey *key, char *bus_str, char *action_str,
-                   char *method, int std_num, int external_num)
+init_hotkey_device(union acpi_hotkey *key, char **config_entry,
+                   int std_num, int external_num)
 {
         acpi_handle tmp_handle;
         acpi_status status = AE_OK;
 
-
         if (std_num < 0 || IS_POLL(std_num) || !key)
                 goto do_fail;
 
-        if (!bus_str || !action_str || !method)
+        if (!config_entry[bus_handle] || !config_entry[action_handle]
+                        || !config_entry[method])
                 goto do_fail;
 
         key->link.hotkey_type = ACPI_HOTKEY_EVENT;
         key->link.hotkey_standard_num = std_num;
         key->event_hotkey.flag = 0;
-        key->event_hotkey.action_method = method;
+        key->event_hotkey.action_method = config_entry[method];
 
-        status =
-            acpi_get_handle(NULL, bus_str, &(key->event_hotkey.bus_handle));
+        status = acpi_get_handle(NULL, config_entry[bus_handle],
+                           &(key->event_hotkey.bus_handle));
         if (ACPI_FAILURE(status))
-                goto do_fail;
+                goto do_fail_zero;
         key->event_hotkey.external_hotkey_num = external_num;
-        status =
-            acpi_get_handle(NULL, action_str,
+        status = acpi_get_handle(NULL, config_entry[action_handle],
                             &(key->event_hotkey.action_handle));
         if (ACPI_FAILURE(status))
-                goto do_fail;
+                goto do_fail_zero;
         status = acpi_get_handle(key->event_hotkey.action_handle,
-                                 method, &tmp_handle);
+                                 config_entry[method], &tmp_handle);
         if (ACPI_FAILURE(status))
-                goto do_fail;
+                goto do_fail_zero;
         return AE_OK;
-      do_fail:
+do_fail_zero:
+        key->event_hotkey.action_method = NULL;
+do_fail:
         return -ENODEV;
 }
 
 static int
-init_poll_hotkey_device(union acpi_hotkey *key,
-                        char *poll_str,
-                        char *poll_method,
-                        char *action_str, char *action_method, int std_num)
+init_poll_hotkey_device(union acpi_hotkey *key, char **config_entry,
+                        int std_num)
 {
         acpi_status status = AE_OK;
         acpi_handle tmp_handle;
 
-
         if (std_num < 0 || IS_EVENT(std_num) || !key)
                 goto do_fail;
-
-        if (!poll_str || !poll_method || !action_str || !action_method)
+        if (!config_entry[bus_handle] ||!config_entry[bus_method] ||
+                !config_entry[action_handle] || !config_entry[method])
                 goto do_fail;
 
         key->link.hotkey_type = ACPI_HOTKEY_POLLING;
         key->link.hotkey_standard_num = std_num;
         key->poll_hotkey.flag = 0;
-        key->poll_hotkey.poll_method = poll_method;
-        key->poll_hotkey.action_method = action_method;
+        key->poll_hotkey.poll_method = config_entry[bus_method];
+        key->poll_hotkey.action_method = config_entry[method];
 
-        status =
-            acpi_get_handle(NULL, poll_str, &(key->poll_hotkey.poll_handle));
+        status = acpi_get_handle(NULL, config_entry[bus_handle],
+                      &(key->poll_hotkey.poll_handle));
         if (ACPI_FAILURE(status))
-                goto do_fail;
+                goto do_fail_zero;
         status = acpi_get_handle(key->poll_hotkey.poll_handle,
-                                 poll_method, &tmp_handle);
+                                 config_entry[bus_method], &tmp_handle);
         if (ACPI_FAILURE(status))
-                goto do_fail;
+                goto do_fail_zero;
         status =
-            acpi_get_handle(NULL, action_str,
+            acpi_get_handle(NULL, config_entry[action_handle],
                             &(key->poll_hotkey.action_handle));
         if (ACPI_FAILURE(status))
-                goto do_fail;
+                goto do_fail_zero;
         status = acpi_get_handle(key->poll_hotkey.action_handle,
-                                 action_method, &tmp_handle);
+                                 config_entry[method], &tmp_handle);
         if (ACPI_FAILURE(status))
-                goto do_fail;
+                goto do_fail_zero;
         key->poll_hotkey.poll_result =
             (union acpi_object *)kmalloc(sizeof(union acpi_object), GFP_KERNEL);
         if (!key->poll_hotkey.poll_result)
-                goto do_fail;
+                goto do_fail_zero;
         return AE_OK;
-      do_fail:
+
+do_fail_zero:
+        key->poll_hotkey.poll_method = NULL;
+        key->poll_hotkey.action_method = NULL;
+do_fail:
         return -ENODEV;
 }
 
@@ -652,17 +660,18 @@ static int hotkey_poll_config_seq_show(struct seq_file *seq, void *offset)
 }
 
 static int
-get_parms(char *config_record,
-          int *cmd,
-          char **bus_handle,
-          char **bus_method,
-          char **action_handle,
-          char **method, int *internal_event_num, int *external_event_num)
+get_parms(char *config_record, int *cmd, char **config_entry,
+               int *internal_event_num, int *external_event_num)
 {
+/* the format of *config_record =
+ * "1:\d+:*" : "cmd:internal_event_num"
+ * "\d+:\w+:\w+:\w+:\w+:\d+:\d+" :
+ * "cmd:bus_handle:bus_method:action_handle:method:internal_event_num:external_event_num"
+ */
         char *tmp, *tmp1, count;
+        int i;
 
         sscanf(config_record, "%d", cmd);
-
         if (*cmd == 1) {
                 if (sscanf(config_record, "%d:%d", cmd, internal_event_num) !=
                     2)
@@ -674,59 +683,27 @@ get_parms(char *config_record,
         if (!tmp)
                 goto do_fail;
         tmp++;
-        tmp1 = strchr(tmp, ':');
-        if (!tmp1)
-                goto do_fail;
-
-        count = tmp1 - tmp;
-        *bus_handle = (char *)kmalloc(count + 1, GFP_KERNEL);
-        if (!*bus_handle)
-                goto do_fail;
-        strncpy(*bus_handle, tmp, count);
-        *(*bus_handle + count) = 0;
-
-        tmp = tmp1;
-        tmp++;
-        tmp1 = strchr(tmp, ':');
-        if (!tmp1)
-                goto do_fail;
-        count = tmp1 - tmp;
-        *bus_method = (char *)kmalloc(count + 1, GFP_KERNEL);
-        if (!*bus_method)
-                goto do_fail;
-        strncpy(*bus_method, tmp, count);
-        *(*bus_method + count) = 0;
-
-        tmp = tmp1;
-        tmp++;
-        tmp1 = strchr(tmp, ':');
-        if (!tmp1)
-                goto do_fail;
-        count = tmp1 - tmp;
-        *action_handle = (char *)kmalloc(count + 1, GFP_KERNEL);
-        if (!*action_handle)
-                goto do_fail;
-        strncpy(*action_handle, tmp, count);
-        *(*action_handle + count) = 0;
-
-        tmp = tmp1;
-        tmp++;
-        tmp1 = strchr(tmp, ':');
-        if (!tmp1)
-                goto do_fail;
-        count = tmp1 - tmp;
-        *method = (char *)kmalloc(count + 1, GFP_KERNEL);
-        if (!*method)
-                goto do_fail;
-        strncpy(*method, tmp, count);
-        *(*method + count) = 0;
-
-        if (sscanf(tmp1 + 1, "%d:%d", internal_event_num, external_event_num) <=
-            0)
-                goto do_fail;
-
-        return 6;
-      do_fail:
+        for (i = 0; i < LAST_CONF_ENTRY; i++) {
+                tmp1 = strchr(tmp, ':');
+                if (!tmp1) {
+                        goto do_fail;
+                }
+                count = tmp1 - tmp;
+                config_entry[i] = kzalloc(count + 1, GFP_KERNEL);
+                if (!config_entry[i])
+                        goto handle_failure;
+                strncpy(config_entry[i], tmp, count);
+                tmp = tmp1 + 1;
+        }
+        if (sscanf(tmp, "%d:%d", internal_event_num, external_event_num) <= 0)
+                goto handle_failure;
+        if (!IS_OTHERS(*internal_event_num)) {
+                return 6;
+        }
+handle_failure:
+        while (i-- > 0)
+                kfree(config_entry[i]);
+do_fail:
         return -1;
 }
 
@@ -736,50 +713,34 @@ static ssize_t hotkey_write_config(struct file *file,
                                    size_t count, loff_t * data)
 {
         char *config_record = NULL;
-        char *bus_handle = NULL;
-        char *bus_method = NULL;
-        char *action_handle = NULL;
-        char *method = NULL;
+        char *config_entry[LAST_CONF_ENTRY];
         int cmd, internal_event_num, external_event_num;
         int ret = 0;
-        union acpi_hotkey *key = NULL;
+        union acpi_hotkey *key = kzalloc(sizeof(union acpi_hotkey), GFP_KERNEL);
 
+        if (!key)
+                return -ENOMEM;
 
-        config_record = (char *)kmalloc(count + 1, GFP_KERNEL);
-        if (!config_record)
+        config_record = kzalloc(count + 1, GFP_KERNEL);
+        if (!config_record) {
+                kfree(key);
                 return -ENOMEM;
+        }
 
         if (copy_from_user(config_record, buffer, count)) {
                 kfree(config_record);
+                kfree(key);
                 printk(KERN_ERR PREFIX "Invalid data\n");
                 return -EINVAL;
         }
-        config_record[count] = 0;
-
-        ret = get_parms(config_record,
-                        &cmd,
-                        &bus_handle,
-                        &bus_method,
-                        &action_handle,
-                        &method, &internal_event_num, &external_event_num);
-
+        ret = get_parms(config_record, &cmd, config_entry,
+                       &internal_event_num, &external_event_num);
         kfree(config_record);
-        if (IS_OTHERS(internal_event_num))
-                goto do_fail;
         if (ret != 6) {
-              do_fail:
-                kfree(bus_handle);
-                kfree(bus_method);
-                kfree(action_handle);
-                kfree(method);
                 printk(KERN_ERR PREFIX "Invalid data format ret=%d\n", ret);
                 return -EINVAL;
         }
 
-        key = kmalloc(sizeof(union acpi_hotkey), GFP_KERNEL);
-        if (!key)
-                goto do_fail;
-        memset(key, 0, sizeof(union acpi_hotkey));
         if (cmd == 1) {
                 union acpi_hotkey *tmp = NULL;
                 tmp = get_hotkey_by_event(&global_hotkey_list,
@@ -791,34 +752,19 @@ static ssize_t hotkey_write_config(struct file *file,
                 goto cont_cmd;
         }
         if (IS_EVENT(internal_event_num)) {
-                kfree(bus_method);
-                ret = init_hotkey_device(key, bus_handle, action_handle, method,
-                                         internal_event_num,
-                                         external_event_num);
-        } else
-                ret = init_poll_hotkey_device(key, bus_handle, bus_method,
-                                              action_handle, method,
-                                              internal_event_num);
-        if (ret) {
-                kfree(bus_handle);
-                kfree(action_handle);
-                if (IS_EVENT(internal_event_num))
-                        free_hotkey_buffer(key);
-                else
-                        free_poll_hotkey_buffer(key);
-                kfree(key);
-                printk(KERN_ERR PREFIX "Invalid hotkey\n");
-                return -EINVAL;
+                if (init_hotkey_device(key, config_entry,
+                        internal_event_num, external_event_num))
+                        goto init_hotkey_fail;
+        } else {
+                if (init_poll_hotkey_device(key, config_entry,
+                               internal_event_num))
+                        goto init_poll_hotkey_fail;
         }
-
-      cont_cmd:
-        kfree(bus_handle);
-        kfree(action_handle);
-
+cont_cmd:
         switch (cmd) {
         case 0:
-                if (get_hotkey_by_event
-                    (&global_hotkey_list, key->link.hotkey_standard_num))
+                if (get_hotkey_by_event(&global_hotkey_list,
+                                key->link.hotkey_standard_num))
                         goto fail_out;
                 else
                         hotkey_add(key);
@@ -827,6 +773,7 @@ static ssize_t hotkey_write_config(struct file *file,
                 hotkey_remove(key);
                 break;
         case 2:
+                /* key is kfree()ed if matched*/
                 if (hotkey_update(key))
                         goto fail_out;
                 break;
@@ -835,11 +782,22 @@ static ssize_t hotkey_write_config(struct file *file,
                 break;
         }
         return count;
-      fail_out:
-        if (IS_EVENT(internal_event_num))
-                free_hotkey_buffer(key);
-        else
-                free_poll_hotkey_buffer(key);
+
+init_poll_hotkey_fail:          /* failed init_poll_hotkey_device */
+        kfree(config_entry[bus_method]);
+        config_entry[bus_method] = NULL;
+init_hotkey_fail:               /* failed init_hotkey_device */
+        kfree(config_entry[method]);
+fail_out:
+        kfree(config_entry[bus_handle]);
+        kfree(config_entry[action_handle]);
+        /* No double free since elements =NULL for error cases */
+        if (IS_EVENT(internal_event_num)) {
+                if (config_entry[bus_method])
+                        kfree(config_entry[bus_method]);
+                free_hotkey_buffer(key);        /* frees [method] */
+        } else
+                free_poll_hotkey_buffer(key);  /* frees [bus_method]+[method] */
         kfree(key);
         printk(KERN_ERR PREFIX "invalid key\n");
         return -EINVAL;
@@ -923,10 +881,9 @@ static ssize_t hotkey_execute_aml_method(struct file *file,
         union acpi_hotkey *key;
 
 
-        arg = (char *)kmalloc(count + 1, GFP_KERNEL);
+        arg = kzalloc(count + 1, GFP_KERNEL);
         if (!arg)
                 return -ENOMEM;
-        arg[count] = 0;
 
         if (copy_from_user(arg, buffer, count)) {
                 kfree(arg);