UBUNTU-CVE-2024-26718

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    UBUNTU-CVE-2024-26718

    Published: 3 Apr 2024Last Modified: 22 Sept 2026
    Upstream:
    CVE-2024-26718
    Aliases:
    USN-6895-1
    USN-6895-2
    USN-6895-3

    Summary:

    Details: In the Linux kernel, the following vulnerability has been resolved: dm-crypt, dm-verity: disable tasklets Tasklets have an inherent problem with memory corruption. The function tasklet_action_common calls tasklet_trylock, then it calls the tasklet callback and then it calls tasklet_unlock. If the tasklet callback frees the structure that contains the tasklet or if it calls some code that may free it, tasklet_unlock will write into free memory. The commits 8e14f610159d and d9a02e016aaf try to fix it for dm-crypt, but it is not a sufficient fix and the data corruption can still happen [1]. There is no fix for dm-verity and dm-verity will write into free memory with every tasklet-processed bio. There will be atomic workqueues implemented in the kernel 6.9 [2]. They will have better interface and they will not suffer from the memory corruption problem. But we need something that stops the memory corruption now and that can be backported to the stable kernels. So, I'm proposing this commit that disables tasklets in both dm-crypt and dm-verity. This commit doesn't remove the tasklet support, because the tasklet code will be reused when atomic workqueues will be implemented. [1] https://lore.kernel.org/all/[email protected]/T/ [2] https://lore.kernel.org/lkml/[email protected]/

    References: https://ubuntu.com/security/CVE-2024-26718, https://git.kernel.org/linus/0a9bab391e336489169b95cb0d4553d921302189, https://git.kernel.org/stable/c/30884a44e0cedc3dfda8c22432f3ba4078ec2d94, https://git.kernel.org/stable/c/5735a2671ffb70ea29ca83969fe01316ee2ed6fc, https://git.kernel.org/stable/c/0c45a20cbe68bc4d681734f5c03891124a274257, https://git.kernel.org/stable/c/0a9bab391e336489169b95cb0d4553d921302189, https://www.cve.org/CVERecord?id=CVE-2024-26718, https://ubuntu.com/security/notices/USN-6895-1, https://ubuntu.com/security/notices/USN-6895-2, https://ubuntu.com/security/notices/USN-6900-1, https://ubuntu.com/security/notices/USN-6895-3, https://ubuntu.com/security/notices/USN-6895-4, https://ubuntu.com/security/notices/USN-7288-1, https://ubuntu.com/security/notices/USN-7289-1, https://ubuntu.com/security/notices/USN-7291-1, https://ubuntu.com/security/notices/USN-7288-2, https://ubuntu.com/security/notices/USN-7289-2, https://ubuntu.com/security/notices/USN-7289-3, https://ubuntu.com/security/notices/USN-7305-1, https://ubuntu.com/security/notices/USN-7289-4, https://ubuntu.com/security/notices/USN-7308-1, https://ubuntu.com/security/notices/USN-7331-1, https://ubuntu.com/security/notices/USN-7388-1, https://ubuntu.com/security/notices/USN-7389-1, https://ubuntu.com/security/notices/USN-7390-1, https://ubuntu.com/security/notices/USN-7458-1

    Affected packages

    Package

    Name: linux-hwe-edge

    Purl: pkg:deb/ubuntu/linux-hwe-edge?arch=source&distro=xenial

    Affected ranges

    Type: ECOSYSTEM

    Events:

    Introduced- 0
    Fixed -None

    Affected versions

    4.8.0-28.30~16.04.1
    4.8.0-30.32~16.04.1
    4.8.0-32.34~16.04.1
    4.8.0-34.36~16.04.1

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High
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