kernel/net/ipv6/ip6mr.c, branch linux-5.1.y

ip6mr: Do not call __IP6_INC_STATS() from preemptible context

2019-03-04T18:55:48Z

Similar to commit 44f49dd8b5a6 ("ipmr: fix possible race resulting from improper usage of IP_INC_STATS_BH() in preemptible context."), we cannot assume preemption is disabled when incrementing the counter and accessing a per-CPU variable. Preemption can be enabled when we add a route in process context that corresponds to packets stored in the unresolved queue, which are then forwarded using this route [1]. Fix this by using IP6_INC_STATS() which takes care of disabling preemption on architectures where it is needed. [1] [ 157.451447] BUG: using __this_cpu_add() in preemptible [00000000] code: smcrouted/2314 [ 157.460409] caller is ip6mr_forward2+0x73e/0x10e0 [ 157.460434] CPU: 3 PID: 2314 Comm: smcrouted Not tainted 5.0.0-rc7-custom-03635-g22f2712113f1 #1336 [ 157.460449] Hardware name: Mellanox Technologies Ltd. MSN2100-CB2FO/SA001017, BIOS 5.6.5 06/07/2016 [ 157.460461] Call Trace: [ 157.460486] dump_stack+0xf9/0x1be [ 157.460553] check_preemption_disabled+0x1d6/0x200 [ 157.460576] ip6mr_forward2+0x73e/0x10e0 [ 157.460705] ip6_mr_forward+0x9a0/0x1510 [ 157.460771] ip6mr_mfc_add+0x16b3/0x1e00 [ 157.461155] ip6_mroute_setsockopt+0x3cb/0x13c0 [ 157.461384] do_ipv6_setsockopt.isra.8+0x348/0x4060 [ 157.462013] ipv6_setsockopt+0x90/0x110 [ 157.462036] rawv6_setsockopt+0x4a/0x120 [ 157.462058] __sys_setsockopt+0x16b/0x340 [ 157.462198] __x64_sys_setsockopt+0xbf/0x160 [ 157.462220] do_syscall_64+0x14d/0x610 [ 157.462349] entry_SYSCALL_64_after_hwframe+0x49/0xbe Fixes: 0912ea38de61 ("[IPV6] MROUTE: Add stats in multicast routing module method ip6_mr_forward().") Signed-off-by: Ido Schimmel Reported-by: Amit Cohen Signed-off-by: David S. Miller

ipmr: ip6mr: Create new sockopt to clear mfc cache or vifs

2019-02-21T21:05:05Z

Currently the only way to clear the forwarding cache was to delete the entries one by one using the MRT_DEL_MFC socket option or to destroy and recreate the socket. Create a new socket option which with the use of optional flags can clear any combination of multicast entries (static or not static) and multicast vifs (static or not static). Calling the new socket option MRT_FLUSH with the flags MRT_FLUSH_MFC and MRT_FLUSH_VIFS will clear all entries and vifs on the socket except for static entries. Signed-off-by: Callum Sinclair Signed-off-by: Nikolay Aleksandrov Signed-off-by: David S. Miller

ip6mr: Fix notifiers call on mroute_clean_tables()

2019-01-28T07:16:07Z

When the MC route socket is closed, mroute_clean_tables() is called to cleanup existing routes. Mistakenly notifiers call was put on the cleanup of the unresolved MC route entries cache. In a case where the MC socket closes before an unresolved route expires, the notifier call leads to a crash, caused by the driver trying to increment a non initialized refcount_t object [1] and then when handling is done, to decrement it [2]. This was detected by a test recently added in commit 6d4efada3b82 ("selftests: forwarding: Add multicast routing test"). Fix that by putting notifiers call on the resolved entries traversal, instead of on the unresolved entries traversal. [1] [ 245.748967] refcount_t: increment on 0; use-after-free. [ 245.754829] WARNING: CPU: 3 PID: 3223 at lib/refcount.c:153 refcount_inc_checked+0x2b/0x30 ... [ 245.802357] Hardware name: Mellanox Technologies Ltd. MSN2740/SA001237, BIOS 5.6.5 06/07/2016 [ 245.811873] RIP: 0010:refcount_inc_checked+0x2b/0x30 ... [ 245.907487] Call Trace: [ 245.910231] mlxsw_sp_router_fib_event.cold.181+0x42/0x47 [mlxsw_spectrum] [ 245.917913] notifier_call_chain+0x45/0x7 [ 245.922484] atomic_notifier_call_chain+0x15/0x20 [ 245.927729] call_fib_notifiers+0x15/0x30 [ 245.932205] mroute_clean_tables+0x372/0x3f [ 245.936971] ip6mr_sk_done+0xb1/0xc0 [ 245.940960] ip6_mroute_setsockopt+0x1da/0x5f0 ... [2] [ 246.128487] refcount_t: underflow; use-after-free. [ 246.133859] WARNING: CPU: 0 PID: 7 at lib/refcount.c:187 refcount_sub_and_test_checked+0x4c/0x60 [ 246.183521] Hardware name: Mellanox Technologies Ltd. MSN2740/SA001237, BIOS 5.6.5 06/07/2016 ... [ 246.193062] Workqueue: mlxsw_core_ordered mlxsw_sp_router_fibmr_event_work [mlxsw_spectrum] [ 246.202394] RIP: 0010:refcount_sub_and_test_checked+0x4c/0x60 ... [ 246.298889] Call Trace: [ 246.301617] refcount_dec_and_test_checked+0x11/0x20 [ 246.307170] mlxsw_sp_router_fibmr_event_work.cold.196+0x47/0x78 [mlxsw_spectrum] [ 246.315531] process_one_work+0x1fa/0x3f0 [ 246.320005] worker_thread+0x2f/0x3e0 [ 246.324083] kthread+0x118/0x130 [ 246.327683] ? wq_update_unbound_numa+0x1b0/0x1b0 [ 246.332926] ? kthread_park+0x80/0x80 [ 246.337013] ret_from_fork+0x1f/0x30 Fixes: 088aa3eec2ce ("ip6mr: Support fib notifications") Signed-off-by: Nir Dotan Reviewed-by: Ido Schimmel Signed-off-by: David S. Miller

ip: validate header length on virtual device xmit

2019-01-01T20:05:02Z

KMSAN detected read beyond end of buffer in vti and sit devices when passing truncated packets with PF_PACKET. The issue affects additional ip tunnel devices. Extend commit 76c0ddd8c3a6 ("ip6_tunnel: be careful when accessing the inner header") and commit ccfec9e5cb2d ("ip_tunnel: be careful when accessing the inner header"). Move the check to a separate helper and call at the start of each ndo_start_xmit function in net/ipv4 and net/ipv6. Minor changes: - convert dev_kfree_skb to kfree_skb on error path, as dev_kfree_skb calls consume_skb which is not for error paths. - use pskb_network_may_pull even though that is pedantic here, as the same as pskb_may_pull for devices without llheaders. - do not cache ipv6 hdrs if used only once (unsafe across pskb_may_pull, was more relevant to earlier patch) Reported-by: syzbot Signed-off-by: Willem de Bruijn Signed-off-by: David S. Miller

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

2018-12-20T19:53:36Z

Lots of conflicts, by happily all cases of overlapping changes, parallel adds, things of that nature. Thanks to Stephen Rothwell, Saeed Mahameed, and others for their guidance in these resolutions. Signed-off-by: David S. Miller

ip6mr: Drop mfc6_cache argument to ip6mr_forward2

2018-12-18T07:31:14Z

mfc6_cache is not needed by ip6mr_forward2 so drop it from the input argument list. Signed-off-by: David Ahern Signed-off-by: David S. Miller

ip6mr: Fix potential Spectre v1 vulnerability

2018-12-14T23:34:28Z

vr.mifi is indirectly controlled by user-space, hence leading to a potential exploitation of the Spectre variant 1 vulnerability. This issue was detected with the help of Smatch: net/ipv6/ip6mr.c:1845 ip6mr_ioctl() warn: potential spectre issue 'mrt->vif_table' [r] (local cap) net/ipv6/ip6mr.c:1919 ip6mr_compat_ioctl() warn: potential spectre issue 'mrt->vif_table' [r] (local cap) Fix this by sanitizing vr.mifi before using it to index mrt->vif_table' Notice that given that speculation windows are large, the policy is to kill the speculation on the first load and not worry if it can be completed with a dependent load/store [1]. [1] https://marc.info/?l=linux-kernel&m=152449131114778&w=2 Signed-off-by: Gustavo A. R. Silva Signed-off-by: David S. Miller

net: core: dev: Add extack argument to dev_open()

2018-12-06T21:26:06Z

In order to pass extack together with NETDEV_PRE_UP notifications, it's necessary to route the extack to __dev_open() from diverse (possibly indirect) callers. One prominent API through which the notification is invoked is dev_open(). Therefore extend dev_open() with and extra extack argument and update all users. Most of the calls end up just encoding NULL, but bond and team drivers have the extack readily available. Signed-off-by: Petr Machata Acked-by: Jiri Pirko Reviewed-by: Ido Schimmel Reviewed-by: David Ahern Signed-off-by: David S. Miller

net: Don't return invalid table id error when dumping all families

2018-10-24T21:06:25Z

When doing a route dump across all address families, do not error out if the table does not exist. This allows a route dump for AF_UNSPEC with a table id that may only exist for some of the families. Do return the table does not exist error if dumping routes for a specific family and the table does not exist. Signed-off-by: David Ahern Signed-off-by: David S. Miller

net: Enable kernel side filtering of route dumps

2018-10-16T07:14:07Z

Update parsing of route dump request to enable kernel side filtering. Allow filtering results by protocol (e.g., which routing daemon installed the route), route type (e.g., unicast), table id and nexthop device. These amount to the low hanging fruit, yet a huge improvement, for dumping routes. ip_valid_fib_dump_req is called with RTNL held, so __dev_get_by_index can be used to look up the device index without taking a reference. From there filter->dev is only used during dump loops with the lock still held. Set NLM_F_DUMP_FILTERED in the answer_flags so the user knows the results have been filtered should no entries be returned. Signed-off-by: David Ahern Signed-off-by: David S. Miller