Bugzilla – Bug 1227797
VUL-0: CVE-2024-40935: kernel: cachefiles: flush all requests after setting CACHEFILES_DEAD
Last modified: 2024-07-15 13:15:00 UTC
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. References: http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2024-40935 https://www.cve.org/CVERecord?id=CVE-2024-40935 https://git.kernel.org/stable/c/320ba9cbca78be79c912143bbba1d1b35ca55cf0 https://git.kernel.org/stable/c/3bf0b8030296e9ee60d3d4c15849ad9ac0b47081 https://git.kernel.org/stable/c/85e833cd7243bda7285492b0653c3abb1e2e757b https://git.kernel.org/stable/c/e73fac95084839c5178d97e81c6a2051251bdc00 https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2024/CVE-2024-40935.mbox