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    Subject[ 18/77] UBIFS: fix double free of ubifs_orphan objects
    Date
    3.8-stable review patch.  If anyone has any objections, please let me know.

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

    From: Adam Thomas <adamthomas1111@gmail.com>

    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@gmail.com>
    Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    fs/ubifs/orphan.c | 5 ++++-
    fs/ubifs/ubifs.h | 2 ++
    2 files changed, 6 insertions(+), 1 deletion(-)

    --- a/fs/ubifs/orphan.c
    +++ b/fs/ubifs/orphan.c
    @@ -126,13 +126,14 @@ void ubifs_delete_orphan(struct ubifs_in
    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_i
    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 ubi
    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,
    --- a/fs/ubifs/ubifs.h
    +++ b/fs/ubifs/ubifs.h
    @@ -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;
    };

    /**



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