CVE-2021-47170

In the Linux kernel, the following vulnerability has been resolved:

USB: usbfs: Dont WARN about excessively large memory allocations

Syzbot found that the kernel generates a WARNing if the user tries to submit a bulk transfer through usbfs with a buffer that is way too large. This isnt a bug in the kernel; its merely an invalid request from the user and the usbfs code does handle it correctly.

In theory the same thing can happen with async transfers, or with the packet descriptor table for isochronous transfers.

To prevent the MM subsystem from complaining about these bad allocation requests, add the __GFP_NOWARN flag to the kmalloc calls for these buffers.

Affected Software

References

• https://git.kernel.org/stable/c/2ab21d6e1411999b5fb43434f421f00bf50002eb
• https://git.kernel.org/stable/c/2c835fede13e03f2743a333e4370b5ed2db91e83
• https://git.kernel.org/stable/c/4f2629ea67e7225c3fd292c7fe4f5b3c9d6392de
• https://git.kernel.org/stable/c/8d83f109e920d2776991fa142bb904d985dca2ed
• https://git.kernel.org/stable/c/9f7cb3f01a10d9064cf13b3d26fb7e7a5827d098