* KMSAN: uninit-value in audit_receive
@ 2020-02-24 8:08 syzbot
2020-02-24 21:46 ` Paul Moore
0 siblings, 1 reply; 2+ messages in thread
From: syzbot @ 2020-02-24 8:08 UTC (permalink / raw)
To: eparis, glider, linux-audit, linux-kernel, paul, syzkaller-bugs
Hello,
syzbot found the following crash on:
HEAD commit: 8bbbc5cf kmsan: don't compile memmove
git tree: https://github.com/google/kmsan.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=15c21c81e00000
kernel config: https://syzkaller.appspot.com/x/.config?x=cd0e9a6b0e555cc3
dashboard link: https://syzkaller.appspot.com/bug?extid=399c44bf1f43b8747403
compiler: clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81)
userspace arch: i386
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10dbda7ee00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1721fe09e00000
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+399c44bf1f43b8747403@syzkaller.appspotmail.com
=====================================================
BUG: KMSAN: uninit-value in audit_set_feature kernel/audit.c:1119 [inline]
BUG: KMSAN: uninit-value in audit_receive_msg kernel/audit.c:1318 [inline]
BUG: KMSAN: uninit-value in audit_receive+0x2691/0x6be0 kernel/audit.c:1513
CPU: 1 PID: 11583 Comm: syz-executor100 Not tainted 5.6.0-rc2-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+0x1c9/0x220 lib/dump_stack.c:118
kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:118
__msan_warning+0x58/0xa0 mm/kmsan/kmsan_instr.c:215
audit_set_feature kernel/audit.c:1119 [inline]
audit_receive_msg kernel/audit.c:1318 [inline]
audit_receive+0x2691/0x6be0 kernel/audit.c:1513
netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline]
netlink_unicast+0xf9e/0x1100 net/netlink/af_netlink.c:1328
netlink_sendmsg+0x1246/0x14d0 net/netlink/af_netlink.c:1917
sock_sendmsg_nosec net/socket.c:652 [inline]
sock_sendmsg net/socket.c:672 [inline]
____sys_sendmsg+0x12b6/0x1350 net/socket.c:2343
___sys_sendmsg net/socket.c:2397 [inline]
__sys_sendmsg+0x451/0x5f0 net/socket.c:2430
__compat_sys_sendmsg net/compat.c:642 [inline]
__do_compat_sys_sendmsg net/compat.c:649 [inline]
__se_compat_sys_sendmsg net/compat.c:646 [inline]
__ia32_compat_sys_sendmsg+0xed/0x130 net/compat.c:646
do_syscall_32_irqs_on arch/x86/entry/common.c:339 [inline]
do_fast_syscall_32+0x3c7/0x6e0 arch/x86/entry/common.c:410
entry_SYSENTER_compat+0x68/0x77 arch/x86/entry/entry_64_compat.S:139
RIP: 0023:0xf7fcbd99
Code: 90 e8 0b 00 00 00 f3 90 0f ae e8 eb f9 8d 74 26 00 89 3c 24 c3 90 90 90 90 90 90 90 90 90 90 90 90 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 eb 0d 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 002b:00000000ff99b74c EFLAGS: 00000246 ORIG_RAX: 0000000000000172
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000200000c0
RDX: 0000000000000000 RSI: 00000000080ea078 RDI: 00000000ff99b7a0
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
Uninit was created at:
kmsan_save_stack_with_flags mm/kmsan/kmsan.c:144 [inline]
kmsan_internal_poison_shadow+0x66/0xd0 mm/kmsan/kmsan.c:127
kmsan_slab_alloc+0x8a/0xe0 mm/kmsan/kmsan_hooks.c:82
slab_alloc_node mm/slub.c:2793 [inline]
__kmalloc_node_track_caller+0xb40/0x1200 mm/slub.c:4401
__kmalloc_reserve net/core/skbuff.c:142 [inline]
__alloc_skb+0x2fd/0xac0 net/core/skbuff.c:210
alloc_skb include/linux/skbuff.h:1051 [inline]
netlink_alloc_large_skb net/netlink/af_netlink.c:1174 [inline]
netlink_sendmsg+0x7d3/0x14d0 net/netlink/af_netlink.c:1892
sock_sendmsg_nosec net/socket.c:652 [inline]
sock_sendmsg net/socket.c:672 [inline]
____sys_sendmsg+0x12b6/0x1350 net/socket.c:2343
___sys_sendmsg net/socket.c:2397 [inline]
__sys_sendmsg+0x451/0x5f0 net/socket.c:2430
__compat_sys_sendmsg net/compat.c:642 [inline]
__do_compat_sys_sendmsg net/compat.c:649 [inline]
__se_compat_sys_sendmsg net/compat.c:646 [inline]
__ia32_compat_sys_sendmsg+0xed/0x130 net/compat.c:646
do_syscall_32_irqs_on arch/x86/entry/common.c:339 [inline]
do_fast_syscall_32+0x3c7/0x6e0 arch/x86/entry/common.c:410
entry_SYSENTER_compat+0x68/0x77 arch/x86/entry/entry_64_compat.S:139
=====================================================
---
This bug 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 syzkaller@googlegroups.com.
syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
syzbot can test patches for this bug, for details see:
https://goo.gl/tpsmEJ#testing-patches
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: KMSAN: uninit-value in audit_receive
2020-02-24 8:08 KMSAN: uninit-value in audit_receive syzbot
@ 2020-02-24 21:46 ` Paul Moore
0 siblings, 0 replies; 2+ messages in thread
From: Paul Moore @ 2020-02-24 21:46 UTC (permalink / raw)
To: linux-audit; +Cc: Eric Paris, glider, linux-kernel, syzkaller-bugs, syzbot
On Mon, Feb 24, 2020 at 3:08 AM syzbot
<syzbot+399c44bf1f43b8747403@syzkaller.appspotmail.com> wrote:
>
> Hello,
>
> syzbot found the following crash on:
>
> HEAD commit: 8bbbc5cf kmsan: don't compile memmove
> git tree: https://github.com/google/kmsan.git master
> console output: https://syzkaller.appspot.com/x/log.txt?x=15c21c81e00000
> kernel config: https://syzkaller.appspot.com/x/.config?x=cd0e9a6b0e555cc3
> dashboard link: https://syzkaller.appspot.com/bug?extid=399c44bf1f43b8747403
> compiler: clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81)
> userspace arch: i386
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10dbda7ee00000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1721fe09e00000
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+399c44bf1f43b8747403@syzkaller.appspotmail.com
>
> =====================================================
> BUG: KMSAN: uninit-value in audit_set_feature kernel/audit.c:1119 [inline]
> BUG: KMSAN: uninit-value in audit_receive_msg kernel/audit.c:1318 [inline]
> BUG: KMSAN: uninit-value in audit_receive+0x2691/0x6be0 kernel/audit.c:1513
I'm guessing that the issue here is that we aren't checking to make
sure a properly formatted message is sent down to the kernel and if a
truncated AUDIT_SET_FEATURE message is sent would could end up looking
into an audit_features struct that isn't complete.
The fix should be relatively simple, verify that the netlink payload
is at least sizeof(audit_features) big before we inspect it. Patch
coming shortly.
> CPU: 1 PID: 11583 Comm: syz-executor100 Not tainted 5.6.0-rc2-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+0x1c9/0x220 lib/dump_stack.c:118
> kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:118
> __msan_warning+0x58/0xa0 mm/kmsan/kmsan_instr.c:215
> audit_set_feature kernel/audit.c:1119 [inline]
> audit_receive_msg kernel/audit.c:1318 [inline]
> audit_receive+0x2691/0x6be0 kernel/audit.c:1513
> netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline]
> netlink_unicast+0xf9e/0x1100 net/netlink/af_netlink.c:1328
> netlink_sendmsg+0x1246/0x14d0 net/netlink/af_netlink.c:1917
> sock_sendmsg_nosec net/socket.c:652 [inline]
> sock_sendmsg net/socket.c:672 [inline]
> ____sys_sendmsg+0x12b6/0x1350 net/socket.c:2343
> ___sys_sendmsg net/socket.c:2397 [inline]
> __sys_sendmsg+0x451/0x5f0 net/socket.c:2430
> __compat_sys_sendmsg net/compat.c:642 [inline]
> __do_compat_sys_sendmsg net/compat.c:649 [inline]
> __se_compat_sys_sendmsg net/compat.c:646 [inline]
> __ia32_compat_sys_sendmsg+0xed/0x130 net/compat.c:646
> do_syscall_32_irqs_on arch/x86/entry/common.c:339 [inline]
> do_fast_syscall_32+0x3c7/0x6e0 arch/x86/entry/common.c:410
> entry_SYSENTER_compat+0x68/0x77 arch/x86/entry/entry_64_compat.S:139
> RIP: 0023:0xf7fcbd99
> Code: 90 e8 0b 00 00 00 f3 90 0f ae e8 eb f9 8d 74 26 00 89 3c 24 c3 90 90 90 90 90 90 90 90 90 90 90 90 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 eb 0d 90 90 90 90 90 90 90 90 90 90 90 90
> RSP: 002b:00000000ff99b74c EFLAGS: 00000246 ORIG_RAX: 0000000000000172
> RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000200000c0
> RDX: 0000000000000000 RSI: 00000000080ea078 RDI: 00000000ff99b7a0
> RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
> R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
>
> Uninit was created at:
> kmsan_save_stack_with_flags mm/kmsan/kmsan.c:144 [inline]
> kmsan_internal_poison_shadow+0x66/0xd0 mm/kmsan/kmsan.c:127
> kmsan_slab_alloc+0x8a/0xe0 mm/kmsan/kmsan_hooks.c:82
> slab_alloc_node mm/slub.c:2793 [inline]
> __kmalloc_node_track_caller+0xb40/0x1200 mm/slub.c:4401
> __kmalloc_reserve net/core/skbuff.c:142 [inline]
> __alloc_skb+0x2fd/0xac0 net/core/skbuff.c:210
> alloc_skb include/linux/skbuff.h:1051 [inline]
> netlink_alloc_large_skb net/netlink/af_netlink.c:1174 [inline]
> netlink_sendmsg+0x7d3/0x14d0 net/netlink/af_netlink.c:1892
> sock_sendmsg_nosec net/socket.c:652 [inline]
> sock_sendmsg net/socket.c:672 [inline]
> ____sys_sendmsg+0x12b6/0x1350 net/socket.c:2343
> ___sys_sendmsg net/socket.c:2397 [inline]
> __sys_sendmsg+0x451/0x5f0 net/socket.c:2430
> __compat_sys_sendmsg net/compat.c:642 [inline]
> __do_compat_sys_sendmsg net/compat.c:649 [inline]
> __se_compat_sys_sendmsg net/compat.c:646 [inline]
> __ia32_compat_sys_sendmsg+0xed/0x130 net/compat.c:646
> do_syscall_32_irqs_on arch/x86/entry/common.c:339 [inline]
> do_fast_syscall_32+0x3c7/0x6e0 arch/x86/entry/common.c:410
> entry_SYSENTER_compat+0x68/0x77 arch/x86/entry/entry_64_compat.S:139
> =====================================================
--
paul moore
www.paul-moore.com
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2020-02-24 21:46 ` Paul Moore
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