kernel.git/net/ipv4/fib_semantics.c, branch linux-3.16.y

ipv4: fix a race in update_or_create_fnhe()

2019-05-11T14:22:48Z

commit caa415270c732505240bb60171c44a7838c555e8 upstream. nh_exceptions is effectively used under rcu, but lacks proper barriers. Between kzalloc() and setting of nh->nh_exceptions(), we need a proper memory barrier. Signed-off-by: Eric Dumazet Fixes: 4895c771c7f00 ("ipv4: Add FIB nexthop exceptions.") Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings

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

2018-12-16T22:09:40Z

commit af7d6cce53694a88d6a1bb60c9a239a6a5144459 upstream. 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 [bwh: Backported to 3.16: - Pass net_device argument to call_netdevice_notifiers_info() - Adjust context] Signed-off-by: Ben Hutchings

net: metrics: add proper netlink validation

2018-11-20T18:05:10Z

commit 5b5e7a0de2bbf2a1afcd9f49e940010e9fb80d53 upstream. 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 [bwh: Backported to 3.16: Metrics are parsed in fib_create_info()] Signed-off-by: Ben Hutchings

ipv4: fix NULL dereference in free_fib_info_rcu()

2017-11-11T13:33:21Z

commit 187e5b3ac84d3421d2de3aca949b2791fbcad554 upstream. If fi->fib_metrics could not be allocated in fib_create_info() we attempt to dereference a NULL pointer in free_fib_info_rcu() : m = fi->fib_metrics; if (m != &dst_default_metrics && atomic_dec_and_test(&m->refcnt)) kfree(m); Before my recent patch, we used to call kfree(NULL) and nothing wrong happened. Instead of using RCU to defer freeing while we are under memory stress, it seems better to take immediate action. This was reported by syzkaller team. Fixes: 3fb07daff8e9 ("ipv4: add reference counting to metrics") Signed-off-by: Eric Dumazet Reported-by: Dmitry Vyukov Signed-off-by: David S. Miller [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings

ipv4: add reference counting to metrics

2017-11-11T13:33:21Z

commit 3fb07daff8e99243366a081e5129560734de4ada upstream. Andrey Konovalov reported crashes in ipv4_mtu() I could reproduce the issue with KASAN kernels, between 10.246.7.151 and 10.246.7.152 : 1) 20 concurrent netperf -t TCP_RR -H 10.246.7.152 -l 1000 & 2) At the same time run following loop : while : do ip ro add 10.246.7.152 dev eth0 src 10.246.7.151 mtu 1500 ip ro del 10.246.7.152 dev eth0 src 10.246.7.151 mtu 1500 done Cong Wang attempted to add back rt->fi in commit 82486aa6f1b9 ("ipv4: restore rt->fi for reference counting") but this proved to add some issues that were complex to solve. Instead, I suggested to add a refcount to the metrics themselves, being a standalone object (in particular, no reference to other objects) I tried to make this patch as small as possible to ease its backport, instead of being super clean. Note that we believe that only ipv4 dst need to take care of the metric refcount. But if this is wrong, this patch adds the basic infrastructure to extend this to other families. Many thanks to Julian Anastasov for reviewing this patch, and Cong Wang for his efforts on this problem. Fixes: 2860583fe840 ("ipv4: Kill rt->fi") Signed-off-by: Eric Dumazet Reported-by: Andrey Konovalov Reviewed-by: Julian Anastasov Acked-by: Cong Wang Signed-off-by: David S. Miller [bwh: Backported to 3.16: - Give DST_METRICS_REFCOUNTED a value of 4 and struct dst_metrics an alignment of 8 - Update dst_metrics cache size - Adjust context] Signed-off-by: Ben Hutchings

dst: Increase alignment of metrics to allow extra flag on pointers

2017-11-11T13:33:20Z

For the backport of "ipv4: add reference counting to metrics", we will need a third flag on metrics pointers. This was not needed upstream as the DST_METRICS_FORCE_OVERWRITE flag has been eliminated there. In order to use three flag bits we need to increase the alignment of metrics from 4 to 8 bytes. Signed-off-by: Ben Hutchings

net/route: enforce hoplimit max value

2017-10-12T14:28:12Z

[ Upstream commit 626abd59e51d4d8c6367e03aae252a8aa759ac78 ] Currently, when creating or updating a route, no check is performed in both ipv4 and ipv6 code to the hoplimit value. The caller can i.e. set hoplimit to 256, and when such route will be used, packets will be sent with hoplimit/ttl equal to 0. This commit adds checks for the RTAX_HOPLIMIT value, in both ipv4 ipv6 route code, substituting any value greater than 255 with 255. This is consistent with what is currently done for ADVMSS and MTU in the ipv4 code. Signed-off-by: Paolo Abeni Signed-off-by: David S. Miller [bwh: Backported to 3.16: for IPv6, add the check to fib6_commit_metrics()] Signed-off-by: Ben Hutchings

ipv4: fix nexthop attlen check in fib_nh_match

2014-11-05T16:32:41Z

commit f76936d07c4eeb36d8dbb64ebd30ab46ff85d9f7 upstream. fib_nh_match does not match nexthops correctly. Example: ip route add 172.16.10/24 nexthop via 192.168.122.12 dev eth0 \ nexthop via 192.168.122.13 dev eth0 ip route del 172.16.10/24 nexthop via 192.168.122.14 dev eth0 \ nexthop via 192.168.122.15 dev eth0 Del command is successful and route is removed. After this patch applied, the route is correctly matched and result is: RTNETLINK answers: No such process Please consider this for stable trees as well. Fixes: 4e902c57417c4 ("[IPv4]: FIB configuration using struct fib_config") Signed-off-by: Jiri Pirko Acked-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Luis Henriques

ipv4: fib_semantics: increment fib_info_cnt after fib_info allocation

2014-05-07T21:14:32Z

Increment fib_info_cnt in fib_create_info() right after successfuly alllocating fib_info structure, overwise fib_metrics allocation failure leads to fib_info_cnt incorrectly decremented in free_fib_info(), called on error path from fib_create_info(). Signed-off-by: Sergey Popovich Signed-off-by: David S. Miller

ipv4, fib: pass LOOPBACK_IFINDEX instead of 0 to flowi4_iif

2014-04-16T19:05:11Z

As suggested by Julian: Simply, flowi4_iif must not contain 0, it does not look logical to ignore all ip rules with specified iif. because in fib_rule_match() we do: if (rule->iifindex && (rule->iifindex != fl->flowi_iif)) goto out; flowi4_iif should be LOOPBACK_IFINDEX by default. We need to move LOOPBACK_IFINDEX to include/net/flow.h: 1) It is mostly used by flowi_iif 2) Fix the following compile error if we use it in flow.h by the patches latter: In file included from include/linux/netfilter.h:277:0, from include/net/netns/netfilter.h:5, from include/net/net_namespace.h:21, from include/linux/netdevice.h:43, from include/linux/icmpv6.h:12, from include/linux/ipv6.h:61, from include/net/ipv6.h:16, from include/linux/sunrpc/clnt.h:27, from include/linux/nfs_fs.h:30, from init/do_mounts.c:32: include/net/flow.h: In function ‘flowi4_init_output’: include/net/flow.h:84:32: error: ‘LOOPBACK_IFINDEX’ undeclared (first use in this function) Cc: Eric Biederman Cc: Julian Anastasov Cc: David S. Miller Signed-off-by: Cong Wang Signed-off-by: Cong Wang Signed-off-by: David S. Miller