Re: [PATCH] HID: Fixed a crash in hid_report_raw_event() function.
From: <hidden>
Date: 2011-05-20 16:02:14
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Possibly related (same subject, not in this thread)
- 2011-05-20 · Re: [PATCH] HID: Fixed a crash in hid_report_raw_event() function. · Jiri Kosina <hidden>
- 2011-05-19 · [PATCH] HID: Fixed a crash in hid_report_raw_event() function. · Armando Visconti <hidden>
On Thu, 19 May 2011 21:41:22 +0200, Armando Visconti said:
quoted hunk
I'm using a Data Modul EasyTouch USB multitouch controller, which is issuing a hid report with a size equals to 0. The rsize value gets set to 536870912 and Linux is crashing in the memset because the value is too big. Signed-off-by: Armando Visconti <redacted> --- drivers/hid/hid-core.c | 3 +++ 1 files changed, 3 insertions(+), 0 deletions(-)diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c index c3d6626..3e972e3 100644 --- a/drivers/hid/hid-core.c +++ b/drivers/hid/hid-core.c@@ -1045,6 +1045,9 @@ void hid_report_raw_event(struct hid_device *hid, int type, u8 *data, int size, rsize = ((report->size - 1) >> 3) + 1; + if (rsize > HID_MAX_BUFFER_SIZE) + rsize = HID_MAX_BUFFER_SIZE; + if (csize < rsize) { dbg_hid("report %d is too short, (%d < %d)\n", report->id, csize, rsize);
I'm thinking this is papering over the bug, and causing us to process a max-sized
buffer when the other end gave *zero* bytes back - this can't be good.
Probably should be more like this:
if (!report->size) then /*
rsize = MIN_VALID_SIZE; /* whatever it should be here */
else {
rsize = ((report->size - 1) >> 3) + 1;
if (rsize > HID_MAX_BUFFER_SIZE)
rsize = HID_MAX_BUFFER_SIZE;
}
if (csize < rsize) {
That last if() still looks squirrely - if we have an effectively zero rsize,
the report is short and the dbg_hid should fire. Did we want "csize > rsize"
instead?
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