Commit a7d9367c authored Aug 21, 2018 by Johan Hovold Committed by Greg Kroah-Hartman Sep 26, 2018

USB: serial: io_ti: fix array underflow in completion handler



commit 691a03cf upstream.

As reported by Dan Carpenter, a malicious USB device could set
port_number to a negative value and we would underflow the port array in
the interrupt completion handler.

As these devices only have one or two ports, fix this by making sure we
only consider the seventh bit when determining the port number (and
ignore bits 0xb0 which are typically set to 0x30).

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Cc: stable <stable@vger.kernel.org>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent d078f295

drivers/usb/serial/io_ti.h

+1 −1

Original line number	Original line	Diff line number	Diff line
	@@ -178,7 +178,7 @@ struct ump_interrupt {
	} __attribute__((packed));		} __attribute__((packed));


	#define TIUMP_GET_PORT_FROM_CODE(c) (((c) >> 4) - 3)		#define TIUMP_GET_PORT_FROM_CODE(c) (((c) >> 6) & 0x01)
	#define TIUMP_GET_FUNC_FROM_CODE(c) ((c) & 0x0f)		#define TIUMP_GET_FUNC_FROM_CODE(c) ((c) & 0x0f)
	#define TIUMP_INTERRUPT_CODE_LSR 0x03		#define TIUMP_INTERRUPT_CODE_LSR 0x03
	#define TIUMP_INTERRUPT_CODE_MSR 0x04		#define TIUMP_INTERRUPT_CODE_MSR 0x04