CVE-2024-44947 Information

Description

In the Linux kernel the following vulnerability has been resolved:

fuse: Initialize beyond-EOF page contents before setting uptodate

fuse_notify_store() unlike fuse_do_readpage() does not enable page zeroing (because it can be used to change partial page contents).

So fuse_notify_store() must be more careful to fully initialize page contents (including parts of the page that are beyond end-of-file) before marking the page uptodate.

The current code can leave beyond-EOF page contents uninitialized which makes these uninitialized page contents visible to userspace via mmap().

This is an information leak but only affects systems which do not enable init-on-alloc (via CONFIG_INIT_ON_ALLOC_DEFAULT_ON=y or the corresponding kernel command line parameter).

Reference

https://git.kernel.org/stable/c/831433527773e665bdb635ab5783d0b95d1246f4 https://git.kernel.org/stable/c/ac42e0f0eb66af966015ee33fd355bc6f5d80cd6 https://git.kernel.org/stable/c/18a067240817bee8a9360539af5d79a4bf5398a5 https://git.kernel.org/stable/c/3c0da3d163eb32f1f91891efaade027fa9b245b9