fuse: Block access to folio overlimit

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: fuse: Block access to folio overlimit syz reported a slab-out-of-bounds Write in fuse_dev_do_write. When the number of bytes to be retrieved is truncated to the upper limit by fc->max_pages and there is an offset, the oob is triggered. Add a loop termination condition to prevent overruns.

References

• https://git.kernel.org/stable/c/623719227b114d73a2cee45f1b343ced63ce09ec
• https://git.kernel.org/stable/c/9d81ba6d49a7457784f0b6a71046818b86ec7e44