diff options
Diffstat (limited to 'drivers/firmware')
| -rw-r--r-- | drivers/firmware/efivars.c | 512 |
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; |