From: Jan Janssen <medhefgo@web.de>
Date: Mon, 10 Jan 2022 10:16:26 +0000 (+0100)
Subject: boot: Fix readdir_harder() on VirtualBox
X-Git-Tag: v251-rc1~555
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ed3abbfbde674bd163cb1c64d9e31dd24e352f85;p=thirdparty%2Fsystemd.git

boot: Fix readdir_harder() on VirtualBox

Fixes: #22073
---

diff --git a/src/boot/efi/boot.c b/src/boot/efi/boot.c
index 189461974ba..6ff1768d9b6 100644
--- a/src/boot/efi/boot.c
+++ b/src/boot/efi/boot.c
@@ -1577,7 +1577,7 @@ static void config_load_entries(
                 _cleanup_freepool_ CHAR8 *content = NULL;
 
                 err = readdir_harder(entries_dir, &f, &f_size);
-                if (f_size == 0 || EFI_ERROR(err))
+                if (EFI_ERROR(err) || !f)
                         break;
 
                 if (f->FileName[0] == '.')
@@ -2019,7 +2019,7 @@ static void config_entry_add_linux(
                 CHAR8 *key, *value;
 
                 err = readdir_harder(linux_dir, &f, &f_size);
-                if (f_size == 0 || EFI_ERROR(err))
+                if (EFI_ERROR(err) || !f)
                         break;
 
                 if (f->FileName[0] == '.')
diff --git a/src/boot/efi/util.c b/src/boot/efi/util.c
index ab21d774a25..db998ca8da9 100644
--- a/src/boot/efi/util.c
+++ b/src/boot/efi/util.c
@@ -592,7 +592,12 @@ EFI_STATUS readdir_harder(
          * the specified buffer needs to be freed by caller, after final use. */
 
         if (!*buffer) {
-                sz = offsetof(EFI_FILE_INFO, FileName) /* + 256 */;
+                /* Some broken firmware violates the EFI spec by still advancing the readdir
+                 * position when returning EFI_BUFFER_TOO_SMALL, effectively skipping over any files when
+                 * the buffer was too small. Therefore, start with a buffer that should handle FAT32 max
+                 * file name length.
+                 * As a side effect, most readdir_harder() calls will now be slightly faster. */
+                sz = sizeof(EFI_FILE_INFO) + 256 * sizeof(CHAR16);
                 *buffer = xallocate_pool(sz);
                 *buffer_size = sz;
         } else