CVE-2022-49873

Summary

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

bpf: Fix wrong reg type conversion in release_reference()

Some helper functions will allocate memory. To avoid memory leaks, the verifier requires the eBPF program to release these memories by calling the corresponding helper functions.

When a resource is released, all pointer registers corresponding to the resource should be invalidated. The verifier use release_references() to do this job, by apply __mark_reg_unknown() to each relevant register.

It will give these registers the type of SCALAR_VALUE. A register that will contain a pointer value at runtime, but of type SCALAR_VALUE, which may allow the unprivileged user to get a kernel pointer by storing this register into a map.

Using __mark_reg_not_init() while NOT allow_ptr_leaks can mitigate this problem.

Affected Software

VendorProductVersion RangeStatus
LinuxLinuxfd978bf7fd312581a7ca454a991f0ffb34c4204b < cedd4f01f67be94735f15123158f485028571037affected
LinuxLinuxfd978bf7fd312581a7ca454a991f0ffb34c4204b < 466ce46f251dfb259a8cbaa895ab9edd6fb56240affected
LinuxLinuxfd978bf7fd312581a7ca454a991f0ffb34c4204b < ae5ccad6c711db0f2ca1231be051935dd128b8f5affected
LinuxLinuxfd978bf7fd312581a7ca454a991f0ffb34c4204b < f1db20814af532f85e091231223e5e4818e8464baffected
LinuxLinux4.20affected
LinuxLinux0 < 4.20unaffected
LinuxLinux5.10.155 <= 5.10.*unaffected
LinuxLinux5.15.79 <= 5.15.*unaffected
LinuxLinux6.0.9 <= 6.0.*unaffected
LinuxLinux6.1 <= *unaffected

Weaknesses

ADP Enrichment

CISA ADP Vulnrichment

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

References