efivars: Use string functions in pstore_write

Instead of open-coding the string operations for comparing the prefix of
the variable names, use the provided utf16_* string functions.

This patch also changes the calls to efi.set_variable to
efivars->ops->set_variable so that the right function gets called in the
case of gsmi (which doesn't have a valid efi structure).

As well, make sure that we only consider variables with the right vendor
string.

Signed-off-by: Mike Waychison <mikew@google.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

1 files changed, 14 insertions, 12 deletions

diff --git a/drivers/firmware/efivars.c b/drivers/firmware/efivars.c
index 15b9a01b6c68..563492e4d5cf 100644
--- a/drivers/firmware/efivars.c
+++ b/drivers/firmware/efivars.c
@@ -512,18 +512,20 @@ static u64 efi_pstore_write(enum pstore_type_id type, unsigned int part,
         list_for_each_entry(entry, &efivars->list, list) {
                 get_var_data_locked(efivars, &entry->var);
 
-                for (i = 0; i < DUMP_NAME_LEN; i++) {
-                        if (efi_name[i] == 0) {
-                                found = entry;
-                                efivars->ops->set_variable(entry->var.VariableName,
-                                                           &entry->var.VendorGuid,
-                                                           EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS,
-                                                           0, NULL);
-                                break;
-                        } else if (efi_name[i] != entry->var.VariableName[i]) {
-                                break;
-                        }
-                }
+                if (efi_guidcmp(entry->var.VendorGuid, vendor))
+                        continue;
+                if (utf16_strncmp(entry->var.VariableName, efi_name,
+                                  utf16_strlen(efi_name)))
+                        continue;
+                /* Needs to be a prefix */
+                if (entry->var.VariableName[utf16_strlen(efi_name)] == 0)
+                        continue;
+
+                /* found */
+                found = entry;
+                efivars->ops->set_variable(entry->var.VariableName, &entry->var.VendorGuid,
+                                           EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS,
+                                           0, NULL);
         }
 
         if (found)