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[76.119.149.155]) by smtp.gmail.com with ESMTPSA id o18sm7360586qkk.91.2020.07.10.09.11.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 10 Jul 2020 09:11:04 -0700 (PDT) From: Peilin Ye To: Marcel Holtmann , Johan Hedberg Cc: Peilin Ye , "David S . Miller" , Jakub Kicinski , Russell King , Greg Kroah-Hartman , 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 v3] net/bluetooth: Fix slab-out-of-bounds read in hci_extended_inquiry_result_evt() Date: Fri, 10 Jul 2020 12:09:15 -0400 Message-Id: <20200710160915.228980-1-yepeilin.cs@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200709130224.214204-1-yepeilin.cs@gmail.com> References: <20200709130224.214204-1-yepeilin.cs@gmail.com> 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. This patch fixes the following syzbot bug: https://syzkaller.appspot.com/bug?id=4bf11aa05c4ca51ce0df86e500fce486552dc8d2 Reported-by: syzbot+d8489a79b781849b9c46@syzkaller.appspotmail.com Cc: stable@vger.kernel.org Signed-off-by: Peilin Ye --- Change in v3: - Minimum `skb->len` requirement was 1 byte inaccurate since `info` starts from `skb->data + 1`. Fix it. Changes in v2: - Use `skb->len` instead of `skb->truesize` as the length limit. - Leave `num_rsp` as of type `int`. net/bluetooth/hci_event.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c index 03a0759f2fc2..13d8802b8137 100644 --- a/net/bluetooth/hci_event.c +++ b/net/bluetooth/hci_event.c @@ -4375,7 +4375,7 @@ static void hci_extended_inquiry_result_evt(struct hci_dev *hdev, BT_DBG("%s num_rsp %d", hdev->name, num_rsp); - if (!num_rsp) + if (!num_rsp || skb->len < num_rsp * sizeof(*info) + 1) return; if (hci_dev_test_flag(hdev, HCI_PERIODIC_INQ)) -- 2.25.1