CVE-2023-52609

Summary

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

binder: fix race between mmput() and do_exit()

Task A calls binder_update_page_range() to allocate and insert pages on a remote address space from Task B. For this, Task A pins the remote mm via mmget_not_zero() first. This can race with Task B do_exit() and the final mmput() refcount decrement will come from Task A.

Task A | Task B ——————+—————— mmget_not_zero() | | do_exit() | exit_mm() | mmput() mmput() | exit_mmap() | remove_vma() | fput() |

In this case, the work of ____fput() from Task B is queued up in Task A as TWA_RESUME. So in theory, Task A returns to userspace and the cleanup work gets executed. However, Task A instead sleep, waiting for a reply from Task B that never comes (it's dead).

This means the binder_deferred_release() is blocked until an unrelated binder event forces Task A to go back to userspace. All the associated death notifications will also be delayed until then.

In order to fix this use mmput_async() that will schedule the work in the corresponding mm->async_put_work WQ instead of Task A.

Affected Software

VendorProductVersion RangeStatus
LinuxLinux457b9a6f09f011ebcb9b52cc203a6331a6fc2de7 < 95b1d336b0642198b56836b89908d07b9a0c9608affected
LinuxLinux457b9a6f09f011ebcb9b52cc203a6331a6fc2de7 < 252a2a5569eb9f8d16428872cc24dea1ac0bb097affected
LinuxLinux457b9a6f09f011ebcb9b52cc203a6331a6fc2de7 < 7e7a0d86542b0ea903006d3f42f33c4f7ead6918affected
LinuxLinux457b9a6f09f011ebcb9b52cc203a6331a6fc2de7 < 98fee5bee97ad47b527a997d5786410430d1f0e9affected
LinuxLinux457b9a6f09f011ebcb9b52cc203a6331a6fc2de7 < 6696f76c32ff67fec26823fc2df46498e70d9bf3affected
LinuxLinux457b9a6f09f011ebcb9b52cc203a6331a6fc2de7 < 67f16bf2cc1698fd50e01ee8a2becc5a8e6d3a3eaffected
LinuxLinux457b9a6f09f011ebcb9b52cc203a6331a6fc2de7 < 77d210e8db4d61d43b2d16df66b1ec46fad2ee01affected
LinuxLinux457b9a6f09f011ebcb9b52cc203a6331a6fc2de7 < 9a9ab0d963621d9d12199df9817e66982582d5a5affected
LinuxLinux2.6.29affected
LinuxLinux0 < 2.6.29unaffected
LinuxLinux4.19.306 <= 4.19.*unaffected
LinuxLinux5.4.268 <= 5.4.*unaffected
LinuxLinux5.10.209 <= 5.10.*unaffected
LinuxLinux5.15.148 <= 5.15.*unaffected
LinuxLinux6.1.75 <= 6.1.*unaffected
LinuxLinux6.6.14 <= 6.6.*unaffected
LinuxLinux6.7.2 <= 6.7.*unaffected
LinuxLinux6.8 <= *unaffected

Weaknesses

ADP Enrichment

CISA ADP Vulnrichment

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

CVE Program Container

Additional References

References