KMSAN: uninit-value in __tipc_nl_bearer_enable

KMSAN: uninit-value in __tipc_nl_bearer_enable

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    0a602458c72c kmsan: random: another take at unpoisoning CR..
git tree:       kmsan
console output: https://syzkaller.appspot.com/x/log.txt?x=125b568b400000
kernel config:  https://syzkaller.appspot.com/x/.config?x=9b071100dcf8e641
dashboard link: https://syzkaller.appspot.com/bug?extid=e820fdc8ce362f2dea51
compiler:       clang version 8.0.0 (trunk 348261)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=139c6347400000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+e820fdc8ce362f2dea51@syzkaller.appspotmail.com

8021q: adding VLAN 0 to HW filter on device team0
8021q: adding VLAN 0 to HW filter on device team0
8021q: adding VLAN 0 to HW filter on device team0
8021q: adding VLAN 0 to HW filter on device team0
==================================================================
BUG: KMSAN: uninit-value in strncpy+0x265/0x590 lib/string.c:119
CPU: 0 PID: 8068 Comm: syz-executor5 Not tainted 4.20.0-rc5+ #2
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:113
  kmsan_report+0x12d/0x290 mm/kmsan/kmsan.c:682
  __msan_warning+0x76/0xc0 mm/kmsan/kmsan_instr.c:316
  strncpy+0x265/0x590 lib/string.c:119
  bearer_name_validate net/tipc/bearer.c:141 [inline]
  tipc_enable_bearer net/tipc/bearer.c:246 [inline]
  __tipc_nl_bearer_enable+0x674/0x1da0 net/tipc/bearer.c:897
  tipc_nl_bearer_enable+0x6c/0xb0 net/tipc/bearer.c:905
  genl_family_rcv_msg net/netlink/genetlink.c:601 [inline]
  genl_rcv_msg+0x185f/0x1a60 net/netlink/genetlink.c:626
  netlink_rcv_skb+0x444/0x640 net/netlink/af_netlink.c:2477
  genl_rcv+0x63/0x80 net/netlink/genetlink.c:637
  netlink_unicast_kernel net/netlink/af_netlink.c:1310 [inline]
  netlink_unicast+0xf80/0x1060 net/netlink/af_netlink.c:1336
  netlink_sendmsg+0x129d/0x1310 net/netlink/af_netlink.c:1917
  sock_sendmsg_nosec net/socket.c:621 [inline]
  sock_sendmsg net/socket.c:631 [inline]
  ___sys_sendmsg+0xdbc/0x11d0 net/socket.c:2116
  __sys_sendmsg net/socket.c:2154 [inline]
  __do_sys_sendmsg net/socket.c:2163 [inline]
  __se_sys_sendmsg+0x305/0x460 net/socket.c:2161
  __x64_sys_sendmsg+0x4a/0x70 net/socket.c:2161
  do_syscall_64+0xcd/0x110 arch/x86/entry/common.c:291
  entry_SYSCALL_64_after_hwframe+0x63/0xe7
RIP: 0033:0x457669
Code: fd b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 cb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f04f1c0ac78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457669
RDX: 0000000000000000 RSI: 00000000200008c0 RDI: 0000000000000003
RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f04f1c0b6d4
R13: 00000000004c421b R14: 00000000004d7160 R15: 00000000ffffffff

Uninit was created at:
  kmsan_save_stack_with_flags mm/kmsan/kmsan.c:247 [inline]
  kmsan_internal_poison_shadow+0x92/0x150 mm/kmsan/kmsan.c:170
  kmsan_kmalloc+0xa1/0x100 mm/kmsan/kmsan_hooks.c:179
  kmsan_slab_alloc+0xe/0x10 mm/kmsan/kmsan_hooks.c:188
  slab_post_alloc_hook mm/slab.h:446 [inline]
  slab_alloc_node mm/slub.c:2759 [inline]
  __kmalloc_node_track_caller+0xf06/0x1120 mm/slub.c:4383
  __kmalloc_reserve net/core/skbuff.c:137 [inline]
  __alloc_skb+0x318/0xa40 net/core/skbuff.c:205
  alloc_skb include/linux/skbuff.h:998 [inline]
  netlink_alloc_large_skb net/netlink/af_netlink.c:1182 [inline]
  netlink_sendmsg+0xba0/0x1310 net/netlink/af_netlink.c:1892
  sock_sendmsg_nosec net/socket.c:621 [inline]
  sock_sendmsg net/socket.c:631 [inline]
  ___sys_sendmsg+0xdbc/0x11d0 net/socket.c:2116
  __sys_sendmsg net/socket.c:2154 [inline]
  __do_sys_sendmsg net/socket.c:2163 [inline]
  __se_sys_sendmsg+0x305/0x460 net/socket.c:2161
  __x64_sys_sendmsg+0x4a/0x70 net/socket.c:2161
  do_syscall_64+0xcd/0x110 arch/x86/entry/common.c:291
  entry_SYSCALL_64_after_hwframe+0x63/0xe7
==================================================================


---
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Re: [syzbot] KMSAN: uninit-value in __tipc_nl_bearer_enable

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit:    d6e2c8c7eb40 x86: kmsan: enable KMSAN builds for x86
git tree:       https://github.com/google/kmsan.git master
console+strace: https://syzkaller.appspot.com/x/log.txt?x=115c49b1f00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=65d9eb7bfd2865c9
dashboard link: https://syzkaller.appspot.com/bug?extid=e820fdc8ce362f2dea51
compiler:       clang version 14.0.0 (/usr/local/google/src/llvm-git-monorepo 2b554920f11c8b763cd9ed9003f4e19b919b8e1f), GNU ld (GNU Binutils for Debian) 2.35.2
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14b563faf00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1310ee59f00000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e820fdc8ce362f2dea51@syzkaller.appspotmail.com

netlink: 20 bytes leftover after parsing attributes in process `syz-executor377'.
=====================================================
BUG: KMSAN: uninit-value in string_nocheck lib/vsprintf.c:644 [inline]
BUG: KMSAN: uninit-value in string+0x4f9/0x6f0 lib/vsprintf.c:725
 string_nocheck lib/vsprintf.c:644 [inline]
 string+0x4f9/0x6f0 lib/vsprintf.c:725
 vsnprintf+0x2222/0x3650 lib/vsprintf.c:2806
 vprintk_store+0x537/0x2150 kernel/printk/printk.c:2158
 vprintk_emit+0x28b/0xab0 kernel/printk/printk.c:2256
 vprintk_default+0x86/0xa0 kernel/printk/printk.c:2283
 vprintk+0x15f/0x180 kernel/printk/printk_safe.c:50
 _printk+0x18d/0x1cf kernel/printk/printk.c:2293
 tipc_enable_bearer net/tipc/bearer.c:371 [inline]
 __tipc_nl_bearer_enable+0x2022/0x22a0 net/tipc/bearer.c:1033
 tipc_nl_bearer_enable+0x6c/0xb0 net/tipc/bearer.c:1042
 genl_family_rcv_msg_doit net/netlink/genetlink.c:731 [inline]
 genl_family_rcv_msg net/netlink/genetlink.c:775 [inline]
 genl_rcv_msg+0x157f/0x1660 net/netlink/genetlink.c:792
 netlink_rcv_skb+0x40c/0x7e0 net/netlink/af_netlink.c:2503
 genl_rcv+0x63/0x80 net/netlink/genetlink.c:803
 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
 netlink_unicast+0x109c/0x1370 net/netlink/af_netlink.c:1345
 netlink_sendmsg+0x14dc/0x1720 net/netlink/af_netlink.c:1921
 sock_sendmsg_nosec net/socket.c:705 [inline]
 sock_sendmsg net/socket.c:725 [inline]
 ____sys_sendmsg+0xe11/0x12c0 net/socket.c:2413
 ___sys_sendmsg net/socket.c:2467 [inline]
 __sys_sendmsg+0x704/0x840 net/socket.c:2496
 __do_sys_sendmsg net/socket.c:2505 [inline]
 __se_sys_sendmsg net/socket.c:2503 [inline]
 __x64_sys_sendmsg+0xe2/0x120 net/socket.c:2503
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x51/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Uninit was created at:
 slab_post_alloc_hook mm/slab.h:754 [inline]
 slab_alloc_node mm/slub.c:3231 [inline]
 __kmalloc_node_track_caller+0xde3/0x14f0 mm/slub.c:4962
 kmalloc_reserve net/core/skbuff.c:354 [inline]
 __alloc_skb+0x545/0xf90 net/core/skbuff.c:426
 alloc_skb include/linux/skbuff.h:1300 [inline]
 netlink_alloc_large_skb net/netlink/af_netlink.c:1191 [inline]
 netlink_sendmsg+0xde3/0x1720 net/netlink/af_netlink.c:1896
 sock_sendmsg_nosec net/socket.c:705 [inline]
 sock_sendmsg net/socket.c:725 [inline]
 ____sys_sendmsg+0xe11/0x12c0 net/socket.c:2413
 ___sys_sendmsg net/socket.c:2467 [inline]
 __sys_sendmsg+0x704/0x840 net/socket.c:2496
 __do_sys_sendmsg net/socket.c:2505 [inline]
 __se_sys_sendmsg net/socket.c:2503 [inline]
 __x64_sys_sendmsg+0xe2/0x120 net/socket.c:2503
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x51/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x44/0xae

CPU: 0 PID: 3475 Comm: syz-executor377 Not tainted 5.18.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
=====================================================