[PATCH 089/139] UBIFS: fix double free of ubifs_orphan objects

From: Luis Henriques
Date: Thu Feb 28 2013 - 10:04:25 EST


3.5.7.7 -stable review patch. If anyone has any objections, please let me know.

------------------

From: Adam Thomas <adamthomas1111@xxxxxxxxx>

commit 8afd500cb52a5d00bab4525dd5a560d199f979b9 upstream.

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@xxxxxxxxx>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@xxxxxxxxxxxxxxx>
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
---
fs/ubifs/orphan.c | 5 ++++-
fs/ubifs/ubifs.h | 2 ++
2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/fs/ubifs/orphan.c b/fs/ubifs/orphan.c
index bd516f1..9ef951f3 100644
--- a/fs/ubifs/orphan.c
+++ b/fs/ubifs/orphan.c
@@ -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,
diff --git a/fs/ubifs/ubifs.h b/fs/ubifs/ubifs.h
index fb89c54..f15c6e7 100644
--- a/fs/ubifs/ubifs.h
+++ b/fs/ubifs/ubifs.h
@@ -906,6 +906,7 @@ 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;
@@ -916,6 +917,7 @@ struct ubifs_orphan {
ino_t inum;
unsigned new:1;
unsigned cmt:1;
+ unsigned del:1;
};

/**
--
1.8.1.2

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