linux/drivers/char/mwave
Gustavo A. R. Silva 701956d401 char/mwave: fix potential Spectre v1 vulnerability
ipcnum is indirectly controlled by user-space, hence leading to
a potential exploitation of the Spectre variant 1 vulnerability.

This issue was detected with the help of Smatch:

drivers/char/mwave/mwavedd.c:299 mwave_ioctl() warn: potential spectre issue 'pDrvData->IPCs' [w] (local cap)

Fix this by sanitizing ipcnum before using it to index pDrvData->IPCs.

Notice that given that speculation windows are large, the policy is
to kill the speculation on the first load and not worry if it can be
completed with a dependent load/store [1].

[1] https://marc.info/?l=linux-kernel&m=152449131114778&w=2

Cc: stable@vger.kernel.org
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-01-18 16:42:05 +01:00
..
3780i.c
3780i.h
Makefile
mwavedd.c char/mwave: fix potential Spectre v1 vulnerability 2019-01-18 16:42:05 +01:00
mwavedd.h
mwavepub.h
README
smapi.c char/mwave: make some arrays static const to make object code smaller 2017-07-17 17:23:16 +02:00
smapi.h
tp3780i.c
tp3780i.h

Module options
--------------

The mwave module takes the following options.  Note that these options
are not saved by the BIOS and so do not persist after unload and reload.

  mwave_debug=value, where value is bitwise OR of trace flags:
	0x0001 mwavedd api tracing
	0x0002 smapi api tracing
	0x0004 3780i tracing
	0x0008 tp3780i tracing

        Tracing only occurs if the driver has been compiled with the
        MW_TRACE macro #defined  (i.e. let ccflags-y := -DMW_TRACE
        in the Makefile).

  mwave_3780i_irq=5/7/10/11/15
	If the dsp irq has not been setup and stored in bios by the 
	thinkpad configuration utility then this parameter allows the
	irq used by the dsp to be configured.

  mwave_3780i_io=0x130/0x350/0x0070/0xDB0
	If the dsp io range has not been setup and stored in bios by the 
	thinkpad configuration utility then this parameter allows the
	io range used by the dsp to be configured.

  mwave_uart_irq=3/4
	If the mwave's uart irq has not been setup and stored in bios by the 
	thinkpad configuration utility then this parameter allows the
	irq used by the mwave uart to be configured.

  mwave_uart_io=0x3f8/0x2f8/0x3E8/0x2E8
	If the uart io range has not been setup and stored in bios by the 
	thinkpad configuration utility then this parameter allows the
	io range used by the mwave uart to be configured.

Example to enable the 3780i DSP using ttyS1 resources:
	
  insmod mwave mwave_3780i_irq=10 mwave_3780i_io=0x0130 mwave_uart_irq=3 mwave_uart_io=0x2f8

Accessing the driver
--------------------

You must also create a node for the driver:
  mkdir -p /dev/modems
  mknod --mode=660 /dev/modems/mwave c 10 219