Bluetooth: add timeout sanity check to hci_inquiry

Syzbot hit "task hung" bug in hci_req_sync(). The problem was in
unreasonable huge inquiry timeout passed from userspace.
Fix it by adding sanity check for timeout value to hci_inquiry().

Since hci_inquiry() is the only user of hci_req_sync() with user
controlled timeout value, it makes sense to check timeout value in
hci_inquiry() and don't touch hci_req_sync().

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-and-tested-by: syzbot+be2baed593ea56c6a84c@syzkaller.appspotmail.com
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index 8622da2d9395995286941e097d0332f54cfcc32b..f033c19e2f3bc301e0b8df59bdc3b710eb62bc76 100644 (file)
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -1343,6 +1343,12 @@ int hci_inquiry(void __user *arg)
                goto done;
        }
 
+       /* Restrict maximum inquiry length to 60 seconds */
+       if (ir.length > 60) {
+               err = -EINVAL;
+               goto done;
+       }
+
        hci_dev_lock(hdev);
        if (inquiry_cache_age(hdev) > INQUIRY_CACHE_AGE_MAX ||
            inquiry_cache_empty(hdev) || ir.flags & IREQ_CACHE_FLUSH) {