diff --git a/fs/efivarfs/vars.c b/fs/efivarfs/vars.c index 114ff0fd4e55..2ad377818d0f 100644 --- a/fs/efivarfs/vars.c +++ b/fs/efivarfs/vars.c @@ -373,7 +373,7 @@ int efivar_init(int (*func)(efi_char16_t *, efi_guid_t, unsigned long, void *, struct list_head *), void *data, bool duplicates, struct list_head *head) { - unsigned long variable_name_size = 1024; + unsigned long variable_name_size = 512; efi_char16_t *variable_name; efi_status_t status; efi_guid_t vendor_guid; @@ -390,12 +390,13 @@ int efivar_init(int (*func)(efi_char16_t *, efi_guid_t, unsigned long, void *, goto free; /* - * Per EFI spec, the maximum storage allocated for both - * the variable name and variable data is 1024 bytes. + * A small set of old UEFI implementations reject sizes + * above a certain threshold, the lowest seen in the wild + * is 512. */ do { - variable_name_size = 1024; + variable_name_size = 512; status = efivar_get_next_variable(&variable_name_size, variable_name, @@ -432,9 +433,13 @@ int efivar_init(int (*func)(efi_char16_t *, efi_guid_t, unsigned long, void *, break; case EFI_NOT_FOUND: break; + case EFI_BUFFER_TOO_SMALL: + pr_warn("efivars: Variable name size exceeds maximum (%lu > 512)\n", + variable_name_size); + status = EFI_NOT_FOUND; + break; default: - printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n", - status); + pr_warn("efivars: get_next_variable: status=%lx\n", status); status = EFI_NOT_FOUND; break; }