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Linus Lüssing e2c34cacff net: bridge: mcast: fix broken length + header check for MRDv6 Adv.
[ Upstream commit 99014088156cd78867d19514a0bc771c4b86b93b ]

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: 4b3087c7e3 ("bridge: Snoop Multicast Router Advertisements")
Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-05-14 09:50:44 +02:00
arch KVM: VMX: Intercept FS/GS_BASE MSR accesses for 32-bit KVM 2021-05-14 09:50:43 +02:00
block block: return -EBUSY when there are open partitions in blkdev_reread_part 2021-04-28 13:39:59 +02:00
certs certs: Fix blacklist flag type confusion 2021-03-04 11:37:59 +01:00
crypto async_xor: increase src_offs when dropping destination page 2021-05-14 09:49:59 +02:00
Documentation media: docs: Fix data organization of MEDIA_BUS_FMT_RGB101010_1X30 2021-05-14 09:50:23 +02:00
drivers RDMA/bnxt_re: Fix a double free in bnxt_qplib_alloc_res 2021-05-14 09:50:44 +02:00
fs ovl: invalidate readdir cache on changes to dir with origin 2021-05-14 09:50:35 +02:00
include net: bridge: mcast: fix broken length + header check for MRDv6 Adv. 2021-05-14 09:50:44 +02:00
init seccomp: Fix CONFIG tests for Seccomp_filters 2021-05-14 09:50:24 +02:00
ipc ipc: adjust proc_ipc_sem_dointvec definition to match prototype 2020-09-05 12:14:29 -07:00
kernel bpf: Fix propagation of 32 bit unsigned bounds from 64 bit bounds 2021-05-14 09:50:44 +02:00
lib bug: Remove redundant condition check in report_bug 2021-05-14 09:50:32 +02:00
LICENSES LICENSES/deprecated: add Zlib license text 2020-09-16 14:33:49 +02:00
mm mm: ptdump: fix build failure 2021-04-21 13:00:57 +02:00
net net: bridge: mcast: fix broken length + header check for MRDv6 Adv. 2021-05-14 09:50:44 +02:00
samples samples, bpf: Add missing munmap in xdpsock 2021-03-17 17:06:12 +01:00
scripts kasan: fix hwasan build for gcc 2021-04-28 13:40:02 +02:00
security ima: Fix the error code for restoring the PCR value 2021-05-14 09:50:30 +02:00
sound ALSA: usb: midi: don't return -ENOMEM when usb_urb_ep_type_check fails 2021-05-14 09:50:40 +02:00
tools bpf: Fix propagation of 32 bit unsigned bounds from 64 bit bounds 2021-05-14 09:50:44 +02:00
usr Merge branch 'work.fdpic' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-08-07 13:29:39 -07:00
virt KVM: Stop looking for coalesced MMIO zones if the bus is destroyed 2021-05-14 09:50:04 +02:00
.clang-format RDMA 5.10 pull request 2020-10-17 11:18:18 -07:00
.cocciconfig
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.gitignore .gitignore: docs: ignore sphinx_*/ directories 2020-09-10 10:44:31 -06:00
.mailmap mailmap: add two more addresses of Uwe Kleine-König 2020-12-06 10:19:07 -08:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Jason Cooper to CREDITS 2020-11-30 10:20:34 +01:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS MAINTAINERS: move the staging subsystem to lists.linux.dev 2021-03-25 09:04:18 +01:00
Makefile Linux 5.10.36 2021-05-11 14:47:41 +02:00
README

Linux kernel
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