From: Jan Janssen <medhefgo@web.de>
Date: Sat, 7 Jan 2023 10:17:29 +0000 (+0100)
Subject: boot: Query EFI var size before fetching them
X-Git-Tag: v254-rc1~1211^2~1
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=a40960748907212883f4b7de7367e6870657016e;p=thirdparty%2Fsystemd.git

boot: Query EFI var size before fetching them
---

diff --git a/src/boot/efi/util.c b/src/boot/efi/util.c
index 683724b66ce..f2e543c6cc6 100644
--- a/src/boot/efi/util.c
+++ b/src/boot/efi/util.c
@@ -186,24 +186,25 @@ EFI_STATUS efivar_get_uint64_le(const EFI_GUID *vendor, const char16_t *name, ui
 }
 
 EFI_STATUS efivar_get_raw(const EFI_GUID *vendor, const char16_t *name, char **ret, size_t *ret_size) {
-        _cleanup_free_ char *buf = NULL;
-        size_t l;
         EFI_STATUS err;
 
         assert(vendor);
         assert(name);
 
-        l = sizeof(char16_t *) * EFI_MAXIMUM_VARIABLE_SIZE;
-        buf = xmalloc(l);
+        size_t size = 0;
+        err = RT->GetVariable((char16_t *) name, (EFI_GUID *) vendor, NULL, &size, NULL);
+        if (err != EFI_BUFFER_TOO_SMALL)
+                return err;
 
-        err = RT->GetVariable((char16_t *) name, (EFI_GUID *) vendor, NULL, &l, buf);
+        _cleanup_free_ void *buf = xmalloc(size);
+        err = RT->GetVariable((char16_t *) name, (EFI_GUID *) vendor, NULL, &size, buf);
         if (err != EFI_SUCCESS)
                 return err;
 
         if (ret)
                 *ret = TAKE_PTR(buf);
         if (ret_size)
-                *ret_size = l;
+                *ret_size = size;
 
         return EFI_SUCCESS;
 }