inet_diag_msg_sctp{,l}addr_fill() and sctp_get_sctp_info() copy
sizeof(sockaddr_storage) bytes to fill in sockaddr structs used
to export diagnostic information to userspace.

However, the memory allocated to store sockaddr information is
smaller than that and depends on the address family, so we leak
up to 100 uninitialized bytes to userspace. Just use the size of
the source structs instead, in all the three cases this is what
userspace expects. Zero out the remaining memory.

Unused bytes (i.e. when IPv4 addresses are used) in source
structs sctp_sockaddr_entry and sctp_transport are already
cleared by sctp_add_bind_addr() and sctp_transport_new(),
respectively.

Noticed while testing KASAN-enabled kernel with 'ss':

[ 2326.885243] BUG: KASAN: slab-out-of-bounds in inet_sctp_diag_fill+0x42c/0x6c0 [sctp_diag] at addr ffff881be8779800
[ 2326.896800] Read of size 128 by task ss/9527
[ 2326.901564] CPU: 0 PID: 9527 Comm: ss Not tainted 4.11.0-22.el7a.x86_64 #1
[ 2326.909236] Hardware name: Dell Inc. PowerEdge R730/072T6D, BIOS 2.4.3 01/17/2017
[ 2326.917585] Call Trace:
[ 2326.920312]  dump_stack+0x63/0x8d
[ 2326.924014]  kasan_object_err+0x21/0x70
[ 2326.928295]  kasan_report+0x288/0x540
[ 2326.932380]  ? inet_sctp_diag_fill+0x42c/0x6c0 [sctp_diag]
[ 2326.938500]  ? skb_put+0x8b/0xd0
[ 2326.942098]  ? memset+0x31/0x40
[ 2326.945599]  check_memory_region+0x13c/0x1a0
[ 2326.950362]  memcpy+0x23/0x50
[ 2326.953669]  inet_sctp_diag_fill+0x42c/0x6c0 [sctp_diag]
[ 2326.959596]  ? inet_diag_msg_sctpasoc_fill+0x460/0x460 [sctp_diag]
[ 2326.966495]  ? __lock_sock+0x102/0x150
[ 2326.970671]  ? sock_def_wakeup+0x60/0x60
[ 2326.975048]  ? remove_wait_queue+0xc0/0xc0
[ 2326.979619]  sctp_diag_dump+0x44a/0x760 [sctp_diag]
[ 2326.985063]  ? sctp_ep_dump+0x280/0x280 [sctp_diag]
[ 2326.990504]  ? memset+0x31/0x40
[ 2326.994007]  ? mutex_lock+0x12/0x40
[ 2326.997900]  __inet_diag_dump+0x57/0xb0 [inet_diag]
[ 2327.003340]  ? __sys_sendmsg+0x150/0x150
[ 2327.007715]  inet_diag_dump+0x4d/0x80 [inet_diag]
[ 2327.012979]  netlink_dump+0x1e6/0x490
[ 2327.017064]  __netlink_dump_start+0x28e/0x2c0
[ 2327.021924]  inet_diag_handler_cmd+0x189/0x1a0 [inet_diag]
[ 2327.028045]  ? inet_diag_rcv_msg_compat+0x1b0/0x1b0 [inet_diag]
[ 2327.034651]  ? inet_diag_dump_compat+0x190/0x190 [inet_diag]
[ 2327.040965]  ? __netlink_lookup+0x1b9/0x260
[ 2327.045631]  sock_diag_rcv_msg+0x18b/0x1e0
[ 2327.050199]  netlink_rcv_skb+0x14b/0x180
[ 2327.054574]  ? sock_diag_bind+0x60/0x60
[ 2327.058850]  sock_diag_rcv+0x28/0x40
[ 2327.062837]  netlink_unicast+0x2e7/0x3b0
[ 2327.067212]  ? netlink_attachskb+0x330/0x330
[ 2327.071975]  ? kasan_check_write+0x14/0x20
[ 2327.076544]  netlink_sendmsg+0x5be/0x730
[ 2327.080918]  ? netlink_unicast+0x3b0/0x3b0
[ 2327.085486]  ? kasan_check_write+0x14/0x20
[ 2327.090057]  ? selinux_socket_sendmsg+0x24/0x30
[ 2327.095109]  ? netlink_unicast+0x3b0/0x3b0
[ 2327.099678]  sock_sendmsg+0x74/0x80
[ 2327.103567]  ___sys_sendmsg+0x520/0x530
[ 2327.107844]  ? __get_locked_pte+0x178/0x200
[ 2327.112510]  ? copy_msghdr_from_user+0x270/0x270
[ 2327.117660]  ? vm_insert_page+0x360/0x360
[ 2327.122133]  ? vm_insert_pfn_prot+0xb4/0x150
[ 2327.126895]  ? vm_insert_pfn+0x32/0x40
[ 2327.131077]  ? vvar_fault+0x71/0xd0
[ 2327.134968]  ? special_mapping_fault+0x69/0x110
[ 2327.140022]  ? __do_fault+0x42/0x120
[ 2327.144008]  ? __handle_mm_fault+0x1062/0x17a0
[ 2327.148965]  ? __fget_light+0xa7/0xc0
[ 2327.153049]  __sys_sendmsg+0xcb/0x150
[ 2327.157133]  ? __sys_sendmsg+0xcb/0x150
[ 2327.161409]  ? SyS_shutdown+0x140/0x140
[ 2327.165688]  ? exit_to_usermode_loop+0xd0/0xd0
[ 2327.170646]  ? __do_page_fault+0x55d/0x620
[ 2327.175216]  ? __sys_sendmsg+0x150/0x150
[ 2327.179591]  SyS_sendmsg+0x12/0x20
[ 2327.183384]  do_syscall_64+0xe3/0x230
[ 2327.187471]  entry_SYSCALL64_slow_path+0x25/0x25
[ 2327.192622] RIP: 0033:0x7f41d18fa3b0
[ 2327.196608] RSP: 002b:00007ffc3b731218 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
[ 2327.205055] RAX: ffffffffffffffda RBX: 00007ffc3b731380 RCX: 00007f41d18fa3b0
[ 2327.213017] RDX: 0000000000000000 RSI: 00007ffc3b731340 RDI: 0000000000000003
[ 2327.220978] RBP: 0000000000000002 R08: 0000000000000004 R09: 0000000000000040
[ 2327.228939] R10: 00007ffc3b730f30 R11: 0000000000000246 R12: 0000000000000003
[ 2327.236901] R13: 00007ffc3b731340 R14: 00007ffc3b7313d0 R15: 0000000000000084
[ 2327.244865] Object at ffff881be87797e0, in cache kmalloc-64 size: 64
[ 2327.251953] Allocated:
[ 2327.254581] PID = 9484
[ 2327.257215]  save_stack_trace+0x1b/0x20
[ 2327.261485]  save_stack+0x46/0xd0
[ 2327.265179]  kasan_kmalloc+0xad/0xe0
[ 2327.269165]  kmem_cache_alloc_trace+0xe6/0x1d0
[ 2327.274138]  sctp_add_bind_addr+0x58/0x180 [sctp]
[ 2327.279400]  sctp_do_bind+0x208/0x310 [sctp]
[ 2327.284176]  sctp_bind+0x61/0xa0 [sctp]
[ 2327.288455]  inet_bind+0x5f/0x3a0
[ 2327.292151]  SYSC_bind+0x1a4/0x1e0
[ 2327.295944]  SyS_bind+0xe/0x10
[ 2327.299349]  do_syscall_64+0xe3/0x230
[ 2327.303433]  return_from_SYSCALL_64+0x0/0x6a
[ 2327.308194] Freed:
[ 2327.310434] PID = 4131
[ 2327.313065]  save_stack_trace+0x1b/0x20
[ 2327.317344]  save_stack+0x46/0xd0
[ 2327.321040]  kasan_slab_free+0x73/0xc0
[ 2327.325220]  kfree+0x96/0x1a0
[ 2327.328530]  dynamic_kobj_release+0x15/0x40
[ 2327.333195]  kobject_release+0x99/0x1e0
[ 2327.337472]  kobject_put+0x38/0x70
[ 2327.341266]  free_notes_attrs+0x66/0x80
[ 2327.345545]  mod_sysfs_teardown+0x1a5/0x270
[ 2327.350211]  free_module+0x20/0x2a0
[ 2327.354099]  SyS_delete_module+0x2cb/0x2f0
[ 2327.358667]  do_syscall_64+0xe3/0x230
[ 2327.362750]  return_from_SYSCALL_64+0x0/0x6a
[ 2327.367510] Memory state around the buggy address:
[ 2327.372855]  ffff881be8779700: fc fc fc fc 00 00 00 00 00 00 00 00 fc fc fc fc
[ 2327.380914]  ffff881be8779780: fb fb fb fb fb fb fb fb fc fc fc fc 00 00 00 00
[ 2327.388972] >ffff881be8779800: 00 00 00 00 fc fc fc fc fb fb fb fb fb fb fb fb
[ 2327.397031]                                ^
[ 2327.401792]  ffff881be8779880: fc fc fc fc fb fb fb fb fb fb fb fb fc fc fc fc
[ 2327.409850]  ffff881be8779900: 00 00 00 00 00 04 fc fc fc fc fc fc 00 00 00 00
[ 2327.417907] ==================================================================

This fixes CVE-2017-7558.

References: https://bugzilla.redhat.com/show_bug.cgi?id=1480266
Fixes: 8f840e47 ("sctp: add the sctp_diag.c file")
Cc: Xin Long <lucien.xin@gmail.com>
Cc: Vlad Yasevich <vyasevich@gmail.com>
Cc: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: NStefano Brivio <sbrivio@redhat.com>
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Reviewed-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Now before dumping a sock in sctp_diag, it only holds the sock while
the ep may be already destroyed. It can cause a use-after-free panic
when accessing ep->asocs.

This patch is to set sctp_sk(sk)->ep NULL in sctp_endpoint_destroy,
and check if this ep is already destroyed before dumping this ep.
Suggested-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NNeil Horman <nhorman@tuxdrver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When sctp dumps all the ep->assocs, it needs to lock_sock first,
but now it locks sock in rcu_read_lock, and lock_sock may sleep,
which would break rcu_read_lock.

This patch is to get and hold one sock when traversing the list.
After that and get out of rcu_read_lock, lock and dump it. Then
it will traverse the list again to get the next one until all
sctp socks are dumped.

For sctp_diag_dump_one, it fixes this issue by holding asoc and
moving cb() out of rcu_read_lock in sctp_transport_lookup_process.

Fixes: 8f840e47 ("sctp: add the sctp_diag.c file")
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This adds the capability for a process that has CAP_NET_ADMIN on
a socket to see the socket mark in socket dumps.

Commit a52e95ab ("net: diag: allow socket bytecode filters to
match socket marks") recently gave privileged processes the
ability to filter socket dumps based on mark. This patch is
complementary: it ensures that the mark is also passed to
userspace in the socket's netlink attributes.  It is useful for
tools like ss which display information about sockets.

Tested: https://android-review.googlesource.com/270210Signed-off-by: NLorenzo Colitti <lorenzo@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The function sctp_diag_dump_one() currently performs a memcpy()
of 64 bytes from a 16 byte field into another 16 byte field. Fix
by using correct size, use sizeof to obtain correct size instead
of using a hard-coded constant.

Fixes: 8f840e47 ("sctp: add the sctp_diag.c file")
Signed-off-by: NLance Richardson <lrichard@redhat.com>
Reviewed-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Since 'ss' always adds TCPF_CLOSE to idiag_states flags, sctp_diag can't
rely upon TCPF_LISTEN flag solely being present when listening sockets
are requested.
Signed-off-by: NPhil Sutter <phil@nwl.cc>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The asoc's timer value is not kept in asoc->timeouts array but in it's
primary transport instead.

Furthermore, we must export the timer only if it is pending, otherwise
the value will underrun when stored in an unsigned variable and
user space will only see a very large timeout value.
Signed-off-by: NPhil Sutter <phil@nwl.cc>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The functions inet_diag_msg_common_fill and inet_diag_msg_attrs_fill
seem to have been missed from the include/linux/inet_diag.h header
file. Add them to fix the following warnings:

net/ipv4/inet_diag.c:69:6: warning: symbol 'inet_diag_msg_common_fill' was not declared. Should it be static?
net/ipv4/inet_diag.c:108:5: warning: symbol 'inet_diag_msg_attrs_fill' was not declared. Should it be static?
Signed-off-by: NBen Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We have this situation: that EP hash table, contains only the EPs
that are listening, while the transports one, has the opposite.
We have to traverse both to dump all.

But when we traverse the transports one we will also get EPs that are
in the EP hash if they are listening. In this case, the EP is dumped
twice.

We will fix it by checking if the endpoint that is in the endpoint
hash table contains any ep->asoc in there, as it means we will also
find it via transport hash, and thus we can/should skip it, depending
on the filters used, like 'ss -l'.

Still, we should NOT skip it if the user is listing only listening
endpoints, because then we are not traversing the transport hash.
so we have to check idiag_states there also.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

For sctp assoc, when rcvbuf_policy is set, it will has it's own
rmem_alloc, when we dump asoc info in sctp_diag, we should use that
value on RMEM_ALLOC as well, just like WMEM_ALLOC.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

I also fix the value of INET_DIAG_MAX. It's wrong since commit 8f840e47
which is only in net-next right now, thus I didn't make a separate patch.

Fixes: 8f840e47 ("sctp: add the sctp_diag.c file")
Signed-off-by: NNicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

EXPIRES_IN_MS macro comes from net/ipv4/inet_diag.c and dates
back to before jiffies_to_msecs() has been introduced.

Now we can remove it and use jiffies_to_msecs().
Suggested-by: NJakub Sitnicki <jkbs@redhat.com>
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NJakub Sitnicki <jkbs@redhat.com>
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This one will implement all the interface of inet_diag, inet_diag_handler.
which includes sctp_diag_dump, sctp_diag_dump_one and sctp_diag_get_info.

It will work as a module, and register inet_diag_handler when loading.

v2->v3:
- fix the mistake in inet_assoc_attr_size().

- change inet_diag_msg_laddrs_fill() name to inet_diag_msg_sctpladdrs_fill.

- change inet_diag_msg_paddrs_fill() name to inet_diag_msg_sctpaddrs_fill.

- add inet_diag_msg_sctpinfo_fill() to make asoc/ep fill code clearer.

- add inet_diag_msg_sctpasoc_fill() to make asoc fill code clearer.

- merge inet_asoc_diag_fill() and inet_ep_diag_fill() to
  inet_sctp_diag_fill().

- call sctp_diag_get_info() directly, instead by handler, cause the caller
  is in the same file with it.

- call lock_sock in sctp_tsp_dump_one() to make sure we call get sctp info
  safely.

- after lock_sock(sk), we should check sk != assoc->base.sk.

- change mem[SK_MEMINFO_WMEM_ALLOC] to asoc->sndbuf_used for asoc dump when
  asoc->ep->sndbuf_policy is set. don't use INET_DIAG_MEMINFO attr any more.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>