USB: sisusbvga: Fix a potential UB casued by left shifting a negative value

The char buffer buf, receives data directly from user space,
so its content might be negative and its elements are left
shifted to form an unsigned integer.

Since left shifting a negative value is undefined behavior, thus
change the char to u8 to elimintate this UB.

Signed-off-by: Changming Liu <charley.ashbringer@gmail.com>
Link: https://lore.kernel.org/r/20200711043018.928-1-charley.ashbringer@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Changming Liu 2020-07-11 00:30:18 -04:00 committed by Greg Kroah-Hartman
parent 48025b4f3f
commit 2b53a19284

View file

@ -761,7 +761,7 @@ static int sisusb_write_mem_bulk(struct sisusb_usb_data *sisusb, u32 addr,
u8 swap8, fromkern = kernbuffer ? 1 : 0;
u16 swap16;
u32 swap32, flag = (length >> 28) & 1;
char buf[4];
u8 buf[4];
/* if neither kernbuffer not userbuffer are given, assume
* data in obuf