diff options
Diffstat (limited to 'drivers/firmware/efi/vars.c')
| -rw-r--r-- | drivers/firmware/efi/vars.c | 144 |
1 files changed, 105 insertions, 39 deletions
diff --git a/drivers/firmware/efi/vars.c b/drivers/firmware/efi/vars.c index 70a0fb10517f..7f2ea21c730d 100644 --- a/drivers/firmware/efi/vars.c +++ b/drivers/firmware/efi/vars.c @@ -165,67 +165,133 @@ validate_ascii_string(efi_char16_t *var_name, int match, u8 *buffer, } struct variable_validate { + efi_guid_t vendor; char *name; bool (*validate)(efi_char16_t *var_name, int match, u8 *data, unsigned long len); }; +/* + * This is the list of variables we need to validate, as well as the + * whitelist for what we think is safe not to default to immutable. + * + * If it has a validate() method that's not NULL, it'll go into the + * validation routine. If not, it is assumed valid, but still used for + * whitelisting. + * + * Note that it's sorted by {vendor,name}, but globbed names must come after + * any other name with the same prefix. + */ static const struct variable_validate variable_validate[] = { - { "BootNext", validate_uint16 }, - { "BootOrder", validate_boot_order }, - { "DriverOrder", validate_boot_order }, - { "Boot*", validate_load_option }, - { "Driver*", validate_load_option }, - { "ConIn", validate_device_path }, - { "ConInDev", validate_device_path }, - { "ConOut", validate_device_path }, - { "ConOutDev", validate_device_path }, - { "ErrOut", validate_device_path }, - { "ErrOutDev", validate_device_path }, - { "Timeout", validate_uint16 }, - { "Lang", validate_ascii_string }, - { "PlatformLang", validate_ascii_string }, - { "", NULL }, + { EFI_GLOBAL_VARIABLE_GUID, "BootNext", validate_uint16 }, + { EFI_GLOBAL_VARIABLE_GUID, "BootOrder", validate_boot_order }, + { EFI_GLOBAL_VARIABLE_GUID, "Boot*", validate_load_option }, + { EFI_GLOBAL_VARIABLE_GUID, "DriverOrder", validate_boot_order }, + { EFI_GLOBAL_VARIABLE_GUID, "Driver*", validate_load_option }, + { EFI_GLOBAL_VARIABLE_GUID, "ConIn", validate_device_path }, + { EFI_GLOBAL_VARIABLE_GUID, "ConInDev", validate_device_path }, + { EFI_GLOBAL_VARIABLE_GUID, "ConOut", validate_device_path }, + { EFI_GLOBAL_VARIABLE_GUID, "ConOutDev", validate_device_path }, + { EFI_GLOBAL_VARIABLE_GUID, "ErrOut", validate_device_path }, + { EFI_GLOBAL_VARIABLE_GUID, "ErrOutDev", validate_device_path }, + { EFI_GLOBAL_VARIABLE_GUID, "Lang", validate_ascii_string }, + { EFI_GLOBAL_VARIABLE_GUID, "OsIndications", NULL }, + { EFI_GLOBAL_VARIABLE_GUID, "PlatformLang", validate_ascii_string }, + { EFI_GLOBAL_VARIABLE_GUID, "Timeout", validate_uint16 }, + { LINUX_EFI_CRASH_GUID, "*", NULL }, + { NULL_GUID, "", NULL }, }; +static bool +variable_matches(const char *var_name, size_t len, const char *match_name, + int *match) +{ + for (*match = 0; ; (*match)++) { + char c = match_name[*match]; + char u = var_name[*match]; + + /* Wildcard in the matching name means we've matched */ + if (c == '*') + return true; + + /* Case sensitive match */ + if (!c && *match == len) + return true; + + if (c != u) + return false; + + if (!c) + return true; + } + return true; +} + bool -efivar_validate(efi_char16_t *var_name, u8 *data, unsigned long len) +efivar_validate(efi_guid_t vendor, efi_char16_t *var_name, u8 *data, + unsigned long data_size) { int i; - u16 *unicode_name = var_name; + unsigned long utf8_size; + u8 *utf8_name; - for (i = 0; variable_validate[i].validate != NULL; i++) { - const char *name = variable_validate[i].name; - int match; + utf8_size = ucs2_utf8size(var_name); + utf8_name = kmalloc(utf8_size + 1, GFP_KERNEL); + if (!utf8_name) + return false; - for (match = 0; ; match++) { - char c = name[match]; - u16 u = unicode_name[match]; + ucs2_as_utf8(utf8_name, var_name, utf8_size); + utf8_name[utf8_size] = '\0'; - /* All special variables are plain ascii */ - if (u > 127) - return true; + for (i = 0; variable_validate[i].name[0] != '\0'; i++) { + const char *name = variable_validate[i].name; + int match = 0; - /* Wildcard in the matching name means we've matched */ - if (c == '*') - return variable_validate[i].validate(var_name, - match, data, len); + if (efi_guidcmp(vendor, variable_validate[i].vendor)) + continue; - /* Case sensitive match */ - if (c != u) + if (variable_matches(utf8_name, utf8_size+1, name, &match)) { + if (variable_validate[i].validate == NULL) break; - - /* Reached the end of the string while matching */ - if (!c) - return variable_validate[i].validate(var_name, - match, data, len); + kfree(utf8_name); + return variable_validate[i].validate(var_name, match, + data, data_size); } } - + kfree(utf8_name); return true; } EXPORT_SYMBOL_GPL(efivar_validate); +bool +efivar_variable_is_removable(efi_guid_t vendor, const char *var_name, + size_t len) +{ + int i; + bool found = false; + int match = 0; + + /* + * Check if our variable is in the validated variables list + */ + for (i = 0; variable_validate[i].name[0] != '\0'; i++) { + if (efi_guidcmp(variable_validate[i].vendor, vendor)) + continue; + + if (variable_matches(var_name, len, + variable_validate[i].name, &match)) { + found = true; + break; + } + } + + /* + * If it's in our list, it is removable. + */ + return found; +} +EXPORT_SYMBOL_GPL(efivar_variable_is_removable); + static efi_status_t check_var_size(u32 attributes, unsigned long size) { @@ -852,7 +918,7 @@ int efivar_entry_set_get_size(struct efivar_entry *entry, u32 attributes, *set = false; - if (efivar_validate(name, data, *size) == false) + if (efivar_validate(*vendor, name, data, *size) == false) return -EINVAL; /* |