perf/core: Fix data race between perf_event_set_output() and… (CVE-2022-49607)

Summary

perf/core: Fix data race between perf_event_set_output() and perf_mmap_close()

Original description

The description as published by the source.

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

perf/core: Fix data race between perf_event_set_output() and perf_mmap_close()

Yang Jihing reported a race between perf_event_set_output() and
perf_mmap_close():

CPU1					CPU2

perf_mmap_close(e2)
  if (atomic_dec_and_test(&e2->rb->mmap_count)) // 1 - > 0
    detach_rest = true

					ioctl(e1, IOC_SET_OUTPUT, e2)
					  perf_event_set_output(e1, e2)

  ...
  list_for_each_entry_rcu(e, &e2->rb->event_list, rb_entry)
    ring_buffer_attach(e, NULL);
    // e1 isn't yet added and
    // therefore not detached

					    ring_buffer_attach(e1, e2->rb)
					      list_add_rcu(&e1->rb_entry,
							   &e2->rb->event_list)

After this; e1 is attached to an unmapped rb and a subsequent
perf_mmap() will loop forever more:

again:
	mutex_lock(&e->mmap_mutex);
	if (event->rb) {
		...
		if (!atomic_inc_not_zero(&e->rb->mmap_count)) {
			...
			mutex_unlock(&e->mmap_mutex);
			goto again;
		}
	}

The loop in perf_mmap_close() holds e2->mmap_mutex, while the attach
in perf_event_set_output() holds e1->mmap_mutex. As such there is no
serialization to avoid this race.

Change perf_event_set_output() to take both e1->mmap_mutex and
e2->mmap_mutex to alleviate that problem. Additionally, have the loop
in perf_mmap() detach the rb directly, this avoids having to wait for
the concurrent perf_mmap_close() to get around to doing it to make
progress.

Source: OSV.dev (Open Source Vulnerabilities) NVD OSV

Affected packages

Linux Kernel

[{"type":"ECOSYSTEM","events":[{"introduced":"3.10.0"},{"fixed":"4.9.325"}]},{"type":"ECOSYSTEM","events":[{"introduced":"4.10.0"},{"fixed":"4.14.290"}]},{"type":"ECOSYSTEM","events":[{"introduced":"4.15.0"},{"fixed":"4.19.254"}]},{"type":"ECOSYSTEM","events":[{"introduced":"4.20.0"},{"fixed":"5.4.208"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.5.0"},{"fixed":"5.10.134"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.58"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"5.18.15"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

Debian DEBIAN-CVE-2022-49607 linux Fixed in: 5.10.136-1
Ubuntu UBUNTU-CVE-2022-49607 linux-azure Fixed in: 4.15.0-1157.172~14.04.2

Summary

Original description

Affected packages

Fix status by distribution

References