UBIFS: fix double free of ubifs_orphan objects
Adam Thomas [Sat, 2 Feb 2013 22:35:08 +0000 (22:35 +0000)]
The last orphan in the dnext list has its dnext set to NULL. Because
of that, ubifs_delete_orphan assumes that it is not on the dnext list
and frees it immediately instead ignoring it as a second delete. The
orphan is later freed again by erase_deleted.

This change adds an explicit flag to ubifs_orphan indicating whether
it is pending delete.

Signed-off-by: Adam Thomas <adamthomas1111@gmail.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Cc: stable@vger.kernel.org

fs/ubifs/orphan.c
fs/ubifs/ubifs.h

index 8534d9c..ba32da3 100644 (file)
@@ -126,13 +126,14 @@ void ubifs_delete_orphan(struct ubifs_info *c, ino_t inum)
                else if (inum > o->inum)
                        p = p->rb_right;
                else {
-                       if (o->dnext) {
+                       if (o->del) {
                                spin_unlock(&c->orphan_lock);
                                dbg_gen("deleted twice ino %lu",
                                        (unsigned long)inum);
                                return;
                        }
                        if (o->cmt) {
+                               o->del = 1;
                                o->dnext = c->orph_dnext;
                                c->orph_dnext = o;
                                spin_unlock(&c->orphan_lock);
@@ -447,6 +448,7 @@ static void erase_deleted(struct ubifs_info *c)
                orphan = dnext;
                dnext = orphan->dnext;
                ubifs_assert(!orphan->new);
+               ubifs_assert(orphan->del);
                rb_erase(&orphan->rb, &c->orph_tree);
                list_del(&orphan->list);
                c->tot_orphans -= 1;
@@ -536,6 +538,7 @@ static int insert_dead_orphan(struct ubifs_info *c, ino_t inum)
        rb_link_node(&orphan->rb, parent, p);
        rb_insert_color(&orphan->rb, &c->orph_tree);
        list_add_tail(&orphan->list, &c->orph_list);
+       orphan->del = 1;
        orphan->dnext = c->orph_dnext;
        c->orph_dnext = orphan;
        dbg_mnt("ino %lu, new %d, tot %d", (unsigned long)inum,
index c16fff7..b2babce 100644 (file)
@@ -905,6 +905,7 @@ struct ubifs_budget_req {
  * @inum: inode number
  * @new: %1 => added since the last commit, otherwise %0
  * @cmt: %1 => commit pending, otherwise %0
+ * @del: %1 => delete pending, otherwise %0
  */
 struct ubifs_orphan {
        struct rb_node rb;
@@ -915,6 +916,7 @@ struct ubifs_orphan {
        ino_t inum;
        unsigned new:1;
        unsigned cmt:1;
+       unsigned del:1;
 };
 
 /**