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c04db81cd0
A buffer overflow vulnerability exists in the USB 9pfs transport layer
where inconsistent size validation between packet header parsing and
actual data copying allows a malicious USB host to overflow heap buffers.
The issue occurs because:
- usb9pfs_rx_header() validates only the declared size in packet header
- usb9pfs_rx_complete() uses req->actual (actual received bytes) for
memcpy
This allows an attacker to craft packets with small declared size
(bypassing validation) but large actual payload (triggering overflow
in memcpy).
Add validation in usb9pfs_rx_complete() to ensure req->actual does not
exceed the buffer capacity before copying data.
Reported-by: Yuhao Jiang <danisjiang@gmail.com>
Closes: https://lkml.kernel.org/r/20250616132539.63434-1-danisjiang@gmail.com
Fixes: a3be076dc1 ("net/9p/usbg: Add new usb gadget function transport")
Cc: stable@vger.kernel.org
Message-ID: <20250622-9p-usb_overflow-v3-1-ab172691b946@codewreck.org>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.