From: Will McVicker willmcvicker@google.com

stable inclusion from linux-4.19.178 commit ffca531f71d078c6caf752d64bc2a592f420f7c6 CVE: CVE-2021-0512

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commit ed9be64eefe26d7d8b0b5b9fa3ffdf425d87a01f upstream.

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.

Cc: stable@vger.kernel.org Signed-off-by: Will McVicker willmcvicker@google.com Signed-off-by: Jiri Kosina jkosina@suse.cz Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com Reviewed-by: Xiu Jianfeng xiujianfeng@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.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 3178580db7fa9..4f6d676c4224c 100644 --- a/drivers/hid/hid-core.c +++ b/drivers/hid/hid-core.c @@ -93,7 +93,7 @@ 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;

@@ -104,7 +104,7 @@ 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;

@@ -294,7 +294,7 @@ 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;