From 8e6e87e7923ca2ae880021cb42a35cc9bb4c8fe2 Mon Sep 17 00:00:00 2001
From: Lidong Chen <lidong.chen@oracle.com>
Date: Thu, 6 Feb 2025 18:16:56 +0000
Subject: [PATCH 70/73] kern/partition: Add sanity check after grub_strtoul()
 call

The current code incorrectly assumes that both the input and the values
returned by grub_strtoul() are always valid which can lead to potential
errors. This fix ensures proper validation to prevent any unintended issues.

Fixes: CID 473843

Signed-off-by: Lidong Chen <lidong.chen@oracle.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
---
 grub-core/kern/partition.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/grub-core/kern/partition.c b/grub-core/kern/partition.c
index 704512a20..c6a578cf4 100644
--- a/grub-core/kern/partition.c
+++ b/grub-core/kern/partition.c
@@ -125,14 +125,22 @@ grub_partition_probe (struct grub_disk *disk, const char *str)
   for (ptr = str; *ptr;)
     {
       grub_partition_map_t partmap;
-      int num;
+      unsigned long num;
       const char *partname, *partname_end;
 
       partname = ptr;
       while (*ptr && grub_isalpha (*ptr))
 	ptr++;
       partname_end = ptr;
-      num = grub_strtoul (ptr, &ptr, 0) - 1;
+
+      num = grub_strtoul (ptr, &ptr, 0);
+      if (*ptr != '\0' || num == 0 || num > GRUB_INT_MAX)
+	{
+	  grub_error (GRUB_ERR_BAD_NUMBER, N_("invalid partition number"));
+	  return 0;
+	}
+
+      num -= 1;
 
       curpart = 0;
       /* Use the first partition map type found.  */
-- 
2.33.0

