kernel/bpf/verifier.c in the Linux kernel through 5.12.7 enforces incorrect limits for pointer arithmetic operations, aka CID-bb01a1bba579. This can be abused to perform out-of-bounds reads and writes in kernel memory, leading to local privilege escalation to root. In particular, there is a corner case where the off reg causes a masking direction change, which then results in an incorrect final aux->alu_limit. A flaw was found in kernel/bpf/verifier.c in BPF in the Linux kernel. An incorrect limit is enforced for pointer arithmetic operations which can be abused to perform out-of-bounds reads and writes in kernel memory, leading to local privilege escalation. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.
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