linux-cve-announce - CVE-2022-49159: scsi: qla2xxx: Implement ref count for SRB

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Message-ID: <2025022610-CVE-2022-49159-58f3@gregkh>
Date: Wed, 26 Feb 2025 02:56:04 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: CVE-2022-49159: scsi: qla2xxx: Implement ref count for SRB

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

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

scsi: qla2xxx: Implement ref count for SRB

The timeout handler and the done function are racing. When
qla2x00_async_iocb_timeout() starts to run it can be preempted by the
normal response path (via the firmware?). qla24xx_async_gpsc_sp_done()
releases the SRB unconditionally. When scheduling back to
qla2x00_async_iocb_timeout() qla24xx_async_abort_cmd() will access an freed
sp->qpair pointer:

  qla2xxx [0000:83:00.0]-2871:0: Async-gpsc timeout - hdl=63d portid=234500 50:06:0e:80:08:77:b6:21.
  qla2xxx [0000:83:00.0]-2853:0: Async done-gpsc res 0, WWPN 50:06:0e:80:08:77:b6:21
  qla2xxx [0000:83:00.0]-2854:0: Async-gpsc OUT WWPN 20:45:00:27:f8:75:33:00 speeds=2c00 speed=0400.
  qla2xxx [0000:83:00.0]-28d8:0: qla24xx_handle_gpsc_event 50:06:0e:80:08:77:b6:21 DS 7 LS 6 rc 0 login 1|1 rscn 1|0 lid 5
  BUG: unable to handle kernel NULL pointer dereference at 0000000000000004
  IP: qla24xx_async_abort_cmd+0x1b/0x1c0 [qla2xxx]

Obvious solution to this is to introduce a reference counter. One reference
is taken for the normal code path (the 'good' case) and one for the timeout
path. As we always race between the normal good case and the timeout/abort
handler we need to serialize it. Also we cannot assume any order between
the handlers. Since this is slow path we can use proper synchronization via
locks.

When we are able to cancel a timer (del_timer returns 1) we know there
can't be any error handling in progress because the timeout handler hasn't
expired yet, thus we can safely decrement the refcounter by one.

If we are not able to cancel the timer, we know an abort handler is
running. We have to make sure we call sp->done() in the abort handlers
before calling kref_put().

The Linux kernel CVE team has assigned CVE-2022-49159 to this issue.

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

	Fixed in 5.15.33 with commit e17111dd2fda81c35f309b1e5b6ab35809a375e7
	Fixed in 5.16.19 with commit e140723f78ff418c8df7d990e102e07b65c87d4a
	Fixed in 5.17.2 with commit ceda7f794f3dfe272491e93e3e93049f8be5f07b
	Fixed in 5.18 with commit 31e6cdbe0eae37badceb5e0d4f06cf051432fd77

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-2022-49159
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/scsi/qla2xxx/qla_bsg.c
	drivers/scsi/qla2xxx/qla_def.h
	drivers/scsi/qla2xxx/qla_edif.c
	drivers/scsi/qla2xxx/qla_gbl.h
	drivers/scsi/qla2xxx/qla_gs.c
	drivers/scsi/qla2xxx/qla_init.c
	drivers/scsi/qla2xxx/qla_inline.h
	drivers/scsi/qla2xxx/qla_iocb.c
	drivers/scsi/qla2xxx/qla_mbx.c
	drivers/scsi/qla2xxx/qla_mid.c
	drivers/scsi/qla2xxx/qla_mr.c
	drivers/scsi/qla2xxx/qla_os.c
	drivers/scsi/qla2xxx/qla_target.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/e17111dd2fda81c35f309b1e5b6ab35809a375e7
	https://git.kernel.org/stable/c/e140723f78ff418c8df7d990e102e07b65c87d4a
	https://git.kernel.org/stable/c/ceda7f794f3dfe272491e93e3e93049f8be5f07b
	https://git.kernel.org/stable/c/31e6cdbe0eae37badceb5e0d4f06cf051432fd77