From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Colin Watson <cjwatson@debian.org>
Date: Fri, 24 Jul 2020 17:18:09 +0100
Subject: [PATCH] efilinux: Fix integer overflows in grub_cmd_initrd

These could be triggered by an extremely large number of arguments to
the initrd command on 32-bit architectures, or a crafted filesystem with
very large files on any architecture.

Signed-off-by: Colin Watson <cjwatson@debian.org>
---
 grub-core/loader/i386/efi/linux.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/grub-core/loader/i386/efi/linux.c b/grub-core/loader/i386/efi/linux.c
index ea9f5134e67..ade7ab8f573 100644
--- a/grub-core/loader/i386/efi/linux.c
+++ b/grub-core/loader/i386/efi/linux.c
@@ -28,6 +28,7 @@
 #include <grub/efi/efi.h>
 #include <grub/efi/linux.h>
 #include <grub/tpm.h>
+#include <grub/safemath.h>
 
 GRUB_MOD_LICENSE ("GPLv3+");
 
@@ -94,7 +95,7 @@ grub_cmd_initrd (grub_command_t cmd __attribute__ ((unused)),
       goto fail;
     }
 
-  files = grub_zalloc (argc * sizeof (files[0]));
+  files = grub_calloc (argc, sizeof (files[0]));
   if (!files)
     goto fail;
 
@@ -105,7 +106,11 @@ grub_cmd_initrd (grub_command_t cmd __attribute__ ((unused)),
       if (! files[i])
         goto fail;
       nfiles++;
-      size += ALIGN_UP (grub_file_size (files[i]), 4);
+      if (grub_add (size, ALIGN_UP (grub_file_size (files[i]), 4), &size))
+	{
+	  grub_error (GRUB_ERR_OUT_OF_RANGE, N_("overflow is detected"));
+	  goto fail;
+	}
     }
 
   initrd_mem = grub_efi_allocate_pages_max (0x3fffffff, BYTES_TO_PAGES(size));