Re: [PATCH] hid_parse failure
From: Jiri Kosina <hidden>
Date: 2012-05-10 10:21:36
On Tue, 1 May 2012, srinivas pandruvada wrote:
When logical maximum is 0xffffffff, the parser fails even if logical minimum is equal to or greater than 0. By HID specification, if both the Logical Minimum and Logical Maximum extents are defined as positive values (0 or greater) then the report field can be assumed to be an unsigned value. Otherwise, all integer values are signed values represented in 2’s complement format.
Signed-off-by: line is missing, could you please fix that?
quoted hunk ↗ jump to hunk
--- drivers/hid/hid-core.c | 12 ++++++++++-- 1 files changed, 10 insertions(+), 2 deletions(-)diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c index c757f10..b616f4b 100644 --- a/drivers/hid/hid-core.c +++ b/drivers/hid/hid-core.c@@ -225,8 +225,16 @@ static int hid_add_field(struct hid_parser *parser, unsigned report_type, unsign return -1; } - if (parser->global.logical_maximum < parser->global.logical_minimum) { - dbg_hid("logical range invalid %d %d\n", parser->global.logical_minimum, parser->global.logical_maximum); + if ((parser->global.logical_minimum < 0 && + parser->global.logical_maximum < + parser->global.logical_minimum) || + (parser->global.logical_minimum >= 0 && + (__u32)parser->global.logical_maximum < + (__u32)parser->global.logical_minimum) + ) { + dbg_hid("logical range invalid 0x%x 0x%x\n", + parser->global.logical_minimum, + parser->global.logical_maximum); return -1; }
The change looks correct per se, but I will have to think a little bit more whether other places of report parsing don't need similar adjustments as well to work properly in such scenarios. How did you find this out? By code/spec inspection, or do you actually have the device that exposes this problem? Thanks, -- Jiri Kosina SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html