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-rw-r--r--fs/efivarfs/vars.c17
1 files changed, 11 insertions, 6 deletions
diff --git a/fs/efivarfs/vars.c b/fs/efivarfs/vars.c
index 9e4f47808b..13bc606989 100644
--- a/fs/efivarfs/vars.c
+++ b/fs/efivarfs/vars.c
@@ -372,7 +372,7 @@ static void dup_variable_bug(efi_char16_t *str16, efi_guid_t *vendor_guid,
int efivar_init(int (*func)(efi_char16_t *, efi_guid_t, unsigned long, void *),
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;
@@ -389,12 +389,13 @@ 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,
@@ -431,9 +432,13 @@ 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;
}