diff options
Diffstat (limited to 'drivers/firmware/efivars.c')
| -rw-r--r-- | drivers/firmware/efivars.c | 345 |
1 files changed, 205 insertions, 140 deletions
diff --git a/drivers/firmware/efivars.c b/drivers/firmware/efivars.c index 7320bf89170..182ce947117 100644 --- a/drivers/firmware/efivars.c +++ b/drivers/firmware/efivars.c @@ -80,6 +80,7 @@ #include <linux/slab.h> #include <linux/pstore.h> #include <linux/ctype.h> +#include <linux/ucs2_string.h> #include <linux/fs.h> #include <linux/ramfs.h> @@ -103,6 +104,11 @@ 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 @@ -165,51 +171,7 @@ 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); - -/* Return the number of unicode characters in data */ -static unsigned long -utf16_strnlen(efi_char16_t *s, size_t maxlength) -{ - unsigned long length = 0; - - while (*s++ != 0 && length < maxlength) - length++; - return length; -} - -static inline unsigned long -utf16_strlen(efi_char16_t *s) -{ - return utf16_strnlen(s, ~0UL); -} - -/* - * Return the number of bytes is the length of this string - * Note: this is NOT the same as the number of unicode characters - */ -static inline unsigned long -utf16_strsize(efi_char16_t *data, unsigned long maxlength) -{ - return utf16_strnlen(data, maxlength/sizeof(efi_char16_t)) * sizeof(efi_char16_t); -} - -static inline int -utf16_strncmp(const efi_char16_t *a, const efi_char16_t *b, size_t len) -{ - while (1) { - if (len == 0) - return 0; - if (*a < *b) - return -1; - if (*a > *b) - return 1; - if (*a == 0) /* implies *b == 0 */ - return 0; - a++; - b++; - len--; - } -} +static bool efivar_wq_enabled = true; static bool validate_device_path(struct efi_variable *var, int match, u8 *buffer, @@ -262,7 +224,7 @@ validate_load_option(struct efi_variable *var, int match, u8 *buffer, u16 filepathlength; int i, desclength = 0, namelen; - namelen = utf16_strnlen(var->VariableName, sizeof(var->VariableName)); + namelen = ucs2_strnlen(var->VariableName, sizeof(var->VariableName)); /* Either "Boot" or "Driver" followed by four digits of hex */ for (i = match; i < match+4; i++) { @@ -285,7 +247,7 @@ validate_load_option(struct efi_variable *var, int match, u8 *buffer, * There's no stored length for the description, so it has to be * found by hand */ - desclength = utf16_strsize((efi_char16_t *)(buffer + 6), len - 6) + 2; + desclength = ucs2_strsize((efi_char16_t *)(buffer + 6), len - 6) + 2; /* Each boot entry must have a descriptor */ if (!desclength) @@ -426,6 +388,32 @@ 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) +{ + const struct efivar_operations *fops = efivars->ops; + + if (!efivars->ops->query_variable_store) + return EFI_UNSUPPORTED; + + return fops->query_variable_store(attributes, size); +} + + +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 +535,16 @@ 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 + ucs2_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 +695,7 @@ 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 +714,18 @@ 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 + ucs2_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 +747,19 @@ 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 +924,8 @@ 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 +1113,22 @@ 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 +1138,7 @@ 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; @@ -1164,7 +1167,7 @@ static int efivarfs_fill_super(struct super_block *sb, void *data, int silent) inode = NULL; - len = utf16_strlen(entry->var.VariableName); + len = ucs2_strlen(entry->var.VariableName); /* name, plus '-', plus GUID, plus NUL*/ name = kmalloc(len + 1 + GUID_LEN + 1, GFP_ATOMIC); @@ -1186,8 +1189,10 @@ 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 +1219,7 @@ fail_inode: fail_name: kfree(name); fail: - return -ENOMEM; + return err; } static struct dentry *efivarfs_mount(struct file_system_type *fs_type, @@ -1234,6 +1239,7 @@ static struct file_system_type efivarfs_type = { .mount = efivarfs_mount, .kill_sb = efivarfs_kill_sb, }; +MODULE_ALIAS_FS("efivarfs"); /* * Handle negative dentry. @@ -1253,9 +1259,7 @@ 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 +1349,6 @@ 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 +1368,11 @@ 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 +1389,7 @@ 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; @@ -1422,8 +1425,8 @@ static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count, if (efi_guidcmp(entry->var.VendorGuid, vendor)) continue; - if (utf16_strncmp(entry->var.VariableName, efi_name, - utf16_strlen(efi_name))) { + if (ucs2_strncmp(entry->var.VariableName, efi_name, + ucs2_strlen(efi_name))) { /* * Check if an old format, * which doesn't support holding @@ -1435,8 +1438,8 @@ static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count, for (i = 0; i < DUMP_NAME_LEN; i++) efi_name_old[i] = name_old[i]; - if (utf16_strncmp(entry->var.VariableName, efi_name_old, - utf16_strlen(efi_name_old))) + if (ucs2_strncmp(entry->var.VariableName, efi_name_old, + ucs2_strlen(efi_name_old))) continue; } @@ -1459,38 +1462,6 @@ 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 +1473,24 @@ 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) @@ -1528,8 +1517,8 @@ static ssize_t efivar_create(struct file *filp, struct kobject *kobj, * Does this variable already exist? */ list_for_each_entry_safe(search_efivar, n, &efivars->list, list) { - strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024); - strsize2 = utf16_strsize(new_var->VariableName, 1024); + strsize1 = ucs2_strsize(search_efivar->var.VariableName, 1024); + strsize2 = ucs2_strsize(new_var->VariableName, 1024); if (strsize1 == strsize2 && !memcmp(&(search_efivar->var.VariableName), new_var->VariableName, strsize1) && @@ -1544,6 +1533,14 @@ 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 + ucs2_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, @@ -1561,7 +1558,7 @@ static ssize_t efivar_create(struct file *filp, struct kobject *kobj, /* Create the entry in sysfs. Locking is not required here */ status = efivar_create_sysfs_entry(efivars, - utf16_strsize(new_var->VariableName, + ucs2_strsize(new_var->VariableName, 1024), new_var->VariableName, &new_var->VendorGuid); @@ -1591,8 +1588,8 @@ static ssize_t efivar_delete(struct file *filp, struct kobject *kobj, * Does this variable already exist? */ list_for_each_entry_safe(search_efivar, n, &efivars->list, list) { - strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024); - strsize2 = utf16_strsize(del_var->VariableName, 1024); + strsize1 = ucs2_strsize(search_efivar->var.VariableName, 1024); + strsize2 = ucs2_strsize(del_var->VariableName, 1024); if (strsize1 == strsize2 && !memcmp(&(search_efivar->var.VariableName), del_var->VariableName, strsize1) && @@ -1638,9 +1635,9 @@ static bool variable_is_present(efi_char16_t *variable_name, efi_guid_t *vendor) unsigned long strsize1, strsize2; bool found = false; - strsize1 = utf16_strsize(variable_name, 1024); + strsize1 = ucs2_strsize(variable_name, 1024); list_for_each_entry_safe(entry, n, &efivars->list, list) { - strsize2 = utf16_strsize(entry->var.VariableName, 1024); + strsize2 = ucs2_strsize(entry->var.VariableName, 1024); if (strsize1 == strsize2 && !memcmp(variable_name, &(entry->var.VariableName), strsize2) && @@ -1653,6 +1650,31 @@ 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 +1715,13 @@ 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 +1920,35 @@ 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 +1997,24 @@ 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 +2034,8 @@ 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); @@ -2010,7 +2075,7 @@ efivars_init(void) ops.get_variable = efi.get_variable; ops.set_variable = efi.set_variable; ops.get_next_variable = efi.get_next_variable; - ops.query_variable_info = efi.query_variable_info; + ops.query_variable_store = efi_query_variable_store; error = register_efivars(&__efivars, &ops, efi_kobj); if (error) |