Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755212AbcKNCJC (ORCPT ); Sun, 13 Nov 2016 21:09:02 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:46260 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754704AbcKNCGY (ORCPT ); Sun, 13 Nov 2016 21:06:24 -0500 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, "Eyal Itkin" , "Stefan Richter" Date: Mon, 14 Nov 2016 00:14:07 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 144/152] firewire: net: guard against rx buffer overflows In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:6f00:88c8:c921:d332 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: 3680 Lines: 120 3.2.84-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Stefan Richter commit 667121ace9dbafb368618dbabcf07901c962ddac upstream. The IP-over-1394 driver firewire-net lacked input validation when handling incoming fragmented datagrams. A maliciously formed fragment with a respectively large datagram_offset would cause a memcpy past the datagram buffer. So, drop any packets carrying a fragment with offset + length larger than datagram_size. In addition, ensure that - GASP header, unfragmented encapsulation header, or fragment encapsulation header actually exists before we access it, - the encapsulated datagram or fragment is of nonzero size. Reported-by: Eyal Itkin Reviewed-by: Eyal Itkin Fixes: CVE 2016-8633 Signed-off-by: Stefan Richter [bwh: Backported to 3.2: fwnet_receive_broadcast() never matches IPv6 packets] Signed-off-by: Ben Hutchings --- --- a/drivers/firewire/net.c +++ b/drivers/firewire/net.c @@ -677,6 +677,9 @@ static int fwnet_incoming_packet(struct int retval; u16 ether_type; + if (len <= RFC2374_UNFRAG_HDR_SIZE) + return 0; + hdr.w0 = be32_to_cpu(buf[0]); lf = fwnet_get_hdr_lf(&hdr); if (lf == RFC2374_HDR_UNFRAG) { @@ -702,7 +705,12 @@ static int fwnet_incoming_packet(struct return fwnet_finish_incoming_packet(net, skb, source_node_id, is_broadcast, ether_type); } + /* A datagram fragment has been received, now the fun begins. */ + + if (len <= RFC2374_FRAG_HDR_SIZE) + return 0; + hdr.w1 = ntohl(buf[1]); buf += 2; len -= RFC2374_FRAG_HDR_SIZE; @@ -716,6 +724,9 @@ static int fwnet_incoming_packet(struct datagram_label = fwnet_get_hdr_dgl(&hdr); dg_size = fwnet_get_hdr_dg_size(&hdr); /* ??? + 1 */ + if (fg_off + len > dg_size) + return 0; + spin_lock_irqsave(&dev->lock, flags); peer = fwnet_peer_find_by_node_id(dev, source_node_id, generation); @@ -822,6 +833,22 @@ static void fwnet_receive_packet(struct fw_send_response(card, r, rcode); } +static int gasp_source_id(__be32 *p) +{ + return be32_to_cpu(p[0]) >> 16; +} + +static u32 gasp_specifier_id(__be32 *p) +{ + return (be32_to_cpu(p[0]) & 0xffff) << 8 | + (be32_to_cpu(p[1]) & 0xff000000) >> 24; +} + +static u32 gasp_version(__be32 *p) +{ + return be32_to_cpu(p[1]) & 0xffffff; +} + static void fwnet_receive_broadcast(struct fw_iso_context *context, u32 cycle, size_t header_length, void *header, void *data) { @@ -832,9 +859,6 @@ static void fwnet_receive_broadcast(stru __be32 *buf_ptr; int retval; u32 length; - u16 source_node_id; - u32 specifier_id; - u32 ver; unsigned long offset; unsigned long flags; @@ -852,17 +876,13 @@ static void fwnet_receive_broadcast(stru spin_unlock_irqrestore(&dev->lock, flags); - specifier_id = (be32_to_cpu(buf_ptr[0]) & 0xffff) << 8 - | (be32_to_cpu(buf_ptr[1]) & 0xff000000) >> 24; - ver = be32_to_cpu(buf_ptr[1]) & 0xffffff; - source_node_id = be32_to_cpu(buf_ptr[0]) >> 16; - - if (specifier_id == IANA_SPECIFIER_ID && ver == RFC2734_SW_VERSION) { - buf_ptr += 2; - length -= IEEE1394_GASP_HDR_SIZE; - fwnet_incoming_packet(dev, buf_ptr, length, source_node_id, + if (length > IEEE1394_GASP_HDR_SIZE && + gasp_specifier_id(buf_ptr) == IANA_SPECIFIER_ID && + gasp_version(buf_ptr) == RFC2734_SW_VERSION) + fwnet_incoming_packet(dev, buf_ptr + 2, + length - IEEE1394_GASP_HDR_SIZE, + gasp_source_id(buf_ptr), context->card->generation, true); - } packet.payload_length = dev->rcv_buffer_size; packet.interrupt = 1;