Am Montag, 18. Dezember 2017, 06:50:01 CET schrieb syzbot: Hi, > Hello, > > syzkaller hit the following crash on > 41d8c16909ebda40f7b4982a7f5e2ad102705ade > git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/master > compiler: gcc (GCC) 7.1.1 20170620 > .config is attached > Raw console output is attached. > C reproducer is attached > syzkaller reproducer is attached. See https://goo.gl/kgGztJ > for information about syzkaller reproducers > > > BUG: unable to handle kernel NULL pointer dereference at 0000000000000020 > IP: __crypto_alg_lookup+0x43/0x190 crypto/api.c:63 > PGD 0 P4D 0 > Oops: 0000 [#1] SMP > Dumping ftrace buffer: > (ftrace buffer empty) > Modules linked in: > CPU: 1 PID: 3321 Comm: cryptomgr_probe Not tainted > 4.15.0-rc3-next-20171213+ #66 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 01/01/2011 > RIP: 0010:__crypto_alg_lookup+0x43/0x190 crypto/api.c:63 > RSP: 0018:ffffc900017ebd28 EFLAGS: 00010293 > RAX: ffff880216762080 RBX: 0000000000000000 RCX: ffffffff81673d23 > RDX: 0000000000000000 RSI: 0000000000000403 RDI: ffff880214eba120 > RBP: ffffc900017ebd70 R08: 0000000000000001 R09: 0000000000000001 > R10: ffffc900017ebcf0 R11: 0000000000000000 R12: 0000000000000000 > R13: 0000000000000000 R14: 000000000000240f R15: 0000000000000403 > FS: 0000000000000000(0000) GS:ffff88021fd00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 0000000000000020 CR3: 000000020dc6b000 CR4: 00000000001406e0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > crypto_alg_lookup+0x31/0x50 crypto/api.c:201 > crypto_larval_lookup.part.8+0x34/0x1c0 crypto/api.c:218 > crypto_larval_lookup crypto/api.c:212 [inline] > crypto_alg_mod_lookup+0x77/0x120 crypto/api.c:271 > crypto_find_alg+0x63/0x70 crypto/api.c:501 > crypto_grab_spawn+0x2f/0x80 crypto/algapi.c:631 > crypto_grab_aead+0x35/0x40 crypto/aead.c:336 > pcrypt_create_aead crypto/pcrypt.c:298 [inline] > pcrypt_create+0xca/0x2c0 crypto/pcrypt.c:346 > cryptomgr_probe+0x40/0x100 crypto/algboss.c:75 > kthread+0x149/0x170 kernel/kthread.c:238 > ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:524 > Code: 89 7d d0 e8 70 66 c4 ff 48 8b 1d 59 e4 a6 01 48 81 fb 60 21 0e 83 0f > 84 4c 01 00 00 c7 45 c4 fe ff ff ff 45 31 e4 e8 4d 66 c4 ff <44> 8b 6b 20 > 41 f6 c5 60 0f 85 03 01 00 00 e8 3a 66 c4 ff 44 89 > RIP: __crypto_alg_lookup+0x43/0x190 crypto/api.c:63 RSP: ffffc900017ebd28 > CR2: 0000000000000020 > ---[ end trace ff8e3661b9c3aa04 ]--- > Kernel panic - not syncing: Fatal exception > Dumping ftrace buffer: > (ftrace buffer empty) > Kernel Offset: disabled > Rebooting in 86400 seconds.. This bug seems to be triggerable again by the fact that some strange mask/type combo is used. When setting it to zero, there is no crash. Therefore I would see that this issue would be covered with the fix that we currently work on to limit the number of allowed mask/type values. Ciao Stephan
