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![]() The FSM can run in a circle allowing rdma_resolve_ip() to be called twice
on the same id_priv. While this cannot happen without going through the
work, it violates the invariant that the same address resolution
background request cannot be active twice.
CPU 1 CPU 2
rdma_resolve_addr():
RDMA_CM_IDLE -> RDMA_CM_ADDR_QUERY
rdma_resolve_ip(addr_handler) #1
process_one_req(): for #1
addr_handler():
RDMA_CM_ADDR_QUERY -> RDMA_CM_ADDR_BOUND
mutex_unlock(&id_priv->handler_mutex);
[.. handler still running ..]
rdma_resolve_addr():
RDMA_CM_ADDR_BOUND -> RDMA_CM_ADDR_QUERY
rdma_resolve_ip(addr_handler)
!! two requests are now on the req_list
rdma_destroy_id():
destroy_id_handler_unlock():
_destroy_id():
cma_cancel_operation():
rdma_addr_cancel()
// process_one_req() self removes it
spin_lock_bh(&lock);
cancel_delayed_work(&req->work);
if (!list_empty(&req->list)) == true
! rdma_addr_cancel() returns after process_on_req #1 is done
kfree(id_priv)
process_one_req(): for #2
addr_handler():
mutex_lock(&id_priv->handler_mutex);
!! Use after free on id_priv
rdma_addr_cancel() expects there to be one req on the list and only
cancels the first one. The self-removal behavior of the work only happens
after the handler has returned. This yields a situations where the
req_list can have two reqs for the same "handle" but rdma_addr_cancel()
only cancels the first one.
The second req remains active beyond rdma_destroy_id() and will
use-after-free id_priv once it inevitably triggers.
Fix this by remembering if the id_priv has called rdma_resolve_ip() and
always cancel before calling it again. This ensures the req_list never
gets more than one item in it and doesn't cost anything in the normal flow
that never uses this strange error path.
Link: https://lore.kernel.org/r/0-v1-3bc675b8006d+22-syz_cancel_uaf_jgg@nvidia.com
Cc: stable@vger.kernel.org
Fixes:
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.. | ||
addr.c | ||
agent.c | ||
agent.h | ||
cache.c | ||
cgroup.c | ||
cm.c | ||
cm_msgs.h | ||
cm_trace.c | ||
cm_trace.h | ||
cma.c | ||
cma_configfs.c | ||
cma_priv.h | ||
cma_trace.c | ||
cma_trace.h | ||
core_priv.h | ||
counters.c | ||
cq.c | ||
device.c | ||
ib_core_uverbs.c | ||
iwcm.c | ||
iwcm.h | ||
iwpm_msg.c | ||
iwpm_util.c | ||
iwpm_util.h | ||
lag.c | ||
mad.c | ||
mad_priv.h | ||
mad_rmpp.c | ||
mad_rmpp.h | ||
Makefile | ||
mr_pool.c | ||
multicast.c | ||
netlink.c | ||
nldev.c | ||
opa_smi.h | ||
packer.c | ||
rdma_core.c | ||
rdma_core.h | ||
restrack.c | ||
restrack.h | ||
roce_gid_mgmt.c | ||
rw.c | ||
sa.h | ||
sa_query.c | ||
security.c | ||
smi.c | ||
smi.h | ||
sysfs.c | ||
trace.c | ||
ucma.c | ||
ud_header.c | ||
umem.c | ||
umem_dmabuf.c | ||
umem_odp.c | ||
user_mad.c | ||
uverbs.h | ||
uverbs_cmd.c | ||
uverbs_ioctl.c | ||
uverbs_main.c | ||
uverbs_marshall.c | ||
uverbs_std_types.c | ||
uverbs_std_types_async_fd.c | ||
uverbs_std_types_counters.c | ||
uverbs_std_types_cq.c | ||
uverbs_std_types_device.c | ||
uverbs_std_types_dm.c | ||
uverbs_std_types_flow_action.c | ||
uverbs_std_types_mr.c | ||
uverbs_std_types_qp.c | ||
uverbs_std_types_srq.c | ||
uverbs_std_types_wq.c | ||
uverbs_uapi.c | ||
verbs.c |