kernel/net/core, branch linux-4.1.y

net: fix uninit-value in __hw_addr_add_ex()

2018-05-23T01:36:40Z

[ Upstream commit 77d36398d99f2565c0a8d43a86fd520a82e64bb8 ] syzbot complained : BUG: KMSAN: uninit-value in memcmp+0x119/0x180 lib/string.c:861 CPU: 0 PID: 3 Comm: kworker/0:0 Not tainted 4.16.0+ #82 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: ipv6_addrconf addrconf_dad_work Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x185/0x1d0 lib/dump_stack.c:53 kmsan_report+0x142/0x240 mm/kmsan/kmsan.c:1067 __msan_warning_32+0x6c/0xb0 mm/kmsan/kmsan_instr.c:676 memcmp+0x119/0x180 lib/string.c:861 __hw_addr_add_ex net/core/dev_addr_lists.c:60 [inline] __dev_mc_add+0x1c2/0x8e0 net/core/dev_addr_lists.c:670 dev_mc_add+0x6d/0x80 net/core/dev_addr_lists.c:687 igmp6_group_added+0x2db/0xa00 net/ipv6/mcast.c:662 ipv6_dev_mc_inc+0xe9e/0x1130 net/ipv6/mcast.c:914 addrconf_join_solict net/ipv6/addrconf.c:2078 [inline] addrconf_dad_begin net/ipv6/addrconf.c:3828 [inline] addrconf_dad_work+0x427/0x2150 net/ipv6/addrconf.c:3954 process_one_work+0x12c6/0x1f60 kernel/workqueue.c:2113 worker_thread+0x113c/0x24f0 kernel/workqueue.c:2247 kthread+0x539/0x720 kernel/kthread.c:239 Fixes: f001fde5eadd ("net: introduce a list of device addresses dev_addr_list (v6)") Signed-off-by: Eric Dumazet Reported-by: syzbot Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

net: initialize skb->peeked when cloning

2018-05-23T01:36:40Z

[ Upstream commit b13dda9f9aa7caceeee61c080c2e544d5f5d85e5 ] syzbot reported __skb_try_recv_from_queue() was using skb->peeked while it was potentially unitialized. We need to clear it in __skb_clone() Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Eric Dumazet Reported-by: syzbot Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

net: fix deadlock while clearing neighbor proxy table

2018-05-23T01:36:37Z

[ Upstream commit 53b76cdf7e8fecec1d09e38aad2f8579882591a8 ] When coming from ndisc_netdev_event() in net/ipv6/ndisc.c, neigh_ifdown() is called with &nd_tbl, locking this while clearing the proxy neighbor entries when eg. deleting an interface. Calling the table's pndisc_destructor() with the lock still held, however, can cause a deadlock: When a multicast listener is available an IGMP packet of type ICMPV6_MGM_REDUCTION may be sent out. When reaching ip6_finish_output2(), if no neighbor entry for the target address is found, __neigh_create() is called with &nd_tbl, which it'll want to lock. Move the elements into their own list, then unlock the table and perform the destruction. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=199289 Fixes: 6fd6ce2056de ("ipv6: Do not depend on rt->n in ip6_finish_output2().") Signed-off-by: Wolfgang Bumiller Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

vlan: Fix reading memory beyond skb->tail in skb_vlan_tagged_multi

2018-05-23T01:36:36Z

[ Upstream commit 7ce2367254e84753bceb07327aaf5c953cfce117 ] Syzkaller spotted an old bug which leads to reading skb beyond tail by 4 bytes on vlan tagged packets. This is caused because skb_vlan_tagged_multi() did not check skb_headlen. BUG: KMSAN: uninit-value in eth_type_vlan include/linux/if_vlan.h:283 [inline] BUG: KMSAN: uninit-value in skb_vlan_tagged_multi include/linux/if_vlan.h:656 [inline] BUG: KMSAN: uninit-value in vlan_features_check include/linux/if_vlan.h:672 [inline] BUG: KMSAN: uninit-value in dflt_features_check net/core/dev.c:2949 [inline] BUG: KMSAN: uninit-value in netif_skb_features+0xd1b/0xdc0 net/core/dev.c:3009 CPU: 1 PID: 3582 Comm: syzkaller435149 Not tainted 4.16.0+ #82 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x185/0x1d0 lib/dump_stack.c:53 kmsan_report+0x142/0x240 mm/kmsan/kmsan.c:1067 __msan_warning_32+0x6c/0xb0 mm/kmsan/kmsan_instr.c:676 eth_type_vlan include/linux/if_vlan.h:283 [inline] skb_vlan_tagged_multi include/linux/if_vlan.h:656 [inline] vlan_features_check include/linux/if_vlan.h:672 [inline] dflt_features_check net/core/dev.c:2949 [inline] netif_skb_features+0xd1b/0xdc0 net/core/dev.c:3009 validate_xmit_skb+0x89/0x1320 net/core/dev.c:3084 __dev_queue_xmit+0x1cb2/0x2b60 net/core/dev.c:3549 dev_queue_xmit+0x4b/0x60 net/core/dev.c:3590 packet_snd net/packet/af_packet.c:2944 [inline] packet_sendmsg+0x7c57/0x8a10 net/packet/af_packet.c:2969 sock_sendmsg_nosec net/socket.c:630 [inline] sock_sendmsg net/socket.c:640 [inline] sock_write_iter+0x3b9/0x470 net/socket.c:909 do_iter_readv_writev+0x7bb/0x970 include/linux/fs.h:1776 do_iter_write+0x30d/0xd40 fs/read_write.c:932 vfs_writev fs/read_write.c:977 [inline] do_writev+0x3c9/0x830 fs/read_write.c:1012 SYSC_writev+0x9b/0xb0 fs/read_write.c:1085 SyS_writev+0x56/0x80 fs/read_write.c:1082 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x3d/0xa2 RIP: 0033:0x43ffa9 RSP: 002b:00007fff2cff3948 EFLAGS: 00000217 ORIG_RAX: 0000000000000014 RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 000000000043ffa9 RDX: 0000000000000001 RSI: 0000000020000080 RDI: 0000000000000003 RBP: 00000000006cb018 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000217 R12: 00000000004018d0 R13: 0000000000401960 R14: 0000000000000000 R15: 0000000000000000 Uninit was created at: kmsan_save_stack_with_flags mm/kmsan/kmsan.c:278 [inline] kmsan_internal_poison_shadow+0xb8/0x1b0 mm/kmsan/kmsan.c:188 kmsan_kmalloc+0x94/0x100 mm/kmsan/kmsan.c:314 kmsan_slab_alloc+0x11/0x20 mm/kmsan/kmsan.c:321 slab_post_alloc_hook mm/slab.h:445 [inline] slab_alloc_node mm/slub.c:2737 [inline] __kmalloc_node_track_caller+0xaed/0x11c0 mm/slub.c:4369 __kmalloc_reserve net/core/skbuff.c:138 [inline] __alloc_skb+0x2cf/0x9f0 net/core/skbuff.c:206 alloc_skb include/linux/skbuff.h:984 [inline] alloc_skb_with_frags+0x1d4/0xb20 net/core/skbuff.c:5234 sock_alloc_send_pskb+0xb56/0x1190 net/core/sock.c:2085 packet_alloc_skb net/packet/af_packet.c:2803 [inline] packet_snd net/packet/af_packet.c:2894 [inline] packet_sendmsg+0x6444/0x8a10 net/packet/af_packet.c:2969 sock_sendmsg_nosec net/socket.c:630 [inline] sock_sendmsg net/socket.c:640 [inline] sock_write_iter+0x3b9/0x470 net/socket.c:909 do_iter_readv_writev+0x7bb/0x970 include/linux/fs.h:1776 do_iter_write+0x30d/0xd40 fs/read_write.c:932 vfs_writev fs/read_write.c:977 [inline] do_writev+0x3c9/0x830 fs/read_write.c:1012 SYSC_writev+0x9b/0xb0 fs/read_write.c:1085 SyS_writev+0x56/0x80 fs/read_write.c:1082 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x3d/0xa2 Fixes: 58e998c6d239 ("offloading: Force software GSO for multiple vlan tags.") Reported-and-tested-by: syzbot+0bbe42c764feafa82c5a@syzkaller.appspotmail.com Signed-off-by: Toshiaki Makita Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

net: fool proof dev_valid_name()

2018-05-23T01:36:31Z

[ Upstream commit a9d48205d0aedda021fc3728972a9e9934c2b9de ] We want to use dev_valid_name() to validate tunnel names, so better use strnlen(name, IFNAMSIZ) than strlen(name) to make sure to not upset KASAN. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

net: fix possible out-of-bound read in skb_network_protocol()

2018-05-23T01:36:30Z

[ Upstream commit 1dfe82ebd7d8fd43dba9948fdfb31f145014baa0 ] skb mac header is not necessarily set at the time skb_network_protocol() is called. Use skb->data instead. BUG: KASAN: slab-out-of-bounds in skb_network_protocol+0x46b/0x4b0 net/core/dev.c:2739 Read of size 2 at addr ffff8801b3097a0b by task syz-executor5/14242 CPU: 1 PID: 14242 Comm: syz-executor5 Not tainted 4.16.0-rc6+ #280 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x24d lib/dump_stack.c:53 print_address_description+0x73/0x250 mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report+0x23c/0x360 mm/kasan/report.c:412 __asan_report_load_n_noabort+0xf/0x20 mm/kasan/report.c:443 skb_network_protocol+0x46b/0x4b0 net/core/dev.c:2739 harmonize_features net/core/dev.c:2924 [inline] netif_skb_features+0x509/0x9b0 net/core/dev.c:3011 validate_xmit_skb+0x81/0xb00 net/core/dev.c:3084 validate_xmit_skb_list+0xbf/0x120 net/core/dev.c:3142 packet_direct_xmit+0x117/0x790 net/packet/af_packet.c:256 packet_snd net/packet/af_packet.c:2944 [inline] packet_sendmsg+0x3aed/0x60b0 net/packet/af_packet.c:2969 sock_sendmsg_nosec net/socket.c:629 [inline] sock_sendmsg+0xca/0x110 net/socket.c:639 ___sys_sendmsg+0x767/0x8b0 net/socket.c:2047 __sys_sendmsg+0xe5/0x210 net/socket.c:2081 Fixes: 19acc327258a ("gso: Handle Trans-Ether-Bridging protocol in skb_network_protocol()") Signed-off-by: Eric Dumazet Cc: Pravin B Shelar Reported-by: Reported-by: syzbot Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

skbuff: only inherit relevant tx_flags

2018-05-23T01:36:28Z

[ Upstream commit fff88030b3ff930ca7a3d74acfee0472f33887ea ] When inheriting tx_flags from one skbuff to another, always apply a mask to avoid overwriting unrelated other bits in the field. The two SKBTX_SHARED_FRAG cases clears all other bits. In practice, tx_flags are zero at this point now. But this is fragile. Timestamp flags are set, for instance, if in tcp_gso_segment, after this clear in skb_segment. The SKBTX_ANY_TSTAMP mask in __skb_tstamp_tx ensures that new skbs do not accidentally inherit flags such as SKBTX_SHARED_FRAG. Signed-off-by: Willem de Bruijn Acked-by: Soheil Hassas Yeganeh Acked-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

skbuff: return -EMSGSIZE in skb_to_sgvec to prevent overflow

2018-05-23T01:36:27Z

[ Upstream commit 48a1df65334b74bd7531f932cca5928932abf769 ] This is a defense-in-depth measure in response to bugs like 4d6fa57b4dab ("macsec: avoid heap overflow in skb_to_sgvec"). There's not only a potential overflow of sglist items, but also a stack overflow potential, so we fix this by limiting the amount of recursion this function is allowed to do. Not actually providing a bounded base case is a future disaster that we can easily avoid here. As a small matter of house keeping, we take this opportunity to move the documentation comment over the actual function the documentation is for. While this could be implemented by using an explicit stack of skbuffs, when implementing this, the function complexity increased considerably, and I don't think such complexity and bloat is actually worth it. So, instead I built this and tested it on x86, x86_64, ARM, ARM64, and MIPS, and measured the stack usage there. I also reverted the recent MIPS changes that give it a separate IRQ stack, so that I could experience some worst-case situations. I found that limiting it to 24 layers deep yielded a good stack usage with room for safety, as well as being much deeper than any driver actually ever creates. Signed-off-by: Jason A. Donenfeld Cc: Steffen Klassert Cc: Herbert Xu Cc: "David S. Miller" Cc: David Howells Cc: Sabrina Dubroca Cc: "Michael S. Tsirkin" Cc: Jason Wang Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

net: move somaxconn init from sysctl code

2018-05-23T01:36:26Z

[ Upstream commit 7c3f1875c66fbc19762760097cabc91849ea0bbb ] The default value for somaxconn is set in sysctl_core_net_init(), but this function is not called when kernel is configured without CONFIG_SYSCTL. This results in the kernel not being able to accept TCP connections, because the backlog has zero size. Usually, the user ends up with: "TCP: request_sock_TCP: Possible SYN flooding on port 7. Dropping request. Check SNMP counters." If SYN cookies are not enabled the connection is rejected. Before ef547f2ac16 (tcp: remove max_qlen_log), the effects were less severe, because the backlog was always at least eight slots long. Signed-off-by: Roman Kapl Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

neighbour: update neigh timestamps iff update is effective

2018-05-23T01:36:24Z

[ Upstream commit 77d7123342dcf6442341b67816321d71da8b2b16 ] It's a common practice to send gratuitous ARPs after moving an IP address to another device to speed up healing of a service. To fulfill service availability constraints, the timing of network peers updating their caches to point to a new location of an IP address can be particularly important. Sometimes neigh_update calls won't touch neither lladdr nor state, for example if an update arrives in locktime interval. The neigh->updated value is tested by the protocol specific neigh code, which in turn will influence whether NEIGH_UPDATE_F_OVERRIDE gets set in the call to neigh_update() or not. As a result, we may effectively ignore the update request, bailing out of touching the neigh entry, except that we still bump its timestamps inside neigh_update. This may be a problem for updates arriving in quick succession. For example, consider the following scenario: A service is moved to another device with its IP address. The new device sends three gratuitous ARP requests into the network with ~1 seconds interval between them. Just before the first request arrives to one of network peer nodes, its neigh entry for the IP address transitions from STALE to DELAY. This transition, among other things, updates neigh->updated. Once the kernel receives the first gratuitous ARP, it ignores it because its arrival time is inside the locktime interval. The kernel still bumps neigh->updated. Then the second gratuitous ARP request arrives, and it's also ignored because it's still in the (new) locktime interval. Same happens for the third request. The node eventually heals itself (after delay_first_probe_time seconds since the initial transition to DELAY state), but it just wasted some time and require a new ARP request/reply round trip. This unfortunate behaviour both puts more load on the network, as well as reduces service availability. This patch changes neigh_update so that it bumps neigh->updated (as well as neigh->confirmed) only once we are sure that either lladdr or entry state will change). In the scenario described above, it means that the second gratuitous ARP request will actually update the entry lladdr. Ideally, we would update the neigh entry on the very first gratuitous ARP request. The locktime mechanism is designed to ignore ARP updates in a short timeframe after a previous ARP update was honoured by the kernel layer. This would require tracking timestamps for state transitions separately from timestamps when actual updates are received. This would probably involve changes in neighbour struct. Therefore, the patch doesn't tackle the issue of the first gratuitous APR ignored, leaving it for a follow-up. Signed-off-by: Ihar Hrachyshka Signed-off-by: David S. Miller Signed-off-by: Sasha Levin