From eebbe8dbd88893b86c25bc24ffe3227a0ca9b245 Mon Sep 17 00:00:00 2001 From: Changming Liu Date: Sat, 11 Jul 2020 00:30:18 -0400 Subject: [PATCH] USB: sisusbvga: Fix a potential UB casued by left shifting a negative value [ Upstream commit 2b53a19284f537168fb506f2f40d7fda40a01162 ] 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 Link: https://lore.kernel.org/r/20200711043018.928-1-charley.ashbringer@gmail.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/usb/misc/sisusbvga/sisusb.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/usb/misc/sisusbvga/sisusb.c b/drivers/usb/misc/sisusbvga/sisusb.c index 22da70fada5e5..971f1165dc4bb 100644 --- a/drivers/usb/misc/sisusbvga/sisusb.c +++ b/drivers/usb/misc/sisusbvga/sisusb.c @@ -790,7 +790,7 @@ 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 -- 2.47.2