Commit 2c42be2d authored by Andy Grover's avatar Andy Grover Committed by Nicholas Bellinger
Browse files

target/tcm_fc: Fix use-after-free of ft_tpg

ft_del_tpg checks tpg->tport is set before unlinking the tpg from the
tport when the tpg is being removed. Set this pointer in ft_tport_create,
or the unlinking won't happen in ft_del_tpg and tport->tpg will reference
a deleted object.

This patch sets tpg->tport in ft_tport_create, because that's what
ft_del_tpg checks, and is the only way to get back to the tport to
clear tport->tpg.

The bug was occuring when:

- lport created, tport (our per-lport, per-provider context) is
  allocated.
  tport->tpg = NULL
- tpg created
- a PRLI is received. ft_tport_create is called, tpg is found and
  tport->tpg is set
- tpg removed. ft_tpg is freed in ft_del_tpg. Since tpg->tport was not
  set, tport->tpg is not cleared and points at freed memory
- Future calls to ft_tport_create return tport via first conditional,
  instead of searching for new tpg by calling ft_lport_find_tpg.
  tport->tpg is still invalid, and will access freed memory.

see https://bugzilla.redhat.com/show_bug.cgi?id=1071340



Cc: stable@vger.kernel.org # 3.0+
Signed-off-by: Andy Grover's avatarAndy Grover <agrover@redhat.com>
Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
parent 47b1584c
......@@ -68,6 +68,7 @@ static struct ft_tport *ft_tport_create(struct fc_lport *lport)
if (tport) {
tport->tpg = tpg;
tpg->tport = tport;
return tport;
}
......
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