Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753324Ab3GXOPo (ORCPT ); Wed, 24 Jul 2013 10:15:44 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:45734 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751923Ab3GXOGt (ORCPT ); Wed, 24 Jul 2013 10:06:49 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "John W. Linville" , "Anderson Lizardo" , "Gustavo Padovan" Date: Wed, 24 Jul 2013 15:02:45 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [21/85] Bluetooth: Fix crash in l2cap_build_cmd() with small MTU In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.101 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4872 Lines: 94 3.2.49-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Anderson Lizardo commit 300b962e5244a1ea010df7e88595faa0085b461d upstream. If a too small MTU value is set with ioctl(HCISETACLMTU) or by a bogus controller, memory corruption happens due to a memcpy() call with negative length. Fix this crash on either incoming or outgoing connections with a MTU smaller than L2CAP_HDR_SIZE + L2CAP_CMD_HDR_SIZE: [ 46.885433] BUG: unable to handle kernel paging request at f56ad000 [ 46.888037] IP: [] memcpy+0x1d/0x40 [ 46.888037] *pdpt = 0000000000ac3001 *pde = 00000000373f8067 *pte = 80000000356ad060 [ 46.888037] Oops: 0002 [#1] SMP DEBUG_PAGEALLOC [ 46.888037] Modules linked in: hci_vhci bluetooth virtio_balloon i2c_piix4 uhci_hcd usbcore usb_common [ 46.888037] CPU: 0 PID: 1044 Comm: kworker/u3:0 Not tainted 3.10.0-rc1+ #12 [ 46.888037] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2007 [ 46.888037] Workqueue: hci0 hci_rx_work [bluetooth] [ 46.888037] task: f59b15b0 ti: f55c4000 task.ti: f55c4000 [ 46.888037] EIP: 0060:[] EFLAGS: 00010212 CPU: 0 [ 46.888037] EIP is at memcpy+0x1d/0x40 [ 46.888037] EAX: f56ac1c0 EBX: fffffff8 ECX: 3ffffc6e EDX: f55c5cf2 [ 46.888037] ESI: f55c6b32 EDI: f56ad000 EBP: f55c5c68 ESP: f55c5c5c [ 46.888037] DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 [ 46.888037] CR0: 8005003b CR2: f56ad000 CR3: 3557d000 CR4: 000006f0 [ 46.888037] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000 [ 46.888037] DR6: ffff0ff0 DR7: 00000400 [ 46.888037] Stack: [ 46.888037] fffffff8 00000010 00000003 f55c5cac f8c6a54c ffffffff f8c69eb2 00000000 [ 46.888037] f4783cdc f57f0070 f759c590 1001c580 00000003 0200000a 00000000 f5a88560 [ 46.888037] f5ba2600 f5a88560 00000041 00000000 f55c5d90 f8c6f4c7 00000008 f55c5cf2 [ 46.888037] Call Trace: [ 46.888037] [] l2cap_send_cmd+0x1cc/0x230 [bluetooth] [ 46.888037] [] ? l2cap_global_chan_by_psm+0x152/0x1a0 [bluetooth] [ 46.888037] [] l2cap_connect+0x3f7/0x540 [bluetooth] [ 46.888037] [] ? trace_hardirqs_off+0xb/0x10 [ 46.888037] [] ? mark_held_locks+0x68/0x110 [ 46.888037] [] ? mutex_lock_nested+0x280/0x360 [ 46.888037] [] ? __mutex_unlock_slowpath+0xa9/0x150 [ 46.888037] [] ? trace_hardirqs_on_caller+0xec/0x1b0 [ 46.888037] [] ? mutex_lock_nested+0x268/0x360 [ 46.888037] [] ? trace_hardirqs_on+0xb/0x10 [ 46.888037] [] l2cap_recv_frame+0xb2d/0x1d30 [bluetooth] [ 46.888037] [] ? mark_held_locks+0x68/0x110 [ 46.888037] [] ? __mutex_unlock_slowpath+0xa9/0x150 [ 46.888037] [] ? trace_hardirqs_on_caller+0xec/0x1b0 [ 46.888037] [] l2cap_recv_acldata+0x2a1/0x320 [bluetooth] [ 46.888037] [] hci_rx_work+0x518/0x810 [bluetooth] [ 46.888037] [] ? hci_rx_work+0x132/0x810 [bluetooth] [ 46.888037] [] process_one_work+0x1a9/0x600 [ 46.888037] [] ? process_one_work+0x12b/0x600 [ 46.888037] [] ? worker_thread+0x19e/0x320 [ 46.888037] [] ? worker_thread+0x19e/0x320 [ 46.888037] [] worker_thread+0xf7/0x320 [ 46.888037] [] ? rescuer_thread+0x290/0x290 [ 46.888037] [] kthread+0xa8/0xb0 [ 46.888037] [] ret_from_kernel_thread+0x1b/0x28 [ 46.888037] [] ? flush_kthread_worker+0x120/0x120 [ 46.888037] Code: c3 90 8d 74 26 00 e8 63 fc ff ff eb e8 90 55 89 e5 83 ec 0c 89 5d f4 89 75 f8 89 7d fc 3e 8d 74 26 00 89 cb 89 c7 c1 e9 02 89 d6 a5 89 d9 83 e1 03 74 02 f3 a4 8b 5d f4 8b 75 f8 8b 7d fc 89 [ 46.888037] EIP: [] memcpy+0x1d/0x40 SS:ESP 0068:f55c5c5c [ 46.888037] CR2: 00000000f56ad000 [ 46.888037] ---[ end trace 0217c1f4d78714a9 ]--- Signed-off-by: Anderson Lizardo Signed-off-by: Gustavo Padovan Signed-off-by: John W. Linville Signed-off-by: Ben Hutchings --- net/bluetooth/l2cap_core.c | 3 +++ 1 file changed, 3 insertions(+) --- a/net/bluetooth/l2cap_core.c +++ b/net/bluetooth/l2cap_core.c @@ -1737,6 +1737,9 @@ static struct sk_buff *l2cap_build_cmd(s BT_DBG("conn %p, code 0x%2.2x, ident 0x%2.2x, len %d", conn, code, ident, dlen); + if (conn->mtu < L2CAP_HDR_SIZE + L2CAP_CMD_HDR_SIZE) + return NULL; + len = L2CAP_HDR_SIZE + L2CAP_CMD_HDR_SIZE + dlen; count = min_t(unsigned int, conn->mtu, len); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/