[PATCH v2] blsuki: Fix grub_errno leakage in blsuki_is_default_entry()

The grub_strtol() call in blsuki_is_default_entry() can set grub_errno
to either GRUB_ERR_BAD_NUMBER or GRUB_ERR_OUT_OF_RANGE if the input
string is invalid or out of range.

This errno value is currently left uncleared, which can lead to
unexpected behavior in subsequent functions that rely on checking
current state of grub_errno.

Clear grub_errno and return false when GRUB_ERR_BAD_NUMBER or
GRUB_ERR_OUT_OF_RANGE is encountered. This ensures that the error is
handled as false return and no grub_errno leakage.

Signed-off-by: Michael Chang <[email protected]>
Reviewed-by: Sudhakar Kuppusamy <[email protected]>
Reviewed-by: Avnish Chouhan <[email protected]>
---
 grub-core/commands/blsuki.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/grub-core/commands/blsuki.c b/grub-core/commands/blsuki.c
index 21d767f05..8a3446336 100644
--- a/grub-core/commands/blsuki.c
+++ b/grub-core/commands/blsuki.c
@@ -1510,6 +1510,12 @@ blsuki_is_default_entry (const char *def_entry, grub_blsuki_entry_t *entry, int
     return true;
 
   def_idx = grub_strtol (def_entry, &def_entry_end, 0);
+  if (grub_errno == GRUB_ERR_BAD_NUMBER || grub_errno == GRUB_ERR_OUT_OF_RANGE)
+    {
+      grub_errno = GRUB_ERR_NONE;
+      return false;
+    }
+
   if (*def_entry_end != '\0' || def_idx < 0 || def_idx > GRUB_INT_MAX)
     return false;
 
-- 
2.51.1


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