Subject: CVE-2022-48692: RDMA/srp: Set scmnd->result only when scmnd is not NULL

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

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

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

RDMA/srp: Set scmnd->result only when scmnd is not NULL

This change fixes the following kernel NULL pointer dereference
which is reproduced by blktests srp/007 occasionally.

BUG: kernel NULL pointer dereference, address: 0000000000000170
PGD 0 P4D 0
Oops: 0002 [#1] PREEMPT SMP NOPTI
CPU: 0 PID: 9 Comm: kworker/0:1H Kdump: loaded Not tainted 6.0.0-rc1+ #37
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.15.0-29-g6a62e0cb0dfe-prebuilt.qemu.org 04/01/2014
Workqueue:  0x0 (kblockd)
RIP: 0010:srp_recv_done+0x176/0x500 [ib_srp]
Code: 00 4d 85 ff 0f 84 52 02 00 00 48 c7 82 80 02 00 00 00 00 00 00 4c 89 df 4c 89 14 24 e8 53 d3 4a f6 4c 8b 14 24 41 0f b6 42 13 <41> 89 87 70 01 00 00 41 0f b6 52 12 f6 c2 02 74 44 41 8b 42 1c b9
RSP: 0018:ffffaef7c0003e28 EFLAGS: 00000282
RAX: 0000000000000000 RBX: ffff9bc9486dea60 RCX: 0000000000000000
RDX: 0000000000000102 RSI: ffffffffb76bbd0e RDI: 00000000ffffffff
RBP: ffff9bc980099a00 R08: 0000000000000001 R09: 0000000000000001
R10: ffff9bca53ef0000 R11: ffff9bc980099a10 R12: ffff9bc956e14000
R13: ffff9bc9836b9cb0 R14: ffff9bc9557b4480 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff9bc97ec00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000170 CR3: 0000000007e04000 CR4: 00000000000006f0
Call Trace:
 <IRQ>
 __ib_process_cq+0xb7/0x280 [ib_core]
 ib_poll_handler+0x2b/0x130 [ib_core]
 irq_poll_softirq+0x93/0x150
 __do_softirq+0xee/0x4b8
 irq_exit_rcu+0xf7/0x130
 sysvec_apic_timer_interrupt+0x8e/0xc0
 </IRQ>

The Linux kernel CVE team has assigned CVE-2022-48692 to this issue.

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

	Issue introduced in 5.14 with commit ad215aaea4f9 and fixed in 5.15.68 with commit a8edd49c94b4
	Issue introduced in 5.14 with commit ad215aaea4f9 and fixed in 5.19.9 with commit f2c70f56f762
	Issue introduced in 5.14 with commit ad215aaea4f9 and fixed in 6.0 with commit 12f35199a2c0

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-2022-48692
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/ulp/srp/ib_srp.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/f022576aa03c2385ea7f2b27ee5b331e43abf624
	https://git.kernel.org/stable/c/a8edd49c94b4b08019ed7d6dd794fca8078a4deb
	https://git.kernel.org/stable/c/f2c70f56f762e5dc3b0d7dc438fbb137cb116413
	https://git.kernel.org/stable/c/12f35199a2c0551187edbf8eb01379f0598659fa