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[112.120.42.27]) by smtp.gmail.com with ESMTPSA id y3sm1699661pfb.18.2020.09.09.00.17.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 09 Sep 2020 00:17:57 -0700 (PDT) From: Peilin Ye To: Marcel Holtmann , Johan Hedberg Cc: Peilin Ye , "David S. Miller" , Jakub Kicinski , Greg Kroah-Hartman , linux-bluetooth@vger.kernel.org, netdev@vger.kernel.org, linux-kernel-mentees@lists.linuxfoundation.org, linux-kernel@vger.kernel.org Subject: [Linux-kernel-mentees] [PATCH net v2] Bluetooth: Fix slab-out-of-bounds read in hci_le_direct_adv_report_evt() Date: Wed, 9 Sep 2020 03:17:00 -0400 Message-Id: <20200909071700.1100748-1-yepeilin.cs@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200805180902.684024-1-yepeilin.cs@gmail.com> References: <20200805180902.684024-1-yepeilin.cs@gmail.com> MIME-Version: 1.0 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org `num_reports` is not being properly checked. A malformed event packet with a large `num_reports` number makes hci_le_direct_adv_report_evt() read out of bounds. Fix it. Cc: stable@vger.kernel.org Fixes: 2f010b55884e ("Bluetooth: Add support for handling LE Direct Advertising Report events") Reported-and-tested-by: syzbot+24ebd650e20bd263ca01@syzkaller.appspotmail.com Link: https://syzkaller.appspot.com/bug?extid=24ebd650e20bd263ca01 Signed-off-by: Peilin Ye --- Change in v2: - add "Cc: stable@" tag. net/bluetooth/hci_event.c | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-) diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c index 4b7fc430793c..aec43ae488d1 100644 --- a/net/bluetooth/hci_event.c +++ b/net/bluetooth/hci_event.c @@ -5863,21 +5863,19 @@ static void hci_le_direct_adv_report_evt(struct hci_dev *hdev, struct sk_buff *skb) { u8 num_reports = skb->data[0]; - void *ptr = &skb->data[1]; + struct hci_ev_le_direct_adv_info *ev = (void *)&skb->data[1]; - hci_dev_lock(hdev); + if (!num_reports || skb->len < num_reports * sizeof(*ev) + 1) + return; - while (num_reports--) { - struct hci_ev_le_direct_adv_info *ev = ptr; + hci_dev_lock(hdev); + for (; num_reports; num_reports--, ev++) process_adv_report(hdev, ev->evt_type, &ev->bdaddr, ev->bdaddr_type, &ev->direct_addr, ev->direct_addr_type, ev->rssi, NULL, 0, false); - ptr += sizeof(*ev); - } - hci_dev_unlock(hdev); }