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* net: bridge: mcast: fix broken length + header check for MRDv6 Adv.Linus Lüssing2021-04-271-5/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The IPv6 Multicast Router Advertisements parsing has the following two issues: For one thing, ICMPv6 MRD Advertisements are smaller than ICMPv6 MLD messages (ICMPv6 MRD Adv.: 8 bytes vs. ICMPv6 MLDv1/2: >= 24 bytes, assuming MLDv2 Reports with at least one multicast address entry). When ipv6_mc_check_mld_msg() tries to parse an Multicast Router Advertisement its MLD length check will fail - and it will wrongly return -EINVAL, even if we have a valid MRD Advertisement. With the returned -EINVAL the bridge code will assume a broken packet and will wrongly discard it, potentially leading to multicast packet loss towards multicast routers. The second issue is the MRD header parsing in br_ip6_multicast_mrd_rcv(): It wrongly checks for an ICMPv6 header immediately after the IPv6 header (IPv6 next header type). However according to RFC4286, section 2 all MRD messages contain a Router Alert option (just like MLD). So instead there is an IPv6 Hop-by-Hop option for the Router Alert between the IPv6 and ICMPv6 header, again leading to the bridge wrongly discarding Multicast Router Advertisements. To fix these two issues, introduce a new return value -ENODATA to ipv6_mc_check_mld() to indicate a valid ICMPv6 packet with a hop-by-hop option which is not an MLD but potentially an MRD packet. This also simplifies further parsing in the bridge code, as ipv6_mc_check_mld() already fully checks the ICMPv6 header and hop-by-hop option. These issues were found and fixed with the help of the mrdisc tool (https://github.com/troglobit/mrdisc). Fixes: 4b3087c7e37f ("bridge: Snoop Multicast Router Advertisements") Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue> Signed-off-by: David S. Miller <davem@davemloft.net>
* treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 343Thomas Gleixner2019-06-051-13/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of version 2 of the gnu general public license as published by the free software foundation this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not see http www gnu org licenses extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 1 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Armijn Hemel <armijn@tjaldur.nl> Reviewed-by: Alexios Zavras <alexios.zavras@intel.com> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190530000437.338011816@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* net: remove unneeded switch fall-throughLi RongQing2019-02-211-1/+0
| | | | | | | | This case block has been terminated by a return, so not need a switch fall-through Signed-off-by: Li RongQing <lirongqing@baidu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* bridge: Snoop Multicast Router AdvertisementsLinus Lüssing2019-01-221-1/+4
| | | | | | | | | | | | | | | | | | | When multiple multicast routers are present in a broadcast domain then only one of them will be detectable via IGMP/MLD query snooping. The multicast router with the lowest IP address will become the selected and active querier while all other multicast routers will then refrain from sending queries. To detect such rather silent multicast routers, too, RFC4286 ("Multicast Router Discovery") provides a standardized protocol to detect multicast routers for multicast snooping switches. This patch implements the necessary MRD Advertisement message parsing and after successful processing adds such routers to the internal multicast router list. Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue> Signed-off-by: David S. Miller <davem@davemloft.net>
* bridge: simplify ip_mc_check_igmp() and ipv6_mc_check_mld() internalsLinus Lüssing2019-01-221-32/+30
| | | | | | | | | | | | | With this patch the internal use of the skb_trimmed is reduced to the ICMPv6/IGMP checksum verification. And for the length checks the newly introduced helper functions are used instead of calculating and checking with skb->len directly. These changes should hopefully make it easier to verify that length checks are performed properly. Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue> Signed-off-by: David S. Miller <davem@davemloft.net>
* bridge: simplify ip_mc_check_igmp() and ipv6_mc_check_mld() callsLinus Lüssing2019-01-221-20/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | This patch refactors ip_mc_check_igmp(), ipv6_mc_check_mld() and their callers (more precisely, the Linux bridge) to not rely on the skb_trimmed parameter anymore. An skb with its tail trimmed to the IP packet length was initially introduced for the following three reasons: 1) To be able to verify the ICMPv6 checksum. 2) To be able to distinguish the version of an IGMP or MLD query. They are distinguishable only by their size. 3) To avoid parsing data for an IGMPv3 or MLDv2 report that is beyond the IP packet but still within the skb. The first case still uses a cloned and potentially trimmed skb to verfiy. However, there is no need to propagate it to the caller. For the second and third case explicit IP packet length checks were added. This hopefully makes ip_mc_check_igmp() and ipv6_mc_check_mld() easier to read and verfiy, as well as easier to use. Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: fix wrong skb_get() usage / crash in IGMP/MLD parsing codeLinus Lüssing2015-08-131-15/+18
| | | | | | | | | | | | | | | | | | | | | | | The recent refactoring of the IGMP and MLD parsing code into ipv6_mc_check_mld() / ip_mc_check_igmp() introduced a potential crash / BUG() invocation for bridges: I wrongly assumed that skb_get() could be used as a simple reference counter for an skb which is not the case. skb_get() bears additional semantics, a user count. This leads to a BUG() invocation in pskb_expand_head() / kernel panic if pskb_may_pull() is called on an skb with a user count greater than one - unfortunately the refactoring did just that. Fixing this by removing the skb_get() call and changing the API: The caller of ipv6_mc_check_mld() / ip_mc_check_igmp() now needs to additionally check whether the returned skb_trimmed is a clone. Fixes: 9afd85c9e455 ("net: Export IGMP/MLD message validation code") Reported-by: Brenden Blanco <bblanco@plumgrid.com> Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: fix two sparse warnings introduced by IGMP/MLD parsing exportsLinus Lüssing2015-05-041-1/+1
| | | | | | | | | | | | > net/core/skbuff.c:4108:13: sparse: incorrect type in assignment (different base types) > net/ipv6/mcast_snoop.c:63 ipv6_mc_check_exthdrs() warn: unsigned 'offset' is never less than zero. Introduced by 9afd85c9e4552b276e2f4cfefd622bdeeffbbf26 ("net: Export IGMP/MLD message validation code") Reported-by: kbuild test robot <fengguang.wu@intel.com> Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: Export IGMP/MLD message validation codeLinus Lüssing2015-05-041-0/+213
With this patch, the IGMP and MLD message validation functions are moved from the bridge code to IPv4/IPv6 multicast files. Some small refactoring was done to enhance readibility and to iron out some differences in behaviour between the IGMP and MLD parsing code (e.g. the skb-cloning of MLD messages is now only done if necessary, just like the IGMP part always did). Finally, these IGMP and MLD message validation functions are exported so that not only the bridge can use it but batman-adv later, too. Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue> Signed-off-by: David S. Miller <davem@davemloft.net>