linux-stable.git/net/ipv4/fib_semantics.c, branch linux-4.18.y

net: ipv4: update fnhe_pmtu when first hop's MTU changes

2018-10-18T07:18:06+00:00

[ Upstream commit af7d6cce53694a88d6a1bb60c9a239a6a5144459 ]

Since commit 5aad1de5ea2c ("ipv4: use separate genid for next hop
exceptions"), exceptions get deprecated separately from cached
routes. In particular, administrative changes don't clear PMTU anymore.

As Stefano described in commit e9fa1495d738 ("ipv6: Reflect MTU changes
on PMTU of exceptions for MTU-less routes"), the PMTU discovered before
the local MTU change can become stale:
 - if the local MTU is now lower than the PMTU, that PMTU is now
   incorrect
 - if the local MTU was the lowest value in the path, and is increased,
   we might discover a higher PMTU

Similarly to what commit e9fa1495d738 did for IPv6, update PMTU in those
cases.

If the exception was locked, the discovered PMTU was smaller than the
minimal accepted PMTU. In that case, if the new local MTU is smaller
than the current PMTU, let PMTU discovery figure out if locking of the
exception is still needed.

To do this, we need to know the old link MTU in the NETDEV_CHANGEMTU
notifier. By the time the notifier is called, dev->mtu has been
changed. This patch adds the old MTU as additional information in the
notifier structure, and a new call_netdevice_notifiers_u32() function.

Fixes: 5aad1de5ea2c ("ipv4: use separate genid for next hop exceptions")
Signed-off-by: Sabrina Dubroca 
Reviewed-by: Stefano Brivio 
Reviewed-by: David Ahern 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net: metrics: add proper netlink validation

2018-06-05T16:29:43+00:00

Before using nla_get_u32(), better make sure the attribute
is of the proper size.

Code recently was changed, but bug has been there from beginning
of git.

BUG: KMSAN: uninit-value in rtnetlink_put_metrics+0x553/0x960 net/core/rtnetlink.c:746
CPU: 1 PID: 14139 Comm: syz-executor6 Not tainted 4.17.0-rc5+ #103
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x185/0x1d0 lib/dump_stack.c:113
 kmsan_report+0x149/0x260 mm/kmsan/kmsan.c:1084
 __msan_warning_32+0x6e/0xc0 mm/kmsan/kmsan_instr.c:686
 rtnetlink_put_metrics+0x553/0x960 net/core/rtnetlink.c:746
 fib_dump_info+0xc42/0x2190 net/ipv4/fib_semantics.c:1361
 rtmsg_fib+0x65f/0x8c0 net/ipv4/fib_semantics.c:419
 fib_table_insert+0x2314/0x2b50 net/ipv4/fib_trie.c:1287
 inet_rtm_newroute+0x210/0x340 net/ipv4/fib_frontend.c:779
 rtnetlink_rcv_msg+0xa32/0x1560 net/core/rtnetlink.c:4646
 netlink_rcv_skb+0x378/0x600 net/netlink/af_netlink.c:2448
 rtnetlink_rcv+0x50/0x60 net/core/rtnetlink.c:4664
 netlink_unicast_kernel net/netlink/af_netlink.c:1310 [inline]
 netlink_unicast+0x1678/0x1750 net/netlink/af_netlink.c:1336
 netlink_sendmsg+0x104f/0x1350 net/netlink/af_netlink.c:1901
 sock_sendmsg_nosec net/socket.c:629 [inline]
 sock_sendmsg net/socket.c:639 [inline]
 ___sys_sendmsg+0xec0/0x1310 net/socket.c:2117
 __sys_sendmsg net/socket.c:2155 [inline]
 __do_sys_sendmsg net/socket.c:2164 [inline]
 __se_sys_sendmsg net/socket.c:2162 [inline]
 __x64_sys_sendmsg+0x331/0x460 net/socket.c:2162
 do_syscall_64+0x152/0x230 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x455a09
RSP: 002b:00007faae5fd8c68 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007faae5fd96d4 RCX: 0000000000455a09
RDX: 0000000000000000 RSI: 0000000020000000 RDI: 0000000000000013
RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000005d0 R14: 00000000006fdc20 R15: 0000000000000000

Uninit was stored to memory at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:279 [inline]
 kmsan_save_stack mm/kmsan/kmsan.c:294 [inline]
 kmsan_internal_chain_origin+0x12b/0x210 mm/kmsan/kmsan.c:685
 __msan_chain_origin+0x69/0xc0 mm/kmsan/kmsan_instr.c:529
 fib_convert_metrics net/ipv4/fib_semantics.c:1056 [inline]
 fib_create_info+0x2d46/0x9dc0 net/ipv4/fib_semantics.c:1150
 fib_table_insert+0x3e4/0x2b50 net/ipv4/fib_trie.c:1146
 inet_rtm_newroute+0x210/0x340 net/ipv4/fib_frontend.c:779
 rtnetlink_rcv_msg+0xa32/0x1560 net/core/rtnetlink.c:4646
 netlink_rcv_skb+0x378/0x600 net/netlink/af_netlink.c:2448
 rtnetlink_rcv+0x50/0x60 net/core/rtnetlink.c:4664
 netlink_unicast_kernel net/netlink/af_netlink.c:1310 [inline]
 netlink_unicast+0x1678/0x1750 net/netlink/af_netlink.c:1336
 netlink_sendmsg+0x104f/0x1350 net/netlink/af_netlink.c:1901
 sock_sendmsg_nosec net/socket.c:629 [inline]
 sock_sendmsg net/socket.c:639 [inline]
 ___sys_sendmsg+0xec0/0x1310 net/socket.c:2117
 __sys_sendmsg net/socket.c:2155 [inline]
 __do_sys_sendmsg net/socket.c:2164 [inline]
 __se_sys_sendmsg net/socket.c:2162 [inline]
 __x64_sys_sendmsg+0x331/0x460 net/socket.c:2162
 do_syscall_64+0x152/0x230 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
Uninit was created at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:279 [inline]
 kmsan_internal_poison_shadow+0xb8/0x1b0 mm/kmsan/kmsan.c:189
 kmsan_kmalloc+0x94/0x100 mm/kmsan/kmsan.c:315
 kmsan_slab_alloc+0x10/0x20 mm/kmsan/kmsan.c:322
 slab_post_alloc_hook mm/slab.h:446 [inline]
 slab_alloc_node mm/slub.c:2753 [inline]
 __kmalloc_node_track_caller+0xb32/0x11b0 mm/slub.c:4395
 __kmalloc_reserve net/core/skbuff.c:138 [inline]
 __alloc_skb+0x2cb/0x9e0 net/core/skbuff.c:206
 alloc_skb include/linux/skbuff.h:988 [inline]
 netlink_alloc_large_skb net/netlink/af_netlink.c:1182 [inline]
 netlink_sendmsg+0x76e/0x1350 net/netlink/af_netlink.c:1876
 sock_sendmsg_nosec net/socket.c:629 [inline]
 sock_sendmsg net/socket.c:639 [inline]
 ___sys_sendmsg+0xec0/0x1310 net/socket.c:2117
 __sys_sendmsg net/socket.c:2155 [inline]
 __do_sys_sendmsg net/socket.c:2164 [inline]
 __se_sys_sendmsg net/socket.c:2162 [inline]
 __x64_sys_sendmsg+0x331/0x460 net/socket.c:2162
 do_syscall_64+0x152/0x230 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Fixes: a919525ad832 ("net: Move fib_convert_metrics to metrics file")
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet 
Reported-by: syzbot 
Cc: David Ahern 
Signed-off-by: David S. Miller

net: Move fib_convert_metrics to metrics file

2018-04-18T03:41:15+00:00

Move logic of fib_convert_metrics into ip_metrics_convert. This allows
the code that converts netlink attributes into metrics struct to be
re-used in a later patch by IPv6.

This is mostly a code move with the following changes to variable names:
  - fi->fib_net becomes net
  - fc_mx and fc_mx_len are passed as inputs pulled from fib_config
  - metrics array is passed as an input from fi->fib_metrics->metrics

Signed-off-by: David Ahern 
Signed-off-by: David S. Miller

route: check sysctl_fib_multipath_use_neigh earlier than hash

2018-04-02T00:57:39+00:00

Prior to this patch, when one packet is hashed into path [1]
(hash <= nh_upper_bound) and it's neigh is dead, it will try
path [2]. However, if path [2]'s neigh is alive but it's
hash > nh_upper_bound, it will not return this alive path.
This packet will never be sent even if path [2] is alive.

 3.3.3.1/24:
  nexthop via 1.1.1.254 dev eth1 weight 1 <--[1] (dead neigh)
  nexthop via 2.2.2.254 dev eth2 weight 1 <--[2]

With sysctl_fib_multipath_use_neigh set is supposed to find an
available path respecting to the l3/l4 hash. But if there is
no available route with this hash, it should at least return
an alive route even with other hash.

This patch is to fix it by processing fib_multipath_use_neigh
earlier than the hash check, so that it will at least return
an alive route if there is when fib_multipath_use_neigh is
enabled. It's also compatible with before when there are alive
routes with the l3/l4 hash.

Fixes: a6db4494d218 ("net: ipv4: Consider failed nexthops in multipath routes")
Reported-by: Jianlin Shi 
Signed-off-by: Xin Long 
Acked-by: David Ahern 
Signed-off-by: David S. Miller

net/ipv4: Pass net to fib_multipath_hash instead of fib_info

2018-03-04T18:04:21+00:00

fib_multipath_hash only needs net struct to check a sysctl. Make it
clear by passing net instead of fib_info. In the end this allows
alignment between the ipv4 and ipv6 versions.

Signed-off-by: David Ahern 
Reviewed-by: Ido Schimmel 
Reviewed-by: Nikolay Aleksandrov 
Signed-off-by: David S. Miller

ipv6: route: dissect flow in input path if fib rules need it

2018-03-01T03:44:44+00:00

Dissect flow in fwd path if fib rules require it. Controlled by
a flag to avoid penatly for the common case. Flag is set when fib
rules with sport, dport and proto match that require flow dissect
are installed. Also passes the dissected hash keys to the multipath
hash function when applicable to avoid dissecting the flow again.
icmp packets will continue to use inner header for hash
calculations (Thanks to Nikolay Aleksandrov for some review here).

Signed-off-by: Roopa Prabhu 
Acked-by: Paolo Abeni 
Acked-by: Nikolay Aleksandrov 
Signed-off-by: David S. Miller

inet: whitespace cleanup

2018-02-28T16:43:28+00:00

Ran simple script to find/remove trailing whitespace and blank lines
at EOF because that kind of stuff git whines about and editors leave
behind.

Signed-off-by: Stephen Hemminger 
Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

2018-02-19T23:46:11+00:00

fib_semantics: Don't match route with mismatching tclassid

2018-02-16T20:19:54+00:00

In fib_nh_match(), if output interface or gateway are passed in
the FIB configuration, we don't have to check next hops of
multipath routes to conclude whether we have a match or not.

However, we might still have routes with different realms
matching the same output interface and gateway configuration,
and this needs to cause the match to fail. Otherwise the first
route inserted in the FIB will match, regardless of the realms:

 # ip route add 1.1.1.1 dev eth0 table 1234 realms 1/2
 # ip route append 1.1.1.1 dev eth0 table 1234 realms 3/4
 # ip route list table 1234
 1.1.1.1 dev eth0 scope link realms 1/2
 1.1.1.1 dev eth0 scope link realms 3/4
 # ip route del 1.1.1.1 dev ens3 table 1234 realms 3/4
 # ip route list table 1234
 1.1.1.1 dev ens3 scope link realms 3/4

whereas route with realms 3/4 should have been deleted instead.

Explicitly check for fc_flow passed in the FIB configuration
(this comes from RTA_FLOW extracted by rtm_to_fib_config()) and
fail matching if it differs from nh_tclassid.

The handling of RTA_FLOW for multipath routes later in
fib_nh_match() is still needed, as we can have multiple RTA_FLOW
attributes that need to be matched against the tclassid of each
next hop.

v2: Check that fc_flow is set before discarding the match, so
    that the user can still select the first matching rule by
    not specifying any realm, as suggested by David Ahern.

Reported-by: Jianlin Shi 
Signed-off-by: Stefano Brivio 
Acked-by: David Ahern 
Signed-off-by: David S. Miller

net/ipv4: Unexport fib_multipath_hash and fib_select_path

2018-02-13T19:00:57+00:00

Do not export fib_multipath_hash or fib_select_path; both are only used
by core ipv4 code.

Signed-off-by: David Ahern 
Signed-off-by: David S. Miller