Stefano Brivio ee6c88bb75 sctp: Avoid out-of-bounds reads from address storage ... 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: 8f840e47f1 ("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: Stefano Brivio <sbrivio@redhat.com> Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Reviewed-by: Xin Long <lucien.xin@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>		2017-08-23 22:35:15 -07:00
..
6lowpan
9p	Merge branch 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2017-07-15 12:00:42 -07:00
802	net: introduce __skb_put_[zero, data, u8]	2017-06-20 13:30:14 -04:00
8021q	net: add netlink_ext_ack argument to rtnl_link_ops.validate	2017-06-26 23:13:22 -04:00
appletalk	networking: make skb_push & __skb_push return void pointers	2017-06-16 11:48:40 -04:00
atm	net, atm: convert eg_cache_entry.use from atomic_t to refcount_t	2017-07-04 22:35:16 +01:00
ax25	net, ax25: convert ax25_cb.refcount from atomic_t to refcount_t	2017-07-04 22:35:19 +01:00
batman-adv	batman-adv: fix TT sync flag inconsistencies	2017-07-31 11:17:38 +02:00
bluetooth	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next	2017-07-05 12:31:59 -07:00
bpf
bridge	net: bridge: fix dest lookup when vlan proto doesn't match	2017-07-14 08:19:23 -07:00
caif	net: convert sock.sk_wmem_alloc from atomic_t to refcount_t	2017-07-01 07:39:08 -07:00
can	networking: introduce and use skb_put_data()	2017-06-16 11:48:37 -04:00
ceph	libceph: make RECOVERY_DELETES feature create a new interval	2017-08-01 16:46:45 +02:00
core	net: core: Specify skb_pad()/skb_put_padto() SKB freeing	2017-08-23 20:33:49 -07:00
dcb	dcb: enforce minimum length on IEEE_APPS attribute	2017-05-21 13:42:33 -04:00
dccp	dccp: defer ccid_hc_tx_delete() at dismantle time	2017-08-16 14:26:26 -07:00
decnet	net, decnet: convert dn_fib_info.fib_clntref from atomic_t to refcount_t	2017-07-04 22:35:15 +01:00
dns_resolver
dsa	net: dsa: use consume_skb()	2017-08-23 22:13:34 -07:00
ethernet	networking: make skb_push & __skb_push return void pointers	2017-06-16 11:48:40 -04:00
hsr	net/hsr: Check skb_put_padto() return value	2017-08-22 13:40:23 -07:00
ieee802154	net: add netlink_ext_ack argument to rtnl_link_ops.validate	2017-06-26 23:13:22 -04:00
ife
ipv4	Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec	2017-08-22 10:27:26 -07:00
ipv6	ipv6: add rcu grace period before freeing fib6_node	2017-08-22 11:03:19 -07:00
ipx	net, ipx: convert ipx_route.refcnt from atomic_t to refcount_t	2017-07-04 22:35:17 +01:00
irda	irda: do not leak initialized list.dev to userspace	2017-08-18 16:21:51 -07:00
iucv	iucv: Convert sk_wmem_alloc accesses to refcount_t.	2017-07-03 02:31:22 -07:00
kcm	net: convert sock.sk_wmem_alloc from atomic_t to refcount_t	2017-07-01 07:39:08 -07:00
key	af_key: do not use GFP_KERNEL in atomic contexts	2017-08-14 22:18:12 -07:00
l2tp	net, l2tp: convert l2tp_session.ref_count from atomic_t to refcount_t	2017-07-04 22:35:15 +01:00
l3mdev
lapb	net, lapb: convert lapb_cb.refcnt from atomic_t to refcount_t	2017-07-04 22:35:16 +01:00
llc	net, llc: convert llc_sap.refcnt from atomic_t to refcount_t	2017-07-04 22:35:15 +01:00
mac80211	mac80211: add api to start ba session timer expired flow	2017-08-09 09:49:42 +03:00
mac802154	net: Fix inconsistent teardown and release of private netdev state.	2017-06-07 15:53:24 -04:00
mpls	mpls: fix uninitialized in_label var warning in mpls_getroute	2017-07-08 11:26:41 +01:00
ncsi	networking: make skb_push & __skb_push return void pointers	2017-06-16 11:48:40 -04:00
netfilter	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net	2017-07-20 16:33:39 -07:00
netlabel
netlink	net: convert sock.sk_refcnt from atomic_t to refcount_t	2017-07-01 07:39:08 -07:00
netrom	net, netrom: convert nr_node.refcount from atomic_t to refcount_t	2017-07-04 22:35:17 +01:00
nfc	NFC: Add sockaddr length checks before accessing sa_family in bind handlers	2017-06-23 00:38:31 +02:00
openvswitch	openvswitch: fix skb_panic due to the incorrect actions attrlen	2017-08-16 14:12:37 -07:00
packet	packet: fix tp_reserve race in packet_set_ring	2017-08-10 09:52:12 -07:00
phonet	net: convert sock.sk_refcnt from atomic_t to refcount_t	2017-07-01 07:39:08 -07:00
psample	networking: make skb_put & friends return void pointers	2017-06-16 11:48:39 -04:00
qrtr	networking: make skb_put & friends return void pointers	2017-06-16 11:48:39 -04:00
rds	rds: Reintroduce statistics counting	2017-08-08 21:03:47 -07:00
rfkill	net: rfkill: gpio: Switch to devm_acpi_dev_add_driver_gpios()	2017-06-13 11:07:51 +02:00
rose
rxrpc	rxrpc: Fix oops when discarding a preallocated service call	2017-08-18 16:23:23 -07:00
sched	net: sched: don't do tcf_chain_flush from tcf_chain_destroy	2017-08-22 14:39:58 -07:00
sctp	sctp: Avoid out-of-bounds reads from address storage	2017-08-23 22:35:15 -07:00
smc
strparser
sunrpc	NFS client bugfixes for 4.13	2017-07-21 16:26:01 -07:00
switchdev	net: switchdev: Change notifier chain to be atomic	2017-06-08 14:16:24 -04:00
tipc	tipc: fix a race condition of releasing subscriber object	2017-08-22 14:25:02 -07:00
tls	TLS: Fix length check in do_tls_getsockopt_tx()	2017-07-06 10:58:19 +01:00
unix	datagram: When peeking datagrams with offset < 0 don't skip empty skbs	2017-08-18 15:12:54 -07:00
vmw_vsock	net: manual clean code which call skb_put_[data:zero]	2017-06-20 13:30:15 -04:00
wimax
wireless	netlink validation fixes for nl80211	2017-07-07 11:35:55 +01:00
x25	net, x25: convert x25_neigh.refcnt from atomic_t to refcount_t	2017-07-04 22:35:18 +01:00
xfrm	xfrm: policy: check policy direction value	2017-08-03 10:15:22 +02:00
compat.c	get_compat_bpf_fprog(): don't copyin field-by-field	2017-07-04 13:14:34 -04:00
Kconfig	tls: kernel TLS support	2017-06-15 12:12:40 -04:00
Makefile	tls: kernel TLS support	2017-06-15 12:12:40 -04:00
socket.c	net/socket: fix type in assignment and trim long line	2017-07-24 14:17:01 -07:00
sysctl_net.c