Subject: CVE-2023-52528: net: usb: smsc75xx: Fix uninit-value access in __smsc75xx_read_reg

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

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

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

net: usb: smsc75xx: Fix uninit-value access in __smsc75xx_read_reg

syzbot reported the following uninit-value access issue:

=====================================================
BUG: KMSAN: uninit-value in smsc75xx_wait_ready drivers/net/usb/smsc75xx.c:975 [inline]
BUG: KMSAN: uninit-value in smsc75xx_bind+0x5c9/0x11e0 drivers/net/usb/smsc75xx.c:1482
CPU: 0 PID: 8696 Comm: kworker/0:3 Not tainted 5.8.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: usb_hub_wq hub_event
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x21c/0x280 lib/dump_stack.c:118
 kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:121
 __msan_warning+0x58/0xa0 mm/kmsan/kmsan_instr.c:215
 smsc75xx_wait_ready drivers/net/usb/smsc75xx.c:975 [inline]
 smsc75xx_bind+0x5c9/0x11e0 drivers/net/usb/smsc75xx.c:1482
 usbnet_probe+0x1152/0x3f90 drivers/net/usb/usbnet.c:1737
 usb_probe_interface+0xece/0x1550 drivers/usb/core/driver.c:374
 really_probe+0xf20/0x20b0 drivers/base/dd.c:529
 driver_probe_device+0x293/0x390 drivers/base/dd.c:701
 __device_attach_driver+0x63f/0x830 drivers/base/dd.c:807
 bus_for_each_drv+0x2ca/0x3f0 drivers/base/bus.c:431
 __device_attach+0x4e2/0x7f0 drivers/base/dd.c:873
 device_initial_probe+0x4a/0x60 drivers/base/dd.c:920
 bus_probe_device+0x177/0x3d0 drivers/base/bus.c:491
 device_add+0x3b0e/0x40d0 drivers/base/core.c:2680
 usb_set_configuration+0x380f/0x3f10 drivers/usb/core/message.c:2032
 usb_generic_driver_probe+0x138/0x300 drivers/usb/core/generic.c:241
 usb_probe_device+0x311/0x490 drivers/usb/core/driver.c:272
 really_probe+0xf20/0x20b0 drivers/base/dd.c:529
 driver_probe_device+0x293/0x390 drivers/base/dd.c:701
 __device_attach_driver+0x63f/0x830 drivers/base/dd.c:807
 bus_for_each_drv+0x2ca/0x3f0 drivers/base/bus.c:431
 __device_attach+0x4e2/0x7f0 drivers/base/dd.c:873
 device_initial_probe+0x4a/0x60 drivers/base/dd.c:920
 bus_probe_device+0x177/0x3d0 drivers/base/bus.c:491
 device_add+0x3b0e/0x40d0 drivers/base/core.c:2680
 usb_new_device+0x1bd4/0x2a30 drivers/usb/core/hub.c:2554
 hub_port_connect drivers/usb/core/hub.c:5208 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5348 [inline]
 port_event drivers/usb/core/hub.c:5494 [inline]
 hub_event+0x5e7b/0x8a70 drivers/usb/core/hub.c:5576
 process_one_work+0x1688/0x2140 kernel/workqueue.c:2269
 worker_thread+0x10bc/0x2730 kernel/workqueue.c:2415
 kthread+0x551/0x590 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293

Local variable ----buf.i87@smsc75xx_bind created at:
 __smsc75xx_read_reg drivers/net/usb/smsc75xx.c:83 [inline]
 smsc75xx_wait_ready drivers/net/usb/smsc75xx.c:968 [inline]
 smsc75xx_bind+0x485/0x11e0 drivers/net/usb/smsc75xx.c:1482
 __smsc75xx_read_reg drivers/net/usb/smsc75xx.c:83 [inline]
 smsc75xx_wait_ready drivers/net/usb/smsc75xx.c:968 [inline]
 smsc75xx_bind+0x485/0x11e0 drivers/net/usb/smsc75xx.c:1482

This issue is caused because usbnet_read_cmd() reads less bytes than requested
(zero byte in the reproducer). In this case, 'buf' is not properly filled.

This patch fixes the issue by returning -ENODATA if usbnet_read_cmd() reads
less bytes than requested.

The Linux kernel CVE team has assigned CVE-2023-52528 to this issue.

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

	Issue introduced in 2.6.34 with commit d0cad871703b and fixed in 4.14.327 with commit 3e0af6eec178
	Issue introduced in 2.6.34 with commit d0cad871703b and fixed in 4.19.296 with commit 2a36d9e2995c
	Issue introduced in 2.6.34 with commit d0cad871703b and fixed in 5.4.258 with commit 310f1c92f65a
	Issue introduced in 2.6.34 with commit d0cad871703b and fixed in 5.10.198 with commit 30bc4d7aebe3
	Issue introduced in 2.6.34 with commit d0cad871703b and fixed in 5.15.135 with commit cda10784a176
	Issue introduced in 2.6.34 with commit d0cad871703b and fixed in 6.1.57 with commit 9ffc5018020f
	Issue introduced in 2.6.34 with commit d0cad871703b and fixed in 6.5.7 with commit 4931e80da946
	Issue introduced in 2.6.34 with commit d0cad871703b and fixed in 6.6 with commit e9c65989920f

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-2023-52528
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/net/usb/smsc75xx.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/3e0af6eec1789fd11934164a7f4dbcad979855a4
	https://git.kernel.org/stable/c/2a36d9e2995c8c3c3f179aab1215a69cff06cbed
	https://git.kernel.org/stable/c/310f1c92f65ad905b7e81fe14de82d979ebbd825
	https://git.kernel.org/stable/c/30bc4d7aebe33904b0f2d3aad4b4a9c6029ad0c5
	https://git.kernel.org/stable/c/cda10784a176d7192f08ecb518f777a4e9575812
	https://git.kernel.org/stable/c/9ffc5018020fe646795a8dc1203224b8f776dc09
	https://git.kernel.org/stable/c/4931e80da9463b03bfe42be54a9a19f213b0f76d
	https://git.kernel.org/stable/c/e9c65989920f7c28775ec4e0c11b483910fb67b8