From 5d69fb2f9cee027c76ff179478ca3ec7069ac7ce Mon Sep 17 00:00:00 2001
From: Daniel Axtens <dja@axtens.net>
Date: Mon, 18 Jan 2021 17:06:19 +1100
Subject: [PATCH] fs/nilfs2: Properly bail on errors in
 grub_nilfs2_btree_node_lookup()

We just introduced an error return in grub_nilfs2_btree_node_lookup().
Make sure the callers catch it.

At the same time, make sure that grub_nilfs2_btree_node_lookup() always
inits the index pointer passed to it.

Reference: http://git.savannah.gnu.org/cgit/grub.git/commit/?id=ca5d9ac206043b1fb4cb06259272fb1c5946bb6d

Signed-off-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
---
 grub-core/fs/nilfs2.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/grub-core/fs/nilfs2.c b/grub-core/fs/nilfs2.c
index 43ac1ad..aaba002 100644
--- a/grub-core/fs/nilfs2.c
+++ b/grub-core/fs/nilfs2.c
@@ -433,7 +433,7 @@ grub_nilfs2_btree_node_lookup (struct grub_nilfs2_data *data,
 			       grub_uint64_t key, int *indexp)
 {
   grub_uint64_t nkey;
-  int index, low, high, s;
+  int index = 0, low, high, s;
 
   low = 0;
 
@@ -441,10 +441,10 @@ grub_nilfs2_btree_node_lookup (struct grub_nilfs2_data *data,
   if (high >= grub_nilfs2_btree_node_nchildren_max (data, node))
     {
       grub_error (GRUB_ERR_BAD_FS, "too many children");
+      *indexp = index;
       return 0;
     }
 
-  index = 0;
   s = 0;
   while (low <= high)
     {
@@ -526,6 +526,10 @@ grub_nilfs2_btree_lookup (struct grub_nilfs2_data *data,
   level = grub_nilfs2_btree_get_level (node);
 
   found = grub_nilfs2_btree_node_lookup (data, node, key, &index);
+
+  if (grub_errno != GRUB_ERR_NONE)
+    goto fail;
+
   ptr = grub_nilfs2_btree_node_get_ptr (data, node, index);
   if (need_translate)
     ptr = grub_nilfs2_dat_translate (data, ptr);
@@ -550,7 +554,8 @@ grub_nilfs2_btree_lookup (struct grub_nilfs2_data *data,
       else
 	index = 0;
 
-      if (index < grub_nilfs2_btree_node_nchildren_max (data, node))
+      if (index < grub_nilfs2_btree_node_nchildren_max (data, node) &&
+	  grub_errno == GRUB_ERR_NONE)
 	{
 	  ptr = grub_nilfs2_btree_node_get_ptr (data, node, index);
 	  if (need_translate)
-- 
2.19.1

