CVE-2023-54181
Unknown Unknown - Not Provided
BPF Verifier Pointer Comparison Flaw in Linux Kernel

Publication date: 2025-12-30

Last updated on: 2025-12-30

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: bpf: Fix issue in verifying allow_ptr_leaks After we converted the capabilities of our networking-bpf program from cap_sys_admin to cap_net_admin+cap_bpf, our networking-bpf program failed to start. Because it failed the bpf verifier, and the error log is "R3 pointer comparison prohibited". A simple reproducer as follows, SEC("cls-ingress") int ingress(struct __sk_buff *skb) { struct iphdr *iph = (void *)(long)skb->data + sizeof(struct ethhdr); if ((long)(iph + 1) > (long)skb->data_end) return TC_ACT_STOLEN; return TC_ACT_OK; } Per discussion with Yonghong and Alexei [1], comparison of two packet pointers is not a pointer leak. This patch fixes it. Our local kernel is 6.1.y and we expect this fix to be backported to 6.1.y, so stable is CCed. [1]. https://lore.kernel.org/bpf/CAADnVQ+Nmspr7Si+pxWn8zkE7hX-7s93ugwC+94aXSy4uQ9vBg@mail.gmail.com/
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Meta Information
Published
2025-12-30
Last Modified
2025-12-30
Generated
2026-05-07
AI Q&A
2025-12-30
EPSS Evaluated
2026-05-05
NVD
CVE-2023-54181
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel 6.1
Helpful Resources
Exploitability
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CWE ID Description
CWE-UNKNOWN
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AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability is related to the Linux kernel's BPF (Berkeley Packet Filter) verifier incorrectly handling pointer comparisons in networking BPF programs. Specifically, the verifier prohibited comparing two packet pointers, resulting in a failure to start the networking-bpf program with an error "R3 pointer comparison prohibited." The issue was that such pointer comparisons were mistakenly treated as pointer leaks, which they are not. The fix involved correcting the verifier to allow these pointer comparisons, resolving the problem.


How can this vulnerability impact me? :

This vulnerability can cause networking BPF programs that rely on pointer comparisons to fail to start because the BPF verifier incorrectly blocks these comparisons. This can lead to disruptions in network packet processing or filtering functionalities that depend on such BPF programs, potentially affecting network performance or behavior.


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