syzbot


WARNING: refcount bug in crypto_destroy_tfm

Status: fixed on 2020/07/17 17:58
Subsystems: crypto
[Documentation on labels]
Reported-by: syzbot+fc0674cde00b66844470@syzkaller.appspotmail.com
Fix commit: 6603523bf5e4 crypto: api - Fix use-after-free and race in crypto_spawn_alg
First crash: 1515d, last: 1489d
Cause bisection: introduced by (bisect log) :
commit 4f87ee118d16b4b2116a477229573ed5003b0d78
Author: Herbert Xu <herbert@gondor.apana.org.au>
Date: Sat Dec 7 14:15:17 2019 +0000

  crypto: api - Do not zap spawn->alg

Crash: WARNING: refcount bug in crypto_destroy_tfm (log)
Repro: C syz .config
  
Discussions (4)
Title Replies (including bot) Last reply
[PATCH 5.7 00/14] 5.7.1-rc1 review 23 (23) 2020/06/07 20:21
[PATCH 5.6 00/43] 5.6.17-rc1 review 50 (50) 2020/06/06 16:12
WARNING: refcount bug in crypto_destroy_tfm 5 (6) 2020/04/16 02:42
Re: crypto: api - Fix use-after-free and race in crypto_spawn_alg 1 (1) 2020/04/10 09:18

Sample crash report:
------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 0 PID: 7336 at lib/refcount.c:28 refcount_warn_saturate+0x1d1/0x1e0 lib/refcount.c:28
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 7336 Comm: syz-executor080 Not tainted 5.7.0-rc3-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+0x188/0x20d lib/dump_stack.c:118
 panic+0x2e3/0x75c kernel/panic.c:221
 __warn.cold+0x2f/0x35 kernel/panic.c:582
 report_bug+0x27b/0x2f0 lib/bug.c:195
 fixup_bug arch/x86/kernel/traps.c:175 [inline]
 fixup_bug arch/x86/kernel/traps.c:170 [inline]
 do_error_trap+0x12b/0x220 arch/x86/kernel/traps.c:267
 do_invalid_op+0x32/0x40 arch/x86/kernel/traps.c:286
 invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1027
RIP: 0010:refcount_warn_saturate+0x1d1/0x1e0 lib/refcount.c:28
Code: e9 db fe ff ff 48 89 df e8 2c 7f 1a fe e9 8a fe ff ff e8 82 b2 dc fd 48 c7 c7 00 5c 72 88 c6 05 e9 16 ee 06 01 e8 87 ed ad fd <0f> 0b e9 af fe ff ff 0f 1f 84 00 00 00 00 00 41 56 41 55 41 54 55
RSP: 0018:ffffc90001be7b20 EFLAGS: 00010286
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff815ce171 RDI: fffff5200037cf56
RBP: 0000000000000003 R08: ffff88808ddb6400 R09: ffffed1015cc66a9
R10: ffff8880ae633547 R11: ffffed1015cc66a8 R12: ffff88809f93c07c
R13: ffff88809e23b400 R14: 0000000000000000 R15: ffff88809e23b410
 refcount_sub_and_test include/linux/refcount.h:274 [inline]
 refcount_dec_and_test include/linux/refcount.h:294 [inline]
 crypto_alg_put crypto/internal.h:93 [inline]
 crypto_mod_put crypto/api.c:45 [inline]
 crypto_destroy_tfm+0x2a1/0x310 crypto/api.c:566
 crypto_exit_ops crypto/api.c:308 [inline]
 crypto_destroy_tfm+0xb1/0x310 crypto/api.c:565
 crypto_free_aead include/crypto/aead.h:191 [inline]
 aead_release+0x2d/0x50 crypto/algif_aead.c:506
 alg_do_release crypto/af_alg.c:114 [inline]
 alg_sock_destruct+0x85/0xe0 crypto/af_alg.c:358
 __sk_destruct+0x4b/0x7c0 net/core/sock.c:1696
 sk_destruct+0xc6/0x100 net/core/sock.c:1740
 __sk_free+0xef/0x3d0 net/core/sock.c:1751
 sk_free+0x78/0xa0 net/core/sock.c:1762
 sock_put include/net/sock.h:1778 [inline]
 af_alg_release+0xdb/0x110 crypto/af_alg.c:121
 __sock_release+0xcd/0x280 net/socket.c:605
 sock_close+0x18/0x20 net/socket.c:1283
 __fput+0x33e/0x880 fs/file_table.c:280
 task_work_run+0xf4/0x1b0 kernel/task_work.c:123
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0xb34/0x2dd0 kernel/exit.c:796
 do_group_exit+0x125/0x340 kernel/exit.c:894
 __do_sys_exit_group kernel/exit.c:905 [inline]
 __se_sys_exit_group kernel/exit.c:903 [inline]
 __x64_sys_exit_group+0x3a/0x50 kernel/exit.c:903
 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x49/0xb3
RIP: 0033:0x43ffc8
Code: 00 00 be 3c 00 00 00 eb 19 66 0f 1f 84 00 00 00 00 00 48 89 d7 89 f0 0f 05 48 3d 00 f0 ff ff 77 21 f4 48 89 d7 44 89 c0 0f 05 <48> 3d 00 f0 ff ff 76 e0 f7 d8 64 41 89 01 eb d8 0f 1f 84 00 00 00
RSP: 002b:00007ffd619a8288 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ffc8
RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000
RBP: 00000000004bf890 R08: 00000000000000e7 R09: ffffffffffffffd0
R10: 00000000004002c8 R11: 0000000000000246 R12: 0000000000000001
R13: 00000000006d1180 R14: 0000000000000000 R15: 0000000000000000
Kernel Offset: disabled
Rebooting in 86400 seconds..

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/04/29 05:27 upstream 3f777e19d171 e3ecea2e .config console log report syz C ci-upstream-kasan-gce-selinux-root
2020/04/09 22:30 upstream 5d30bcacd91a a8c6a3f8 .config console log report syz C ci-upstream-kasan-gce
2020/04/03 21:34 net-old 468c2a100208 5ed396e6 .config console log report syz C ci-upstream-net-this-kasan-gce
2020/04/03 22:26 net-next-old 1a323ea5356e 5ed396e6 .config console log report syz C ci-upstream-net-kasan-gce
* Struck through repros no longer work on HEAD.