Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754571AbcKYJCb (ORCPT ); Fri, 25 Nov 2016 04:02:31 -0500 Received: from mx2.suse.de ([195.135.220.15]:45342 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752461AbcKYIbH (ORCPT ); Fri, 25 Nov 2016 03:31:07 -0500 X-Amavis-Alert: BAD HEADER SECTION, Duplicate header field: "References" From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Stefan Richter , Jiri Slaby Subject: [PATCH 3.12 033/127] firewire: net: fix fragmented datagram_size off-by-one Date: Fri, 25 Nov 2016 09:29:06 +0100 Message-Id: <9b2e380324a14d10fe73a1dbbcc5f73fd89f12a5.1480062521.git.jslaby@suse.cz> X-Mailer: git-send-email 2.10.2 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3442 Lines: 88 From: Stefan Richter 3.12-stable review patch. If anyone has any objections, please let me know. =============== commit e9300a4b7bbae83af1f7703938c94cf6dc6d308f upstream. RFC 2734 defines the datagram_size field in fragment encapsulation headers thus: datagram_size: The encoded size of the entire IP datagram. The value of datagram_size [...] SHALL be one less than the value of Total Length in the datagram's IP header (see STD 5, RFC 791). Accordingly, the eth1394 driver of Linux 2.6.36 and older set and got this field with a -/+1 offset: ether1394_tx() /* transmit */ ether1394_encapsulate_prep() hdr->ff.dg_size = dg_size - 1; ether1394_data_handler() /* receive */ if (hdr->common.lf == ETH1394_HDR_LF_FF) dg_size = hdr->ff.dg_size + 1; else dg_size = hdr->sf.dg_size + 1; Likewise, I observe OS X 10.4 and Windows XP Pro SP3 to transmit 1500 byte sized datagrams in fragments with datagram_size=1499 if link fragmentation is required. Only firewire-net sets and gets datagram_size without this offset. The result is lacking interoperability of firewire-net with OS X, Windows XP, and presumably Linux' eth1394. (I did not test with the latter.) For example, FTP data transfers to a Linux firewire-net box with max_rec smaller than the 1500 bytes MTU - from OS X fail entirely, - from Win XP start out with a bunch of fragmented datagrams which time out, then continue with unfragmented datagrams because Win XP temporarily reduces the MTU to 576 bytes. So let's fix firewire-net's datagram_size accessors. Note that firewire-net thereby loses interoperability with unpatched firewire-net, but only if link fragmentation is employed. (This happens with large broadcast datagrams, and with large datagrams on several FireWire CardBus cards with smaller max_rec than equivalent PCI cards, and it can be worked around by setting a small enough MTU.) Signed-off-by: Stefan Richter Signed-off-by: Jiri Slaby --- drivers/firewire/net.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/firewire/net.c b/drivers/firewire/net.c index 641eeab43c57..2a260443061d 100644 --- a/drivers/firewire/net.c +++ b/drivers/firewire/net.c @@ -73,13 +73,13 @@ struct rfc2734_header { #define fwnet_get_hdr_lf(h) (((h)->w0 & 0xc0000000) >> 30) #define fwnet_get_hdr_ether_type(h) (((h)->w0 & 0x0000ffff)) -#define fwnet_get_hdr_dg_size(h) (((h)->w0 & 0x0fff0000) >> 16) +#define fwnet_get_hdr_dg_size(h) ((((h)->w0 & 0x0fff0000) >> 16) + 1) #define fwnet_get_hdr_fg_off(h) (((h)->w0 & 0x00000fff)) #define fwnet_get_hdr_dgl(h) (((h)->w1 & 0xffff0000) >> 16) -#define fwnet_set_hdr_lf(lf) ((lf) << 30) +#define fwnet_set_hdr_lf(lf) ((lf) << 30) #define fwnet_set_hdr_ether_type(et) (et) -#define fwnet_set_hdr_dg_size(dgs) ((dgs) << 16) +#define fwnet_set_hdr_dg_size(dgs) (((dgs) - 1) << 16) #define fwnet_set_hdr_fg_off(fgo) (fgo) #define fwnet_set_hdr_dgl(dgl) ((dgl) << 16) @@ -635,7 +635,7 @@ static int fwnet_incoming_packet(struct fwnet_device *dev, __be32 *buf, int len, fg_off = fwnet_get_hdr_fg_off(&hdr); } datagram_label = fwnet_get_hdr_dgl(&hdr); - dg_size = fwnet_get_hdr_dg_size(&hdr); /* ??? + 1 */ + dg_size = fwnet_get_hdr_dg_size(&hdr); if (fg_off + len > dg_size) return 0; -- 2.10.2