diff options
Diffstat (limited to 'drivers/firmware/efivars.c')
-rw-r--r-- | drivers/firmware/efivars.c | 281 |
1 files changed, 201 insertions, 80 deletions
diff --git a/drivers/firmware/efivars.c b/drivers/firmware/efivars.c index 7320bf891706..7acafb80fd4c 100644 --- a/drivers/firmware/efivars.c +++ b/drivers/firmware/efivars.c @@ -103,6 +103,11 @@ MODULE_VERSION(EFIVARS_VERSION); */ #define GUID_LEN 36 +static bool efivars_pstore_disable = + IS_ENABLED(CONFIG_EFI_VARS_PSTORE_DEFAULT_DISABLE); + +module_param_named(pstore_disable, efivars_pstore_disable, bool, 0644); + /* * The maximum size of VariableName + Data = 1024 * Therefore, it's reasonable to save that much @@ -165,6 +170,7 @@ efivar_create_sysfs_entry(struct efivars *efivars, static void efivar_update_sysfs_entries(struct work_struct *); static DECLARE_WORK(efivar_work, efivar_update_sysfs_entries); +static bool efivar_wq_enabled = true; /* Return the number of unicode characters in data */ static unsigned long @@ -426,6 +432,44 @@ get_var_data(struct efivars *efivars, struct efi_variable *var) return status; } +static efi_status_t +check_var_size_locked(struct efivars *efivars, u32 attributes, + unsigned long size) +{ + u64 storage_size, remaining_size, max_size; + efi_status_t status; + const struct efivar_operations *fops = efivars->ops; + + if (!efivars->ops->query_variable_info) + return EFI_UNSUPPORTED; + + status = fops->query_variable_info(attributes, &storage_size, + &remaining_size, &max_size); + + if (status != EFI_SUCCESS) + return status; + + if (!storage_size || size > remaining_size || size > max_size || + (remaining_size - size) < (storage_size / 2)) + return EFI_OUT_OF_RESOURCES; + + return status; +} + + +static efi_status_t +check_var_size(struct efivars *efivars, u32 attributes, unsigned long size) +{ + efi_status_t status; + unsigned long flags; + + spin_lock_irqsave(&efivars->lock, flags); + status = check_var_size_locked(efivars, attributes, size); + spin_unlock_irqrestore(&efivars->lock, flags); + + return status; +} + static ssize_t efivar_guid_read(struct efivar_entry *entry, char *buf) { @@ -547,11 +591,16 @@ efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count) } spin_lock_irq(&efivars->lock); - status = efivars->ops->set_variable(new_var->VariableName, - &new_var->VendorGuid, - new_var->Attributes, - new_var->DataSize, - new_var->Data); + + status = check_var_size_locked(efivars, new_var->Attributes, + new_var->DataSize + utf16_strsize(new_var->VariableName, 1024)); + + if (status == EFI_SUCCESS || status == EFI_UNSUPPORTED) + status = efivars->ops->set_variable(new_var->VariableName, + &new_var->VendorGuid, + new_var->Attributes, + new_var->DataSize, + new_var->Data); spin_unlock_irq(&efivars->lock); @@ -702,8 +751,7 @@ static ssize_t efivarfs_file_write(struct file *file, 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; + unsigned long newdatasize, varsize; ssize_t bytes = 0; if (count < sizeof(attributes)) @@ -722,28 +770,18 @@ static ssize_t efivarfs_file_write(struct file *file, * amounts of memory. Pick a default size of 64K if * QueryVariableInfo() isn't supported by the firmware. */ - spin_lock_irq(&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_irq(&efivars->lock); + varsize = datasize + utf16_strsize(var->var.VariableName, 1024); + status = check_var_size(efivars, attributes, varsize); if (status != EFI_SUCCESS) { if (status != EFI_UNSUPPORTED) return efi_status_to_err(status); - remaining_size = 65536; + if (datasize > 65536) + return -ENOSPC; } - if (datasize > remaining_size) - return -ENOSPC; - data = kmalloc(datasize, GFP_KERNEL); if (!data) return -ENOMEM; @@ -765,6 +803,19 @@ static ssize_t efivarfs_file_write(struct file *file, */ spin_lock_irq(&efivars->lock); + /* + * Ensure that the available space hasn't shrunk below the safe level + */ + + status = check_var_size_locked(efivars, attributes, varsize); + + if (status != EFI_SUCCESS && status != EFI_UNSUPPORTED) { + spin_unlock_irq(&efivars->lock); + kfree(data); + + return efi_status_to_err(status); + } + status = efivars->ops->set_variable(var->var.VariableName, &var->var.VendorGuid, attributes, datasize, @@ -929,8 +980,8 @@ static bool efivarfs_valid_name(const char *str, int len) if (len < GUID_LEN + 2) return false; - /* GUID should be right after the first '-' */ - if (s - 1 != strchr(str, '-')) + /* GUID must be preceded by a '-' */ + if (*(s - 1) != '-') return false; /* @@ -1118,15 +1169,22 @@ static struct dentry_operations efivarfs_d_ops = { static struct dentry *efivarfs_alloc_dentry(struct dentry *parent, char *name) { + struct dentry *d; struct qstr q; + int err; q.name = name; q.len = strlen(name); - if (efivarfs_d_hash(NULL, NULL, &q)) - return NULL; + err = efivarfs_d_hash(NULL, NULL, &q); + if (err) + return ERR_PTR(err); + + d = d_alloc(parent, &q); + if (d) + return d; - return d_alloc(parent, &q); + return ERR_PTR(-ENOMEM); } static int efivarfs_fill_super(struct super_block *sb, void *data, int silent) @@ -1136,6 +1194,7 @@ static int efivarfs_fill_super(struct super_block *sb, void *data, int silent) struct efivar_entry *entry, *n; struct efivars *efivars = &__efivars; char *name; + int err = -ENOMEM; efivarfs_sb = sb; @@ -1186,8 +1245,10 @@ static int efivarfs_fill_super(struct super_block *sb, void *data, int silent) goto fail_name; dentry = efivarfs_alloc_dentry(root, name); - if (!dentry) + if (IS_ERR(dentry)) { + err = PTR_ERR(dentry); goto fail_inode; + } /* copied by the above to local storage in the dentry. */ kfree(name); @@ -1214,7 +1275,7 @@ fail_inode: fail_name: kfree(name); fail: - return -ENOMEM; + return err; } static struct dentry *efivarfs_mount(struct file_system_type *fs_type, @@ -1234,6 +1295,7 @@ static struct file_system_type efivarfs_type = { .mount = efivarfs_mount, .kill_sb = efivarfs_kill_sb, }; +MODULE_ALIAS_FS("efivarfs"); /* * Handle negative dentry. @@ -1253,9 +1315,7 @@ static const struct inode_operations efivarfs_dir_inode_operations = { .create = efivarfs_create, }; -static struct pstore_info efi_pstore_info; - -#ifdef CONFIG_PSTORE +#ifdef CONFIG_EFI_VARS_PSTORE static int efi_pstore_open(struct pstore_info *psi) { @@ -1345,7 +1405,6 @@ static int efi_pstore_write(enum pstore_type_id type, efi_guid_t vendor = LINUX_EFI_CRASH_GUID; struct efivars *efivars = psi->data; int i, ret = 0; - u64 storage_space, remaining_space, max_variable_size; efi_status_t status = EFI_NOT_FOUND; unsigned long flags; @@ -1365,11 +1424,11 @@ static int efi_pstore_write(enum pstore_type_id type, * size: a size of logging data * DUMP_NAME_LEN * 2: a maximum size of variable name */ - status = efivars->ops->query_variable_info(PSTORE_EFI_ATTRIBUTES, - &storage_space, - &remaining_space, - &max_variable_size); - if (status || remaining_space < size + DUMP_NAME_LEN * 2) { + + status = check_var_size_locked(efivars, PSTORE_EFI_ATTRIBUTES, + size + DUMP_NAME_LEN * 2); + + if (status) { spin_unlock_irqrestore(&efivars->lock, flags); *id = part; return -ENOSPC; @@ -1386,7 +1445,7 @@ static int efi_pstore_write(enum pstore_type_id type, spin_unlock_irqrestore(&efivars->lock, flags); - if (reason == KMSG_DUMP_OOPS) + if (reason == KMSG_DUMP_OOPS && efivar_wq_enabled) schedule_work(&efivar_work); *id = part; @@ -1459,38 +1518,6 @@ static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count, return 0; } -#else -static int efi_pstore_open(struct pstore_info *psi) -{ - return 0; -} - -static int efi_pstore_close(struct pstore_info *psi) -{ - return 0; -} - -static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type, int *count, - struct timespec *timespec, - char **buf, struct pstore_info *psi) -{ - return -1; -} - -static int efi_pstore_write(enum pstore_type_id type, - enum kmsg_dump_reason reason, u64 *id, - unsigned int part, int count, size_t size, - struct pstore_info *psi) -{ - return 0; -} - -static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count, - struct timespec time, struct pstore_info *psi) -{ - return 0; -} -#endif static struct pstore_info efi_pstore_info = { .owner = THIS_MODULE, @@ -1502,6 +1529,24 @@ static struct pstore_info efi_pstore_info = { .erase = efi_pstore_erase, }; +static void efivar_pstore_register(struct efivars *efivars) +{ + efivars->efi_pstore_info = efi_pstore_info; + efivars->efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL); + if (efivars->efi_pstore_info.buf) { + efivars->efi_pstore_info.bufsize = 1024; + efivars->efi_pstore_info.data = efivars; + spin_lock_init(&efivars->efi_pstore_info.buf_lock); + pstore_register(&efivars->efi_pstore_info); + } +} +#else +static void efivar_pstore_register(struct efivars *efivars) +{ + return; +} +#endif + static ssize_t efivar_create(struct file *filp, struct kobject *kobj, struct bin_attribute *bin_attr, char *buf, loff_t pos, size_t count) @@ -1544,6 +1589,14 @@ static ssize_t efivar_create(struct file *filp, struct kobject *kobj, return -EINVAL; } + status = check_var_size_locked(efivars, new_var->Attributes, + new_var->DataSize + utf16_strsize(new_var->VariableName, 1024)); + + if (status && status != EFI_UNSUPPORTED) { + spin_unlock_irq(&efivars->lock); + return efi_status_to_err(status); + } + /* now *really* create the variable via EFI */ status = efivars->ops->set_variable(new_var->VariableName, &new_var->VendorGuid, @@ -1653,6 +1706,31 @@ static bool variable_is_present(efi_char16_t *variable_name, efi_guid_t *vendor) return found; } +/* + * Returns the size of variable_name, in bytes, including the + * terminating NULL character, or variable_name_size if no NULL + * character is found among the first variable_name_size bytes. + */ +static unsigned long var_name_strnsize(efi_char16_t *variable_name, + unsigned long variable_name_size) +{ + unsigned long len; + efi_char16_t c; + + /* + * The variable name is, by definition, a NULL-terminated + * string, so make absolutely sure that variable_name_size is + * the value we expect it to be. If not, return the real size. + */ + for (len = 2; len <= variable_name_size; len += sizeof(c)) { + c = variable_name[(len / sizeof(c)) - 1]; + if (!c) + break; + } + + return min(len, variable_name_size); +} + static void efivar_update_sysfs_entries(struct work_struct *work) { struct efivars *efivars = &__efivars; @@ -1693,10 +1771,13 @@ static void efivar_update_sysfs_entries(struct work_struct *work) if (!found) { kfree(variable_name); break; - } else + } else { + variable_name_size = var_name_strnsize(variable_name, + variable_name_size); efivar_create_sysfs_entry(efivars, variable_name_size, variable_name, &vendor); + } } } @@ -1895,6 +1976,35 @@ void unregister_efivars(struct efivars *efivars) } EXPORT_SYMBOL_GPL(unregister_efivars); +/* + * Print a warning when duplicate EFI variables are encountered and + * disable the sysfs workqueue since the firmware is buggy. + */ +static void dup_variable_bug(efi_char16_t *s16, efi_guid_t *vendor_guid, + unsigned long len16) +{ + size_t i, len8 = len16 / sizeof(efi_char16_t); + char *s8; + + /* + * Disable the workqueue since the algorithm it uses for + * detecting new variables won't work with this buggy + * implementation of GetNextVariableName(). + */ + efivar_wq_enabled = false; + + s8 = kzalloc(len8, GFP_KERNEL); + if (!s8) + return; + + for (i = 0; i < len8; i++) + s8[i] = s16[i]; + + printk(KERN_WARNING "efivars: duplicate variable: %s-%pUl\n", + s8, vendor_guid); + kfree(s8); +} + int register_efivars(struct efivars *efivars, const struct efivar_operations *ops, struct kobject *parent_kobj) @@ -1943,6 +2053,24 @@ int register_efivars(struct efivars *efivars, &vendor_guid); switch (status) { case EFI_SUCCESS: + variable_name_size = var_name_strnsize(variable_name, + variable_name_size); + + /* + * Some firmware implementations return the + * same variable name on multiple calls to + * get_next_variable(). Terminate the loop + * immediately as there is no guarantee that + * we'll ever see a different variable name, + * and may end up looping here forever. + */ + if (variable_is_present(variable_name, &vendor_guid)) { + dup_variable_bug(variable_name, &vendor_guid, + variable_name_size); + status = EFI_NOT_FOUND; + break; + } + efivar_create_sysfs_entry(efivars, variable_name_size, variable_name, @@ -1962,15 +2090,8 @@ int register_efivars(struct efivars *efivars, if (error) unregister_efivars(efivars); - efivars->efi_pstore_info = efi_pstore_info; - - efivars->efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL); - if (efivars->efi_pstore_info.buf) { - efivars->efi_pstore_info.bufsize = 1024; - efivars->efi_pstore_info.data = efivars; - spin_lock_init(&efivars->efi_pstore_info.buf_lock); - pstore_register(&efivars->efi_pstore_info); - } + if (!efivars_pstore_disable) + efivar_pstore_register(efivars); register_filesystem(&efivarfs_type); |