This is a note to let you know that I've just added the patch titled usb: early: xhci-dbc: Fix a potential out-of-bound memory access to the 6.2-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: usb-early-xhci-dbc-fix-a-potential-out-of-bound-memo.patch and it can be found in the queue-6.2 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit d342c57b6e5e0269b8bcb86dedd83f31dc05f179 Author: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx> Date: Sun Jan 29 19:23:08 2023 +0100 usb: early: xhci-dbc: Fix a potential out-of-bound memory access [ Upstream commit a4a97ab3db5c081eb6e7dba91306adefb461e0bd ] 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. Fixes: aeb9dd1de98c ("usb/early: Add driver for xhci debug capability") Signed-off-by: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx> Link: https://lore.kernel.org/r/d6a7562c5e839a195cee85db6dc81817f9372cb1.1675016180.git.christophe.jaillet@xxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/usb/early/xhci-dbc.c b/drivers/usb/early/xhci-dbc.c index 7970471548202..f3e23be227d41 100644 --- a/drivers/usb/early/xhci-dbc.c +++ b/drivers/usb/early/xhci-dbc.c @@ -874,7 +874,8 @@ static int xdbc_bulk_write(const char *bytes, int size) static void early_xdbc_write(struct console *con, const char *str, u32 n) { - static char buf[XDBC_MAX_PACKET]; + /* static variables are zeroed, so buf is always NULL terminated */ + static char buf[XDBC_MAX_PACKET + 1]; int chunk, ret; int use_cr = 0;