linux-stable.git/net/ipv6, branch v5.14.7

ip6_gre: Revert "ip6_gre: add validation for csum_start"

2021-09-22T10:39:32+00:00

[ Upstream commit fe63339ef36bfb1cc12962015a9b254170eea057 ]

This reverts commit 9cf448c200ba9935baa94e7a0964598ce947db9d.

This commit was added for equivalence with a similar fix to ip_gre.
That fix proved to have a bug. Upon closer inspection, ip6_gre is not
susceptible to the original bug.

So revert the unnecessary extra check.

In short, ipgre_xmit calls skb_pull to remove ipv4 headers previously
inserted by dev_hard_header. ip6gre_tunnel_xmit does not.

Link: https://lore.kernel.org/netdev/CA+FuTSe+vJgTVLc9SojGuN-f9YQ+xWLPKE_S4f=f+w+_P2hgUg@mail.gmail.com/#t
Fixes: 9cf448c200ba ("ip6_gre: add validation for csum_start")
Signed-off-by: Willem de Bruijn 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

netfilter: socket: icmp6: fix use-after-scope

2021-09-22T10:39:31+00:00

[ Upstream commit 730affed24bffcd1eebd5903171960f5ff9f1f22 ]

Bug reported by KASAN:

BUG: KASAN: use-after-scope in inet6_ehashfn (net/ipv6/inet6_hashtables.c:40)
Call Trace:
(...)
inet6_ehashfn (net/ipv6/inet6_hashtables.c:40)
(...)
nf_sk_lookup_slow_v6 (net/ipv6/netfilter/nf_socket_ipv6.c:91
net/ipv6/netfilter/nf_socket_ipv6.c:146)

It seems that this bug has already been fixed by Eric Dumazet in the
past in:
commit 78296c97ca1f ("netfilter: xt_socket: fix a stack corruption bug")

But a variant of the same issue has been introduced in
commit d64d80a2cde9 ("netfilter: x_tables: don't extract flow keys on early demuxed sks in socket match")

`daddr` and `saddr` potentially hold a reference to ipv6_var that is no
longer in scope when the call to `nf_socket_get_sock_v6` is made.

Fixes: d64d80a2cde9 ("netfilter: x_tables: don't extract flow keys on early demuxed sks in socket match")
Acked-by: Matthieu Baerts 
Signed-off-by: Benjamin Hesmans 
Reviewed-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Sasha Levin

ipv6: make exception cache less predictible

2021-09-15T08:02:31+00:00

[ Upstream commit a00df2caffed3883c341d5685f830434312e4a43 ]

Even after commit 4785305c05b2 ("ipv6: use siphash in rt6_exception_hash()"),
an attacker can still use brute force to learn some secrets from a victim
linux host.

One way to defeat these attacks is to make the max depth of the hash
table bucket a random value.

Before this patch, each bucket of the hash table used to store exceptions
could contain 6 items under attack.

After the patch, each bucket would contains a random number of items,
between 6 and 10. The attacker can no longer infer secrets.

This is slightly increasing memory size used by the hash table,
we do not expect this to be a problem.

Following patch is dealing with the same issue in IPv4.

Fixes: 35732d01fe31 ("ipv6: introduce a hash table to store dst cache")
Signed-off-by: Eric Dumazet 
Reported-by: Keyu Man 
Cc: Wei Wang 
Cc: Martin KaFai Lau 
Reviewed-by: David Ahern 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

ipv6: use siphash in rt6_exception_hash()

2021-08-26T09:20:34+00:00

A group of security researchers brought to our attention
the weakness of hash function used in rt6_exception_hash()

Lets use siphash instead of Jenkins Hash, to considerably
reduce security risks.

Following patch deals with IPv4.

Fixes: 35732d01fe31 ("ipv6: introduce a hash table to store dst cache")
Signed-off-by: Eric Dumazet 
Reported-by: Keyu Man 
Cc: Wei Wang 
Cc: Martin KaFai Lau 
Acked-by: Wei Wang 
Signed-off-by: David S. Miller

ipv6: correct comments about fib6_node sernum

2021-08-24T08:59:01+00:00

correct comments in set and get fn_sernum

Signed-off-by: zhang kai 
Reviewed-by: David Ahern 
Signed-off-by: David S. Miller

ip6_gre: add validation for csum_start

2021-08-22T20:24:41+00:00

Validate csum_start in gre_handle_offloads before we call _gre_xmit so
that we do not crash later when the csum_start value is used in the
lco_csum function call.

This patch deals with ipv6 code.

Fixes: Fixes: b05229f44228 ("gre6: Cleanup GREv6 transmit path, call common
GRE functions")
Reported-by: syzbot+ff8e1b9f2f36481e2efc@syzkaller.appspotmail.com
Signed-off-by: Shreyansh Chouhan 
Reviewed-by: Willem de Bruijn 
Signed-off-by: David S. Miller

ipv6: decrease hop limit counter in ip6_forward()

2021-07-23T15:40:41+00:00

Decrease hop limit counter when deliver skb to ndp proxy.

Signed-off-by: Kangmin Park 
Signed-off-by: David S. Miller

udp: check encap socket in __udp_lib_err

2021-07-21T15:49:31+00:00

Commit d26796ae5894 ("udp: check udp sock encap_type in __udp_lib_err")
added checks for encapsulated sockets but it broke cases when there is
no implementation of encap_err_lookup for encapsulation, i.e. ESP in
UDP encapsulation. Fix it by calling encap_err_lookup only if socket
implements this method otherwise treat it as legal socket.

Fixes: d26796ae5894 ("udp: check udp sock encap_type in __udp_lib_err")
Signed-off-by: Vadim Fedorenko 
Reviewed-by: Xin Long 
Signed-off-by: David S. Miller

ipv6: fix another slab-out-of-bounds in fib6_nh_flush_exceptions

2021-07-20T14:25:25+00:00

While running the self-tests on a KASAN enabled kernel, I observed a
slab-out-of-bounds splat very similar to the one reported in
commit 821bbf79fe46 ("ipv6: Fix KASAN: slab-out-of-bounds Read in
 fib6_nh_flush_exceptions").

We additionally need to take care of fib6_metrics initialization
failure when the caller provides an nh.

The fix is similar, explicitly free the route instead of calling
fib6_info_release on a half-initialized object.

Fixes: f88d8ea67fbdb ("ipv6: Plumb support for nexthop object in a fib6_info")
Signed-off-by: Paolo Abeni 
Signed-off-by: David S. Miller

ipv6: ip6_finish_output2: set sk into newly allocated nskb

2021-07-20T09:52:36+00:00

skb_set_owner_w() should set sk not to old skb but to new nskb.

Fixes: 5796015fa968 ("ipv6: allocate enough headroom in ip6_finish_output2()")
Signed-off-by: Vasily Averin 
Link: https://lore.kernel.org/r/70c0744f-89ae-1869-7e3e-4fa292158f4b@virtuozzo.com
Signed-off-by: Jakub Kicinski