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[76.119.149.155]) by smtp.gmail.com with ESMTPSA id p7sm2502952qki.61.2020.07.08.22.19.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 08 Jul 2020 22:19:58 -0700 (PDT) From: Peilin Ye To: Marcel Holtmann , Johan Hedberg Cc: Peilin Ye , "David S . Miller" , Jakub Kicinski , Russell King , linux-bluetooth@vger.kernel.org, netdev@vger.kernel.org, syzkaller-bugs@googlegroups.com, linux-kernel-mentees@lists.linuxfoundation.org, linux-kernel@vger.kernel.org Subject: [Linux-kernel-mentees] [PATCH] net/bluetooth: Fix slab-out-of-bounds read in hci_extended_inquiry_result_evt() Date: Thu, 9 Jul 2020 01:18:02 -0400 Message-Id: <20200709051802.185168-1-yepeilin.cs@gmail.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-bluetooth-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-bluetooth@vger.kernel.org Check upon `num_rsp` is insufficient. A malformed event packet with a large `num_rsp` number makes hci_extended_inquiry_result_evt() go out of bounds. Fix it. Also, make `num_rsp` unsigned. This patch fixes the following syzbot bug: https://syzkaller.appspot.com/bug?id=4bf11aa05c4ca51ce0df86e500fce486552dc8d2 Reported-by: syzbot+d8489a79b781849b9c46@syzkaller.appspotmail.com Signed-off-by: Peilin Ye --- net/bluetooth/hci_event.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c index 03a0759f2fc2..29aff5e7dec2 100644 --- a/net/bluetooth/hci_event.c +++ b/net/bluetooth/hci_event.c @@ -4369,13 +4369,13 @@ static void hci_extended_inquiry_result_evt(struct hci_dev *hdev, struct sk_buff *skb) { struct inquiry_data data; - struct extended_inquiry_info *info = (void *) (skb->data + 1); - int num_rsp = *((__u8 *) skb->data); + struct extended_inquiry_info *info = (void *)(skb->data + 1); + __u8 num_rsp = *((__u8 *)skb->data); size_t eir_len; BT_DBG("%s num_rsp %d", hdev->name, num_rsp); - if (!num_rsp) + if (!num_rsp || num_rsp * sizeof(*info) > skb->truesize) return; if (hci_dev_test_flag(hdev, HCI_PERIODIC_INQ)) -- 2.25.1