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.

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