CVE-2024-45020: bpf: Fix a kernel verifier crash in stacksafe()
First published: Wed Sep 11 2024(Updated: )
In the Linux kernel, the following vulnerability has been resolved: bpf: Fix a kernel verifier crash in stacksafe() Daniel Hodges reported a kernel verifier crash when playing with sched-ext. Further investigation shows that the crash is due to invalid memory access in stacksafe(). More specifically, it is the following code: if (exact != NOT_EXACT && old->stack[spi].slot_type[i % BPF_REG_SIZE] != cur->stack[spi].slot_type[i % BPF_REG_SIZE]) return false; The 'i' iterates old->allocated_stack. If cur->allocated_stack < old->allocated_stack the out-of-bound access will happen. To fix the issue add 'i >= cur->allocated_stack' check such that if the condition is true, stacksafe() should fail. Otherwise, cur->stack[spi].slot_type[i % BPF_REG_SIZE] memory access is legal.
Credit: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 416baaa9-dc9f-4396-8d5f-8c081fb06d67
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Linux Kernel | >=6.6.15<6.6.48 | |
| Linux Kernel | >=6.7<6.10.7 | |
| Linux Kernel | =6.11-rc1 | |
| Linux Kernel | =6.11-rc2 | |
| Linux Kernel | =6.11-rc3 | |
| debian/linux | 5.10.223-1 5.10.234-1 6.1.129-1 6.1.135-1 6.12.22-1 6.12.25-1 |
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Reference Links
- https://git.kernel.org/stable/c/6e3987ac310c74bb4dd6a2fa8e46702fe505fb2b
- https://git.kernel.org/stable/c/7cad3174cc79519bf5f6c4441780264416822c08
- https://git.kernel.org/stable/c/bed2eb964c70b780fb55925892a74f26cb590b25
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2024-45020
- https://nvd.nist.gov/vuln/detail/CVE-2024-45020
- https://launchpad.net/bugs/cve/CVE-2024-45020
- https://security-tracker.debian.org/tracker/CVE-2024-45020
- https://ubuntu.com/security/CVE-2024-45020
- https://git.kernel.org/linus/bed2eb964c70b780fb55925892a74f26cb590b25
- https://lore.kernel.org/linux-cve-announce/2024091108-CVE-2024-45020-afcc@gregkh/T
- https://access.redhat.com/errata/RHSA-2024:11486
- https://bugzilla.redhat.com/show_bug.cgi?id=2311717
Frequently Asked Questions
What is the severity of CVE-2024-45020?
CVE-2024-45020 has been classified as a moderate severity vulnerability due to its potential to cause a kernel verifier crash.
How do I fix CVE-2024-45020?
To fix CVE-2024-45020, update the Linux kernel to a version that is not affected by this vulnerability, such as versions 5.10.223-1, 5.10.226-1, or 6.12.11-1.
Which versions of the Linux Kernel are affected by CVE-2024-45020?
CVE-2024-45020 affects Linux Kernel versions between 6.6.15 and 6.6.48, as well as versions between 6.7 and 6.10.7.
Who reported CVE-2024-45020?
CVE-2024-45020 was reported by Daniel Hodges following a kernel verifier crash.
What components are involved in the CVE-2024-45020 vulnerability?
The vulnerability involves a kernel verifier crash related to invalid memory access in the stacksafe() function.
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