CVE-2024-40935

Summary

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

cachefiles: flush all requests after setting CACHEFILES_DEAD

In ondemand mode, when the daemon is processing an open request, if the kernel flags the cache as CACHEFILES_DEAD, the cachefiles_daemon_write() will always return -EIO, so the daemon can't pass the copen to the kernel. Then the kernel process that is waiting for the copen triggers a hung_task.

Since the DEAD state is irreversible, it can only be exited by closing /dev/cachefiles. Therefore, after calling cachefiles_io_error() to mark the cache as CACHEFILES_DEAD, if in ondemand mode, flush all requests to avoid the above hungtask. We may still be able to read some of the cached data before closing the fd of /dev/cachefiles.

Note that this relies on the patch that adds reference counting to the req, otherwise it may UAF.

Affected Software

VendorProductVersion RangeStatus
LinuxLinuxc8383054506c77b814489c09877b5db83fd4abf2 < 320ba9cbca78be79c912143bbba1d1b35ca55cf0affected
LinuxLinuxc8383054506c77b814489c09877b5db83fd4abf2 < 3bf0b8030296e9ee60d3d4c15849ad9ac0b47081affected
LinuxLinuxc8383054506c77b814489c09877b5db83fd4abf2 < e73fac95084839c5178d97e81c6a2051251bdc00affected
LinuxLinuxc8383054506c77b814489c09877b5db83fd4abf2 < 85e833cd7243bda7285492b0653c3abb1e2e757baffected
LinuxLinux5.19affected
LinuxLinux0 < 5.19unaffected
LinuxLinux6.1.95 <= 6.1.*unaffected
LinuxLinux6.6.35 <= 6.6.*unaffected
LinuxLinux6.9.6 <= 6.9.*unaffected
LinuxLinux6.10 <= *unaffected

Weaknesses

ADP Enrichment

CVE Program Container

Additional References

CISA ADP Vulnrichment

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

References