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Commit 8afd500c authored by Adam Thomas's avatar Adam Thomas Committed by Artem Bityutskiy
Browse files

UBIFS: fix double free of ubifs_orphan objects 



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: default avatarAdam Thomas <adamthomas1111@gmail.com>
Signed-off-by: default avatarArtem Bityutskiy <artem.bityutskiy@linux.intel.com>
Cc: stable@vger.kernel.org
parent 2928f0d0

fs/ubifs/orphan.c

+4 −1
Original line number Diff line number Diff line
@@ -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,

fs/ubifs/ubifs.h

+2 −0
Original line number Diff line number Diff line
@@ -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;

};



/**