Subject: CVE-2021-47392: RDMA/cma: Fix listener leak in rdma_cma_listen_on_all() failure

From: Greg Kroah-Hartman <[email-masked]>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

RDMA/cma: Fix listener leak in rdma_cma_listen_on_all() failure

If cma_listen_on_all() fails it leaves the per-device ID still on the
listen_list but the state is not set to RDMA_CM_ADDR_BOUND.

When the cmid is eventually destroyed cma_cancel_listens() is not called
due to the wrong state, however the per-device IDs are still holding the
refcount preventing the ID from being destroyed, thus deadlocking:

 task:rping state:D stack:   0 pid:19605 ppid: 47036 flags:0x00000084
 Call Trace:
  __schedule+0x29a/0x780
  ? free_unref_page_commit+0x9b/0x110
  schedule+0x3c/0xa0
  schedule_timeout+0x215/0x2b0
  ? __flush_work+0x19e/0x1e0
  wait_for_completion+0x8d/0xf0
  _destroy_id+0x144/0x210 [rdma_cm]
  ucma_close_id+0x2b/0x40 [rdma_ucm]
  __destroy_id+0x93/0x2c0 [rdma_ucm]
  ? __xa_erase+0x4a/0xa0
  ucma_destroy_id+0x9a/0x120 [rdma_ucm]
  ucma_write+0xb8/0x130 [rdma_ucm]
  vfs_write+0xb4/0x250
  ksys_write+0xb5/0xd0
  ? syscall_trace_enter.isra.19+0x123/0x190
  do_syscall_64+0x33/0x40
  entry_SYSCALL_64_after_hwframe+0x44/0xa9

Ensure that cma_listen_on_all() atomically unwinds its action under the
lock during error.

The Linux kernel CVE team has assigned CVE-2021-47392 to this issue.

Affected and fixed versions
===========================

	Issue introduced in 5.10.4 with commit 70ba8b1697e3 and fixed in 5.10.71 with commit 3f4e68902d2e
	Issue introduced in 5.11 with commit c80a0c52d85c and fixed in 5.14.10 with commit e56a5146ef8c
	Issue introduced in 5.11 with commit c80a0c52d85c and fixed in 5.15 with commit ca465e1f1f9b

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2021-47392
will be updated if fixes are backported, please check that for the most
up to date information about this issue.

Affected files
==============

The file(s) affected by this issue are:
	drivers/infiniband/core/cma.c

Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/3f4e68902d2e545033c80d7ad62fd9a439e573f4
	https://git.kernel.org/stable/c/e56a5146ef8cb51cd7c9e748267dce7564448a35
	https://git.kernel.org/stable/c/ca465e1f1f9b38fe916a36f7d80c5d25f2337c81