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2baae35453
linux/kernel/bpf
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Eric Dumazet 2baae35453 bpf: devmap: fix use-after-free Read in __dev_map_entry_free 
synchronize_rcu() is fine when the rcu callbacks only need
to free memory (kfree_rcu() or direct kfree() call rcu call backs)

__dev_map_entry_free() is a bit more complex, so we need to make
sure that call queued __dev_map_entry_free() callbacks have completed.

sysbot report:

BUG: KASAN: use-after-free in dev_map_flush_old kernel/bpf/devmap.c:365
[inline]
BUG: KASAN: use-after-free in __dev_map_entry_free+0x2a8/0x300
kernel/bpf/devmap.c:379
Read of size 8 at addr ffff8801b8da38c8 by task ksoftirqd/1/18

CPU: 1 PID: 18 Comm: ksoftirqd/1 Not tainted 4.17.0+ #39
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
  __dump_stack lib/dump_stack.c:77 [inline]
  dump_stack+0x1b9/0x294 lib/dump_stack.c:113
  print_address_description+0x6c/0x20b mm/kasan/report.c:256
  kasan_report_error mm/kasan/report.c:354 [inline]
  kasan_report.cold.7+0x242/0x2fe mm/kasan/report.c:412
  __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
  dev_map_flush_old kernel/bpf/devmap.c:365 [inline]
  __dev_map_entry_free+0x2a8/0x300 kernel/bpf/devmap.c:379
  __rcu_reclaim kernel/rcu/rcu.h:178 [inline]
  rcu_do_batch kernel/rcu/tree.c:2558 [inline]
  invoke_rcu_callbacks kernel/rcu/tree.c:2818 [inline]
  __rcu_process_callbacks kernel/rcu/tree.c:2785 [inline]
  rcu_process_callbacks+0xe9d/0x1760 kernel/rcu/tree.c:2802
  __do_softirq+0x2e0/0xaf5 kernel/softirq.c:284
  run_ksoftirqd+0x86/0x100 kernel/softirq.c:645
  smpboot_thread_fn+0x417/0x870 kernel/smpboot.c:164
  kthread+0x345/0x410 kernel/kthread.c:240
  ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412

Allocated by task 6675:
  save_stack+0x43/0xd0 mm/kasan/kasan.c:448
  set_track mm/kasan/kasan.c:460 [inline]
  kasan_kmalloc+0xc4/0xe0 mm/kasan/kasan.c:553
  kmem_cache_alloc_trace+0x152/0x780 mm/slab.c:3620
  kmalloc include/linux/slab.h:513 [inline]
  kzalloc include/linux/slab.h:706 [inline]
  dev_map_alloc+0x208/0x7f0 kernel/bpf/devmap.c:102
  find_and_alloc_map kernel/bpf/syscall.c:129 [inline]
  map_create+0x393/0x1010 kernel/bpf/syscall.c:453
  __do_sys_bpf kernel/bpf/syscall.c:2351 [inline]
  __se_sys_bpf kernel/bpf/syscall.c:2328 [inline]
  __x64_sys_bpf+0x303/0x510 kernel/bpf/syscall.c:2328
  do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:290
  entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 26:
  save_stack+0x43/0xd0 mm/kasan/kasan.c:448
  set_track mm/kasan/kasan.c:460 [inline]
  __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:521
  kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528
  __cache_free mm/slab.c:3498 [inline]
  kfree+0xd9/0x260 mm/slab.c:3813
  dev_map_free+0x4fa/0x670 kernel/bpf/devmap.c:191
  bpf_map_free_deferred+0xba/0xf0 kernel/bpf/syscall.c:262
  process_one_work+0xc64/0x1b70 kernel/workqueue.c:2153
  worker_thread+0x181/0x13a0 kernel/workqueue.c:2296
  kthread+0x345/0x410 kernel/kthread.c:240
  ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412

The buggy address belongs to the object at ffff8801b8da37c0
  which belongs to the cache kmalloc-512 of size 512
The buggy address is located 264 bytes inside of
  512-byte region [ffff8801b8da37c0, ffff8801b8da39c0)
The buggy address belongs to the page:
page:ffffea0006e368c0 count:1 mapcount:0 mapping:ffff8801da800940
index:0xffff8801b8da3540
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffffea0007217b88 ffffea0006e30cc8 ffff8801da800940
raw: ffff8801b8da3540 ffff8801b8da3040 0000000100000004 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
  ffff8801b8da3780: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
  ffff8801b8da3800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> ffff8801b8da3880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                               ^
  ffff8801b8da3900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
  ffff8801b8da3980: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc

Fixes: 546ac1ffb7 ("bpf: add devmap, a map for storing net device references")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot+457d3e2ffbcf31aee5c0@syzkaller.appspotmail.com
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-05-14 01:25:49 +02:00
..
arraymap.c bpf: allow for key-less BTF in array map 2019-04-09 17:05:46 -07:00
bpf_lru_list.c bpf: lru: Lower the PERCPU_NR_SCANS from 16 to 4 2017-04-17 13:55:52 -04:00
bpf_lru_list.h bpf: Only set node->ref = 1 if it has not been set 2017-09-01 09:57:39 -07:00
btf.c bpf: allow for key-less BTF in array map 2019-04-09 17:05:46 -07:00
cgroup.c bpf: add map helper functions push, pop, peek in more BPF programs 2019-04-16 10:24:02 +02:00
core.c bpf: fix out of bounds backwards jmps due to dead code removal 2019-05-10 18:49:27 -07:00
cpumap.c bpf: cpumap memory prefetchw optimizations for struct page 2019-04-17 19:09:25 -07:00
devmap.c bpf: devmap: fix use-after-free Read in __dev_map_entry_free 2019-05-14 01:25:49 +02:00
disasm.c bpf: implement lookup-free direct value access for maps 2019-04-09 17:05:46 -07:00
disasm.h bpf: Remove struct bpf_verifier_env argument from print_bpf_insn 2018-03-23 17:38:57 +01:00
hashtab.c bpf: add program side {rd, wr}only support for maps 2019-04-09 17:05:46 -07:00
helpers.c bpf: Introduce bpf_strtol and bpf_strtoul helpers 2019-04-12 13:54:59 -07:00
inode.c bpf: switch to ->free_inode() 2019-05-01 22:43:26 -04:00
local_storage.c bpf: add program side {rd, wr}only support for maps 2019-04-09 17:05:46 -07:00
lpm_trie.c bpf: add program side {rd, wr}only support for maps 2019-04-09 17:05:46 -07:00
Makefile bpf: add queue and stack maps 2018-10-19 13:24:31 -07:00
map_in_map.c bpf: set inner_map_meta->spin_lock_off correctly 2019-02-27 17:03:13 -08:00
map_in_map.h bpf: Add syscall lookup support for fd array and htab 2017-06-29 13:13:25 -04:00
offload.c bpf: offload: add priv field for drivers 2019-02-12 17:07:09 +01:00
percpu_freelist.c bpf: fix lockdep false positive in percpu_freelist 2019-01-31 23:18:21 +01:00
percpu_freelist.h bpf: fix lockdep false positive in percpu_freelist 2019-01-31 23:18:21 +01:00
queue_stack_maps.c bpf: add program side {rd, wr}only support for maps 2019-04-09 17:05:46 -07:00
reuseport_array.c bpf: Introduce BPF_MAP_TYPE_REUSEPORT_SOCKARRAY 2018-08-11 01:58:46 +02:00
stackmap.c bpf: fix lockdep false positive in stackmap 2019-02-11 16:36:24 +01:00
syscall.c bpf: Introduce bpf sk local storage 2019-04-27 09:07:04 -07:00
tnum.c bpf/verifier: improve register value range tracking with ARSH 2018-04-29 08:45:53 -07:00
verifier.c bpf: fix undefined behavior in narrow load handling 2019-05-13 02:05:50 +02:00
xskmap.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-10-19 11:03:06 -07:00