* KMSAN: uninit-value in number (2)
@ 2020-02-24 8:28 syzbot
2020-02-24 8:54 ` Marc Kleine-Budde
0 siblings, 1 reply; 2+ messages in thread
From: syzbot @ 2020-02-24 8:28 UTC (permalink / raw)
To: davem, glider, kuba, linux-can, linux-kernel, mkl, netdev,
socketcan, 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=1661da7ee00000
kernel config: https://syzkaller.appspot.com/x/.config?x=cd0e9a6b0e555cc3
dashboard link: https://syzkaller.appspot.com/bug?extid=9bcb0c9409066696d3aa
compiler: clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=111141a1e00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13ad5245e00000
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+9bcb0c9409066696d3aa@syzkaller.appspotmail.com
=====================================================
BUG: KMSAN: uninit-value in number+0x9f8/0x2000 lib/vsprintf.c:459
CPU: 1 PID: 11897 Comm: syz-executor136 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
number+0x9f8/0x2000 lib/vsprintf.c:459
vsnprintf+0x1d85/0x31b0 lib/vsprintf.c:2640
vscnprintf+0xc2/0x180 lib/vsprintf.c:2677
vprintk_store+0xef/0x11d0 kernel/printk/printk.c:1917
vprintk_emit+0x2c0/0x860 kernel/printk/printk.c:1984
vprintk_default+0x90/0xa0 kernel/printk/printk.c:2029
vprintk_func+0x636/0x820 kernel/printk/printk_safe.c:386
printk+0x18b/0x1d3 kernel/printk/printk.c:2062
canfd_rcv+0x370/0x3a0 net/can/af_can.c:697
__netif_receive_skb_one_core net/core/dev.c:5198 [inline]
__netif_receive_skb net/core/dev.c:5312 [inline]
netif_receive_skb_internal net/core/dev.c:5402 [inline]
netif_receive_skb+0xe77/0xf20 net/core/dev.c:5461
tun_rx_batched include/linux/skbuff.h:4321 [inline]
tun_get_user+0x6aef/0x6f60 drivers/net/tun.c:1997
tun_chr_write_iter+0x1f2/0x360 drivers/net/tun.c:2026
call_write_iter include/linux/fs.h:1901 [inline]
new_sync_write fs/read_write.c:483 [inline]
__vfs_write+0xa5a/0xca0 fs/read_write.c:496
vfs_write+0x44a/0x8f0 fs/read_write.c:558
ksys_write+0x267/0x450 fs/read_write.c:611
__do_sys_write fs/read_write.c:623 [inline]
__se_sys_write+0x92/0xb0 fs/read_write.c:620
__x64_sys_write+0x4a/0x70 fs/read_write.c:620
do_syscall_64+0xb8/0x160 arch/x86/entry/common.c:296
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x440239
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 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 0f 83 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffd3d6d1f28 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000003172 RCX: 0000000000440239
RDX: 0000000000000004 RSI: 0000000020000200 RDI: 0000000000000003
RBP: 656c6c616b7a7973 R08: 0000000000401ac0 R09: 0000000000401ac0
R10: 0000000000401ac0 R11: 0000000000000246 R12: 0000000000401ac0
R13: 0000000000401b50 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]
alloc_skb_with_frags+0x18c/0xa70 net/core/skbuff.c:5766
sock_alloc_send_pskb+0xada/0xc60 net/core/sock.c:2242
tun_alloc_skb drivers/net/tun.c:1529 [inline]
tun_get_user+0x10ae/0x6f60 drivers/net/tun.c:1843
tun_chr_write_iter+0x1f2/0x360 drivers/net/tun.c:2026
call_write_iter include/linux/fs.h:1901 [inline]
new_sync_write fs/read_write.c:483 [inline]
__vfs_write+0xa5a/0xca0 fs/read_write.c:496
vfs_write+0x44a/0x8f0 fs/read_write.c:558
ksys_write+0x267/0x450 fs/read_write.c:611
__do_sys_write fs/read_write.c:623 [inline]
__se_sys_write+0x92/0xb0 fs/read_write.c:620
__x64_sys_write+0x4a/0x70 fs/read_write.c:620
do_syscall_64+0xb8/0x160 arch/x86/entry/common.c:296
entry_SYSCALL_64_after_hwframe+0x44/0xa9
=====================================================
---
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 number (2)
2020-02-24 8:28 KMSAN: uninit-value in number (2) syzbot
@ 2020-02-24 8:54 ` Marc Kleine-Budde
0 siblings, 0 replies; 2+ messages in thread
From: Marc Kleine-Budde @ 2020-02-24 8:54 UTC (permalink / raw)
To: syzbot, davem, glider, kuba, linux-can, linux-kernel, netdev,
socketcan, syzkaller-bugs, Oliver Hartkopp
On 2/24/20 9:28 AM, syzbot 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=1661da7ee00000
> kernel config: https://syzkaller.appspot.com/x/.config?x=cd0e9a6b0e555cc3
> dashboard link: https://syzkaller.appspot.com/bug?extid=9bcb0c9409066696d3aa
> compiler: clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81)
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=111141a1e00000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13ad5245e00000
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+9bcb0c9409066696d3aa@syzkaller.appspotmail.com
>
> =====================================================
> BUG: KMSAN: uninit-value in number+0x9f8/0x2000 lib/vsprintf.c:459
> CPU: 1 PID: 11897 Comm: syz-executor136 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
> number+0x9f8/0x2000 lib/vsprintf.c:459
> vsnprintf+0x1d85/0x31b0 lib/vsprintf.c:2640
> vscnprintf+0xc2/0x180 lib/vsprintf.c:2677
> vprintk_store+0xef/0x11d0 kernel/printk/printk.c:1917
> vprintk_emit+0x2c0/0x860 kernel/printk/printk.c:1984
> vprintk_default+0x90/0xa0 kernel/printk/printk.c:2029
> vprintk_func+0x636/0x820 kernel/printk/printk_safe.c:386
> printk+0x18b/0x1d3 kernel/printk/printk.c:2062
> canfd_rcv+0x370/0x3a0 net/can/af_can.c:697
> __netif_receive_skb_one_core net/core/dev.c:5198 [inline]
> __netif_receive_skb net/core/dev.c:5312 [inline]
> netif_receive_skb_internal net/core/dev.c:5402 [inline]
> netif_receive_skb+0xe77/0xf20 net/core/dev.c:5461
> tun_rx_batched include/linux/skbuff.h:4321 [inline]
> tun_get_user+0x6aef/0x6f60 drivers/net/tun.c:1997
> tun_chr_write_iter+0x1f2/0x360 drivers/net/tun.c:2026
> call_write_iter include/linux/fs.h:1901 [inline]
> new_sync_write fs/read_write.c:483 [inline]
> __vfs_write+0xa5a/0xca0 fs/read_write.c:496
> vfs_write+0x44a/0x8f0 fs/read_write.c:558
> ksys_write+0x267/0x450 fs/read_write.c:611
> __do_sys_write fs/read_write.c:623 [inline]
> __se_sys_write+0x92/0xb0 fs/read_write.c:620
> __x64_sys_write+0x4a/0x70 fs/read_write.c:620
> do_syscall_64+0xb8/0x160 arch/x86/entry/common.c:296
> entry_SYSCALL_64_after_hwframe+0x44/0xa9
> RIP: 0033:0x440239
> Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 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 0f 83 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00
> RSP: 002b:00007ffd3d6d1f28 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
> RAX: ffffffffffffffda RBX: 0000000000003172 RCX: 0000000000440239
> RDX: 0000000000000004 RSI: 0000000020000200 RDI: 0000000000000003
> RBP: 656c6c616b7a7973 R08: 0000000000401ac0 R09: 0000000000401ac0
> R10: 0000000000401ac0 R11: 0000000000000246 R12: 0000000000401ac0
> R13: 0000000000401b50 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]
> alloc_skb_with_frags+0x18c/0xa70 net/core/skbuff.c:5766
> sock_alloc_send_pskb+0xada/0xc60 net/core/sock.c:2242
> tun_alloc_skb drivers/net/tun.c:1529 [inline]
> tun_get_user+0x10ae/0x6f60 drivers/net/tun.c:1843
> tun_chr_write_iter+0x1f2/0x360 drivers/net/tun.c:2026
> call_write_iter include/linux/fs.h:1901 [inline]
> new_sync_write fs/read_write.c:483 [inline]
> __vfs_write+0xa5a/0xca0 fs/read_write.c:496
> vfs_write+0x44a/0x8f0 fs/read_write.c:558
> ksys_write+0x267/0x450 fs/read_write.c:611
> __do_sys_write fs/read_write.c:623 [inline]
> __se_sys_write+0x92/0xb0 fs/read_write.c:620
> __x64_sys_write+0x4a/0x70 fs/read_write.c:620
> do_syscall_64+0xb8/0x160 arch/x86/entry/common.c:296
> entry_SYSCALL_64_after_hwframe+0x44/0xa9
> =====================================================
> static int canfd_rcv(struct sk_buff *skb, struct net_device *dev,
> struct packet_type *pt, struct net_device *orig_dev)
> {
> struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
>
> if (unlikely(dev->type != ARPHRD_CAN || skb->len != CANFD_MTU ||
> cfd->len > CANFD_MAX_DLEN)) {
> pr_warn_once("PF_CAN: dropped non conform CAN FD skbuf: dev type %d, len %d, datalen %d\n",
> dev->type, skb->len, cfd->len);
^^^^^^^^
If the skb is to short, we'll access the skb->data out of bounds, when
dereferencing cfd. I think we have to remove the "datalen" from the
warning message.
> kfree_skb(skb);
> return NET_RX_DROP;
> }
>
> can_receive(skb, dev);
> return NET_RX_SUCCESS;
> }
Marc
--
Pengutronix e.K. | Marc Kleine-Budde |
Embedded Linux | https://www.pengutronix.de |
Vertretung West/Dortmund | Phone: +49-231-2826-924 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
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