usb: early: xhci-dbc: Fix a potential out-of-bound memory access

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: usb: early: xhci-dbc: Fix a potential out-of-bound memory access If xdbc_bulk_write() fails, the values in 'buf' can be anything. So the string is not guaranteed to be NULL terminated when xdbc_trace() is called. Reserve an extra byte, which will be zeroed automatically because 'buf' is a static variable, in order to avoid troubles, should it happen.

References

• https://git.kernel.org/stable/c/e8fb0f13e45cf361fd06593d3cb2d89915cd3bd0
• https://git.kernel.org/stable/c/351c8d8650d1ccc006255fa01f98b6c6496a02e5
• https://git.kernel.org/stable/c/df7c8aba7309f4dc55df94e06b67f576c0f52406
• https://git.kernel.org/stable/c/a4a97ab3db5c081eb6e7dba91306adefb461e0bd