CVE-2021-47613: linux kernel — Fix

Description

In the Linux kernel, the following vulnerability has been resolved: i2c: virtio: fix completion handling The driver currently assumes that the notify callback is only received when the device is done with all the queued buffers. However, this is not true, since the notify callback could be called without any of the queued buffers being completed (for example, with virtio-pci and shared interrupts) or with only some of the buffers being completed (since the driver makes them available to the device in multiple separate virtqueue_add_sgs() calls). This can lead to incorrect data on the I2C bus or memory corruption in the guest if the device operates on buffers which are have been freed by the driver. (The WARN_ON in the driver is also triggered.) BUG kmalloc-128 (Tainted: G W ): Poison overwritten First byte 0x0 instead of 0x6b Allocated in i2cdev_ioctl_rdwr+0x9d/0x1de age=243 cpu=0 pid=28 memdup_user+0x2e/0xbd i2cdev_ioctl_rdwr+0x9d/0x1de i2cdev_ioctl+0x247/0x2ed vfs_ioctl+0x21/0x30 sys_ioctl+0xb18/0xb41 Freed in i2cdev_ioctl_rdwr+0x1bb/0x1de age=68 cpu=0 pid=28 kfree+0x1bd/0x1cc i2cdev_ioctl_rdwr+0x1bb/0x1de i2cdev_ioctl+0x247/0x2ed vfs_ioctl+0x21/0x30 sys_ioctl+0xb18/0xb41 Fix this by calling virtio_get_buf() from the notify handler like other virtio drivers and by actually waiting for all the buffers to be completed.

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CVSS v3.1 Score

7.8

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected Products

Vendor	Product	Versions
linux	linux_kernel	5.15 — 5.15.10
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All

References

Advisories & Patches

https://git.kernel.org/stable/c/9cbb957441ed8873577d7d313a3d79d69f1dad5c https://git.kernel.org/stable/c/b503de239f62eca898cfb7e820d9a35499137d22 https://git.kernel.org/stable/c/9cbb957441ed8873577d7d313a3d79d69f1dad5c https://git.kernel.org/stable/c/b503de239f62eca898cfb7e820d9a35499137d22

Frequently Asked Questions

What is CVE-2021-47613? +

In the Linux kernel, the following vulnerability has been resolved: i2c: virtio: fix completion handling The driver currently assumes that the notify callback is only received when the device is done with all the queued buffers. However, this is not true, since the notify callback could be called without any of the queued buffers being completed (for example, with virtio-pci and shared interrupts) or with only some of the buffers being completed (since the driver makes them available to the device in multiple separate virtqueue_add_sgs() calls). This can lead to incorrect data on the I2C bus or memory corruption in the guest if the device operates on buffers which are have been freed by the driver. (The WARN_ON in the driver is also triggered.) BUG kmalloc-128 (Tainted: G W ): Poison overwritten First byte 0x0 instead of 0x6b Allocated in i2cdev_ioctl_rdwr+0x9d/0x1de age=243 cpu=0 pid=28 memdup_user+0x2e/0xbd i2cdev_ioctl_rdwr+0x9d/0x1de i2cdev_ioctl+0x247/0x2ed vfs_ioctl+0x21/0x30 sys_ioctl+0xb18/0xb41 Freed in i2cdev_ioctl_rdwr+0x1bb/0x1de age=68 cpu=0 pid=28 kfree+0x1bd/0x1cc i2cdev_ioctl_rdwr+0x1bb/0x1de i2cdev_ioctl+0x247/0x2ed vfs_ioctl+0x21/0x30 sys_ioctl+0xb18/0xb41 Fix this by calling virtio_get_buf() from the notify handler like other virtio drivers and by actually waiting for all the buffers to be completed. It has a CVSS v3.1 base score of 7.8 (HIGH).

How severe is CVE-2021-47613? +

CVE-2021-47613 has a CVSS v3.1 score of 7.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

What products are affected by CVE-2021-47613? +

CVE-2021-47613 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2021-47613? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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CVE-2021-47613