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Vulnerability CVE-2024-40935
Published: 2024-07-12
| Description: |
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: |
https://git.kernel.org/stable/c/320ba9cbca78be79c912143bbba1d1b35ca55cf0
https://git.kernel.org/stable/c/3bf0b8030296e9ee60d3d4c15849ad9ac0b47081
https://git.kernel.org/stable/c/e73fac95084839c5178d97e81c6a2051251bdc00
https://git.kernel.org/stable/c/85e833cd7243bda7285492b0653c3abb1e2e757b
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