From: Pavel Skripkin <paskripkin@gmail.com>
Date: Thu, 19 Aug 2021 15:15:21 +0000 (+0300)
Subject: Bluetooth: add timeout sanity check to hci_inquiry
X-Git-Tag: v5.10.65~62
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=50e6f34499a548a9ebe43a36d2c85915e95cc3d8;p=thirdparty%2Fkernel%2Fstable.git

Bluetooth: add timeout sanity check to hci_inquiry

[ Upstream commit f41a4b2b5eb7872109723dab8ae1603bdd9d9ec1 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index 2f1868e426ab2..a9097fb7eb825 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -1336,6 +1336,12 @@ 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) {