media: pvrusb2: fix array-index-out-of-bounds in pvr2_i2c_core_init

stable inclusion
from stable-v5.10.121
commit a3304766d9384886e6d3092c776273526947a2e9
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5L6CQ

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=a3304766d9384886e6d3092c776273526947a2e9

--------------------------------

[ Upstream commit 471bec68 ]

Syzbot reported that -1 is used as array index. The problem was in
missing validation check.

hdw->unit_number is initialized with -1 and then if init table walk fails
this value remains unchanged. Since code blindly uses this member for
array indexing adding sanity check is the easiest fix for that.

hdw->workpoll initialization moved upper to prevent warning in
__flush_work.

Reported-and-tested-by: syzbot+1a247e36149ffd709a9b@syzkaller.appspotmail.com

Fixes: d855497e ("V4L/DVB (4228a): pvrusb2 to kernel 2.6.18")
Signed-off-by: NPavel Skripkin <paskripkin@gmail.com>
Signed-off-by: NHans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: NMauro Carvalho Chehab <mchehab@kernel.org>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>
Acked-by: NXie XiuQi <xiexiuqi@huawei.com>

drivers/media/usb/pvrusb2/pvrusb2-hdw.c

@@ -2569,6 +2569,11 @@ struct pvr2_hdw *pvr2_hdw_create(struct usb_interface *intf,
 	} while (0);
 	mutex_unlock(&pvr2_unit_mtx);
 
+	INIT_WORK(&hdw->workpoll, pvr2_hdw_worker_poll);
+
+	if (hdw->unit_number == -1)
+		goto fail;
+
 	cnt1 = 0;
 	cnt2 = scnprintf(hdw->name+cnt1,sizeof(hdw->name)-cnt1,"pvrusb2");
 	cnt1 += cnt2;
@@ -2580,8 +2585,6 @@ struct pvr2_hdw *pvr2_hdw_create(struct usb_interface *intf,
 	if (cnt1 >= sizeof(hdw->name)) cnt1 = sizeof(hdw->name)-1;
 	hdw->name[cnt1] = 0;
 
-	INIT_WORK(&hdw->workpoll,pvr2_hdw_worker_poll);
-
 	pvr2_trace(PVR2_TRACE_INIT,"Driver unit number is %d, name is %s",
 		   hdw->unit_number,hdw->name);