general protection fault in scatterwalk_copychunks

[syzbot]

Hello,

syzkaller hit the following crash on
1ea8d039f9edcfefb20d8ddfe136930f6e551529
git://git.cmpxchg.org/linux-mmots.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


kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] SMP KASAN
Dumping ftrace buffer:
(ftrace buffer empty)
Modules linked in:
CPU: 0 PID: 17658 Comm: syzkaller625686 Not tainted 4.14.0-mm1+ #25
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
task: ffff8801c734e280 task.stack: ffff8801c5f10000
RIP: 0010:scatterwalk_start include/crypto/scatterwalk.h:86 [inline]
RIP: 0010:scatterwalk_pagedone include/crypto/scatterwalk.h:111 [inline]
RIP: 0010:scatterwalk_copychunks+0x337/0x480 crypto/scatterwalk.c:55
RSP: 0018:ffff8801c5f175c8 EFLAGS: 00010202
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff82502da9
RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000000000000008
RBP: ffff8801c5f17628 R08: ffff8801c5f177c0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: ffff8801c5f177c0 R14: dffffc0000000000 R15: 0000000000000000
FS: 00007f8ce5e49700(0000) GS:ffff8801db400000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020284000 CR3: 00000001ce96c000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
blkcipher_next_slow crypto/blkcipher.c:175 [inline]
blkcipher_walk_next+0xca0/0x13d0 crypto/blkcipher.c:255
blkcipher_walk_first+0x261/0x570 crypto/blkcipher.c:346
blkcipher_walk_virt+0x219/0x2a0 crypto/blkcipher.c:308
skcipher_null_crypt+0x10e/0x2d0 crypto/crypto_null.c:85
skcipher_crypt_blkcipher crypto/skcipher.c:619 [inline]
skcipher_encrypt_blkcipher+0x213/0x310 crypto/skcipher.c:628
crypto_skcipher_encrypt include/crypto/skcipher.h:445 [inline]
crypto_aead_copy_sgl crypto/algif_aead.c:90 [inline]
_aead_recvmsg crypto/algif_aead.c:228 [inline]
aead_recvmsg+0xc96/0x1970 crypto/algif_aead.c:313
aead_recvmsg_nokey+0x60/0x80 crypto/algif_aead.c:431
sock_recvmsg_nosec net/socket.c:805 [inline]
sock_recvmsg+0xc9/0x110 net/socket.c:812
___sys_recvmsg+0x29b/0x630 net/socket.c:2207
__sys_recvmsg+0xe2/0x210 net/socket.c:2252
SYSC_recvmsg net/socket.c:2264 [inline]
SyS_recvmsg+0x2d/0x50 net/socket.c:2259
entry_SYSCALL_64_fastpath+0x1f/0x96
RIP: 0033:0x4466c9
RSP: 002b:00007f8ce5e48dc8 EFLAGS: 00000202 ORIG_RAX: 000000000000002f
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00000000004466c9
RDX: 0000000000002000 RSI: 0000000020222fc8 RDI: 0000000000000006
RBP: 0000000000000086 R08: 00007f8ce5e49700 R09: 00007f8ce5e49700
R10: 00007f8ce5e49700 R11: 0000000000000202 R12: 0000000000000000
R13: 00007ffe3cc2e51f R14: 00007f8ce5e499c0 R15: 0000000000000000
Code: 89 ff e8 6d 6f 2a 00 4c 89 ea 49 89 c7 48 c1 ea 03 42 80 3c 32 00 0f
85 c9 00 00 00 49 8d 7f 08 4d 89 7d 00 48 89 fa 48 c1 ea 03 <42> 0f b6 14
32 84 d2 74 09 80 fa 03 0f 8e 9e 00 00 00 48 8b 45
RIP: scatterwalk_start include/crypto/scatterwalk.h:86 [inline] RSP:
ffff8801c5f175c8
RIP: scatterwalk_pagedone include/crypto/scatterwalk.h:111 [inline] RSP:
ffff8801c5f175c8
RIP: scatterwalk_copychunks+0x337/0x480 crypto/scatterwalk.c:55 RSP:
ffff8801c5f175c8
---[ end trace 52b72f449649c1ea ]---


---
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[Stephan Müller]

Am Dienstag, 28. November 2017, 18:24:01 CET schrieb syzbot:

Hi,

After compiling the kernel with the given config and execute the test app for
now 10 minutes, I am unable to reproduce the issue.

Ok, granted, I use the patches https://git.kernel.org/pub/scm/linux/kernel/
git/herbert/crypto-2.6.git/commit/?id=7d2c3f54e6f646887d019faa45f35d6fe9fe82ce
and https://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6.git/
commit/?id=8e1fa89aa8bc2870009b4486644e4a58f2e2a4f5

Do you have an idea what I need to change to reproduce the issue? Note, my
test system is a KVM/QEMU 64 bit virtual machine.

Thanks.

Ciao
Stephan

[Eric Biggers]

#syz fix: crypto: algif_aead - skip SGL entries with NULL page