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UPSTREAM: HID: core: Correctly handle ReportSize being zero

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commit bce1305c0e upstream.

It appears that a ReportSize value of zero is legal, even if a bit
non-sensical. Most of the HID code seems to handle that gracefully,
except when computing the total size in bytes. When fed as input to
memset, this leads to some funky outcomes.

Detect the corner case and correctly compute the size.

Cc: stable@vger.kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit bce1305c0e)
Change-Id: I5ab5febc22b8d5d8c5d398c3ff93f73cb3c90e05
Signed-off-by: Todd Kjos <tkjos@google.com>
This commit is contained in:
Marc Zyngier
2020-08-29 12:26:01 +01:00
committed by Todd Kjos
parent bdf78f318d
commit e7eb07515d
1 changed files with 13 additions and 2 deletions
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15
drivers/hid/hid-core.c
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@@ -1597,6 +1597,17 @@ static void hid_output_field(const struct hid_device *hid,
}
}
/*
* Compute the size of a report.
*/
static size_t hid_compute_report_size(struct hid_report *report)
{
if (report->size)
return ((report->size - 1) >> 3) + 1;
return 0;
}
/*
* Create a report. 'data' has to be allocated using
* hid_alloc_report_buf() so that it has proper size.
@@ -1609,7 +1620,7 @@ void hid_output_report(struct hid_report *report, __u8 *data)
if (report->id > 0)
*data++ = report->id;
memset(data, 0, ((report->size - 1) >> 3) + 1);
memset(data, 0, hid_compute_report_size(report));
for (n = 0; n < report->maxfield; n++)
hid_output_field(report->device, report->field[n], data);
}
@@ -1739,7 +1750,7 @@ int hid_report_raw_event(struct hid_device *hid, int type, u8 *data, u32 size,
csize--;
}
rsize = ((report->size - 1) >> 3) + 1;
rsize = hid_compute_report_size(report);
if (report_enum->numbered && rsize >= HID_MAX_BUFFER_SIZE)
rsize = HID_MAX_BUFFER_SIZE - 1;