[syzbot] UBSAN: shift-out-of-bounds in xfrm_get_default

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syzbot

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Aug 30, 2021, 4:19:27 PM8/30/21
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Hello,

syzbot found the following issue on:

HEAD commit: eaf2aaec0be4 Merge tag 'wireless-drivers-next-2021-08-29' ..
git tree: net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=1219326d300000
kernel config: https://syzkaller.appspot.com/x/.config?x=d2f9d4c9ff8c5ae7
dashboard link: https://syzkaller.appspot.com/bug?extid=b2be9dd8ca6f6c73ee2d
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.1
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11e6e3a9300000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10de8a6d300000

The issue was bisected to:

commit 2d151d39073aff498358543801fca0f670fea981
Author: Steffen Klassert <steffen....@secunet.com>
Date: Sun Jul 18 07:11:06 2021 +0000

xfrm: Add possibility to set the default to block if we have no policy

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=114523fe300000
final oops: https://syzkaller.appspot.com/x/report.txt?x=134523fe300000
console output: https://syzkaller.appspot.com/x/log.txt?x=154523fe300000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b2be9d...@syzkaller.appspotmail.com
Fixes: 2d151d39073a ("xfrm: Add possibility to set the default to block if we have no policy")

netlink: 172 bytes leftover after parsing attributes in process `syz-executor354'.
================================================================================
UBSAN: shift-out-of-bounds in net/xfrm/xfrm_user.c:2010:49
shift exponent 224 is too large for 32-bit type 'int'
CPU: 1 PID: 8447 Comm: syz-executor354 Not tainted 5.14.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:105
ubsan_epilogue+0xb/0x5a lib/ubsan.c:148
__ubsan_handle_shift_out_of_bounds.cold+0xb1/0x181 lib/ubsan.c:327
xfrm_get_default.cold+0x1f/0x75 net/xfrm/xfrm_user.c:2010
xfrm_user_rcv_msg+0x430/0xa20 net/xfrm/xfrm_user.c:2869
netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2504
xfrm_netlink_rcv+0x6b/0x90 net/xfrm/xfrm_user.c:2891
netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline]
netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1340
netlink_sendmsg+0x86d/0xdb0 net/netlink/af_netlink.c:1929
sock_sendmsg_nosec net/socket.c:704 [inline]
sock_sendmsg+0xcf/0x120 net/socket.c:724
sock_no_sendpage+0xf3/0x130 net/core/sock.c:2980
kernel_sendpage.part.0+0x1a0/0x340 net/socket.c:3496
kernel_sendpage net/socket.c:3493 [inline]
sock_sendpage+0xe5/0x140 net/socket.c:1003
pipe_to_sendpage+0x2ad/0x380 fs/splice.c:364
splice_from_pipe_feed fs/splice.c:418 [inline]
__splice_from_pipe+0x43e/0x8a0 fs/splice.c:562
splice_from_pipe fs/splice.c:597 [inline]
generic_splice_sendpage+0xd4/0x140 fs/splice.c:746
do_splice_from fs/splice.c:767 [inline]
direct_splice_actor+0x110/0x180 fs/splice.c:936
splice_direct_to_actor+0x34b/0x8c0 fs/splice.c:891
do_splice_direct+0x1b3/0x280 fs/splice.c:979
do_sendfile+0x9f0/0x1120 fs/read_write.c:1260
__do_sys_sendfile64 fs/read_write.c:1325 [inline]
__se_sys_sendfile64 fs/read_write.c:1311 [inline]
__x64_sys_sendfile64+0x1cc/0x210 fs/read_write.c:1311
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x43f019
Code: 28 c3 e8 2a 14 00 00 66 2e 0f 1f 84 00 00 00 00 00 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 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd24165888 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 0000000000400488 RCX: 000000000043f019
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000005
RBP: 0000000000403000 R08: 0000000000400488 R09: 0000000000400488
R10: 0000000100000002 R11: 0000000000000246 R12: 0000000000403090
R13: 0000000000000000 R14: 00000000004ac018 R15: 0000000000400488
================================================================================


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
For information about bisection process see: https://goo.gl/tpsmEJ#bisection
syzbot can test patches for this issue, for details see:
https://goo.gl/tpsmEJ#testing-patches

Pavel Skripkin

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Sep 1, 2021, 2:56:22 PM9/1/21
to syzbot, antony...@secunet.com, christian...@secunet.com, da...@davemloft.net, her...@gondor.apana.org.au, ku...@kernel.org, linux-...@vger.kernel.org, net...@vger.kernel.org, steffen....@secunet.com, syzkall...@googlegroups.com
#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git




With regards,
Pavel Skripkin
0001-net-xfrm-fix-shift-out-of-bounds-in-xfrm_get_default.patch

syzbot

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Sep 1, 2021, 2:56:23 PM9/1/21
to Pavel Skripkin, antony...@secunet.com, christian...@secunet.com, da...@davemloft.net, her...@gondor.apana.org.au, ku...@kernel.org, linux-...@vger.kernel.org, net...@vger.kernel.org, paskr...@gmail.com, steffen....@secunet.com, syzkall...@googlegroups.com
want 2 args (repo, branch), got 3

>
>
>
>
> With regards,
> Pavel Skripkin

syzbot

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Sep 1, 2021, 2:56:24 PM9/1/21
to Pavel Skripkin, antony...@secunet.com, christian...@secunet.com, da...@davemloft.net, her...@gondor.apana.org.au, ku...@kernel.org, linux-...@vger.kernel.org, net...@vger.kernel.org, paskr...@gmail.com, steffen....@secunet.com, syzkall...@googlegroups.com
want 2 args (repo, branch), got 3

>
>
>
>
> With regards,
> Pavel Skripkin
>
> --
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Pavel Skripkin

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Sep 1, 2021, 2:57:20 PM9/1/21
to syzbot, antony...@secunet.com, christian...@secunet.com, da...@davemloft.net, her...@gondor.apana.org.au, ku...@kernel.org, linux-...@vger.kernel.org, net...@vger.kernel.org, steffen....@secunet.com, syzkall...@googlegroups.com
Whoops... :(



#syz test:
git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git master




With regards,
Pavel Skripkin
0001-net-xfrm-fix-shift-out-of-bounds-in-xfrm_get_default.patch

syzbot

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Sep 1, 2021, 4:15:15 PM9/1/21
to antony...@secunet.com, christian...@secunet.com, da...@davemloft.net, her...@gondor.apana.org.au, ku...@kernel.org, linux-...@vger.kernel.org, net...@vger.kernel.org, paskr...@gmail.com, steffen....@secunet.com, syzkall...@googlegroups.com
Hello,

syzbot tried to test the proposed patch but the build/boot failed:

arch/x86/kernel/setup.c:916:6: error: implicit declaration of function 'acpi_mps_check' [-Werror=implicit-function-declaration]
arch/x86/kernel/setup.c:1110:2: error: implicit declaration of function 'acpi_table_upgrade' [-Werror=implicit-function-declaration]
arch/x86/kernel/setup.c:1112:2: error: implicit declaration of function 'acpi_boot_table_init' [-Werror=implicit-function-declaration]
arch/x86/kernel/setup.c:1120:2: error: implicit declaration of function 'early_acpi_boot_init'; did you mean 'early_cpu_init'? [-Werror=implicit-function-declaration]
arch/x86/kernel/setup.c:1162:2: error: implicit declaration of function 'acpi_boot_init' [-Werror=implicit-function-declaration]


Tested on:

commit: 9e9fb765 Merge tag 'net-next-5.15' of git://git.kernel..
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git master
patch: https://syzkaller.appspot.com/x/patch.diff?x=14a2a34d300000

Pavel Skripkin

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Sep 1, 2021, 4:21:03 PM9/1/21
to syzbot, antony...@secunet.com, christian...@secunet.com, da...@davemloft.net, her...@gondor.apana.org.au, ku...@kernel.org, linux-...@vger.kernel.org, net...@vger.kernel.org, steffen....@secunet.com, syzkall...@googlegroups.com
Ok, net-next is also broken....
0001-net-xfrm-fix-shift-out-of-bounds-in-xfrm_get_default.patch

syzbot

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Sep 1, 2021, 10:15:08 PM9/1/21
to antony...@secunet.com, christian...@secunet.com, da...@davemloft.net, her...@gondor.apana.org.au, ku...@kernel.org, linux-...@vger.kernel.org, net...@vger.kernel.org, paskr...@gmail.com, steffen....@secunet.com, syzkall...@googlegroups.com
Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+b2be9d...@syzkaller.appspotmail.com

Tested on:

commit: 9e9fb765 Merge tag 'net-next-5.15' of git://git.kernel..
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git master
kernel config: https://syzkaller.appspot.com/x/.config?x=bd61edfef9fa14b1
dashboard link: https://syzkaller.appspot.com/bug?extid=b2be9dd8ca6f6c73ee2d
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.1
patch: https://syzkaller.appspot.com/x/patch.diff?x=12546ba9300000

Note: testing is done by a robot and is best-effort only.
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