From: Will McVicker <willmcvicker@google.com>
To: Jiri Kosina <jikos@kernel.org>,
Benjamin Tissoires <benjamin.tissoires@redhat.com>,
security@kernel.org
Cc: linux-input@vger.kernel.org, linux-kernel@vger.kernel.org,
kernel-team@android.com, Will Coster <willcoster@google.com>,
Will McVicker <willmcvicker@google.com>
Subject: [PATCH v1] HID: make arrays usage and value to be the same
Date: Sat, 5 Dec 2020 00:48:48 +0000 [thread overview]
Message-ID: <20201205004848.2541215-1-willmcvicker@google.com> (raw)
The HID subsystem allows an "HID report field" to have a different
number of "values" and "usages" when it is allocated. When a field
struct is created, the size of the usage array is guaranteed to be at
least as large as the values array, but it may be larger. This leads to
a potential out-of-bounds write in
__hidinput_change_resolution_multipliers() and an out-of-bounds read in
hidinput_count_leds().
To fix this, let's make sure that both the usage and value arrays are
the same size.
Signed-off-by: Will McVicker <willmcvicker@google.com>
---
drivers/hid/hid-core.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index 56172fe6995c..8a8b2b982f83 100644
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -90,7 +90,7 @@ EXPORT_SYMBOL_GPL(hid_register_report);
* Register a new field for this report.
*/
-static struct hid_field *hid_register_field(struct hid_report *report, unsigned usages, unsigned values)
+static struct hid_field *hid_register_field(struct hid_report *report, unsigned usages)
{
struct hid_field *field;
@@ -101,7 +101,7 @@ static struct hid_field *hid_register_field(struct hid_report *report, unsigned
field = kzalloc((sizeof(struct hid_field) +
usages * sizeof(struct hid_usage) +
- values * sizeof(unsigned)), GFP_KERNEL);
+ usages * sizeof(unsigned)), GFP_KERNEL);
if (!field)
return NULL;
@@ -300,7 +300,7 @@ static int hid_add_field(struct hid_parser *parser, unsigned report_type, unsign
usages = max_t(unsigned, parser->local.usage_index,
parser->global.report_count);
- field = hid_register_field(report, usages, parser->global.report_count);
+ field = hid_register_field(report, usages);
if (!field)
return 0;
--
2.29.2.576.ga3fc446d84-goog
next reply other threads:[~2020-12-05 0:49 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-05 0:48 Will McVicker [this message]
2020-12-05 8:59 ` [PATCH v1] HID: make arrays usage and value to be the same Greg KH
2020-12-07 17:55 ` Will McVicker
2020-12-07 18:24 ` Greg KH
2020-12-07 19:05 ` Will McVicker
2020-12-14 19:15 ` Will McVicker
2020-12-17 10:19 ` Jiri Kosina
2020-12-17 18:42 ` Will McVicker
2021-01-14 18:19 ` Will McVicker
2021-01-18 8:11 ` Jiri Kosina
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