From: Ian Abbott Date: Tue, 27 Oct 2015 16:59:13 +0000 (+0000) Subject: staging: comedi: comedi_test: limit maximum convert_arg X-Git-Tag: firefly_0821_release~176^2~802^2~43 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=5afdcad2f818ed623f61e79ea63fcd347bef1a8c;p=firefly-linux-kernel-4.4.55.git staging: comedi: comedi_test: limit maximum convert_arg When testing the parameters for setting up an asynchronous command on the AI subdevice, limit the maximum conversion period (`cmd->convert_arg`) so that the number of conversions in a scan (`cmd->scan_end_arg`, same as `cmd->chanlist_len`) multiplied by the conversion period fits within an `unsigned int`, as that is used to limit the minimum scan period (`cmd->scan_begin_arg`). Also ensure rounding of the conversion period and scan period to the nearest microsecond both fit in an `unsigned int`. Do all this in stage 4 ("fix up any arguments") of the command testing. Signed-off-by: Ian Abbott Reviewed-by: H Hartley Sweeten Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/staging/comedi/drivers/comedi_test.c b/drivers/staging/comedi/drivers/comedi_test.c index d9810caae475..f011fbd2fd96 100644 --- a/drivers/staging/comedi/drivers/comedi_test.c +++ b/drivers/staging/comedi/drivers/comedi_test.c @@ -234,7 +234,7 @@ static int waveform_ai_cmdtest(struct comedi_device *dev, struct comedi_cmd *cmd) { int err = 0; - unsigned int arg; + unsigned int arg, limit; /* Step 1 : check if triggers are trivially valid */ @@ -265,16 +265,8 @@ static int waveform_ai_cmdtest(struct comedi_device *dev, if (cmd->convert_src == TRIG_NOW) err |= comedi_check_trigger_arg_is(&cmd->convert_arg, 0); - if (cmd->scan_begin_src == TRIG_TIMER) { - err |= comedi_check_trigger_arg_min(&cmd->scan_begin_arg, - NSEC_PER_USEC); - if (cmd->convert_src == TRIG_TIMER) { - err |= comedi_check_trigger_arg_min(&cmd-> - scan_begin_arg, - cmd->convert_arg * - cmd->chanlist_len); - } - } + err |= comedi_check_trigger_arg_min(&cmd->scan_begin_arg, + NSEC_PER_USEC); err |= comedi_check_trigger_arg_min(&cmd->chanlist_len, 1); err |= comedi_check_trigger_arg_is(&cmd->scan_end_arg, @@ -290,21 +282,29 @@ static int waveform_ai_cmdtest(struct comedi_device *dev, /* step 4: fix up any arguments */ - if (cmd->scan_begin_src == TRIG_TIMER) { - arg = cmd->scan_begin_arg; - /* round to nearest microsec */ - arg = NSEC_PER_USEC * - ((arg + (NSEC_PER_USEC / 2)) / NSEC_PER_USEC); - err |= comedi_check_trigger_arg_is(&cmd->scan_begin_arg, arg); - } if (cmd->convert_src == TRIG_TIMER) { + /* round convert_arg to nearest microsecond */ arg = cmd->convert_arg; - /* round to nearest microsec */ - arg = NSEC_PER_USEC * - ((arg + (NSEC_PER_USEC / 2)) / NSEC_PER_USEC); + arg = min(arg, + rounddown(UINT_MAX, (unsigned int)NSEC_PER_USEC)); + arg = NSEC_PER_USEC * DIV_ROUND_CLOSEST(arg, NSEC_PER_USEC); + /* limit convert_arg to keep scan_begin_arg in range */ + limit = UINT_MAX / cmd->scan_end_arg; + limit = rounddown(limit, (unsigned int)NSEC_PER_SEC); + arg = min(arg, limit); err |= comedi_check_trigger_arg_is(&cmd->convert_arg, arg); } + /* round scan_begin_arg to nearest microsecond */ + arg = cmd->scan_begin_arg; + arg = min(arg, rounddown(UINT_MAX, (unsigned int)NSEC_PER_USEC)); + arg = NSEC_PER_USEC * DIV_ROUND_CLOSEST(arg, NSEC_PER_USEC); + if (cmd->convert_src == TRIG_TIMER) { + /* but ensure scan_begin_arg is large enough */ + arg = max(arg, cmd->convert_arg * cmd->scan_end_arg); + } + err |= comedi_check_trigger_arg_is(&cmd->scan_begin_arg, arg); + if (err) return 4;