Linux Kernel up to 6.6.16/6.7.4 _ASM_EXTABLE_UA denial of service

Summaryinfo

A vulnerability classified as critical has been found in Linux Kernel up to 6.6.16/6.7.4. This issue affects the function _ASM_EXTABLE_UA. Performing a manipulation results in denial of service. This vulnerability is cataloged as CVE-2024-26674. There is no exploit available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.6.16/6.7.4. It has been classified as critical. This affects the function _ASM_EXTABLE_UA. The manipulation with an unknown input leads to a denial of service vulnerability. CWE is classifying the issue as CWE-404. The product does not release or incorrectly releases a resource before it is made available for re-use. This is going to have an impact on availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: x86/lib: Revert to _ASM_EXTABLE_UA() for {get,put}_user() fixups During memory error injection test on kernels >= v6.4, the kernel panics like below. However, this issue couldn't be reproduced on kernels <= v6.3. mce: [Hardware Error]: CPU 296: Machine Check Exception: f Bank 1: bd80000000100134 mce: [Hardware Error]: RIP 10: {__get_user_nocheck_4+0x6/0x20} mce: [Hardware Error]: TSC 411a93533ed ADDR 346a8730040 MISC 86 mce: [Hardware Error]: PROCESSOR 0:a06d0 TIME 1706000767 SOCKET 1 APIC 211 microcode 80001490 mce: [Hardware Error]: Run the above through 'mcelog --ascii' mce: [Hardware Error]: Machine check: Data load in unrecoverable area of kernel Kernel panic - not syncing: Fatal local machine check The MCA code can recover from an in-kernel #MC if the fixup type is EX_TYPE_UACCESS, explicitly indicating that the kernel is attempting to access userspace memory. However, if the fixup type is EX_TYPE_DEFAULT the only thing that is raised for an in-kernel #MC is a panic. ex_handler_uaccess() would warn if users gave a non-canonical addresses (with bit 63 clear) to {get, put}_user(), which was unexpected. Therefore, commit b19b74bc99b1 ("x86/mm: Rework address range check in get_user() and put_user()") replaced _ASM_EXTABLE_UA() with _ASM_EXTABLE() for {get, put}_user() fixups. However, the new fixup type EX_TYPE_DEFAULT results in a panic. Commit 6014bc27561f ("x86-64: make access_ok() independent of LAM") added the check gp_fault_address_ok() right before the WARN_ONCE() in ex_handler_uaccess() to not warn about non-canonical user addresses due to LAM. With that in place, revert back to _ASM_EXTABLE_UA() for {get,put}_user() exception fixups in order to be able to handle in-kernel MCEs correctly again. [ bp: Massage commit message. ]

It is possible to read the advisory at git.kernel.org. This vulnerability is uniquely identified as CVE-2024-26674 since 02/19/2024. The exploitability is told to be easy. Technical details of the vulnerability are known, but there is no available exploit.

The vulnerability scanner Nessus provides a plugin with the ID 210815 (RHEL 9 : kernel (RHSA-2024:9315)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.6.17, 6.7.5 or 6.8 eliminates this vulnerability. Applying the patch 2aed1b6c33af/2da241c5ed78/8eed4e00a370 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at Tenable (210815). Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.6.0
• 6.6.1
• 6.6.2
• 6.6.3
• 6.6.4
• 6.6.5
• 6.6.6
• 6.6.7
• 6.6.8
• 6.6.9
• 6.6.10
• 6.6.11
• 6.6.12
• 6.6.13
• 6.6.14
• 6.6.15
• 6.6.16
• 6.7.0
• 6.7.1
• 6.7.2
• 6.7.3
• 6.7.4

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

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CPE 2.2info

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Entryinfo

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