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Eric Dumazet 8aaeed81fc bpf: Fix error path in htab_map_alloc() 
syzbot was able to trigger a use-after-free in htab_map_alloc() [1]

htab_map_alloc() lacks a call to lockdep_unregister_key() in its error path.

lockdep_register_key() and lockdep_unregister_key() can not fail,
it seems better to use them right after htab allocation and before
htab freeing, avoiding more goto/labels in htab_map_alloc()

[1]
BUG: KASAN: use-after-free in lockdep_register_key+0x356/0x3e0 kernel/locking/lockdep.c:1182
Read of size 8 at addr ffff88805fa67ad8 by task syz-executor.3/2356

CPU: 1 PID: 2356 Comm: syz-executor.3 Not tainted 5.9.0-syzkaller #0
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+0x107/0x163 lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xae/0x4c8 mm/kasan/report.c:385
 __kasan_report mm/kasan/report.c:545 [inline]
 kasan_report.cold+0x1f/0x37 mm/kasan/report.c:562
 lockdep_register_key+0x356/0x3e0 kernel/locking/lockdep.c:1182
 htab_init_buckets kernel/bpf/hashtab.c:144 [inline]
 htab_map_alloc+0x6c5/0x14a0 kernel/bpf/hashtab.c:521
 find_and_alloc_map kernel/bpf/syscall.c:122 [inline]
 map_create kernel/bpf/syscall.c:825 [inline]
 __do_sys_bpf+0xa80/0x5180 kernel/bpf/syscall.c:4381
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45deb9
Code: 0d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 db b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f0eafee1c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 0000000000001a00 RCX: 000000000045deb9
RDX: 0000000000000040 RSI: 0000000020000040 RDI: 405a020000000000
RBP: 000000000118bf60 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118bf2c
R13: 00007ffd3cf9eabf R14: 00007f0eafee29c0 R15: 000000000118bf2c

Allocated by task 2053:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48
 kasan_set_track mm/kasan/common.c:56 [inline]
 __kasan_kmalloc.constprop.0+0xc2/0xd0 mm/kasan/common.c:461
 kmalloc include/linux/slab.h:554 [inline]
 kzalloc include/linux/slab.h:666 [inline]
 htab_map_alloc+0xdf/0x14a0 kernel/bpf/hashtab.c:454
 find_and_alloc_map kernel/bpf/syscall.c:122 [inline]
 map_create kernel/bpf/syscall.c:825 [inline]
 __do_sys_bpf+0xa80/0x5180 kernel/bpf/syscall.c:4381
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 2053:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48
 kasan_set_track+0x1c/0x30 mm/kasan/common.c:56
 kasan_set_free_info+0x1b/0x30 mm/kasan/generic.c:355
 __kasan_slab_free+0x102/0x140 mm/kasan/common.c:422
 slab_free_hook mm/slub.c:1544 [inline]
 slab_free_freelist_hook+0x5d/0x150 mm/slub.c:1577
 slab_free mm/slub.c:3142 [inline]
 kfree+0xdb/0x360 mm/slub.c:4124
 htab_map_alloc+0x3f9/0x14a0 kernel/bpf/hashtab.c:549
 find_and_alloc_map kernel/bpf/syscall.c:122 [inline]
 map_create kernel/bpf/syscall.c:825 [inline]
 __do_sys_bpf+0xa80/0x5180 kernel/bpf/syscall.c:4381
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

The buggy address belongs to the object at ffff88805fa67800
 which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 728 bytes inside of
 1024-byte region [ffff88805fa67800, ffff88805fa67c00)
The buggy address belongs to the page:
page:000000003c5582c4 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x5fa60
head:000000003c5582c4 order:3 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head)
raw: 00fff00000010200 ffffea0000bc1200 0000000200000002 ffff888010041140
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88805fa67980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88805fa67a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                    ^
 ffff88805fa67b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88805fa67b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb

Fixes: c50eb518e2 ("bpf: Use separate lockdep class for each hashtab")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20201102114100.3103180-1-eric.dumazet@gmail.com
2020-11-02 17:20:21 +01:00
..
preload bpf: Move prog->aux->linked_prog and trampoline into bpf_link on attach 2020-09-29 13:09:23 -07:00
arraymap.c bpf: Allow for map-in-map with dynamic inner array map entries 2020-10-11 10:21:04 -07:00
bpf_inode_storage.c bpf: Allow specifying a BTF ID per argument in function protos 2020-09-21 15:00:40 -07:00
bpf_iter.c bpf: Permit cond_resched for some iterators 2020-10-28 14:54:31 -07:00
bpf_local_storage.c bpf: Use hlist_add_head_rcu when linking to local_storage 2020-09-19 01:12:35 +02:00
bpf_lru_list.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 206 2019-05-30 11:29:53 -07:00
bpf_lru_list.h bpf: Fix a typo "inacitve" -> "inactive" 2020-04-06 21:54:10 +02:00
bpf_lsm.c bpf: Change bpf_sk_storage_*() to accept ARG_PTR_TO_BTF_ID_SOCK_COMMON 2020-09-25 13:58:01 -07:00
bpf_struct_ops_types.h bpf: tcp: Support tcp_congestion_ops in bpf 2020-01-09 08:46:18 -08:00
bpf_struct_ops.c bpf: Move btf_resolve_size into __btf_resolve_size 2020-08-25 15:37:41 -07:00
btf.c bpf: Introduce bpf_per_cpu_ptr() 2020-10-02 15:00:49 -07:00
cgroup.c Merge branch 'work.set_fs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-10-22 09:59:21 -07:00
core.c networking changes for the 5.10 merge window 2020-10-15 18:42:13 -07:00
cpumap.c bpf, cpumap: Remove rcpu pointer from cpu_map_build_skb signature 2020-09-28 23:30:42 +02:00
devmap.c bpf: {cpu,dev}map: Change various functions return type from int to void 2020-09-01 15:45:58 +02:00
disasm.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 295 2019-06-05 17:36:38 +02:00
disasm.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 295 2019-06-05 17:36:38 +02:00
dispatcher.c bpf: Remove bpf_image tree 2020-03-13 12:49:52 -07:00
hashtab.c bpf: Fix error path in htab_map_alloc() 2020-11-02 17:20:21 +01:00
helpers.c bpf: Introducte bpf_this_cpu_ptr() 2020-10-02 15:00:49 -07:00
inode.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-09-22 16:45:34 -07:00
local_storage.c bpf/local_storage: Fix build without CONFIG_CGROUP 2020-07-25 20:16:36 -07:00
lpm_trie.c bpf: Add map_meta_equal map ops 2020-08-28 15:41:30 +02:00
Makefile bpf: Implement bpf_local_storage for inodes 2020-08-25 15:00:04 -07:00
map_in_map.c bpf: Relax max_entries check for most of the inner map types 2020-08-28 15:41:30 +02:00
map_in_map.h bpf: Add map_meta_equal map ops 2020-08-28 15:41:30 +02:00
map_iter.c bpf: Implement link_query callbacks in map element iterators 2020-08-21 14:01:39 -07:00
net_namespace.c bpf: Add support for forced LINK_DETACH command 2020-08-01 20:38:28 -07:00
offload.c bpf, offload: Replace bitwise AND by logical AND in bpf_prog_offload_info_fill 2020-02-17 16:53:49 +01:00
percpu_freelist.c bpf: Use raw_spin_trylock() for pcpu_freelist_push/pop in NMI 2020-10-06 00:04:11 +02:00
percpu_freelist.h bpf: Use raw_spin_trylock() for pcpu_freelist_push/pop in NMI 2020-10-06 00:04:11 +02:00
prog_iter.c bpf: Refactor bpf_iter_reg to have separate seq_info member 2020-07-25 20:16:32 -07:00
queue_stack_maps.c bpf: Add map_meta_equal map ops 2020-08-28 15:41:30 +02:00
reuseport_array.c bpf, net: Rework cookie generator as per-cpu one 2020-09-30 11:50:35 -07:00
ringbuf.c bpf: Add map_meta_equal map ops 2020-08-28 15:41:30 +02:00
stackmap.c bpf: Allow specifying a BTF ID per argument in function protos 2020-09-21 15:00:40 -07:00
syscall.c bpf: Remove unneeded break 2020-10-19 20:40:21 +02:00
sysfs_btf.c bpf: Fix sysfs export of empty BTF section 2020-09-21 21:50:24 +02:00
task_iter.c bpf: Permit cond_resched for some iterators 2020-10-28 14:54:31 -07:00
tnum.c bpf: Verifier, do explicit ALU32 bounds tracking 2020-03-30 14:59:53 -07:00
trampoline.c bpf: Move prog->aux->linked_prog and trampoline into bpf_link on attach 2020-09-29 13:09:23 -07:00
verifier.c bpf: Enforce id generation for all may-be-null register type 2020-10-19 15:57:42 -07:00