CVE-2022-48929

In the Linux kernel, the following vulnerability has been resolved:

bpf: Fix crash due to out of bounds access into reg2btf_ids.

When commit e6ac2450d6de ("bpf: Support bpf program calling kernel function") added kfunc support, it defined reg2btfids as a cheap way to translate the verifier reg type to the appropriate btfvmlinux BTF ID, however commit c25b2ae13603 ("bpf: Replace PTRTOXXXORNULL with PTRTOXXX | PTRMAYBENULL") moved the _BPFREGTYPEMAX from the last member of bpfregtype enum to after the base register types, and defined other variants using type flag composition. However, now, the direct usage of reg->type to index into reg2btfids may no longer fall into _BPFREGTYPE_MAX range, and hence lead to out of bounds access and kernel crash on dereference of bad pointer.