[SECURITY PATCH 081/117] fs/nilfs2: Properly bail on errors in grub_nilfs2_btree_node_lookup()

[Daniel Kiper]

From: Daniel Axtens <dja@axtens.net>

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.

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 7963b4ef5..9b76982b3 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)
-- 
2.11.0