HID: core: detect and skip invalid inputs to snto32()

Prevent invalid (0, 0) inputs to hid-core's snto32() function.

Maybe it is just the dummy device here that is causing this, but
there are hundreds of calls to snto32(0, 0). Having n (bits count)
of 0 is causing the current UBSAN trap with a shift value of
0xffffffff (-1, or n - 1 in this function).

Either of the value to shift being 0 or the bits count being 0 can be
handled by just returning 0 to the caller, avoiding the following
complex shift + OR operations:

	return value & (1 << (n - 1)) ? value | (~0U << n) : value;

Fixes: dde5845a529f ("[PATCH] Generic HID layer - code split")
Signed-off-by: Randy Dunlap <[email protected]>
Reported-by: [email protected]
Cc: Jiri Kosina <[email protected]>
Cc: Benjamin Tissoires <[email protected]>
Cc: [email protected]
Signed-off-by: Jiri Kosina <[email protected]>

0 files changed, 0 insertions, 0 deletions