ee6c88bb75
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:
|
||
---|---|---|
Documentation | ||
arch | ||
block | ||
certs | ||
crypto | ||
drivers | ||
firmware | ||
fs | ||
include | ||
init | ||
ipc | ||
kernel | ||
lib | ||
mm | ||
net | ||
samples | ||
scripts | ||
security | ||
sound | ||
tools | ||
usr | ||
virt | ||
.cocciconfig | ||
.get_maintainer.ignore | ||
.gitattributes | ||
.gitignore | ||
.mailmap | ||
COPYING | ||
CREDITS | ||
Kbuild | ||
Kconfig | ||
MAINTAINERS | ||
Makefile | ||
README |
README
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.