CVE-2022-48929

Summary

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 reg2btf_ids as a cheap way to translate the verifier reg type to the appropriate btf_vmlinux BTF ID, however commit c25b2ae13603 ("bpf: Replace PTR_TO_XXX_OR_NULL with PTR_TO_XXX | PTR_MAYBE_NULL") moved the __BPF_REG_TYPE_MAX from the last member of bpf_reg_type 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 reg2btf_ids may no longer fall into __BPF_REG_TYPE_MAX range, and hence lead to out of bounds access and kernel crash on dereference of bad pointer.

Affected Software

VendorProductVersion RangeStatus
LinuxLinux8d38cde47a7e17b646401fa92d916503caa5375e < 8c39925e98d498b9531343066ef82ae39e41adaeaffected
LinuxLinux77459bc4d5e2c6f24db845780b4d9d60cf82d06a < f0ce1bc9e0235dd7412240be493d7ea65ed9eadcaffected
LinuxLinuxc25b2ae136039ffa820c26138ed4a5e5f3ab3841 < 45ce4b4f9009102cd9f581196d480a59208690c1affected
LinuxLinux5.16.11 < 5.16.12affected

Weaknesses

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: partial

References