[PATCH 4.12 08/84] net: core: Fix slab-out-of-bounds in netdev_stats_to_stats64

From: Greg Kroah-Hartman
Date: Wed Jul 19 2017 - 05:45:10 EST

4.12-stable review patch. If anyone has any objections, please let me know.

------------------

From: Alban Browaeys <alban.browaeys@xxxxxxxxx>


[ Upstream commit 9af9959e142c274f4a30fefb71d97d2b028b337f ]

commit 9256645af098 ("net/core: relax BUILD_BUG_ON in
netdev_stats_to_stats64") made an attempt to read beyond
the size of the source a possibility.

Fix to only copy src size to dest. As dest might be bigger than src.

==================================================================
BUG: KASAN: slab-out-of-bounds in netdev_stats_to_stats64+0xe/0x30 at addr ffff8801be248b20
Read of size 192 by task VBoxNetAdpCtl/6734
CPU: 1 PID: 6734 Comm: VBoxNetAdpCtl Tainted: G O 4.11.4prahal+intel+ #118
Hardware name: LENOVO 20CDCTO1WW/20CDCTO1WW, BIOS GQET52WW (1.32 ) 05/04/2017
Call Trace:
dump_stack+0x63/0x86
kasan_object_err+0x1c/0x70
kasan_report+0x270/0x520
? netdev_stats_to_stats64+0xe/0x30
? sched_clock_cpu+0x1b/0x190
? __module_address+0x3e/0x3b0
? unwind_next_frame+0x1ea/0xb00
check_memory_region+0x13c/0x1a0
memcpy+0x23/0x50
netdev_stats_to_stats64+0xe/0x30
dev_get_stats+0x1b9/0x230
rtnl_fill_stats+0x44/0xc00
? nla_put+0xc6/0x130
rtnl_fill_ifinfo+0xe9e/0x3700
? rtnl_fill_vfinfo+0xde0/0xde0
? sched_clock+0x9/0x10
? sched_clock+0x9/0x10
? sched_clock_local+0x120/0x130
? __module_address+0x3e/0x3b0
? unwind_next_frame+0x1ea/0xb00
? sched_clock+0x9/0x10
? sched_clock+0x9/0x10
? sched_clock_cpu+0x1b/0x190
? VBoxNetAdpLinuxIOCtlUnlocked+0x14b/0x280 [vboxnetadp]
? depot_save_stack+0x1d8/0x4a0
? depot_save_stack+0x34f/0x4a0
? depot_save_stack+0x34f/0x4a0
? save_stack+0xb1/0xd0
? save_stack_trace+0x16/0x20
? save_stack+0x46/0xd0
? kasan_slab_alloc+0x12/0x20
? __kmalloc_node_track_caller+0x10d/0x350
? __kmalloc_reserve.isra.36+0x2c/0xc0
? __alloc_skb+0xd0/0x560
? rtmsg_ifinfo_build_skb+0x61/0x120
? rtmsg_ifinfo.part.25+0x16/0xb0
? rtmsg_ifinfo+0x47/0x70
? register_netdev+0x15/0x30
? vboxNetAdpOsCreate+0xc0/0x1c0 [vboxnetadp]
? vboxNetAdpCreate+0x210/0x400 [vboxnetadp]
? VBoxNetAdpLinuxIOCtlUnlocked+0x14b/0x280 [vboxnetadp]
? do_vfs_ioctl+0x17f/0xff0
? SyS_ioctl+0x74/0x80
? do_syscall_64+0x182/0x390
? __alloc_skb+0xd0/0x560
? __alloc_skb+0xd0/0x560
? save_stack_trace+0x16/0x20
? init_object+0x64/0xa0
? ___slab_alloc+0x1ae/0x5c0
? ___slab_alloc+0x1ae/0x5c0
? __alloc_skb+0xd0/0x560
? sched_clock+0x9/0x10
? kasan_unpoison_shadow+0x35/0x50
? kasan_kmalloc+0xad/0xe0
? __kmalloc_node_track_caller+0x246/0x350
? __alloc_skb+0xd0/0x560
? kasan_unpoison_shadow+0x35/0x50
? memset+0x31/0x40
? __alloc_skb+0x31f/0x560
? napi_consume_skb+0x320/0x320
? br_get_link_af_size_filtered+0xb7/0x120 [bridge]
? if_nlmsg_size+0x440/0x630
rtmsg_ifinfo_build_skb+0x83/0x120
rtmsg_ifinfo.part.25+0x16/0xb0
rtmsg_ifinfo+0x47/0x70
register_netdevice+0xa2b/0xe50
? __kmalloc+0x171/0x2d0
? netdev_change_features+0x80/0x80
register_netdev+0x15/0x30
vboxNetAdpOsCreate+0xc0/0x1c0 [vboxnetadp]
vboxNetAdpCreate+0x210/0x400 [vboxnetadp]
? vboxNetAdpComposeMACAddress+0x1d0/0x1d0 [vboxnetadp]
? kasan_check_write+0x14/0x20
VBoxNetAdpLinuxIOCtlUnlocked+0x14b/0x280 [vboxnetadp]
? VBoxNetAdpLinuxOpen+0x20/0x20 [vboxnetadp]
? lock_acquire+0x11c/0x270
? __audit_syscall_entry+0x2fb/0x660
do_vfs_ioctl+0x17f/0xff0
? __audit_syscall_entry+0x2fb/0x660
? ioctl_preallocate+0x1d0/0x1d0
? __audit_syscall_entry+0x2fb/0x660
? kmem_cache_free+0xb2/0x250
? syscall_trace_enter+0x537/0xd00
? exit_to_usermode_loop+0x100/0x100
SyS_ioctl+0x74/0x80
? do_sys_open+0x350/0x350
? do_vfs_ioctl+0xff0/0xff0
do_syscall_64+0x182/0x390
entry_SYSCALL64_slow_path+0x25/0x25
RIP: 0033:0x7f7e39a1ae07
RSP: 002b:00007ffc6f04c6d8 EFLAGS: 00000206 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007ffc6f04c730 RCX: 00007f7e39a1ae07
RDX: 00007ffc6f04c730 RSI: 00000000c0207601 RDI: 0000000000000007
RBP: 00007ffc6f04c700 R08: 00007ffc6f04c780 R09: 0000000000000008
R10: 0000000000000541 R11: 0000000000000206 R12: 0000000000000007
R13: 00000000c0207601 R14: 00007ffc6f04c730 R15: 0000000000000012
Object at ffff8801be248008, in cache kmalloc-4096 size: 4096
Allocated:
PID = 6734
save_stack_trace+0x16/0x20
save_stack+0x46/0xd0
kasan_kmalloc+0xad/0xe0
__kmalloc+0x171/0x2d0
alloc_netdev_mqs+0x8a7/0xbe0
vboxNetAdpOsCreate+0x65/0x1c0 [vboxnetadp]
vboxNetAdpCreate+0x210/0x400 [vboxnetadp]
VBoxNetAdpLinuxIOCtlUnlocked+0x14b/0x280 [vboxnetadp]
do_vfs_ioctl+0x17f/0xff0
SyS_ioctl+0x74/0x80
do_syscall_64+0x182/0x390
return_from_SYSCALL_64+0x0/0x6a
Freed:
PID = 5600
save_stack_trace+0x16/0x20
save_stack+0x46/0xd0
kasan_slab_free+0x73/0xc0
kfree+0xe4/0x220
kvfree+0x25/0x30
single_release+0x74/0xb0
__fput+0x265/0x6b0
____fput+0x9/0x10
task_work_run+0xd5/0x150
exit_to_usermode_loop+0xe2/0x100
do_syscall_64+0x26c/0x390
return_from_SYSCALL_64+0x0/0x6a
Memory state around the buggy address:
ffff8801be248a80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff8801be248b00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8801be248b80: 00 00 00 00 00 00 00 00 00 00 00 07 fc fc fc fc
^
ffff8801be248c00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8801be248c80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================

Signed-off-by: Alban Browaeys <alban.browaeys@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/core/dev.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -7751,7 +7751,7 @@ void netdev_stats_to_stats64(struct rtnl
{
#if BITS_PER_LONG == 64
BUILD_BUG_ON(sizeof(*stats64) < sizeof(*netdev_stats));
- memcpy(stats64, netdev_stats, sizeof(*stats64));
+ memcpy(stats64, netdev_stats, sizeof(*netdev_stats));
/* zero out counters that only exist in rtnl_link_stats64 */
memset((char *)stats64 + sizeof(*netdev_stats), 0,
sizeof(*stats64) - sizeof(*netdev_stats));