From: "F.A.Sulaiman" asha.16@itfac.mrt.ac.lk

stable inclusion from stable-v4.19.209 commit bb8b72374db69afa25a5b65cf1c092860c6fe914 bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9R4OM CVE: CVE-2021-47404

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...

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commit 1e4ce418b1cb1a810256b5fb3fd33d22d1325993 upstream.

Syzbot reported slab-out-of-bounds Write bug in hid-betopff driver. The problem is the driver assumes the device must have an input report but some malicious devices violate this assumption.

So this patch checks hid_device's input is non empty before it's been used.

Reported-by: syzbot+07efed3bc5a1407bd742@syzkaller.appspotmail.com Signed-off-by: F.A. SULAIMAN asha.16@itfac.mrt.ac.lk Reviewed-by: Pavel Skripkin paskripkin@gmail.com Signed-off-by: Jiri Kosina jkosina@suse.cz Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Li Huafei lihuafei1@huawei.com --- drivers/hid/hid-betopff.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/hid/hid-betopff.c b/drivers/hid/hid-betopff.c index 69cfc8dc6af1e..9b60efe6ec441 100644 --- a/drivers/hid/hid-betopff.c +++ b/drivers/hid/hid-betopff.c @@ -59,15 +59,22 @@ static int betopff_init(struct hid_device *hid) { struct betopff_device *betopff; struct hid_report *report; - struct hid_input *hidinput = - list_first_entry(&hid->inputs, struct hid_input, list); + struct hid_input *hidinput; struct list_head *report_list = &hid->report_enum[HID_OUTPUT_REPORT].report_list; - struct input_dev *dev = hidinput->input; + struct input_dev *dev; int field_count = 0; int error; int i, j;

+ if (list_empty(&hid->inputs)) { + hid_err(hid, "no inputs found\n"); + return -ENODEV; + } + + hidinput = list_first_entry(&hid->inputs, struct hid_input, list); + dev = hidinput->input; + if (list_empty(report_list)) { hid_err(hid, "no output reports found\n"); return -ENODEV;