In the Linux kernel, the following vulnerability has been resolved:
USB: core: Fix race by not overwriting udev->descriptor in hub_port_init()
Syzbot reported an out-of-bounds read in sysfs.c:read_descriptors():
BUG: KASAN: slab-out-of-bounds in read_descriptors+0x263/0x280 drivers/usb/core/sysfs.c:883
Read of size 8 at addr ffff88801e78b8c8 by task udevd/5011
CPU: 0 PID: 5011 Comm: udevd Not tainted 6.4.0-rc6-syzkaller-00195-g40f71e7cd3c6 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106
print_address_description.constprop.0+0x2c/0x3c0 mm/kasan/report.c:351
print_report mm/kasan/report.c:462 [inline]
kasan_report+0x11c/0x130 mm/kasan/report.c:572
read_descriptors+0x263/0x280 drivers/usb/core/sysfs.c:883
...
Allocated by task 758:
...
__do_kmalloc_node mm/slab_common.c:966 [inline]
__kmalloc+0x5e/0x190 mm/slab_common.c:979
kmalloc include/linux/slab.h:563 [inline]
kzalloc include/linux/slab.h:680 [inline]
usb_get_configuration+0x1f7/0x5170 drivers/usb/core/config.c:887
usb_enumerate_device drivers/usb/core/hub.c:2407 [inline]
usb_new_device+0x12b0/0x19d0 drivers/usb/core/hub.c:2545
As analyzed by Khazhy Kumykov, the cause of this bug is a race between
read_descriptors() and hub_port_init(): The first routine uses a field
in udev->descriptor, not expecting it to change, while the second
overwrites it.
Prior to commit 45bf39f8df7f ("USB: core: Don't hold device lock while
reading the "descriptors" sysfs file") this race couldn't occur,
because the routines were mutually exclusive thanks to the device
locking. Removing that locking from read_descriptors() exposed it to
the race.
The best way to fix the bug is to keep hub_port_init() from changing
udev->descriptor once udev has been initialized and registered.
Drivers expect the descriptors stored in the kernel to be immutable;
we should not undermine this expectation. In fact, this change should
have been made long ago.
So now hub_port_init() will take an additional argument, specifying a
buffer in which to store the device descriptor it reads. (If udev has
not yet been initialized, the buffer pointer will be NULL and then
hub_port_init() will store the device descriptor in udev as before.)
This eliminates the data race responsible for the out-of-bounds read.
The changes to hub_port_init() appear more extensive than they really
are, because of indentation changes resulting from an attempt to avoid
writing to other parts of the usb_device structure after it has been
initialized. Similar changes should be made to the code that reads
the BOS descriptor, but that can be handled in a separate patch later
on. This patch is sufficient to fix the bug found by syzbot.
Metrics
Affected Vendors & Products
References
History
Wed, 11 Sep 2024 13:30:00 +0000
Type | Values Removed | Values Added |
---|---|---|
Metrics |
ssvc
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Wed, 21 Aug 2024 17:45:00 +0000
Type | Values Removed | Values Added |
---|---|---|
First Time appeared |
Linux
Linux linux Kernel |
|
CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
Vendors & Products |
Linux
Linux linux Kernel |
|
Metrics |
cvssV3_1
|
cvssV3_1
|
MITRE
Status: PUBLISHED
Assigner: Linux
Published: 2024-07-16T09:40:58.495Z
Updated: 2024-12-19T08:27:55.390Z
Reserved: 2024-05-21T15:35:00.782Z
Link: CVE-2023-52886
Vulnrichment
Updated: 2024-09-11T12:42:21.869Z
NVD
Status : Modified
Published: 2024-07-16T10:15:02.493
Modified: 2024-11-21T08:40:48.173
Link: CVE-2023-52886
Redhat