1 files changed, 504 insertions, 8 deletions

diff --git a/drivers/firmware/efivars.c b/drivers/firmware/efivars.c
index 6e51c1e81f14..52c5d8956d7d 100644
--- a/drivers/firmware/efivars.c
+++ b/drivers/firmware/efivars.c
@@ -80,6 +80,10 @@
 #include <linux/slab.h>
 #include <linux/pstore.h>
 
+#include <linux/fs.h>
+#include <linux/ramfs.h>
+#include <linux/pagemap.h>
+
 #include <asm/uaccess.h>
 
 #define EFIVARS_VERSION "0.08"
@@ -93,6 +97,12 @@ MODULE_VERSION(EFIVARS_VERSION);
 #define DUMP_NAME_LEN 52
 
 /*
+ * Length of a GUID string (strlen("aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee"))
+ * not including trailing NUL
+ */
+#define GUID_LEN 36
+
+/*
  * The maximum size of VariableName + Data = 1024
  * Therefore, it's reasonable to save that much
  * space in each part of the structure,
@@ -108,7 +118,6 @@ struct efi_variable {
         __u32         Attributes;
 } __attribute__((packed));
 
-
 struct efivar_entry {
         struct efivars *efivars;
         struct efi_variable var;
@@ -122,6 +131,9 @@ struct efivar_attribute {
         ssize_t (*store)(struct efivar_entry *entry, const char *buf, size_t count);
 };
 
+static struct efivars __efivars;
+static struct efivar_operations ops;
+
 #define PSTORE_EFI_ATTRIBUTES \
         (EFI_VARIABLE_NON_VOLATILE | \
          EFI_VARIABLE_BOOTSERVICE_ACCESS | \
@@ -629,14 +641,482 @@ static struct kobj_type efivar_ktype = {
         .default_attrs = def_attrs,
 };
 
-static struct pstore_info efi_pstore_info;
-
 static inline void
 efivar_unregister(struct efivar_entry *var)
 {
         kobject_put(&var->kobj);
 }
 
+static int efivarfs_file_open(struct inode *inode, struct file *file)
+{
+        file->private_data = inode->i_private;
+        return 0;
+}
+
+static int efi_status_to_err(efi_status_t status)
+{
+        int err;
+
+        switch (status) {
+        case EFI_INVALID_PARAMETER:
+                err = -EINVAL;
+                break;
+        case EFI_OUT_OF_RESOURCES:
+                err = -ENOSPC;
+                break;
+        case EFI_DEVICE_ERROR:
+                err = -EIO;
+                break;
+        case EFI_WRITE_PROTECTED:
+                err = -EROFS;
+                break;
+        case EFI_SECURITY_VIOLATION:
+                err = -EACCES;
+                break;
+        case EFI_NOT_FOUND:
+                err = -ENOENT;
+                break;
+        default:
+                err = -EINVAL;
+        }
+
+        return err;
+}
+
+static ssize_t efivarfs_file_write(struct file *file,
+                const char __user *userbuf, size_t count, loff_t *ppos)
+{
+        struct efivar_entry *var = file->private_data;
+        struct efivars *efivars;
+        efi_status_t status;
+        void *data;
+        u32 attributes;
+        struct inode *inode = file->f_mapping->host;
+        unsigned long datasize = count - sizeof(attributes);
+        unsigned long newdatasize;
+        u64 storage_size, remaining_size, max_size;
+        ssize_t bytes = 0;
+
+        if (count < sizeof(attributes))
+                return -EINVAL;
+
+        if (copy_from_user(&attributes, userbuf, sizeof(attributes)))
+                return -EFAULT;
+
+        if (attributes & ~(EFI_VARIABLE_MASK))
+                return -EINVAL;
+
+        efivars = var->efivars;
+
+        /*
+         * Ensure that the user can't allocate arbitrarily large
+         * amounts of memory. Pick a default size of 64K if
+         * QueryVariableInfo() isn't supported by the firmware.
+         */
+        spin_lock(&efivars->lock);
+
+        if (!efivars->ops->query_variable_info)
+                status = EFI_UNSUPPORTED;
+        else {
+                const struct efivar_operations *fops = efivars->ops;
+                status = fops->query_variable_info(attributes, &storage_size,
+                                                   &remaining_size, &max_size);
+        }
+
+        spin_unlock(&efivars->lock);
+
+        if (status != EFI_SUCCESS) {
+                if (status != EFI_UNSUPPORTED)
+                        return efi_status_to_err(status);
+
+                remaining_size = 65536;
+        }
+
+        if (datasize > remaining_size)
+                return -ENOSPC;
+
+        data = kmalloc(datasize, GFP_KERNEL);
+        if (!data)
+                return -ENOMEM;
+
+        if (copy_from_user(data, userbuf + sizeof(attributes), datasize)) {
+                bytes = -EFAULT;
+                goto out;
+        }
+
+        if (validate_var(&var->var, data, datasize) == false) {
+                bytes = -EINVAL;
+                goto out;
+        }
+
+        /*
+         * The lock here protects the get_variable call, the conditional
+         * set_variable call, and removal of the variable from the efivars
+         * list (in the case of an authenticated delete).
+         */
+        spin_lock(&efivars->lock);
+
+        status = efivars->ops->set_variable(var->var.VariableName,
+                                            &var->var.VendorGuid,
+                                            attributes, datasize,
+                                            data);
+
+        if (status != EFI_SUCCESS) {
+                spin_unlock(&efivars->lock);
+                kfree(data);
+
+                return efi_status_to_err(status);
+        }
+
+        bytes = count;
+
+        /*
+         * Writing to the variable may have caused a change in size (which
+         * could either be an append or an overwrite), or the variable to be
+         * deleted. Perform a GetVariable() so we can tell what actually
+         * happened.
+         */
+        newdatasize = 0;
+        status = efivars->ops->get_variable(var->var.VariableName,
+                                            &var->var.VendorGuid,
+                                            NULL, &newdatasize,
+                                            NULL);
+
+        if (status == EFI_BUFFER_TOO_SMALL) {
+                spin_unlock(&efivars->lock);
+                mutex_lock(&inode->i_mutex);
+                i_size_write(inode, newdatasize + sizeof(attributes));
+                mutex_unlock(&inode->i_mutex);
+
+        } else if (status == EFI_NOT_FOUND) {
+                list_del(&var->list);
+                spin_unlock(&efivars->lock);
+                efivar_unregister(var);
+                drop_nlink(inode);
+                dput(file->f_dentry);
+
+        } else {
+                spin_unlock(&efivars->lock);
+                pr_warn("efivarfs: inconsistent EFI variable implementation? "
+                                "status = %lx\n", status);
+        }
+
+out:
+        kfree(data);
+
+        return bytes;
+}
+
+static ssize_t efivarfs_file_read(struct file *file, char __user *userbuf,
+                size_t count, loff_t *ppos)
+{
+        struct efivar_entry *var = file->private_data;
+        struct efivars *efivars = var->efivars;
+        efi_status_t status;
+        unsigned long datasize = 0;
+        u32 attributes;
+        void *data;
+        ssize_t size = 0;
+
+        spin_lock(&efivars->lock);
+        status = efivars->ops->get_variable(var->var.VariableName,
+                                            &var->var.VendorGuid,
+                                            &attributes, &datasize, NULL);
+        spin_unlock(&efivars->lock);
+
+        if (status != EFI_BUFFER_TOO_SMALL)
+                return efi_status_to_err(status);
+
+        data = kmalloc(datasize + sizeof(attributes), GFP_KERNEL);
+
+        if (!data)
+                return -ENOMEM;
+
+        spin_lock(&efivars->lock);
+        status = efivars->ops->get_variable(var->var.VariableName,
+                                            &var->var.VendorGuid,
+                                            &attributes, &datasize,
+                                            (data + sizeof(attributes)));
+        spin_unlock(&efivars->lock);
+
+        if (status != EFI_SUCCESS) {
+                size = efi_status_to_err(status);
+                goto out_free;
+        }
+
+        memcpy(data, &attributes, sizeof(attributes));
+        size = simple_read_from_buffer(userbuf, count, ppos,
+                                       data, datasize + sizeof(attributes));
+out_free:
+        kfree(data);
+
+        return size;
+}
+
+static void efivarfs_evict_inode(struct inode *inode)
+{
+        clear_inode(inode);
+}
+
+static const struct super_operations efivarfs_ops = {
+        .statfs = simple_statfs,
+        .drop_inode = generic_delete_inode,
+        .evict_inode = efivarfs_evict_inode,
+        .show_options = generic_show_options,
+};
+
+static struct super_block *efivarfs_sb;
+
+static const struct inode_operations efivarfs_dir_inode_operations;
+
+static const struct file_operations efivarfs_file_operations = {
+        .open   = efivarfs_file_open,
+        .read   = efivarfs_file_read,
+        .write  = efivarfs_file_write,
+        .llseek = no_llseek,
+};
+
+static struct inode *efivarfs_get_inode(struct super_block *sb,
+                                const struct inode *dir, int mode, dev_t dev)
+{
+        struct inode *inode = new_inode(sb);
+
+        if (inode) {
+                inode->i_ino = get_next_ino();
+                inode->i_uid = inode->i_gid = 0;
+                inode->i_mode = mode;
+                inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
+                switch (mode & S_IFMT) {
+                case S_IFREG:
+                        inode->i_fop = &efivarfs_file_operations;
+                        break;
+                case S_IFDIR:
+                        inode->i_op = &efivarfs_dir_inode_operations;
+                        inode->i_fop = &simple_dir_operations;
+                        inc_nlink(inode);
+                        break;
+                }
+        }
+        return inode;
+}
+
+static void efivarfs_hex_to_guid(const char *str, efi_guid_t *guid)
+{
+        guid->b[0] = hex_to_bin(str[6]) << 4 | hex_to_bin(str[7]);
+        guid->b[1] = hex_to_bin(str[4]) << 4 | hex_to_bin(str[5]);
+        guid->b[2] = hex_to_bin(str[2]) << 4 | hex_to_bin(str[3]);
+        guid->b[3] = hex_to_bin(str[0]) << 4 | hex_to_bin(str[1]);
+        guid->b[4] = hex_to_bin(str[11]) << 4 | hex_to_bin(str[12]);
+        guid->b[5] = hex_to_bin(str[9]) << 4 | hex_to_bin(str[10]);
+        guid->b[6] = hex_to_bin(str[16]) << 4 | hex_to_bin(str[17]);
+        guid->b[7] = hex_to_bin(str[14]) << 4 | hex_to_bin(str[15]);
+        guid->b[8] = hex_to_bin(str[19]) << 4 | hex_to_bin(str[20]);
+        guid->b[9] = hex_to_bin(str[21]) << 4 | hex_to_bin(str[22]);
+        guid->b[10] = hex_to_bin(str[24]) << 4 | hex_to_bin(str[25]);
+        guid->b[11] = hex_to_bin(str[26]) << 4 | hex_to_bin(str[27]);
+        guid->b[12] = hex_to_bin(str[28]) << 4 | hex_to_bin(str[29]);
+        guid->b[13] = hex_to_bin(str[30]) << 4 | hex_to_bin(str[31]);
+        guid->b[14] = hex_to_bin(str[32]) << 4 | hex_to_bin(str[33]);
+        guid->b[15] = hex_to_bin(str[34]) << 4 | hex_to_bin(str[35]);
+}
+
+static int efivarfs_create(struct inode *dir, struct dentry *dentry,
+                          umode_t mode, bool excl)
+{
+        struct inode *inode;
+        struct efivars *efivars = &__efivars;
+        struct efivar_entry *var;
+        int namelen, i = 0, err = 0;
+
+        /*
+         * We need a GUID, plus at least one letter for the variable name,
+         * plus the '-' separator
+         */
+        if (dentry->d_name.len < GUID_LEN + 2)
+                return -EINVAL;
+
+        inode = efivarfs_get_inode(dir->i_sb, dir, mode, 0);
+        if (!inode)
+                return -ENOMEM;
+
+        var = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
+        if (!var) {
+                err = -ENOMEM;
+                goto out;
+        }
+
+        /* length of the variable name itself: remove GUID and separator */
+        namelen = dentry->d_name.len - GUID_LEN - 1;
+
+        efivarfs_hex_to_guid(dentry->d_name.name + namelen + 1,
+                        &var->var.VendorGuid);
+
+        for (i = 0; i < namelen; i++)
+                var->var.VariableName[i] = dentry->d_name.name[i];
+
+        var->var.VariableName[i] = '\0';
+
+        inode->i_private = var;
+        var->efivars = efivars;
+        var->kobj.kset = efivars->kset;
+
+        err = kobject_init_and_add(&var->kobj, &efivar_ktype, NULL, "%s",
+                             dentry->d_name.name);
+        if (err)
+                goto out;
+
+        kobject_uevent(&var->kobj, KOBJ_ADD);
+        spin_lock(&efivars->lock);
+        list_add(&var->list, &efivars->list);
+        spin_unlock(&efivars->lock);
+        d_instantiate(dentry, inode);
+        dget(dentry);
+out:
+        if (err) {
+                kfree(var);
+                iput(inode);
+        }
+        return err;
+}
+
+static int efivarfs_unlink(struct inode *dir, struct dentry *dentry)
+{
+        struct efivar_entry *var = dentry->d_inode->i_private;
+        struct efivars *efivars = var->efivars;
+        efi_status_t status;
+
+        spin_lock(&efivars->lock);
+
+        status = efivars->ops->set_variable(var->var.VariableName,
+                                            &var->var.VendorGuid,
+                                            0, 0, NULL);
+
+        if (status == EFI_SUCCESS || status == EFI_NOT_FOUND) {
+                list_del(&var->list);
+                spin_unlock(&efivars->lock);
+                efivar_unregister(var);
+                drop_nlink(dir);
+                dput(dentry);
+                return 0;
+        }
+
+        spin_unlock(&efivars->lock);
+        return -EINVAL;
+};
+
+static int efivarfs_fill_super(struct super_block *sb, void *data, int silent)
+{
+        struct inode *inode = NULL;
+        struct dentry *root;
+        struct efivar_entry *entry, *n;
+        struct efivars *efivars = &__efivars;
+        char *name;
+
+        efivarfs_sb = sb;
+
+        sb->s_maxbytes          = MAX_LFS_FILESIZE;
+        sb->s_blocksize         = PAGE_CACHE_SIZE;
+        sb->s_blocksize_bits    = PAGE_CACHE_SHIFT;
+        sb->s_magic             = EFIVARFS_MAGIC;
+        sb->s_op                = &efivarfs_ops;
+        sb->s_time_gran         = 1;
+
+        inode = efivarfs_get_inode(sb, NULL, S_IFDIR | 0755, 0);
+        if (!inode)
+                return -ENOMEM;
+        inode->i_op = &efivarfs_dir_inode_operations;
+
+        root = d_make_root(inode);
+        sb->s_root = root;
+        if (!root)
+                return -ENOMEM;
+
+        list_for_each_entry_safe(entry, n, &efivars->list, list) {
+                struct dentry *dentry, *root = efivarfs_sb->s_root;
+                unsigned long size = 0;
+                int len, i;
+
+                inode = NULL;
+
+                len = utf16_strlen(entry->var.VariableName);
+
+                /* name, plus '-', plus GUID, plus NUL*/
+                name = kmalloc(len + 1 + GUID_LEN + 1, GFP_ATOMIC);
+                if (!name)
+                        goto fail;
+
+                for (i = 0; i < len; i++)
+                        name[i] = entry->var.VariableName[i] & 0xFF;
+
+                name[len] = '-';
+
+                efi_guid_unparse(&entry->var.VendorGuid, name + len + 1);
+
+                name[len+GUID_LEN+1] = '\0';
+
+                inode = efivarfs_get_inode(efivarfs_sb, root->d_inode,
+                                          S_IFREG | 0644, 0);
+                if (!inode)
+                        goto fail_name;
+
+                dentry = d_alloc_name(root, name);
+                if (!dentry)
+                        goto fail_inode;
+
+                /* copied by the above to local storage in the dentry. */
+                kfree(name);
+
+                spin_lock(&efivars->lock);
+                efivars->ops->get_variable(entry->var.VariableName,
+                                           &entry->var.VendorGuid,
+                                           &entry->var.Attributes,
+                                           &size,
+                                           NULL);
+                spin_unlock(&efivars->lock);
+
+                mutex_lock(&inode->i_mutex);
+                inode->i_private = entry;
+                i_size_write(inode, size+4);
+                mutex_unlock(&inode->i_mutex);
+                d_add(dentry, inode);
+        }
+
+        return 0;
+
+fail_inode:
+        iput(inode);
+fail_name:
+        kfree(name);
+fail:
+        return -ENOMEM;
+}
+
+static struct dentry *efivarfs_mount(struct file_system_type *fs_type,
+                                    int flags, const char *dev_name, void *data)
+{
+        return mount_single(fs_type, flags, data, efivarfs_fill_super);
+}
+
+static void efivarfs_kill_sb(struct super_block *sb)
+{
+        kill_litter_super(sb);
+        efivarfs_sb = NULL;
+}
+
+static struct file_system_type efivarfs_type = {
+        .name    = "efivarfs",
+        .mount   = efivarfs_mount,
+        .kill_sb = efivarfs_kill_sb,
+};
+
+static const struct inode_operations efivarfs_dir_inode_operations = {
+        .lookup = simple_lookup,
+        .unlink = efivarfs_unlink,
+        .create = efivarfs_create,
+};
+
+static struct pstore_info efi_pstore_info;
+
 #ifdef CONFIG_PSTORE
 
 static int efi_pstore_open(struct pstore_info *psi)
@@ -1065,11 +1545,18 @@ efivar_create_sysfs_entry(struct efivars *efivars,
                           efi_char16_t *variable_name,
                           efi_guid_t *vendor_guid)
 {
-        int i, short_name_size = variable_name_size / sizeof(efi_char16_t) + 38;
+        int i, short_name_size;
         char *short_name;
         struct efivar_entry *new_efivar;
 
-        short_name = kzalloc(short_name_size + 1, GFP_KERNEL);
+        /*
+         * Length of the variable bytes in ASCII, plus the '-' separator,
+         * plus the GUID, plus trailing NUL
+         */
+        short_name_size = variable_name_size / sizeof(efi_char16_t)
+                                + 1 + GUID_LEN + 1;
+
+        short_name = kzalloc(short_name_size, GFP_KERNEL);
         new_efivar = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
 
         if (!short_name || !new_efivar)  {
@@ -1189,6 +1676,7 @@ void unregister_efivars(struct efivars *efivars)
                 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->del_var);
         kfree(efivars->new_var);
         kfree(efivars->del_var);
+        kobject_put(efivars->kobject);
         kset_unregister(efivars->kset);
 }
 EXPORT_SYMBOL_GPL(unregister_efivars);
@@ -1220,6 +1708,14 @@ int register_efivars(struct efivars *efivars,
                 goto out;
         }
 
+        efivars->kobject = kobject_create_and_add("efivars", parent_kobj);
+        if (!efivars->kobject) {
+                pr_err("efivars: Subsystem registration failed.\n");
+                error = -ENOMEM;
+                kset_unregister(efivars->kset);
+                goto out;
+        }
+
         /*
          * Per EFI spec, the maximum storage allocated for both
          * the variable name and variable data is 1024 bytes.
@@ -1262,6 +1758,8 @@ int register_efivars(struct efivars *efivars,
                 pstore_register(&efivars->efi_pstore_info);
         }
 
+        register_filesystem(&efivarfs_type);
+
 out:
         kfree(variable_name);
 
@@ -1269,9 +1767,6 @@ out:
 }
 EXPORT_SYMBOL_GPL(register_efivars);
 
-static struct efivars __efivars;
-static struct efivar_operations ops;
-
 /*
  * For now we register the efi subsystem with the firmware subsystem
  * and the vars subsystem with the efi subsystem.  In the future, it
@@ -1302,6 +1797,7 @@ efivars_init(void)
         ops.set_variable = efi.set_variable;
         ops.get_next_variable = efi.get_next_variable;
         ops.query_variable_info = efi.query_variable_info;
+
         error = register_efivars(&__efivars, &ops, efi_kobj);
         if (error)
                 goto err_put;