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/openbmc/linux/drivers/target/tcm_fc/ |
H A D | tfc_sess.c | 2c42be2d Fri Apr 04 18:44:37 CDT 2014 Andy Grover <agrover@redhat.com> 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 <agrover@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org> 2c42be2d Fri Apr 04 18:44:37 CDT 2014 Andy Grover <agrover@redhat.com> 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 <agrover@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
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