// For flags

CVE-2021-47561

i2c: virtio: disable timeout handling

Severity Score

"-"
*CVSS v-

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

0
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

Track
*SSVC
Descriptions

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

i2c: virtio: disable timeout handling

If a timeout is hit, it can result is incorrect data on the I2C bus
and/or memory corruptions in the guest since the device can still be
operating on the buffers it was given while the guest has freed them.

Here is, for example, the start of a slub_debug splat which was
triggered on the next transfer after one transfer was forced to timeout
by setting a breakpoint in the backend (rust-vmm/vhost-device):

BUG kmalloc-1k (Not tainted): Poison overwritten
First byte 0x1 instead of 0x6b
Allocated in virtio_i2c_xfer+0x65/0x35c age=350 cpu=0 pid=29
__kmalloc+0xc2/0x1c9
virtio_i2c_xfer+0x65/0x35c
__i2c_transfer+0x429/0x57d
i2c_transfer+0x115/0x134
i2cdev_ioctl_rdwr+0x16a/0x1de
i2cdev_ioctl+0x247/0x2ed
vfs_ioctl+0x21/0x30
sys_ioctl+0xb18/0xb41
Freed in virtio_i2c_xfer+0x32e/0x35c age=244 cpu=0 pid=29
kfree+0x1bd/0x1cc
virtio_i2c_xfer+0x32e/0x35c
__i2c_transfer+0x429/0x57d
i2c_transfer+0x115/0x134
i2cdev_ioctl_rdwr+0x16a/0x1de
i2cdev_ioctl+0x247/0x2ed
vfs_ioctl+0x21/0x30
sys_ioctl+0xb18/0xb41

There is no simple fix for this (the driver would have to always create
bounce buffers and hold on to them until the device eventually returns
the buffers), so just disable the timeout support for now.

En el kernel de Linux, se resolvió la siguiente vulnerabilidad: i2c: virtio: deshabilita el manejo del tiempo de espera Si se alcanza un tiempo de espera, puede resultar en datos incorrectos en el bus I2C y/o daños en la memoria del invitado, ya que el dispositivo aún puede estar funcionando. en los buffers que se le dieron mientras el huésped los liberó. Aquí está, por ejemplo, el inicio de un splat slub_debug que se activó en la siguiente transferencia después de que se obligó a que una transferencia expirara estableciendo un punto de interrupción en el backend (rust-vmm/vhost-device): ERROR kmalloc-1k (No contaminado ): Veneno sobrescrito Primer byte 0x1 en lugar de 0x6b Asignado en virtio_i2c_xfer+0x65/0x35c age=350 cpu=0 pid=29 __kmalloc+0xc2/0x1c9 virtio_i2c_xfer+0x65/0x35c __i2c_transfer+0x429/0x57d 0x115/0x134 i2cdev_ioctl_rdwr+0x16a/ 0x1de i2cdev_ioctl+0x247/0x2ed vfs_ioctl+0x21/0x30 sys_ioctl+0xb18/0xb41 Liberado en virtio_i2c_xfer+0x32e/0x35c edad=244 cpu=0 pid=29 kfree+0x1bd/0x1cc x32e/0x35c __i2c_transfer+0x429/0x57d i2c_transfer+0x115 /0x134 i2cdev_ioctl_rdwr+0x16a/0x1de i2cdev_ioctl+0x247/0x2ed vfs_ioctl+0x21/0x30 sys_ioctl+0xb18/0xb41 No existe una solución sencilla para esto (el controlador siempre tendría que crear búferes de rebote y conservarlos hasta que el dispositivo finalmente devuelva el búferes), así que simplemente deshabilite el soporte de tiempo de espera por ahora.

*Credits: N/A
CVSS Scores
Attack Vector
-
Attack Complexity
-
Privileges Required
-
User Interaction
-
Scope
-
Confidentiality
-
Integrity
-
Availability
-
* Common Vulnerability Scoring System
SSVC
  • Decision:Track
Exploitation
None
Automatable
No
Tech. Impact
Partial
* Organization's Worst-case Scenario
Timeline
  • 2024-05-24 CVE Reserved
  • 2024-05-24 CVE Published
  • 2024-05-25 EPSS Updated
  • 2024-12-19 CVE Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
  • ---------- First Exploit
CWE
CAPEC
Affected Vendors, Products, and Versions
Vendor Product Version Other Status
Vendor Product Version Other Status <-- --> Vendor Product Version Other Status
Linux
Search vendor "Linux"
Linux Kernel
Search vendor "Linux" for product "Linux Kernel"
>= 5.15 < 5.15.6
Search vendor "Linux" for product "Linux Kernel" and version " >= 5.15 < 5.15.6"
en
Affected
Linux
Search vendor "Linux"
Linux Kernel
Search vendor "Linux" for product "Linux Kernel"
>= 5.15 < 5.16
Search vendor "Linux" for product "Linux Kernel" and version " >= 5.15 < 5.16"
en
Affected