UBIFS: mark unused key objects as invalid

When scanning the flash, UBIFS builds a list of flash nodes of type
'struct ubifs_scan_node'. Each scanned node has a 'snod->key' field. This field
is valid for most of the nodes, but invalid for some node type, e.g., truncation
nodes. It is safer to explicitly initialize such keys to something invalid,
rather than leaving them initialized to all zeros, which has key type of
UBIFS_INO_KEY.

This patch introduces new "fake" key type UBIFS_INVALID_KEY and initializes
unused 'snod->key' objects to this type. It also adds debugging assertions in
the TNC code to make sure no one ever tries to look these nodes up in the TNC.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/fs/ubifs/scan.c b/fs/ubifs/scan.c
index a0a305ca61af..3e1ee57dbeaa 100644
--- a/fs/ubifs/scan.c
+++ b/fs/ubifs/scan.c
@@ -197,7 +197,7 @@ int ubifs_add_snod(const struct ubifs_info *c, struct ubifs_scan_leb *sleb,
         struct ubifs_ino_node *ino = buf;
         struct ubifs_scan_node *snod;
 
-        snod = kzalloc(sizeof(struct ubifs_scan_node), GFP_NOFS);
+        snod = kmalloc(sizeof(struct ubifs_scan_node), GFP_NOFS);
         if (!snod)
                 return -ENOMEM;
 
@@ -218,6 +218,9 @@ int ubifs_add_snod(const struct ubifs_info *c, struct ubifs_scan_leb *sleb,
                  */
                 key_read(c, &ino->key, &snod->key);
                 break;
+        default:
+                invalid_key_init(c, &snod->key);
+                break;
         }
         list_add_tail(&snod->list, &sleb->nodes);
         sleb->nodes_cnt += 1;